scholarly journals Proline, A Peculiar Amino Acid with Astucious Functions in Development and Salt Tolerance Process in Plants

Author(s):  
Faiçal Brini ◽  
Walid Saibi ◽  
Faiçal Brini

Proline is known to play diverse functions in plants. Some aspects of its biological functions are still unclear. This review highlights some cases in the proline, structure, metabolism, functions in development and also its involvement in salt tolerance process in planta. Indeed, we report the clever roles of proline in cellular homeostasis, including redox balance and their implication as effector during some causal enzymological and physiological processes. Furthermore, the proline functions under abiotic stresses are not yet completely understood. The engineering of proline metabolism could lead to new opportunities to improve plant tolerance against environmental stresses, especially salinity. Eventually, we note that the purpose through this review is to provide a rich, concise and mostly cohesive source on proline, considered as a platform and an anchor between several disciplines and biological functions. We also provide insight on some important research gaps that need to be filled to advance our scientific understanding in this area of research on proline in soil-plant systems.

2021 ◽  
Author(s):  
liang xu ◽  
Jia-Qian Song ◽  
yuelin wang ◽  
Xiao-Han Liu ◽  
Xue-Li Li ◽  
...  

Abstract Plants have evolved a lot of strategies to improve salt tolerance to cope with salt stress. Recent studies have suggested that thymol (a nature medicine) enhances the plant tolerance against abiotic stresses, but the mechanisms are rarely known. Here, we found that thymol played an important role in maintaining root growth under salt stress. Thymol rescued root growth from salt stress via ameliorating ROS (reactive oxygen species) accumulation, lipid peroxidation, and cell death. In addition, thymol enhanced the level of NO (nitric oxide) and GSH (glutathione) to repress ROS accumulation, further protecting the stability of cell membrane. Thymol-induced Na+ efflux in roots and leaves under salt stress may depend on the upregulation of SOS1, HKT1 and NHX1. Consequently, all of these evidences suggested that thymol improved tobacco salt tolerance via enhancing NO and GSH content as well as inducing Na+ efflux.


2021 ◽  
Author(s):  
liang xu ◽  
Jia-Qian Song ◽  
yuelin wang ◽  
Xiao-Han Liu ◽  
Xue-Li Li ◽  
...  

Abstract Plants have evolved a lot of strategies to improve salt tolerance to cope with salt stress. Recent studies have suggested that thymol (a nature medicine) enhances the plant tolerance against abiotic stresses, but the mechanisms are rarely known. Here, we found that thymol played an important role in maintaining root growth under salt stress. Thymol rescued root growth from salt stress via ameliorating ROS (reactive oxygen species) accumulation, lipid peroxidation, and cell death. In addition, thymol enhanced the level of NO (nitric oxide) and GSH (glutathione) to repress ROS accumulation, further protecting the stability of cell membrane. Thymol-induced Na+ efflux in roots and leaves under salt stress may depend on the upregulation of SOS1, HKT1 and NHX1. Consequently, all of these evidences suggested that thymol improved tobacco salt tolerance via enhancing NO and GSH content as well as inducing Na+ efflux.


Hydrogen ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 319-342
Author(s):  
Kanika Khanna ◽  
Nandni Sharma ◽  
Sandeep Kour ◽  
Mohd. Ali ◽  
Puja Ohri ◽  
...  

Hydrogen sulfide (H2S) is predominantly considered as a gaseous transmitter or signaling molecule in plants. It has been known as a crucial player during various plant cellular and physiological processes and has been gaining unprecedented attention from researchers since decades. They regulate growth and plethora of plant developmental processes such as germination, senescence, defense, and maturation in plants. Owing to its gaseous state, they are effectively diffused towards different parts of the cell to counterbalance the antioxidant pools as well as providing sulfur to cells. H2S participates actively during abiotic stresses and enhances plant tolerance towards adverse conditions by regulation of the antioxidative defense system, oxidative stress signaling, metal transport, Na+/K+ homeostasis, etc. They also maintain H2S-Cys-cycle during abiotic stressed conditions followed by post-translational modifications of cysteine residues. Besides their role during abiotic stresses, crosstalk of H2S with other biomolecules such as NO and phytohormones (abscisic acid, salicylic acid, melatonin, ethylene, etc.) have also been explored in plant signaling. These processes also mediate protein post-translational modifications of cysteine residues. We have mainly highlighted all these biological functions along with proposing novel relevant issues that are required to be addressed further in the near future. Moreover, we have also proposed the possible mechanisms of H2S actions in mediating redox-dependent mechanisms in plant physiology.


Author(s):  
Min CHEN ◽  
Nan Chen ◽  
Jiwu WANG ◽  
YuJian Zhou ◽  
Liangliang Han ◽  
...  

