 Your new post is loading...
Your new post is loading...
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: 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."
Authors: Rui Deng, Shuhua Huang, Jia Du, Dan Luo, Jianwei Liu, Yan Zhao, Chongyang Zheng, Tiantian Lei, Qi Li, Siwei Zhang, Meng Jiang, Tong Jin, Dehai Liu, Shufen Wang, Yanfeng Zhang and Xiaofeng Wang.
The Plant Cell (2024)
Abstract: "Abstract The brassinosteroid (BR) receptor BRASSINOSTEROID-INSENSITIVE 1 (BRI1) plays a critical role in plant growth and development. Although much is known about how BR signaling regulates growth and development in many crop species, the role of StBRI1 in regulating potato (Solanum tuberosum) tuber development is not well understood. To address this question, a series of comprehensive genetic and biochemical methods were applied in this investigation. It was determined that StBRI1 and Solanum tuberosum PLASMA MEMBRANE (PM) PROTON ATPASE2 (PHA2), a PM-localized proton ATPase, play important roles in potato tuber development. The individual overexpression of StBRI1 and PHA2 led to a 22% and 25% increase in tuber yield per plant, respectively. Consistent with the genetic evidence, in vivo interaction analysis using double transgenic lines and PM H+-ATPase activity assays indicated that StBRI1 interacts with the C-terminus of PHA2, which restrains the intramolecular interaction of the PHA2 C-terminus with the PHA2 central loop to attenuate autoinhibition of PM H+-ATPase activity, resulting in increased PHA2 activity. Furthermore, the extent of PM H+-ATPase autoinhibition involving phosphorylation-dependent mechanisms corresponds to phosphorylation of the penultimate Thr residue (Thr-951) in PHA2. These results suggest that StBRI1 phosphorylates PHA2 and enhances its activity, which subsequently promotes tuber development. Altogether, our results uncover a BR–StBRI1–PHA2 module that regulates tuber development and suggest a prospective strategy for improving tuberous crop growth and increasing yield via the cell surface-based BR signaling pathway."
Authors: Monica L. García-Gómez and Kirsten ten Tusscher.
The Plant Journal (2024)
Significance Statement: This review proposes a conceptual model of the molecular mechanisms underlying root tip regeneration, from regeneration competence to the spatio-temporal repatterning of the root stump. We also discuss the use of multi-scale modeling to address open questions in the field.
Abstract: "Plants possess an outstanding capacity to regenerate enabling them to repair damages caused by suboptimal environmental conditions, biotic attacks, or mechanical damages impacting the survival of these sessile organisms. Although the extent of regeneration varies greatly between localized cell damage and whole organ recovery, the process of regeneration can be subdivided into a similar sequence of interlinked regulatory processes. That is, competence to regenerate, cell fate reprogramming, and the repatterning of the tissue. Here, using root tip regeneration as a paradigm system to study plant regeneration, we provide a synthesis of the molecular responses that underlie both regeneration competence and the repatterning of the root stump. Regarding regeneration competence, we discuss the role of wound signaling, hormone responses and synthesis, and rapid changes in gene expression observed in the cells close to the cut. Then, we consider how this rapid response is followed by the tissue repatterning phase, where cells experience cell fate changes in a spatial and temporal order to recreate the lost stem cell niche and columella. Lastly, we argue that a multi-scale modeling approach is fundamental to uncovering the mechanisms underlying root regeneration, as it allows to integrate knowledge of cell-level gene expression, cell-to-cell transport of hormones and transcription factors, and tissue-level growth dynamics to reveal how the bi-directional feedbacks between these processes enable self-organized repatterning of the root apex."
