scholarly journals Instinctive Plant Tolerance Towards Abiotic Stresses in Arid Regions

10.5772/26273 ◽  
2012 ◽  
Author(s):  
Mohamed Mohamed
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 ◽  
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.


2018 ◽  
Vol 19 (11) ◽  
pp. 3681 ◽  
Author(s):  
Alia Anwar ◽  
Maoyun She ◽  
Ke Wang ◽  
Bisma Riaz ◽  
Xingguo Ye

Plant tolerance to biotic and abiotic stresses is complicated by interactions between different stresses. Maintaining crop yield under abiotic stresses is the most daunting challenge for breeding resilient crop varieties. In response to environmental stresses, plants produce several metabolites, such as proline (Pro), polyamines (PAs), asparagine, serine, carbohydrates including glucose and fructose, and pools of antioxidant reactive oxygen species. Among these metabolites, Pro has long been known to accumulate in cells and to be closely related to drought, salt, and pathogen resistance. Pyrroline-5-carboxylate (P5C) is a common intermediate of Pro synthesis and metabolism that is produced by ornithine aminotransferase (OAT), an enzyme that functions in an alternative Pro metabolic pathway in the mitochondria under stress conditions. OAT is highly conserved and, to date, has been found in all prokaryotic and eukaryotic organisms. In addition, ornithine (Orn) and arginine (Arg) are both precursors of PAs, which confer plant resistance to drought and salt stresses. OAT is localized in the cytosol in prokaryotes and fungi, while OAT is localized in the mitochondria in higher plants. We have comprehensively reviewed the research on Orn, Arg, and Pro metabolism in plants, as all these compounds allow plants to tolerate different kinds of stresses.


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.


2020 ◽  
Author(s):  
Chong Yang ◽  
Juanjuan Li ◽  
Faisal Islam ◽  
Luyang Hu ◽  
Jiansu Wang ◽  
...  

Abstract Background: WRKY transcription factors play important roles in various physiological processes and stress responses in flowering plants. However, the information about WRKY genes in Helianthus annuus L. (common sunflower) is limited. Results: Ninety WRKY (HaWRKY) genes were identified and renamed according to their locations on chromosomes. Further phylogenetic analyses classified them into four main groups including a species-specific WKKY group and HaWRKY genes within same group or subgroup generally showed similar exon-intron structures and motif compositions. The tandem and segmental duplication possibly contributed to the diversity and expansion of HaWRKY gene families. Synteny analyses of sunflower WRKY genes provided deep insight to the evolution of HaWRKY genes. Transcriptomic and qRT-PCR analyses of HaWRKY genes displayed distinct expression patterns in different plant tissues, as well as under various abiotic and biotic stresses. Conclusions: Ninety WRKY (HaWRKY) genes were identified from H. annuus L. and classified into four groups. Structures of HaWRKY proteins and their evolutionary characteristics were also investigated. The characterization of HaWRKY genes and their expression profiles under biotic and abiotic stresses in this study provide a foundation for further functional analyses of these genes. Therefore, these functional genes related to increasing the plant tolerance or improving the crop quality, could be applied for the crop improvement..


2021 ◽  
Vol 12 ◽  
Author(s):  
Li Jiang ◽  
Chaowen She ◽  
Changyan Tian ◽  
Mohsin Tanveer ◽  
Lei Wang

On degraded land in arid regions, cultivation of Apocynum species can provide significant environmental benefits by preventing soil erosion and desertification. Furthermore, Apocynum venetum and Apocynum pictum, which are mainly distributed in salt-barren lands in the northwestern region of China, are traditionally used to produce natural fiber and herbal tea. Direct sowing of both species may encounter various abiotic stresses such as drought and salinity. However, these effects on germination remain largely unknown, especially for seeds with different storage periods. The aim of this study was to evaluate the effects of storage period, light condition, temperature regime, drought, and salinity on germination performances of both species. Germination experiment was carried out in November 2017. There were four replicates for each treatment, and each petri dish contained 25 seeds. The results indicated that prolongation of storage period significantly decreased the germination percentage and velocity, especially under abiotic stresses. Light did not affect seed germination of A. venetum and A. pictum under any conditions. Seeds had better germination performance at 10/25 and 15/30°C than those of seeds incubated at any other temperatures. With the increase of polyethylene glycol (PEG) and salinity concentrations, seed germination for both species gradually decreased, especially for seeds stored for 2 years. Low PEG (0–20%) and salinity concentration (0–200 mM) did not significantly affect germination percentage of freshly matured seeds. However, long-time storage significantly decreased drought and salinity tolerance in A. venetum and A. pictum during germination stage. For saline soils in arid and semi-arid regions, freshly matured seeds or 1-year-stored seeds of both Apocynum species are recommended to be sown by using drip-irrigation in spring.


2020 ◽  
Vol 5 (6) ◽  
Author(s):  
Waleed Fouad Abobatta

Plant stimulants is an organic substance and micro-organisms, used by small quantities, Biostimulants categorize according to their nature, modes of action, and types of effects on crops, there are main groups of plant stimulants include Protein hydrolysates, Humate substances, Seaweed extracts, Biopolymers (Chitosan and other polymers), and Microbial biostimulants like mycorrhizal, non-mycorrhizal fungi, Rhizobium, and Trichoderma. Horticulture crop production facing several challenges particularly abiotic stresses and malnutrition resulting in yield loss and affects negatively fruit quality. The main effects of plant stimulants due to its working as the auxin-like effect, enhancing Nitrogen uptake, and stimulate plant growth. There is various stimulation effects on horticulture crops including promote plant growth, increase plant tolerance for biotic and abiotic stresses. Applying plant stimulants to plants or the rhizosphere stimulating plant metabolic processes, increase the efficiency of the nutrients, and increase plant tolerance to abiotic stress, consequently, improving plant growth increases yield, and enhancing fruit quality.


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.


2019 ◽  
Vol 11 (2) ◽  
pp. 167-174
Author(s):  
Francisca I. OKUNGBOWA ◽  
Hakeem O. SHITTU ◽  
Henry O. OBIAZIKWOR

An endophyte is a microorganism, usually bacterium or fungus, which lives within the internal tissue of a host plant, causing no apparent harm. Some characteristics of an endophyte include ability to promote plant growth and to confer plant tolerance to biotic and abiotic stresses. Endophytic bacteria spread across many phyla including the Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. Endophytic bacteria are recruited by hosts and they get attached to the surface and eventually find their way into the internal tissues where they spread to the intercellular spaces of host plants. These bacteria have been isolated and characterized from different plants. Currently, culture-independent methods such as sequencing of the 16S rRNA gene or metalogenomics are used for identification and characterization of endophytes. The mechanisms by which the endophyte-induced plant protection is brought about can be through direct and/or indirect methods. The direct strategy antagonizes phytopathogens by the production of chemical substances while the indirect mechanisms improve resistance of hosts to pathogens. Global gene expression studies on some common endophytic bacteria implicated these direct and indirect strategies of bacterial-induced protection. More research should be geared towards how the economic importance of endophytic bacteria could be utilized to enhance global food security.


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