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How to use this site to your advantage ... and not get lost
How to benefit the most of this site?
Just follow the steps as below:
- The first possibility (and a highly recommended one) is just to visit it frequently, in order to stay aware of the newly published articles or sources of information as soon as they are posted.
- Further, since the most recent 4,520 postings from the total of 8,080 originally posted are presently available (as of May 19, 2024) and arranged as per date of posting, you can do a search according to your specific interests. In doing that, you go to the upper right corner ("Search in topic" depicted with a label), where you can just use the descriptors that are available there, i.e. "Tags", which are ordered alphabetically. Another possibility is to type there a keyword (or an entire phrase) that can be the name of an author or a word/phrase contained in the title/abstract or anything you deem relevant. That way you will be shown a reduced number of sources being more relevant to your specific interest(s).
Hoping this will be useful and waiting for feedback to keep improving the site, I wish all the best
Julio Retamales (the curator)
NOTE: Certainly, given the sheer number of articles being published currently on the relevant issues, no claim for completeness can be provided. Therefore, only samples of papers and/or sources arbitrarily selected by the curator are posted here, intending to show the diversity of phenomena in which plant hormones can be involved.
Authors: Yan-Qiu Zhao, Xue-Qin Song, Wei Guo, Cheng Jiang, Jin Zhang and Meng-Zhu Lu.
Plant, Cell & Environment (2024)
Summary Statement: PagKNAT2/6b responds to shoot apical injury and regulates shoot branching through the IAA-SL pathway in poplar.
Abstract: "Shoot branching from axillary bud (AB) directly determines plant architecture. However, the mechanism through which AB remains dormant or emerges to form branches as plants grow remains largely unknown. Here, the auxin-strigolactone (IAA-SL) pathway was first shown to regulate shoot branching in poplar, and we found that PagKNAT2/6b could modulate this pathway. PagKNAT2/6b was expressed mainly in the shoot apical meristem and AB and was induced by shoot apex damage. PagKNAT2/6b overexpressing poplar plants (PagKNAT2/6b OE) exhibited multiple branches that mimicked the branching phenotype of nontransgenic plants after decapitation treatment, while compared with nontransgenic controls, PagKNAT2/6b antisense transgenic poplar and Pagknat2/6b mutant lines exhibited a significantly decreased number of branches after shoot apex damage treatment. In addition, we found that PagKNAT2/6b directly inhibits the expression of the key IAA synthesis gene PagYUC6a, which is specifically expressed in the shoot apex. Moreover, overexpression of PagYUC6a in the PagKNAT2/6b OE background reduced the number of branches after shoot apex damage treatment. Overall, we conclude that PagKNAT2/6b responds to shoot apical injury and regulates shoot branching through the IAA-SL pathway. These findings may provide a theoretical basis and candidate genes for genetic engineering to create new forest tree species with different crown types."
Authors: Da Cao, Thomas Depaepe, Raul Sanchez-Muñoz, Hilde Janssens, Filip Lemière, Tim Willems, Johan Winne, Els Prinsen and Dominique Van Der Straeten.
New Phytologist (2024)
Abstract: "The plant hormone ethylene is of vital importance in the regulation of plant development and stress responses. Recent studies revealed that 1-aminocyclopropane-1-carboxylic acid (ACC) plays a role beyond its function as an ethylene precursor. However, the absence of reliable methods to quantify ACC and its conjugates malonyl-ACC (MACC), glutamyl-ACC (GACC), and jasmonyl-ACC (JA-ACC) hinders related research. Combining synthetic and analytical chemistry, we present the first, validated methodology to rapidly extract and quantify ACC and its conjugates using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Its relevance was confirmed by application to Arabidopsis mutants with altered ACC metabolism and wild-type plants under stress. Pharmacological and genetic suppression of ACC synthesis resulted in decreased ACC and MACC content, whereas induction led to elevated levels. Salt, wounding, and submergence stress enhanced ACC and MACC production. GACC and JA-ACC were undetectable in vivo; however, GACC was identified in vitro, underscoring the broad applicability of the method. This method provides an efficient tool to study individual functions of ACC and its conjugates, paving the road toward exploration of novel avenues in ACC and ethylene metabolism, and revisiting ethylene literature in view of the recent discovery of an ethylene-independent role of ACC."
Authors: Saravanappriyan Kamali, Kamankshi Sonkar and Amarjeet Singh.
Journal of Plant Growth Regulation (2024)
Abstract: "Jasmonates (JAs) are well documented for their role in plant defense and growth regulation. Cellular transport of JAs during their biosynthesis and signaling constitutes an important layer of their functional regulation. However, most of the information about JAs transport has been gathered in recent years. Therefore, understanding the mechanism of intracellular transport of JAs in plants is of great importance to comprehend their function. In addition, in recent years, JAs have emerged as key regulators of nutrient deficiency response in plants. Under nutrient deficiency, plants show unique adaptive responses, including altered root growth, remodeling of root system architecture (RSA), triggering nutrient uptake-related genes, and activation of nutrient transporters. JAs have been found to regulate these responses in relation to the variable availability of macro- and micronutrients. Evidence indicates that in response to deficiencies of macronutrients such as nitrogen (N), phosphorus (P), and potassium (K+), the JA biosynthesis pathway is modulated, leading to higher JA accumulation. Furthermore, the JA-signaling pathway has been shown to regulate nutrient deficiency-related transcription factors, transporters, and RSA for optimum plant development. In this review, recent developments and updates on molecular mechanisms of cellular transport of JAs during JA biosynthesis and signaling are presented. In addition, new insights on involvement of JAs in nutrient uptake, homeostasis, deficiency response, and plant development have been provided."