Authors: Yao Xiao, Melina Zourelidou, Alkistis E. Lanassa Bassukas, Benjamin Weller, Dorina P. Janacek, Lukas Schulz, Sarah Brajkovic, Jan Šimura, Karen Ljung, Bernhard Kuster, Ulrich Z. Hammes, Jia Li and Claus Schwechheimer.
bioRxiv (2024)
Abstract: "Plants use environmental cues, such as the direction of gravity or the direction, quantity and quality of light, to orientate organ and plant growth. During germination of angiosperm seeds in the soil, hypocotyl elongation is directed by negative gravitropism responses such that the seedling can reach the light for photosynthesis and autotrophic growth. Hypocotyl elongation in the soil, however, also requires mechanisms to efficiently grow around obstacles such as soil particles. Here, we identify KIPK (KINESIN-LIKE CALMODULIN-BINDING PROTEIN INTERACTING PROTEIN KINASE) and the paralogous KIPKL1 (KIPK-LIKE1) as genetically redundant regulators of hypocotyl bending, in that KIPK and KIPKL1 are required to efficiently align hypocotyl growth with the gravity vector after obstacle avoidance. At the same time, we find that the highly homologous KIPKL2 (KIPK-LIKE2) must be functionally distinct. We further find that KIPK, and likely also KIPKL1, phosphorylate BRXL2 (BREVIS RADIX LIKE2) and ARKs (ARMADILLO REPEAT KINESINs), that mutants of both KIPK phosphorylation substrates share the overbending phenotype with kipk kipkl1 mutants, and that KIPK and KIPKL1 act synergistically with the ARK-regulatory NEK6 (NIMA-RELATED PROTEIN KINASE6). We propose that KIPK and KIPKL1 regulate ARK kinesins and thereby cortical microtubules for efficient gravitropic hypocotyl bending."
Authors: Qiao Cheng, Jiayang Li and Bing Wang.
The Innovation Life (2024)
Excerpts: "The auxin concentration gradients are further perceived by auxin receptors, including the canonical nuclear receptor TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-Boxes (TIR1/AFBs), the non-canonical nuclear receptor ETTIN/ AUXIN RESPONSE FACTOR 3 (ETT/ARF3), and the extracellular receptor complex Auxin Binding Protein 1−TransMembrane Kinases (ABP1−TMKs) (Figure 1).1 However, the perception and signaling pathway of extracellular auxin has been controversial over the past few years."
"It is possible that a class of auxin receptors distinct from the nuclear TIR1/AFB receptors can regulate these rapid auxin responses and are presumably localized on the cell surface. The plasma-membrane-localized protein ABP1 is the first identified auxin-binding protein with high affinity and is a receptor candidate for extracellular auxin."
"These milestone studies demonstrate that ABLs and TMKs are co-receptors for extracellular auxin and trigger fast phosphorylation through RAF-like protein kinases. In general, extracellular auxin is perceived by apoplast-localized ABP1/ABLs and the extracellular domain of TMKs, triggering the direct interaction of TMKs with ABP1/ABLs and the phosphorylation of TMKs."
Authors: Chang Zhang, Zhenxiang Li, Tingting Sun, Shoujian Zang, Dongjiao Wang, Yachun Su, Qibin Wu and Youxiong Que.
Journal of Agricultural and Food Chemistry (2024)
Abstract: "Calcium (Ca2+) is a second messenger in various physiological processes within plants. The significance of the Ca2+/H+ exchanger (CAX) has been established in facilitating Ca2+ transport in plants; however, disease resistance functions of the CAX gene remain elusive. In this study, we conducted sequence characterization and expression analysis for a sugarcane CAX gene, ScCAX4 (GenBank Accession Number: MW206380). In order to further investigate the disease resistance functions, this gene was then transiently overexpressed in Nicotiana benthamiana leaves, which were subsequently inoculated with Fusarium solani var. coeruleum. Results showed that ScCAX4 overexpression increased the susceptibility of N. benthamiana to pathogen infection by regulating the expression of genes related to salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) pathways, suggesting its negative role in disease resistance. Furthermore, we genetically transformed the ScCAX4 gene into N. benthamiana and obtained three positive T2 generation lines. Interestingly, the symptomatology of transgenic plants was consistent with that of transient overexpression after pathogen inoculation. Notably, the JA content in transgenic overexpression lines was significantly higher than that in the wild-type. RNA-seq revealed that ScCAX4 could mediate multiple signaling pathways, and the JA signaling pathway played a key role in modulating disease resistance. Finally, a regulatory model was depicted for the increased susceptibility to pathogen infection conferred by the ScCAX4 gene. This study provides genetic resources for sugarcane molecular breeding and the research direction for plant CAX genes."
