Plant hormones (Literature sources on phytohormones and plant signalling)

Authors: Juraj Kleman and Radoslava Matusova

Biologia (2023)

Abstract: "The discovery of strigolactones has resulted in a confluence of various research topics like parasitic plants, arbuscular mycorrhizal fungi and phytohormones, which all play a big role in current global agricultural production. Over the past few decades, strigolactone research swiftly gained a spotlight, as to reveal their possible functions within plants and also the surrounding organisms in the rhizosphere. In this review, we explore the discovered functions of strigolactones with the main focus on the chemical structure of strigolactones and how it relates to the various biological responses they cause. We highlight their involvement in plant responses to abiotic stressors, like lack of available nutrients, high salinity, drought, extreme temperatures and presence of potentially toxic elements of environmental importance, while reflecting upon the strigolactone-mediated plant associations with arbuscular mycorrhizal fungi and nodule-forming, N-fixing bacteria. Furthermore, we elaborate on the current state of applied strigolactone research in agriculture and the probable bright future these compounds have in commercial use and what hurdles need to be overcome before they can be fully utilized."

Authors: Kazuo Shinozaki and Kazuko Yamaguchi-Shinozaki.

Proceedings of the Japan Academy, Series B (2022)

Abstract: "Land plants have developed sophisticated systems to cope with severe stressful environmental conditions during evolution. Plants have complex molecular systems to respond and adapt to abiotic stress, including drought, cold, and heat stress. Since 1989, we have been working to understand the complex molecular mechanisms of plant responses to severe environmental stress conditions based on functional genomics approaches with Arabidopsis thaliana as a model plant. We focused on the function of drought-inducible genes and the regulation of their stress-inducible transcription, perception and cellular signal transduction of stress signals to describe plant stress responses and adaptation at the molecular and cellular levels. We have identified key genes and factors in the regulation of complex responses and tolerance of plants in response to dehydration and temperature stresses. In this review article, we describe our 30-year experience in research and development based on functional genomics to understand sophisticated systems in plant response and adaptation to environmental stress conditions."

Authors: Chong Ren, Yangfu Kuang, Yanping Lin, Yuchen Guo, Huayang Li, Peige Fan, Shaohua Li and Zhenchang Liang.

BMC Plant Biology (2022)

Abstract: "Background - Abscisic acid (ABA) plays a crucial role in abiotic stress responses. The pyrabactin resistance (PYR)/PYR-like (PYL)/regulatory component of ABA receptor (RCAR) proteins that have been characterized as ABA receptors function as the core components in ABA signaling pathway. However, the functions of grape PYL genes in response to different abiotic stresses, particularly cold stress, remain less studied. Results - In this study, we investigated the expression profiles of grape PYL genes upon cold treatment and isolated the VaPYL4 gene from Vitis amurensis, a cold-hardy grape species. Overexpression of VaPYL4 gene in grape calli and Arabidopsis resulted in enhanced cold tolerance. Moreover, plant resistance to drought and salt stress was also improved by overexpressing VaPYL4 in Arabidopsis. More importantly, we evaluated the contribution of VaPYL4 to plant growth and development after the treatment with cold, salt and drought stress simultaneously. The transgenic plants showed higher survival rates, earlier flowering phenotype, and heavier fresh weight of seedlings and siliques when compared with wild-type plants. Physiological analyses showed that transgenic plants had much lower content of malondialdehyde (MDA) and higher peroxidase (POD) activity. Stress-responsive genes such as RD29A (Responsive to desiccation 29A), COR15A (Cold responsive 15A) and KIN2 (Kinase 2) were also significantly up-regulated in VaPYL4-overexpressing Arabidopsis plants. Conclusions - Our results show that overexpression of VaPYL4 could improve plant performance upon different abiotic stresses, which therefore provides a useful strategy for engineering future crops to deal with adverse environments.

Authors: Xuexue Chen, Yanglin Ding, Yongqing Yang, Chunpeng Song, Baoshan Wang, Shuhua Yang, Yan Guo and Zhizhong Gong.

Journal of Integrative Plant Biology (2021)

Abstract: "Protein kinases are major players in various signal transduction pathways. Understanding the molecular mechanisms behind plant responses to biotic and abiotic stresses has become critical for developing and breeding climate‐resilient crops. In this review, we summarize recent progress on understanding plant drought, salt, and cold stress responses, with a focus on signal perception and transduction by different protein kinases, especially sucrose nonfermenting1 (SNF1)‐related protein kinases (SnRKs), mitogen‐activated protein kinase (MAPK) cascades, calcium‐dependent protein kinases (CDPKs/CPKs), and receptor‐like kinases (RLKs). We also discuss future challenges in these research fields."

Authors: June-Sik Kim, Satoshi Kidokoro, Kazuko Yamaguchi-Shinozaki and Kazuo Shinozaki.

Plant Physiology (2024)

Abstract: "Drought and cold represent distinct types of abiotic stress, each initiating unique primary signaling pathways in response to dehydration and temperature changes, respectively. However, a convergence at the gene regulatory level is observed where a common set of stress-responsive genes is activated to mitigate the impacts of both stresses. In this review, we explore these intricate regulatory networks, illustrating how plants coordinate distinct stress signals into a collective transcriptional strategy. We delve into the molecular mechanisms of stress perception, stress signaling, and the activation of gene regulatory pathways, with a focus on insights gained from model species. By elucidating both the shared and distinct aspects of plant responses to drought and cold, we provide insight into the adaptive strategies of plants, paving the way for the engineering of stress-resilient crop varieties that can withstand a changing climate."

Authors: Junhong Guo, Hongyan Wang, Shengqun Liu, Yongjun Wang, Fulai Liu and Xiangnan Li.

Functional Plant Biology (2022)

Abstract: "Low temperature is one of the major environmental stresses that limit crop growth and grain yield in wheat (Triticum aestivum L.). Drought priming at the vegetative stage could enhance wheat tolerance to later cold stress; however, the transgenerational effects of drought priming on wheat offspring’s cold stress tolerance remains unclear. Here, the low temperature responses of offspring were tested after the parental drought priming treatment at grain filling stage. The offspring plants from parental drought priming treatment had a higher abscisic acid (ABA) level and lower osmotic potential (Ψo) than the control plants under cold conditions. Moreover, parental drought priming increased the antioxidant enzyme activities and decreased hydrogen peroxide (H2O2) accumulation in offspring. In comparison to control plants, parental drought priming plants had a higher ATP concentration and higher activities of ATPase and the enzymes involved in sucrose biosynthesis and starch metabolism. The results indicated that parental drought priming induced low temperature tolerance in offspring by regulating endogenous ABA levels and maintaining the redox homeostasis and the balance of carbohydrate metabolism, which provided a potential approach for cold resistant cultivation in wheat."