Authors: Shan Sun, Liling Peng, Qianqian Huang, Zhibo Huang, Chengjing Wang, Jia Zhao, Zhoufei Wang and Yongqi He.
The Crop Journal (2024)
Abstract: "Seed germination is a complex trait regulated by multiple genes in rice. However, the regulators of rice seed germination have yet to be sufficiently determined. Here, a quantitative trait locus (QTL) for rice seed germination was identified in a genome-wide association study. The candidate gene JASMONATE ZIM-DOMAIN 5 (OsJAZ5) of the QTL was verified that positively regulates seed germination. OsJAZ5 regulation of seed germination involves an OsABI3-mediated abscisic acid pathway. Overexpression of OsJAZ5 facilitated seed germination. The application of OsJAZ5 might be useful for increasing seed germination for rice direct seeding."
Authors: Adrián González Ortega-Villaizán, Eoghan King, Manish K. Patel, Marta-Marina Pérez-Alonso, Sandra S. Scholz, Hitoshi Sakakibara, Takatoshi Kiba, Mikiko Kojima, Yumiko Takebayashi, Patricio Ramos, Luis Morales-Quintana, Sarah Breitenbach, Ana Smolko, Branka Salopek-Sondi, Nataša Bauer, Jutta Ludwig-Müller, Anne Krapp, Ralf Oelmüller, Jesús Vicente-Carbajosa and Stephan Pollmann.
Plant, Cell & Environment (2024)
Abstract: "Plants share their habitats with a multitude of different microbes. This close vicinity promoted the evolution of interorganismic interactions between plants and many different microorganisms that provide mutual growth benefits both to the plant and the microbial partner. The symbiosis of Arabidopsis thaliana with the beneficial root colonizing endophyte Serendipita indica represents a well-studied system. Colonization of Arabidopsis roots with S. indica promotes plant growth and stress tolerance of the host plant. However, until now, the molecular mechanism by which S. indica reprograms plant growth remains largely unknown. This study used comprehensive transcriptomics, metabolomics, reverse genetics, and life cell imaging to reveal the intricacies of auxin-related processes that affect root growth in the symbiosis between A. thaliana and S. indica. Our experiments revealed the sustained stimulation of auxin signalling in fungus infected Arabidopsis roots and disclosed the essential role of tightly controlled auxin conjugation in the plant–fungus interaction. It particularly highlighted the importance of two GRETCHEN HAGEN 3 (GH3) genes, GH3.5 and GH3.17, for the fungus infection-triggered stimulation of biomass production, thus broadening our knowledge about the function of GH3s in plants. Furthermore, we provide evidence for the transcriptional alteration of the PIN2 auxin transporter gene in roots of Arabidopsis seedlings infected with S. indica and demonstrate that this transcriptional adjustment affects auxin signalling in roots, which results in increased plant growth."
Authors: Takuya Kaji, Yuho Nishizato, Hidenori Yoshimatsu, Akiyoshi Yoda, Wenting Liang, Andrea Chini, Gemma Fernández-Barbero, Kei Nozawa, Junko Kyozuka, Roberto Solano and Minoru Ueda.
iScience (2024)
Highlights: • Δ4-dn-iso-OPDA is identified as the major bioactive isomer of Δ4-dn-OPDAs. • Δ4-dn-iso-OPDA is biosynthesized through isomerization of Δ4-dn-cis-OPDA in M. polymorpha. • Δ4-dn-OPDAs are distributed in bryophyte lineages, including a liverwort, a moss, and a hornwort.
Abstract: "Significant progress has been recently made in our understanding of the evolution of jasmonates biosynthesis and signaling. The bioactive jasmonate activating COI1-JAZ co-receptor differs in bryophytes and vascular plants. Dinor-iso-12-oxo-phytodienoic acid (dn-iso-OPDA) is the bioactive hormone in bryophytes and lycophytes. However, further studies showed that the full activation of hormone signaling in Marchantia polymorpha requires additional unidentified hormones. Δ4-dn-OPDAs were previously identified as novel bioactive jasmonates in M. polymorpha. In this paper, we describe the major bioactive isomer of Δ4-dn-OPDAs as Δ4-dn-iso-OPDA through chemical synthesis, receptor binding assay, and biological activity in M. polymorpha. In addition, we disclosed that Δ4-dn-cis-OPDA is a biosynthetic precursor of Δ4-dn-iso-OPDA. We demonstrated that in planta cis-to-iso conversion of Δ4-dn-cis-OPDA occurs in the biosynthesis of Δ4-dn-iso-OPDA, defining a key biosynthetic step in the chemical evolution of hormone structure. We predict that these findings will facilitate further understanding of the molecular evolution of plant hormone signaling."
Authors: Junhao Li, Yan Huang, Xiaosong Yu, Qiqi Wu, Xiaxia Man, Zhihong Diao, Huang You, Jinbo Shen and Yi Cai.