Authors: Nidhi Kandhol, Sangeeta Pandey, Vijay Pratap Singh, Luis Herrera-Estrella, Lam-Son Phan Tran and Durgesh Kumar Tripathi.
Research (2024)
Abstract: "The menace of drought has persistently loomed over global crop production, posing a significant threat to agricultural sustainability. Research on drought stress highlights the significant role of the phytohormone abscisic acid (ABA) in orchestrating plant responses to drought conditions. ABA regulates various drought/dehydration-responsive genes, initiates stomatal closure, and influences cellular responses to drought stress. Additionally, plants employ a phosphate starvation response (PSR) mechanism to manage phosphate (Pi) deficiency, with ABA playing a role in its regulation. However, despite intensive research in these fields, the precise connection among PSRs, drought stress, and ABA signalling still needs to be determined. The recent study by Nagatoshi and colleagues (2023) demonstrates that PSR-related gene induction occurs before the induction of ABA-responsive genes under progressive mild drought. Mild drought decreases Pi uptake and contents in plants, triggering PSRs, which play an important role in plant growth during mild drought. Both ABA-responsive and PSR-related gene expression could indicate plant perception of external moisture conditions. Thus, integrating the information regarding their associated gene expression with soil moisture contents and thermographic data can enable timely irrigation optimization to mitigate the effect of drought on crop productivity."
Authors: Fuli Huang, Mimi Sun, Zhijin Yao, Jing Zhou, Qian Bai, Xuexue Chen, Yun Huang and Yuanyue Shen.
Journal of Experimental Botany (2024)
Abstract: "Strawberry (Fragaria×ananassa) is a model plant for studying non-climacteric fruit ripening regulated by abscisic acid (ABA). However, the signaling of ABA in the regulation of fruit coloration is not fully understood. Here, a transcription factor FabHLH3 key to fruit coloration is identified by yeast two hybrid library screening using FaSnRK2.6 as a bait, an ABA core signaling component negative to ripening. Indeed, this interaction is also confirmed by firefly luciferase complementation assay and pull-down assay. RT-qPCR and Western blotting analysis confirm FabHLH3 is expressed ubiquitously in strawberry and stably during fruit development. Manipulating both FabHLH3 and FaSnRK2.6 expression by overexpression and interference demonstrates that FabHLH3 and FaSnRK2.6 promote and inhibit strawberry fruit coloration, respectively, using the marker gene FaUFGT, key to anthocyanin biosynthesis. FaSnRK2.6 can phosphorylate FabHLH3, which promotes FaUFGT expression by the directly binding to its promoter. The phosphorylation inhibits the binding of FabHLH3 to FaUFGT promoter, consequently suppressing FaUFGT expression. Altogether, FaSnRK2.6, a negative kinase in ripening, interacts with and phosphorylates FabHLH3 to suppress FaUFGT expression. With the increase of ABA content in strawberry fruit ripening, the expression of FaSnRK2.6 decreased, which released FabHLH3 transcription activity and enhanced FaUFGT expression, finally promoting the coloration. Thus, our findings fill a gap how FaSnRK2.6 negatively regulates strawberry fruit coloration and ripening by FabHLH3."
Authors: Zilin Zhang, Huihuang Chen, Shuaiying Peng and Huibin Han.
Journal of Experimental Botany (2024)
Highlights: An update of current understanding of slow and rapid responses that triggered by plant phytohormone auxin.
Excerpts: "The plant phytohormone auxin coordinates cellular responses to various developmental and environmental signals, thus optimizing plant growth and development. Auxin controls not only the slow transcriptional responses, but also transcriptional-independent rapid responses occurring in seconds (Box 1 and Box 2; Das et al., 2021; Dubey et al., 2021; Fiedler and Friml, 2023)."
"The nuclear auxin signaling pathway can explain majority of auxin effects on plant growth. However, several developmental processes including rapid root growth inhibition (Fendrych et al. 2018; Li et al., 2021), Ca2+ influxes (Shih et al., 2015), cytoplasmic streaming (Friml et al., 2022), apoplast alkalinization (Li et al., 2021) and membrane depolarization (Serre et al., 2021) are too fast to be mediated by the TIR1/AFB2-5-dependent transcriptional regulation, suggesting a rapid auxin-responsive system exists."