Ralstonia solanacearum RSc0454 is predicated as a FAD-linked oxidase based on protein homologies, while containing distinct domains of LDH and SDH. Current study demonstrates RSc0454 exhibits LDH activity and is essential for pathogenicity. Here, we characterized involvement of RSc0454 on bacterial growth and expression of the T3SS in R. solanacearum. RSc0454 mutant grew normally in rich medium but grew faintly in host plants, and failed to grow in minimal medium. Supplementary succinate, but not lactate, substantially restored some phenotypes of RSc0454 mutants, including faint growth in plants, diminished growth in minimal medium, and lost pathogenicity. The T3SS Expression is directly controlled by a master regulator HrpB, and HrpG and PrhG positively regulate hrpB expression in parallel ways. Deletion of RSc0454 substantially reduced expression levels of hrpB and T3SS both in vitro and in planta. Moreover, RSc0454 is revealed to be required for the T3SS expression via HrpG and PrhG, but through novel pathway, and impaired expression of these genes was not due to growth deficiency of RSc0454 mutants. RSc0454 is suggested to be important for redox balance inside cells and supplementary NADH partially restored diminished growth of RSc0454 mutant in minimal medium at presence of succinate at some moderate concentrations, indicating that unbalanced redox in RSc0454 mutant might be responsible for its no growth in minimal medium. All taken together, these results provide novel insights into understanding of various biological functions of this FAD-linked oxidase RSc0454 and involvement of the redox balance on expression of the T3SS in R. solanacearum.


Author(s):  
Priyanka Singh ◽  
Yamshi Arif ◽  
Andrzej Bajguz ◽  
Shamsul Hayat

Flavonoids are a special category of hydroxylated phenolic compounds having an aromatic ring structure. Quercetin is a special subclass of flavonoid. It is a bioactive natural compound built upon the flavon structure nC6(ring A)-C3(ring C)-C6(ring B). Quercetin facilitates several plant physiological processes, such as seed germination, pollen growth, antioxidant machinery, and photosynthesis, as well as induces proper plant growth and development. Quercetin is a powerful antioxidant, so it potently provides plant tolerance against several biotic and abiotic stresses. This review highlights quercetin’s role in increasing several physiological and biochemical processes in under stress and non-stress environments. Additionally, this review briefly assesses quercetin’s role in mitigating biotic and abiotic stresses (e.g., salt, heavy metal, and UV stress). The biosynthesis of flavonoids, their signaling pathways, and quercetin’s role in plant signaling are also discussed.


Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 626
Author(s):  
Tinashe Zenda ◽  
Songtao Liu ◽  
Anyi Dong ◽  
Huijun Duan

Sulphur plays crucial roles in plant growth and development, with its functions ranging from being a structural constituent of macro-biomolecules to modulating several physiological processes and tolerance to abiotic stresses. In spite of these numerous sulphur roles being well acknowledged, agriculture has paid scant regard for sulphur nutrition, until only recently. Serious problems related to soil sulphur deficiencies have emerged and the intensification of food, fiber, and animal production is escalating to feed the ever-increasing human population. In the wake of huge demand for high quality cereal and vegetable diets, sulphur can play a key role in augmenting the production, productivity, and quality of crops. Additionally, in light of the emerging problems of soil fertility exhaustion and climate change-exacerbated environmental stresses, sulphur assumes special importance in crop production, particularly under intensively cropped areas. Here, citing several relevant examples, we highlight, in addition to its plant biological and metabolism functions, how sulphur can significantly enhance crop productivity and quality, as well as acclimation to abiotic stresses. By this appraisal, we also aim to stimulate readers interests in crop sulphur research by providing priorities for future pursuance, including bettering our understanding of the molecular processes and dynamics of sulphur availability and utilization in plants, dissecting the role of soil rhizospherical microbes in plant sulphur transformations, enhancing plant phenotyping and diagnosis for nutrient deficiencies, and matching site-specific crop sulphur demands with fertilizer amendments in order to reduce nutrient use inefficiencies in both crop and livestock production systems. This will facilitate the proper utilization of sulphur in crop production and eventually enhance sustainable and environmentally friend food production.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dan Jiang ◽  
Bin Lu ◽  
Liantao Liu ◽  
Wenjing Duan ◽  
Yanjun Meng ◽  
...  