Journal of Agricultural and Food Chemistry (2024)
Abstract: "The CLE (CLAVATA3/Embryo Surrounding Region-related) family, a group of peptides with hormone-like features, plays a pivotal role in plant growth, development, and adaptation to stress. Through homology-based blast analysis of 32 Arabidopsis thaliana CLE peptide sequences, we have identified 5, 14, and 10 CLE family members in Nicotiana tabacum, Capsicum annuum, and Solanum melongena, respectively. Chemical synthesis and functional assays of the peptides led to the discovery that NtCLE3 substantially enhances the drought resistance of these three Solanaceae crops. Our transcriptome, RT-qPCR, and antioxidant enzyme activity data showed that NtCLE3 increased antioxidant capacity and ABA synthesis in tobacco. Moreover, the recombinant protein RPNtCLE3, composed of 6*NtCLE3, preserved the capacity to foster drought resilience and proved to be a promising drought resistance regulator, which presents a more favorable alternative for field applications compared to ABA which degrades rapidly under sunlight exposure. This research unveils the prospective utility of NtCLE3 in enhancing drought tolerance in Solanaceae crops and provides new ideas for the development of novel bioregulators aimed at mitigating drought stress."
Authors: Yakong Wang, Xiangyang Sun, Jun Peng, Fuguang Li, Faiza Ali and Zhi Wang.
Journal of Advanced Research (2024)
Highlights: • ROS, epigenetics, and hormones play crucial roles in regulating seed germination processes. • ROS regulates seed germination by influencing hormone levels through Ca2+, NO signaling, and MAPK cascade reaction. • ROS plays a role in seed germination through DNA methylation, chromatin remodeling, and protein post-translational modification. • Sophisticated feedback regulations between ROS, phytohormones, and epigenetic modifications determine seed germination.
Abstract: "Background -The whole life of a plant is regulated by complex environmental or hormonal signaling networks that control genomic stability, environmental signal transduction, and gene expression affecting plant development and viability. Seed germination, responsible for the transformation from seed to seedling, is a key initiation step in plant growth and is controlled by unique physiological and biochemical processes. It is continuously modulated by various factors including epigenetic modifications, hormone transport, ROS signaling, and interaction among them. ROS showed versatile crucial functions in seed germination including various physiological oxidations to nucleic acid, protein, lipid, or chromatin in the cytoplasm, cell wall, and nucleus. Aim of review - This review intends to provide novel insights into underlying mechanisms of seed germination especially associated with the ROS, and considers how these versatile regulatory mechanisms can be developed as useful tools for crop improvement. Key scientific concepts of review - We have summarized the generation and elimination of ROS during seed germination, with a specific focus on uncovering and understanding the mechanisms of seed germination at the level of phytohormones, ROS, and epigenetic switches, as well as the close connections between them. The findings exhibit that ROS plays multiple roles in regulating the ethylene, ABA, and GA homeostasis as well as the Ca2+ signaling, NO signaling, and MAPK cascade in seed germination via either the signal trigger or the oxidative modifier agent. Further, ROS shows the potential in the nuclear genome remodeling and some epigenetic modifiers function, although the detailed mechanisms are unclear in seed germination. We propose that ROS functions as a hub in the complex network regulating seed germination."
Authors: Zachary J. Wright and Bonnie Bartel.
Developmental Cell (2024)
Summary: "The ability to germinate, develop, and thrive underwater is key to efficient rice cultivation. In this issue of Developmental Cell, Wang et al. (2024) illuminate a hormone synthesis and inactivation cascade that promotes germination of submerged rice seeds and may allow improved germination in the field."
Authors: Han Wei, Xiao Wang, Kaitong Wang, Xun Tang, Ning Zhang and Huaijun Si.
Physiologia Plantarum (2024)
Abstract: "Plants often experience abiotic stress, which severely affects their growth. With the advent of global warming, drought stress has become a pivotal factor affecting crop yield and quality. Increasing numbers of studies have focused on elucidating the molecular mechanisms underlying plant responses to drought stress. As molecular switches, transcription factors (TFs) are key participants in drought-resistance regulatory networks in crops. TFs regulate the transcription of downstream genes and are regulated by various upstream regulatory factors. Therefore, understanding the mechanisms of action of TFs in regulating drought stress can help enhance the adaptive capacity of crops under drought conditions. In this review, we summarize the structural characteristics of several common TFs, their multiple drought-response pathways, and recently employed research strategies. We describe the application of new technologies such as analysis of stress granule dynamics and function, multi-omics data, gene editing, and molecular crosstalk between TFs in drought resistance. This review aims to familiarize readers with the regulatory network of TFs in drought resistance and to provide a reference for examining the molecular mechanisms of drought resistance in plants and improving agronomic traits."