Authors: N. Butel, Y. Qiu, W. Xu, J. Santos-González and C. Köhler.
Nature Plants (2024)
Editor's view: In most flowering plants, early divisions of endosperm nuclei are not succeeded by cellularization. This study uncovered a family of clustered auxin response factors as dosage-sensitive, maternally expressed regulators of endosperm cellularization.
Abstract: "The endosperm is a reproductive tissue supporting embryo development. In most flowering plants, the initial divisions of endosperm nuclei are not succeeded by cellularization; this process occurs only after a specific number of mitotic cycles have taken place. The timing of cellularization significantly influences seed viability and size. Previous research implicated auxin as a key factor in initiating nuclear divisions and determining the timing of cellularization. Here we uncover the involvement of a family of clustered auxin response factors (cARFs) as dosage-sensitive regulators of endosperm cellularization. cARFs, maternally expressed and paternally silenced, are shown to induce cellularization, thereby restricting seed growth. Our findings align with the predictions of the parental conflict theory, suggesting that cARFs represent major molecular targets in this conflict. We further demonstrate a recurring amplification of cARFs in the Brassicaceae, suggesting an evolutionary response to parental conflict by reinforcing maternal control over endosperm cellularization. Our study highlights that antagonistic parental control on endosperm cellularization converges on auxin biosynthesis and signalling."
Authors: Bin Yang, Patrick Federmann, Viktoria Warth, Mingzhe Ren, Xin Mu, Haibo Wu and Jan-E. Bäckvall.
Organic Letters (2024)
Abstract: "Here we report an efficient route for synthesizing strigolactones (SLs) and their derivatives. Our method relies on a palladium-catalyzed oxidative carbonylation/carbocyclization/carbonylation/alkoxylation cascade reaction, which involves the formation of three new C–C bonds and a new C–O bond while cleaving one C(sp3)–H bond in a single step. With our versatile synthetic strategy, both naturally occurring and artificial SLs were prepared."
Authors: Arnau Rovira, Nil Veciana, Aina Basté-Miquel, Martí Quevedo, Antonella Locascio, Lynne Yenush, Gabriela Toledo-Ortiz, Pablo Leivar and Elena Monte.
Nature Communications (2024)
Editor's view: Stomata function is essential for photosynthesis and the global carbon and oxygen cycles. Here, the authors report the regulatory framework that establishes rhythmic pore movements to prevent water loss at night and allow CO2 uptake during the day.
Abstract: "Stomata govern the gaseous exchange between the leaf and the external atmosphere, and their function is essential for photosynthesis and the global carbon and oxygen cycles. Rhythmic stomata movements in daily dark/light cycles prevent water loss at night and allow CO2 uptake during the day. How the actors involved are transcriptionally regulated and how this might contribute to rhythmicity is largely unknown. Here, we show that morning stomata opening depends on the previous night period. The transcription factors PHYTOCHROME-INTERACTING FACTORS (PIFs) accumulate at the end of the night and directly induce the guard cell-specific K+ channel KAT1. Remarkably, PIFs and KAT1 are required for blue light-induced stomata opening. Together, our data establish a molecular framework for daily rhythmic stomatal movements under well-watered conditions, whereby PIFs are required for accumulation of KAT1 at night, which upon activation by blue light in the morning leads to the K+ intake driving stomata opening."
|
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."
Authors: Chengjuan Cao, Shuaiqiang Guo, Ping Deng, Shiyi Yang, Jing Xu, Tengfei Hu, Zhijuan Hu, Di Chen, Hongsheng Zhang, Ian Paul Navea, Joong Hyoun Chin, Wenhua Zhang and Wen Jing.
The Plant Journal (2024)
Significance Statement: "GA 2-oxidases (GA2oxs) play crucial roles in regulating plant architecture and yield by inactivating endogenous bioactive GAs and their precursors, but the regulatory mechanisms of GA2ox gene expression remain unclear. This study identifies that OsBLH4, a member of the BEL1-like homeodomain proteins, acts upstream of OsGA2ox1, modulates endogenous bioactive GA levels, and regulates stem elongation and reproductive development in rice."