Abstract Background As damage to the ecological environment continues to increase amid unreasonable amounts of irrigation, soil salinization has become a major challenge to agricultural development. Melatonin (MT) is a pleiotropic signal molecule and indole hormone, which alleviates the damage of abiotic stress to plants. MT has been confirmed to eliminate reactive oxygen species (ROS) by improving the antioxidant system and reducing oxidative damage under adversity. However, the mechanism by which exogenous MT mediates salt tolerance by regulating the photosynthetic capacity and ion balance of cotton seedlings still remains unknown. In this study, the regulatory effects of MT on the photosynthetic system, osmotic modulators, chloroplast, and anatomical structure of cotton seedlings were determined under 0–500 μM MT treatments with salt stress induced by treatment with 150 mM NaCl. Results Salt stress reduces the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, PSII photochemical efficiency, PSII actual photochemical quantum yield, the apparent electron transfer efficiency, stomata opening, and biomass. In addition, it increases non-photochemical quenching. All of these responses were effectively alleviated by exogenous treatment with MT. Exogenous MT reduces oxidative damage and lipid peroxidation by reducing salt-induced ROS and protects the plasma membrane from oxidative toxicity. MT also reduces the osmotic pressure by reducing the salt-induced accumulation of Na+ and increasing the contents of K+ and proline. Exogenous MT can facilitate stomatal opening and protect the integrity of cotton chloroplast grana lamella structure and mitochondria under salt stress, protect the photosynthetic system of plants, and improve their biomass. An anatomical analysis of leaves and stems showed that MT can improve xylem and phloem and other properties and aides in the transportation of water, inorganic salts, and organic substances. Therefore, the application of MT attenuates salt-induced stress damage to plants. Treatment with exogenous MT positively increased the salt tolerance of cotton seedlings by improving their photosynthetic capacity, stomatal characteristics, ion balance, osmotic substance biosynthetic pathways, and chloroplast and anatomical structures (xylem vessels and phloem vessels). Conclusions Our study attributes help to protect the structural stability of photosynthetic organs and increase the amount of material accumulation, thereby reducing salt-induced secondary stress. The mechanisms of MT-induced plant tolerance to salt stress provide a theoretical basis for the use of MT to alleviate salt stress caused by unreasonable irrigation, fertilization, and climate change.


2015 ◽  
Vol 2015 ◽  
pp. 1-17 ◽  
Author(s):  
Aditya Banerjee ◽  
Aryadeep Roychoudhury

WRKY proteins are emerging players in plant signaling and have been thoroughly reported to play important roles in plants under biotic stress like pathogen attack. However, recent advances in this field do reveal the enormous significance of these proteins in eliciting responses induced by abiotic stresses. WRKY proteins act as major transcription factors, either as positive or negative regulators. Specific WRKY factors which help in the expression of a cluster of stress-responsive genes are being targeted and genetically modified to induce improved abiotic stress tolerance in plants. The knowledge regarding the signaling cascade leading to the activation of the WRKY proteins, their interaction with other proteins of the signaling pathway, and the downstream genes activated by them are altogether vital for justified targeting of theWRKYgenes. WRKY proteins have also been considered to generate tolerance against multiple abiotic stresses with possible roles in mediating a cross talk between abiotic and biotic stress responses. In this review, we have reckoned the diverse signaling pattern and biological functions of WRKY proteins throughout the plant kingdom along with the growing prospects in this field of research.


2022 ◽  
Vol 23 (2) ◽  
pp. 702
Author(s):  
Shuya Tan ◽  
Jie Cao ◽  
Xinli Xia ◽  
Zhonghai Li

Priming is an adaptive strategy that improves plant defenses against biotic and abiotic stresses. Stimuli from chemicals, abiotic cues, and pathogens can trigger the establishment of priming state. Priming with 5-aminolevulinic acid (ALA), a potential plant growth regulator, can enhance plant tolerance to the subsequent abiotic stresses, including salinity, drought, heat, cold, and UV-B. However, the molecular mechanisms underlying the remarkable effects of ALA priming on plant physiology remain to be elucidated. Here, we summarize recent progress made in the stress tolerance conferred by ALA priming in plants and provide the underlying molecular and physiology mechanisms of this phenomenon. Priming with ALA results in changes at the physiological, transcriptional, metabolic, and epigenetic levels, and enhances photosynthesis and antioxidant capacity, as well as nitrogen assimilation, which in turn increases the resistance of abiotic stresses. However, the signaling pathway of ALA, including receptors as well as key components, is currently unknown, which hinders the deeper understanding of the defense priming caused by ALA. In the future, there is an urgent need to reveal the molecular mechanisms by which ALA regulates plant development and enhances plant defense with the help of forward genetics, multi-omics technologies, as well as genome editing technology.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vishakha Chauhan ◽  
Mahim Sagar

Purpose The purpose of this paper is to systematically review and analyse extant marketing literature on consumer confusion to propose an integrated conceptual framework and highlight important research gaps. Design/methodology/approach Systematic literature review methodology was followed for article selection. Selected articles were subjected to content analysis to derive thematic as well as descriptive results. Findings Antecedents, consequences, moderators, mediators and application of the construct in the different contexts have been reported. An integrated framework along with research questions and future directions has also been proposed. Originality/value To the best of the authors’ knowledge, this study is notably the first attempt to systematically review the marketing literature on consumer confusion. The conceptual framework and proposed research questions create a research agenda around the problem of consumer confusion and contribute towards the advancement of extant literature.


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