Authors: Isaia Vardanega, Jan Eric Maika, Edgar Demesa-Arevalo, Tianyu Lan, Gwendolyn K. Kirschner, Jafargholi Imani, Ivan F. Acosta, Katarzyna Makowska, Götz Hensel, Thilanka Ranaweera, Shin-Han Shiu, Thorsten Schnurbusch, Maria von Korff Schmising and Rüdiger Simon.
bioRxiv (2024)
Abstract: "Grasses exhibit a large variety of diverse inflorescence architectures, from complex branched inflorescences in Oryzeae (rice) to simple spike-type inflorescences in Triticeae (e.g. barley, wheat). Inflorescence architecture depends on shape, longevity and determinacy of meristems that direct growth of the main rachis and lateral branches, but how individual meristem activities are determined and integrated within complex inflorescences is not yet understood. We found that activity of distinct meristems in the barley inflorescence is coordinated by a signalling pathway comprising the receptor like kinase Hordeum vulgare CLAVATA1 (HvCLV1) and the secreted CLAVATA3/ENDOSPERM SURROUNDING REGION (CLE)-family peptide FON2- LIKE CLE PROTEIN1 (HvFCP1). HvFCP1 interacts with HvCLV1 to promote spikelet formation but restricts inflorescence meristem and rachilla meristem proliferation. Hvfcp1 or Hvclv1 mutants generate branched inflorescences with additional rows of spikelets and supernumerary florets. Transcriptome analysis reveals that HvFCP1/HvCLV1 signalling controls inflorescence branching through the regulation of trehalose-6-phosphate synthesis and sugar transport. Our discoveries reveal the potential to engineer barley inflorescence architecture by manipulating regulation of distinct meristem activities."
Authors: Alice Robustelli Test, Giorgio Perrella, Sara Colanero, Beatrice Landoni, Aldo Sutti, Paolo Korwin Krukowski, Elisa Vellutini, Giulia Castorina, Massimo Galbiati, Damiano Martignago, Eirini Kaiserli, Chiara Tonelli and Lucio Conti.
bioRxiv (2024)
Highlight: ABA and GIGANTEA signalling promote FLOWERING LOCUS T (FT) transcriptional activation by regulating the binding of the transcription factor CONSTANS to the proximal FT promoter.
Abstract: "Plants align flowering with optimal seasonal conditions to increase reproductive success. This process depends on modulating signalling pathways that respond to diverse environmental and hormonal inputs, thereby regulating the transition to flowering at the shoot apical meristem. In Arabidopsis, long-day photoperiods (LDs) stimulate the transcription of FLOWERING LOCUS T (FT), encoding the main florigenic signal. FT activation is mediated by the transcriptional regulator CONSTANS (CO), which binds to the CO responsive elements (COREs) located in the proximal FT promoter region. The phytohormone abscisic acid also (ABA) contributes to FT activation together with GIGANTEA (GI) to regulate drought escape (DE). Whether CO is a target of ABA and GI actions for the regulation of FT is, however, unknown. Here we report that ABA and its signalling components promote CO recruitment to the COREs, without causing clear effects on the diel pattern of CO protein accumulation. We also found that GI promotes CO recruitment to the COREs region, and that CO recruitment is required for the accumulation of RNAPol II at the TRANSCRIPTION START SITE of FT. Finally, we show that GI and ABA signalling pathways are largely epistatic in the control of flowering time, suggesting their involvement in the same molecular process. Taken together, these observations suggest that varying water deficit conditions modulate CO recruitment and FT expression, thus dictating DE strategies in Arabidopsis."
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Authors: Tom Rankenberg, Hans van Veen, Mastoureh Sedaghatmehr, Che-Yang Liao, Muthanna Biddanda Devaiah, Evelien A. Stouten, Salma Balazadeh and Rashmi Sasidharan.
Plant Communications (2024)
Abstract: "The phytohormone ethylene is a major regulator of plant adaptive responses to flooding. In flooded plant tissues, ethylene quickly increases to high concentrations owing to its low solubility and diffusion rates in water. Ethylene accumulation in submerged plant tissues makes it a reliable cue for triggering flood acclimation responses, including metabolic adjustments to cope with flood-induced hypoxia. However, persistent ethylene accumulation also accelerates leaf senescence. Stress-induced senescence hampers photosynthetic capacity and stress recovery. In submerged Arabidopsis, senescence follows a strict age-dependent pattern starting with the older leaves. Although mechanisms underlying ethylene-mediated senescence have been uncovered, it is unclear how submerged plants avoid indiscriminate breakdown of leaves despite high systemic ethylene accumulation. We demonstrate that although submergence triggers leaf-age-independent activation of ethylene signaling via EIN3 in Arabidopsis, senescence is initiated only in old leaves. EIN3 stabilization also leads to overall transcript and protein accumulation of the senescence-promoting transcription factor ORESARA1 (ORE1) in both old and young leaves during submergence. However, leaf-age-dependent senescence can be explained by ORE1 protein activation via phosphorylation specifically in old leaves, independent of the previously identified age-dependent control of ORE1 via miR164. A systematic analysis of the roles of the major flooding stress cues and signaling pathways shows that only the combination of ethylene and darkness is sufficient to mimic submergence-induced senescence involving ORE1 accumulation and phosphorylation. Hypoxia, most often associated with flooding stress in plants, appears to have no role in these processes. Our results reveal a mechanism by which plants regulate the speed and pattern of senescence during environmental stresses such as flooding. Age-dependent ORE1 activity ensures that older, expendable leaves are dismantled first, thus prolonging the life of younger leaves and meristematic tissues that are vital to whole-plant survival."