Abstract: "Gibberellins (GAs) play crucial roles in regulating plant architecture and grain yield of crops. In rice, the inactivation of endogenous bioactive GAs and their precursors by GA 2-oxidases (GA2oxs) regulates stem elongation and reproductive development. However, the regulatory mechanisms of GA2ox gene expression, especially in rice reproductive organs, are unknown. The BEL1-like homeodomain protein OsBLH4, a negative regulatory factor for the rice OsGA2ox1 gene, was identified in this study. Loss of OsBLH4 function results in decreased bioactive GA levels and pleiotropic phenotypes, including reduced plant height, decreased grain number per panicle, and delayed heading date, as also observed in OsGA2ox1-overexpressing plants. Consistent with the mutant phenotype, OsBLH4 was predominantly expressed in shoots and young spikelets; its encoded protein was exclusively localized in the nucleus. Molecular analysis demonstrated that OsBLH4 directly bound to the promoter region of OsGA2ox1 to repress its expression. Genetic assays revealed that OsBLH4 acts upstream of OsGA2ox1 to control rice plant height, grain number, and heading date. Taken together, these results indicate a crucial role for OsBLH4 in regulating rice plant architecture and yield potential via regulation of bioactive GA levels, and provide a potential strategy for genetic improvements of rice."
Authors: Xuexue Chen, Jiahui Gao and Yuanyue Shen.
The Plant Journal (2024)
Significance Statement: We unravel a novel abscisic acid signaling transduction pathway in sugar transport via “FaRIPK1-FaTCP7-FaSTP13/FaSPT,” which channels to strawberry fruit ripening.
Abstract: "Strawberry is considered as a model plant for studying the ripening of abscisic acid (ABA)-regulated non-climacteric fruits, a process in which sugar plays a fundamental role, while how ABA regulates sugar accumulation remains unclear. This study provides a direct line of physiological, biochemical, and molecular evidence that ABA signaling regulates sugar accumulation via the FaRIPK1-FaTCP7-FaSTP13/FaSPT signaling pathway. Herein, FaRIPK1, a red-initial protein kinase 1 previously identified in strawberry fruit, not only interacted with the transcription factor FaTCP7 (TEOSINTE BRANCHEN 1, CYCLOIDEA, and PCF) but also phosphorylated the critical Ser89 and Thr93 sites of FaTCP7, which negatively regulated strawberry fruit ripening, as evidenced by the transient overexpression (OE) and virus-induced gene silencing transgenic system. Furthermore, the DAP-seq experiments revealed that FvTCP7 bound the motif “GTGG CCCNC” in the promoters of two sugar transporter genes, FaSTP13 (sugar transport protein 13) and FaSPT (sugar phosphate/phosphate translocator), inhibiting their transcription activities as determined by the electrophoretic mobility shift assay, yeast one-hybrid, and dual-luciferase reporter assays. The downregulated FaSTP13 and FaSPT transcripts in the FaTCP7-OE fruit resulted in a reduction in soluble sugar content. Consistently, the yeast absorption test revealed that the two transporters had hexose transport activity. Especially, the phosphorylation-inhibited binding of FaTCP7 to the promoters of FaSTP13 and FaSPT could result in the release of their transcriptional activities. In addition, the phosphomimetic form FaTCP7S89D or FaTCP7T93D could rescue the phenotype of FaTCP7-OE fruits. Importantly, exogenous ABA treatment enhanced the FaRIPK1–FaTCP7 interaction. Overall, we found direct evidence that ABA signaling controls sugar accumulation during strawberry fruit ripening via the “FaRIPK1-FaTCP7-FaSTP13/FaSPT” module."
Authors: Yonghui Dong, Ning Su and Yuqin Zhang.
The Innovation Life (2024)
Abstract: "In a recent groundbreaking study published in Science by Ying et al. (2024), it was discovered that ABCB19, a member of the ATP-binding cassette (ABC) transporter superfamily, and previously known as a primary auxin exporter, also functions as a brassinosteroid (BR) exporter. This finding represents a significant advancement in the identification of BR transporters, which have been a long-overlooked component of BR transport models.Our commentary aims to discuss the key findings of this study, the methodologies employed to support these findings, and the implications and future directions that this discovery may yield. By highlighting the novelty of ABCB19's dual function and the implications for our understanding of BR signaling and transport, we hope to contribute to the ongoing efforts in optimizing plant growth and productivity."
Authors: Xiaodi Wang, Xuqing Luo, Jianyang Guo, Nianwan Yang, Fanghao Wan, Zhichuang Lü and Wanxue Liu.
iScience (2024)
Highlights: • REPAT38 induces stomatal closure • REPAT38 inhibits the synthesis of JA, ET and ABA • REPAT38 inhibits the expression of plant hormone-responsive genes • REPAT38 acts as an effector to weaken host plant defense
Abstract: "Insects have evolved effectors to regulate host defenses for efficient feeding, yet their impact on chewing insects, like the tomato leaf miner (Phthorimaea absoluta), a significant pest, is poorly understood. We used RNAi to target the REPAT38 gene in larvae, monitoring changes at 0.5, 1, 2, and 4 h in leaf stomata, plant hormone concentrations (jasmonic acid (JA), jasmonoyl-L-isoleucine (JA-Ile), salicylic acid (SA), ethylene (ET), and abscisic acid (ABA)), and 12 hormone-responsive genes to explore the molecular mechanism of REPAT38-mediated plant-insect interactions. The results showed that the effector induced stomatal closure at 0.5 h and inhibited the synthesis of JA, ET, and ABA at 1 h. Additionally, seven plant hormone-responsive genes—AOC, MYC2, ACS1A, PAL, PR1, EIL2, and SRK2E—were inhibited at various time points. Our data suggest that REPAT38, as an effector with conserved functions, can weaken tomato host defenses and conducive to insect adaptation to host plants."
Authors: Sara Hailemariam, Chao-Jan Liao and Tesfaye Mengiste.
Trends in Plant Science (2024)
Highlights: Receptor-like cytoplasmic kinases (RLCKs) have become major players in plant immunity regardless of the pathways involved. RLCKs form regulatory nodes that link receptors to downstream regulators that modulate plant hormones, Ca2+ signaling, reactive oxygen species (ROS) accumulation as well as activation of mitogen-activated protein kinases (MAPKs), transcription regulators, and immune gene expression. Phosphorylation, ubiquitination, and other post-translational modifications by effectors regulate RLCKs, enabling functional versatility and homeostasis. As major integrators of signals from receptors, RLCKs are potential targets for biotechnological applications. RLCKs play pivotal roles in plant immunity by contributing to both PTI and ETI. Due to their critical functions, these kinases are targets for manipulation by pathogen effectors to attenuate PTI. RLCKs also directly or indirectly recognize effectors and activate ETI. The function of RLCKs in crop plant immunity is emerging.
Abstract: "The receptor-like kinase (RLK) family of receptors and the associated receptor-like cytoplasmic kinases (RLCKs) have expanded in plants because of selective pressure from environmental stress and evolving pathogens. RLCKs link pathogen perception to activation of coping mechanisms. RLK–RLCK modules regulate hormone synthesis and responses, reactive oxygen species (ROS) production, Ca2+ signaling, activation of mitogen-activated protein kinase (MAPK), and immune gene expression, all of which contribute to immunity. Some RLCKs integrate responses from multiple receptors recognizing distinct ligands. RLKs/RLCKs and nucleotide-binding domain, leucine-rich repeats (NLRs) were found to synergize, demonstrating the intertwined genetic network in plant immunity. Studies in arabidopsis (Arabidopsis thaliana) have provided paradigms about RLCK functions, but a lack of understanding of crop RLCKs undermines their application. In this review, we summarize current understanding of the diverse functions of RLCKs, based on model systems and observations in crop species, and the emerging role of RLCKs in pathogen and abiotic stress response signaling."