Authors: Yufan Sun, Haiming Yang, Tiantian Ren, Jiateng Zhao, Xinmei Lang, Lanchun Nie and Wensheng Zhao.
Plant Molecular Biology (2024)
Abstract: "Melon (Cucumis melo L.) is an important horticultural and economic crop. ETHYLENE RESPONSE FACTOR1 (ERF1) plays an important role in regulating plant development, and the resistance to multiple biotic and abiotic stresses. In this study, developmental biology, molecular biology and biochemical assays were performed to explore the biological function of CmERF1 in melon. Abundant transcripts of CmERF1 were found in ovary at green-yellow bud (GYB) and rapid enlargement (ORE) stages. In CmERF1 promoter, the cis-regulatory elements for indoleacetic acid (IAA), methyl jasmonate (MeJA), salicylic acid (SA), abscisic acid (ABA), gibberellic acid (GA), light and low temperature responses were found. CmERF1 could be significantly induced by ethylene, IAA, MeJA, SA, ABA, and respond to continuous light and low temperature stresses in melon. Ectopic expression of CmERF1 increased the length of siliqua and carpopodium, and expanded the size of leaves in Arabidopsis. Knockdown of CmERF1 led to smaller ovary at anthesis, mature fruit and leaves in melon. In CmERF1-RNAi #2 plants, 75 genes were differently expressed compared with control, and the promoter regions of 28 differential expression genes (DEGs) contained the GCC-box (AGCCGCC) or DRE (A/GCCGAC) cis-acting elements of CmERF1. A homolog of cell division cycle protein 48 (CmCDC48) was proved to be the direct target of CmERF1 by the yeast one-hybrid assay and dual-luciferase (LUC) reporter (DLR) system. These results indicated that CmERF1 was able to promote the growth of fruits and leaves, and involved in multiple hormones and environmental signaling pathways in melon."
Authors: Donald A. Hunter, Kristie O’Donnell, Huaibi Zhang, Zoe A. Erridge, Nathanael J. Napier, Paul Pidakala, Ellen Baylis, Ali Saei, Catrin Günther, Janine M. Cooney, Charles David, Benjamin Franzmayr, Nigel E. Gapper, Jason W. Johnston, David A. Brummell and Allan B. Woolf.
Postharvest Biology and Technology (2024)
Highlights: • Avocado fruit do not ripen on the tree. • Fruit detached from the tree initiated ripening at varying times. • The acquisition of ethylene sensitivity controlled when ripening began. • Ethylene insensitive fruit were linked to auxin and gibberellin transcripts. • GMT, GAO and IAA13 mRNA abundance could predict fruit ethylene-insensitivity.
Abstract: "Avocado (Persea americana Mill.) fruit hang on the tree in a physiologically mature but unripe state for many months. We hypothesised that this was due to an on-tree ripening block that prevents the development of ethylene sensitivity in the fruit. Physiologically mature fruit, determined by size and dry matter content, were categorised into ethylene sensitive or insensitive based on whether an ethylene treatment at harvest accelerated ripening. Using tissue biopsies taken from the fruit 2 d prior to their harvest, ethylene-insensitive mature fruit were found to have retained the transcriptome profile of very young immature fruit and were enriched in transcripts related to gibberellin biosynthesis and auxin signalling. Transcript abundance of GIBBERELLIN 20-OXIDASE, GIBBERELLIN METHYLTRANSFERASE and IAA13 in mesocarp biopsies taken 7 d before the fruit were harvested could predict the ethylene sensitivity status of the fruit. Upon harvest, the fruit with low transcript abundance of these genes responded to the ethylene challenge by producing ethylene and ripening earlier, whereas the fruit with high transcript abundance were unresponsive to ethylene and ripened with similar timing to fruit not exposed to ethylene. We conclude that avocado fruit on-tree have different strengths of ripening inhibition, which is caused by the differential retention of gibberellin and auxin-related biology that affects their sensitivity to ethylene."
Authors: Jiapeng Xing, Ying Feng, Yushi Zhang, Yubin Wang, Zhaohu Li and Mingcai Zhang.
The Crop Journal (2024)
Abstract: "Leaf senescence is an orderly and highly coordinated process, and finely regulated by ethylene and nitrogen (N), ultimately affecting grain yield and nitrogen-use efficiency (NUE). However, the underlying regulatory mechanisms on the crosstalk between ethylene- and N-regulated leaf senescence remain a mystery in maize. In this study, ethylene biosynthesis gene ZmACS7 overexpressing (OE-ZmACS7) plants were used to study the role of ethylene regulating leaf senescence in response to N deficiency, and they exhibited the premature leaf senescence accompanied by increased ethylene release, decreased chlorophyll content and Fv/Fm ratio, and accelerated chloroplast degradation. Then, we investigated the dynamics changes of transcriptome reprogramming underlying ethylene-accelerated leaf senescence in response to N deficiency. The differentially expressed genes (DEGs) involved in chlorophyll biosynthesis were significantly down-regulated, while DEGs involved in chlorophyll degradation and autophagy processes were significantly up-regulated, especially in OE-ZmACS7 plants in response to N deficiency. A gene regulatory network (GRN) was predicted during ethylene-accelerated leaf senescence in response to N deficiency. Three transcription factors (TFs) ZmHSF4, ZmbHLH106, and ZmEREB147 were identified as the key regulatory genes, which targeted chlorophyll biosynthesis gene ZmLES22, chlorophyll degradation gene ZmNYC1, and autophagy-related gene ZmATG5, respectively. Furthermore, ethylene signaling key genes might be located upstream of these TFs, generating the signaling cascade networks during ethylene-accelerated leaf senescence in response to N deficiency. Collectively, these findings improve our molecular knowledge of ethylene-accelerated maize leaf senescence in response to N deficiency, which is promising to improve NUE by manipulating the progress of leaf senescence in maize."