Authors: Rishabh Pankaj, Rita B. Lima, Guan-Yu Luo, Sinah Ehlert, Gerardo del Toro-de León, Heinrich Bente, Pascal Finger, Hikaru Sato and Duarte D. Figueiredo.
bioRxiv (2024)
Abstract: "Seed development in angiosperms starts with double fertilization, where two paternal sperm cells fertilize the maternal gametes. This leads to the formation of the embryo and of the endosperm. These fertilization products are enveloped by the maternally-derived seed coat, the development of which is inhibited prior to fertilization by the Polycomb Repressive Complex 2 (PRC2). This complex deposits the repressive histone mark H3K27me3, whose removal is necessary for seed coat formation. Here, we show that JUMONJI-type (JMJ) histone demethylases are expressed in the seed coats of Arabidopsis thaliana (Arabidopsis) and are necessary for its formation. We propose that JMJ activity is coupled to Brassinosteroid (BR) function, as BR effectors physically recruit JMJ proteins to target loci. Consistent with this, we show that loss of BR biosynthesis and signaling leads to seed coat defects, and that loss of the main BR receptor, BRI1, results in H3K27me3 hypermethylation. Moreover, our data points to BRI1 mediating H3K27me3 removal independently of BRs, while a different receptor, BRL3, likely regulates seed coat formation in a BR-dependent manner. We thus propose a model where seed coat development relies on canonical and non-canonical functions of BR receptors."
Authors: Guicai Cui, Yu Li, Leiying Zheng, Caroline Smith, Michael W. Bevan and Yunhai Li.
Nature Communications (2024)
Editor's view: The transcription factor WUSCHEL is essential for stem cell function, but factors that directly modulate WUS stability are unclear. This work discovers that the peptidase DA1 cleaves and destabilizes WUS to control shoot apical meristem size.
Abstract: "Stem cells in plants and animals are the source of new tissues and organs. In plants, stem cells are maintained in the central zone (CZ) of multicellular meristems, and large shoot meristems with an increased stem cell population hold promise for enhancing yield. The mobile homeodomain transcription factor WUSCHEL (WUS) is a central regulator of stem cell function in plant shoot meristems. Despite its central importance, the factors that directly modulate WUS protein stability have been a long-standing question. Here, we show that the peptidase DA1 physically interacts with and cleaves the WUS protein, leading to its destabilization. Furthermore, our results reveal that cytokinin signaling represses the level of DA1 protein in the shoot apical meristem, thereby increasing the accumulation of WUS protein. Consistent with these observations, loss of DA1 function results in larger shoot apical meristems with an increased stem cell population and also influences cytokinin-induced enlargement of shoot apical meristem. Collectively, our findings uncover a previously unrecognized mechanism by which the repression of DA1 by cytokinin signaling stabilizes WUS, resulting in the enlarged shoot apical meristems with the increased stem cell number during plant growth and development."
Authors: Leila Feiz, Christine Shyu, Shan Wu, Kevin R. Ahern, Iram Gull, Ying Rong, Caroline J. Artymowicz, Miguel A. Piñeros, Zhangjun Fei, Thomas P. Brutnell and Georg Jander.
The Plant Cell (2024)
One-sentence summary: Hormonal regulation of maize stalk height is influenced by four members of a gene family that has similarity to genes previously associated with insect defense induction in numerous other plant species.
Abstract: "The F-box protein Coronatine Insensitive (COI) is a receptor for the jasmonic acid signaling pathway in plants. To investigate the functions of the six maize (Zea mays) COI proteins (COI1a, COI1b, COI1c, COI1d, COI2a, and COI2b), we generated single, double, and quadruple loss-of-function mutants. The pollen of the coi2a coi2b double mutant was inviable. The coi1 quadruple mutant (coi1-4x) exhibited shorter internodes, decreased photosynthesis, leaf discoloration, microelement deficiencies, and accumulation of DWARF8 and/or DWARF9, two DELLA family proteins that repress the gibberellic acid signaling pathway. Co-expression of COI and DELLA in Nicotiana benthamiana showed that the COI proteins trigger proteasome-dependent DELLA degradation. Many genes that are downregulated in the coi1-4x mutant are gibberellic acid-inducible. In addition, most of the proteins encoded by the downregulated genes are predicted to be bundle sheath- or mesophyll-enriched, including those encoding C4-specific photosynthetic enzymes. Heterologous expression of maize Coi genes in N. benthamiana showed that COI2a is nucleus-localized and interacts with maize jasmonate ZIM (zinc-finger inflorescence meristem) domain (JAZ) proteins, the canonical COI repressor partners. However, maize COI1a and COI1c showed only partial nuclear localization and reduced binding efficiency to the tested JAZ proteins. Together, these results show the divergent functions of the six COI proteins in regulating maize growth and defense pathways."
Authors: Wenwen Chang, Qiao Qiao, Qingtian Li, Xin Li, Yanyan Li, Xiahe Huang, Yingchun Wang, Jiayang Li, Bing Wang and Lei Wang.
Molecular Plant (2024)
Abstract: "Karrikins and strigolactones govern plant development and environmental responses through closely related signaling pathways. The transcriptional repressor proteins SUPPRESSOR OF MAX2 1 (SMAX1), SMAX1-like2 (SMXL2), and D53-like SMXLs, mediate karrikin and strigolactone signaling through direct binding downstream genes or by inhibiting the activities of transcription factors. In this study, we characterized the non-transcriptional regulatory activities of SMXL proteins in Arabidopsis. We discovered that SMAX1 and SMXL2 with mutations in their ethylene-response factor-associated amphiphilic repression (EAR) motif had undetected or weak transcriptional repression activities, but can still partially rescued the hypocotyl elongation defects and fully reversed the cotyledon epinasty defects of smax1 smxl2 mutant. SMAX1 and SMXL2 directly interacted with PHYTOCHROME INTERACTION FACTOR 4 (PIF4) and PIF5 and enhanced the protein stability of PIF4 and PIF5 by interacting with phytochrome B (phyB) and suppressing the association of phyB with PIF4 and PIF5. The karrikin-responsive genes were further identified by treatment with GR24ent-5DS, a GR24 analog showing karrikin activity. Interestingly, INDOLE-3-ACETIC ACID INDUCIBLE 29 (IAA29) expression was repressed by GR24ent-5DS treatment in a PIF4- and PIF5-dependent and EAR-independent manner, whereas KARRIKIN UPREGULATED F-BOX 1 (KUF1) expression was induced in a PIF4- and PIF5-independent and EAR-dependent manner. Furthermore, the non-transcriptional regulatory activity of SMAX1 that is independent of the EAR motif had a global effect on gene expression. Taken together, these results reveal that the non-transcriptional regulatory activities of SMAX1 and SMXL2 mediates the karrikin-regulated seedling response to red light."
Authors: Brian Zebosi, Erik Vollbrecht and Norman B. Best.
Plant Communications (2024)
Abstract: "Brassinosteroids (BRs) are important regulators that control myriad aspects of plant growth and development, including biotic and abiotic stress responses, such that modulating BR homeostasis and signaling presents abundant opportunities for plant breeding and crop improvement. Enzymes and other proteins involved in the biosynthesis and signaling of BRs are well understood from molecular genetics and phenotypic analysis in Arabidopsis thaliana; however, knowledge of molecular functions of these genes in other plant species, especially cereal crop plants, is minimal. In this manuscript, we comprehensively review functional studies of BR genes in Arabidopsis, maize, rice, Setaria, Brachypodium, and soybean to identify conserved and diversified functions across plant species and to highlight cases where additional research is in order. We performed phylogenetic analysis of gene families involved in the biosynthesis and signaling of BRs and re-analyzed publicly available transcriptomic data. Gene trees coupled with expression data provide a valuable guide to supplement future research on BRs in these important crop species, allowing researchers to identify genes to target through gene editing techniques to perform BR-related functional studies."
Authors: Stephan Pollmann, Adrián González Ortega-Villaizán, Eoghan King, Manish K. Patel, Marta-Marina Pérez-Alonso, Sandra 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 and Jesús Vicente-Carbajosa.
Authorea (2024)
Abstract: "Plants share their habitats with a multitude of different microbes. This close vicinity promoted the evolution of inter-organismic 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. Co-colonization of Arabidopsis roots with S. indica significantly promotes plant growth. Due to the notable phenotypic alterations of fungus-infected root systems, the involvement of a reprogramming of plant hormone levels, especially that of indole-3-acetic acid, has been suggested earlier. However, until now, the molecular mechanism by which S. indica promotes 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 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 signaling in roots, which results in increased plant growth.
|