Authors: Hsin-Ya Huang, Siqi Zhang, Fadi Abou Choucha, Marion Verdenaud, Feng-Quan Tan, Clement Pichot, Hadi Shirazi Parsa, Filip Slavkovic, Qinghe Chen, Christelle Troadec, Fabien Marcel, Catherine Dogimont, Leandro Quadrana, Adnane Boualem and Abdelhafid Bendahmane.
Nature Communications (2024)
Editor's view: In flowering plants, hermaphroditism is widespread. Here the authors identified a transposon insertion that triggers plant sexual transition. This study highlights the role of transposons in plant adaptation and evolution.
Abstract: "In flowering plants, the predominant sexual morph is hermaphroditism, and the emergence of unisexuality is poorly understood. Using Cucumis melo (melon) as a model system, we explore the mechanisms driving sexual forms. We identify a spontaneous mutant exhibiting a transition from bisexual to unisexual male flower, and identify the causal mutation as a Harbinger transposon impairing the expression of Ethylene Insensitive 2 (CmEIN2) gene. Genetics and transcriptomic analysis reveal a dual role of CmEIN2 in both sex determination and fruit shape formation. Upon expression of CmACS11, EIN2 is recruited to repress the expression of the carpel inhibitor, CmWIP1. Subsequently, EIN2 is recruited to mediate stamina inhibition. Following the sex determination phase, EIN2 promotes fruit shape elongation. Genome-wide analysis reveals that Harbinger transposon mobilization is triggered by environmental cues, and integrates preferentially in active chromatin, particularly within promoter regions. Characterization of a large collection of melon germplasm points to active transpositions in the wild, compared to cultivated accessions. Our study underscores the association between chromatin dynamics and the temporal aspects of mobile genetic element insertions, providing valuable insights into plant adaptation and crop genome evolution."
Authors: Jie Yao, Qinjie Chu, Xing Guo, Wenwen Shao, Nianmin Shang, Kang Luo, Xiaohan Li, Hongyu Chen, Qing Cheng, Fangyu Mo, Dihuai Zheng, Fan Xu, Fu Guo, Qian-Hao Zhu, Shuiguang Deng, Chengcai Chu, Xun Xu, Huan Liu and Longjiang Fan.
Developmental Cell (2024)
Editor's view: Yao et al. establish the spatiotemporal transcriptomic cell census of rice seed embryo during germination. Employing cell bin and segmentation, they identify transcriptional disparities among embryo cells and delineate scutellum parenchyma cell developmental trajectory, as well as dynamics of pathways related to cell, hormones, and nutrition metabolism during germination.
Highlights • Establish a rice embryo germination spatiotemporal transcriptomic census • Develop AI-based plant cell wall segmentation for precise cell-type identification • Identify scutellum cell subtypes and cell-type-specific gene expression pattern • OsMFT2 specifically expressed in SCL2, with decreasing trends during seed germination
Abstract: "Characterizing cellular features during seed germination is crucial for understanding the complex biological functions of different embryonic cells in regulating seed vigor and seedling establishment. We performed spatially enhanced resolution omics sequencing (Stereo-seq) and single-cell RNA sequencing (scRNA-seq) to capture spatially resolved single-cell transcriptomes of germinating rice embryos. An automated cell-segmentation model, employing deep learning, was developed to accommodate the analysis requirements. The spatial transcriptomes of 6, 24, 36, and 48 h after imbibition unveiled both known and previously unreported embryo cell types, including two unreported scutellum cell types, corroborated by in situ hybridization and functional exploration of marker genes. Temporal transcriptomic profiling delineated gene expression dynamics in distinct embryonic cell types during seed germination, highlighting key genes involved in nutrient metabolism, biosynthesis, and signaling of phytohormones, reprogrammed in a cell-type-specific manner. Our study provides a detailed spatiotemporal transcriptome of rice embryo and presents a previously undescribed methodology for exploring the roles of different embryonic cells in seed germination."
Authors: Yewubnesh Wendimu Seifu, Vendula Pukyšová, Nikola Rýdza, Veronika Bilanovičová, Marta Zwiewka, Marek Sedláček and Tomasz Nodzyński.
Plant Methods (2024)
Abstract: "PIN proteins establish the auxin concentration gradient, which coordinates plant growth. PIN1-4 and 7 localized at the plasma membrane (PM) and facilitate polar auxin transport while the endoplasmic reticulum (ER) localized PIN5 and PIN8 maintain the intracellular auxin homeostasis. Although an antagonistic activity of PIN5 and PIN8 proteins in regulating the intracellular auxin homeostasis and other developmental events have been reported, the membrane topology of these proteins, which might be a basis for their antagonistic function, is poorly understood. In this study we optimized digitonin based PM-permeabilizing protocols coupled with immunocytochemistry labeling to map the membrane topology of PIN5 and PIN8 in Arabidopsis thaliana root cells. Our results indicate that, except for the similarities in the orientation of the N-terminus, PIN5 and PIN8 have an opposite orientation of the central hydrophilic loop and the C-terminus, as well as an unequal number of transmembrane domains (TMDs). PIN8 has ten TMDs with groups of five alpha-helices separated by the central hydrophilic loop (HL) residing in the ER lumen, and its N- and C-terminals are positioned in the cytoplasm. However, the topology of PIN5 comprises nine TMDs. Its N-terminal end and the central HL face the cytoplasm while its C-terminus resides in the ER lumen. Overall, this study shows that PIN5 and PIN8 proteins have a divergent membrane topology while introducing a toolkit of methods for studying membrane topology of integral proteins including those localized at the ER membrane."
Authors: Daniel Nedvěd, Martin Hudeček, Petr Klíma, Jozef Lacek, Karel Müller, Petr Hošek, Ján Šmeringai, Markéta Pernisová, Václav Motyka, Ondřej Plíhal and Klára Hoyerová.
BioRxiv (2024)
Abstract: "Ribosylated forms of plant hormones cytokinins (CKs) are the dominant CK species translocated at long distances. Their particular roles in plant physiology imply the existence of a yet uncharacterized CK riboside-specific membrane transport system. In this work, we report significant differences in the kinetics of the membrane transport of CK nucleobases and ribosides and the overall affinity of membrane-bound carriers towards the two CK forms. We show that CK ribosides can inhibit the uptake of CK nucleobases in tobacco Bright Yellow 2 cell suspensions but not vice versa, confirming the existence of a membrane transport system that strictly recognizes CK ribosides. We further characterize the membrane transport of CK nucleobases and ribosides mediated by AtENT3 (EQUiLIBRATIVE NUCLEOSIDE TRANSPORTER 3), showing its preference towards trans-zeatin riboside (tZR) over isopentenyl adenosine (iPR). With the molecular docking and molecular dynamics, we assess the interactions among the side chain of tZR and AtENT3 residues Tyr61 and Asp129, which are conserved in all AtENTs but not in the ENTs from non-plant species. Lastly, we show that atent3 mutation affects shoot phenotype, demonstrating the impact of CK riboside membrane transport on shoot development."
Authors: Xiaobo Song, Naifu Zhou, Yingying Chang, Junpei Zhang and Dong Pei.
Trees (2024)
Abstract: "Plant grafting involves naturally or intentionally merging distinct plant parts to form a single organism. Although it is a common horticultural practice used to improve the yield, quality, and resistance of horticultural crops and study the long-distance transport of molecules, the underlying mechanism of graft union formation (GUF) remains poorly understood. In this study, we optimized the in situ analysis method for plant hormones and explored the spatial and temporal distribution of endogenous hormones (IAA, ABA, and ZR) during walnut GUF. The results demonstrated that changes in endogenous IAA and ZR levels in the graft union were consistent, with an increase during the rapid proliferation phase of callus tissue and enrichment in the cambium and cells of the grafting interface. As callus tissue entered the differentiation stage, endogenous IAA and ZR levels rapidly decreased and were mainly distributed in the callus tissue. Conversely, the level and distribution of endogenous ABA showed no significant changes during the rapid proliferation phase of callus tissue. However, they increased rapidly after entering the differentiation stage, mainly in the scion cambium and callus tissue. We also observed "S"-shaped, “M”-shaped, and “N”-shaped trends in the dynamic changes of IAA/ABA, IAA/ZR, and ZR/ABA ratios, respectively. Based on these results, we propose a spatial and temporal distribution model of endogenous hormones during walnut GUF. This provides a foundation for further investigation into the molecular mechanisms of hormone-mediated GUF in walnut and other woody plants."
Authors: David Biermann and Sebastian Wolf.
eLife (2024)
Subheading: Modification of pectin, a component of the plant cell wall, is required to facilitate signaling by a RALF peptide, which is essential for many physiological and developmental processes.
Excerpts: "Now, in eLife, Jürgen Kleine-Vehn, Elke Barbez and colleagues at the University of Freiburg – including Ann-Kathrin Rößling as first author – report new insights into the relationship between pectin and a group of signaling molecules known as rapid alkalinization factors (RALFs; Rößling et al., 2024)."
"The work of Rößling et al. deepens our understanding of peptide signaling at the surface of plant cells. In summary, these findings demonstrate that RALF1 signaling depends on PMEs to demethylate pectin, which is likely because RALF1 and pectin require opposing charges to work together. One interesting possibility raised here is that pectin might act as a reservoir of signaling molecules that are released under certain conditions, reminiscent of the role of the extracellular matrix in some signaling pathways in animals."
Authors: Xueyuan Han, Chi Shen, Fangfang He, Yuxin Liu and Zisheng Luo.
Postharvest Biology and Technology (2024)
Highlights: • Both ethylene (ET) and ABA promoted the aroma recovery of cold-stored kiwifruit. • The pathways related to aroma synthesis were influenced by ABA or ET treatment. • ABA and ET may have different regulatory tendencies in kiwifruit aroma recovery.
Abstract: "Cold storage (CS) combined with preservative treatment is widely employed to effectively extend the storage duration of kiwifruit. Nevertheless, the olfactory quality of cold-stored kiwifruit tends to deteriorate during the post-ripening phase. In this study, abscisic acid (ABA) or ethylene (ET) was supplementary administered to cold-stored kiwifruit (CS combined with a preservative 1-MCP treatment) prior to transferring from CS, with the aim of examining the impact of ABA and ET on aroma restitution during the post-ripening period (designated as MCP+ABA and MCP+ET, respectively). The results revealed that the firmness of the MCP+ABA and MCP+ET treatments remained higher than that of the control (CK, without 1-MCP treatment) throughout the post-ripening phase, both of which moreover promoted the accumulation of soluble solids and titratable acids in kiwifruit comparing to 1-MCP group. The ethylene production and respiration rate of the fruit treated with MCP+ET and MCP+ABA fell within the intermediate range between the 1-MCP and CK groups. Compared to the 1-MCP group, both MCP+ABA and MCP+ET treatments significantly improved the accumulation of volatile components, particularly aldehydes and ketones during the early stage, and esters during the later stage of post-ripening. The activity analysis of pivotal enzymes involved in aroma biosynthesis revealed that ABA stimulated an increase in alcohol dehydrogenase (ADH) activity, while ET had a notable inducing effect on alcohol acyltransferase (AAT) and hydroperoxide lyase (HPL) activities. Furthermore, transcriptomic sequencing analysis revealed differential induction of gene expression in the pathways associated with aroma biosynthesis by ABA and ET, wherein they significantly upregulated distinct genes. Additionally, principal component analysis provided a more intuitive depiction that ABA and ET appeared to enhance the restoration of aroma in cold-stored kiwifruit by activating diverse metabolic pathways or key genes. In a comprehensive assessment, the present study postulates that both ABA and ET exert restorative effects on the aroma of cold-stored kiwifruit, thus offering theoretical support for aroma restitution technology in cold-stored fruit."
Authors: Patricio Olmedo, Gerardo Núñez-Lillo, Excequel Ponce, Juan E. Alvaro, Jorge Baños, Esther Carrera, José Jorge González-Fernández, José Ignacio Hormaza, David Campos, Rosana Chirinos, Reinaldo Campos-Vargas, Bruno Giorgio Defilippi, Encarna Aguayo and Romina Pedreschi.
Food Science (2024)
Highlights: • 'Hass' avocados accumulated higher amounts of sucrose, mannoheptulose, and perseitol in both tissues. • 'Fuerte' avocados accumulated stearic acid, oleic acid, and linoleic acid in the exocarp. • Cultivars presented differences in amino acid and carbohydrate metabolisms. • 'Hass' avocado exocarp showed higher abscisic acid and salicylic acid content. • Cytokinins, trans-zeatin and dihydrozeatin were found accumulated in 'Fuerte' skins.
Abstract: "Color development in avocado fruits is a complex mechanism influenced by several factors. To understand this process, a comparative analysis was conducted between fruits of 'Fuerte' and 'Hass' avocado cultivars using metabolomic approaches. Pigment content in the exocarp differs between cultivars, accumulating anthocyanins in 'Hass' avocado. Carbohydrate abundance differed at ready-to-eat stage showing that 'Hass' accumulated higher amounts of sucrose, mannoheptulose, and perseitol than ‘Fuerte’ in both tissues. Higher amounts of fatty acids were observed in both tissues of 'Fuerte'. Polar metabolites indicated differences in amino acid and carbohydrate metabolisms between cultivars. Hormone analysis suggested that abscisic acid is involved in pigment biosynthesis. These findings showed that hormone and primary metabolites cross-talk plays an important role in color development in the exocarp and in the softening in the mesocarp of ‘Hass', opening new perspectives about this metabolic interplay and its relation to the development of the exocarp-mesocarp synchronization during ripening."
Authors: Qunwei Bai, Shurong Xuan, Wenjuan Li, Khawar Ali, Bowen Zheng and Hongyan Ren.
BMC Plant Biology (2024)
Abstract: "Background - Brassinosteroids (BRs) are a class of phytohormones that regulate a wide range of developmental processes in plants. BR-associated mutants display impaired growth and response to developmental and environmental stimuli. Results - Here, we found that a BR-deficient mutant det2-1 displayed abnormal root gravitropic growth in Arabidopsis, which was not present in other BR mutants. To further elucidate the role of DET2 in gravity, we performed transcriptome sequencing and analysis of det2-1 and bri1-116, bri1 null mutant allele. Expression levels of auxin, gibberellin, cytokinin, and other related genes in the two mutants of det2-1 and bri1-116 were basically the same. However, we only found that a large number of JAZ (JASMONATE ZIM-domain) genes and jasmonate synthesis-related genes were upregulated in det2-1 mutant, suggesting increased levels of endogenous JA. Conclusions - Our results also suggested that DET2 not only plays a role in BR synthesis but may also be involved in JA regulation. Our study provides a new insight into the molecular mechanism of BRs on the root gravitropism."
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