Salt and Drought Stress Signal Transduction in Plants
Salt and drought stress signal transduction consists of ionic and osmotic homeostasis signaling pathways, detoxification (i.e., control and repair) response pathways, and pathways for growth regulation. The ionic aspect of salt stress is signaled via the SOS pathway where a calcium-responsive SOS3-SOS2 protein kinase complex controls the expression and activity of ion transporters like SOS1. Osmotic stress activates several protein kinases including mitogen-activated kinases, which can mediate osmotic homeostasis and/or detoxification responses. variety of phospholipid systems are activated by osmotic stress, generating a various array of messenger molecules, a number of which can function upstream of the osmotic stress–activated protein kinases. Abscisic acid biosynthesis is regulated by osmotic stress at multiple steps. Both ABA-dependent and -independent osmotic stress signaling first modify constitutively expressed transcription factors, resulting in the expression of early response transcriptional activators, which then activate downstream stress tolerance effector genes. [1]
Gene networks involved in drought stress response and tolerance
Plants answer survive under water-deficit conditions via a series of physiological, cellular, and molecular processes culminating in stress tolerance. Many drought-inducible genes with various functions are identified by molecular and genomic analyses in Arabidopsis, rice, and other plants, including variety of transcription factors that regulate stress-inducible organic phenomenon . The products of stress-inducible genes function both within the initial stress response and in establishing plant stress tolerance. during this short review, recent progress resulting from analysis of organic phenomenon during the drought-stress response in plants also as in elucidating the functions of genes implicated within the stress response and/or stress tolerance are summarized. an outline is additionally provided of how various genes involved in stress tolerance were applied in gene-splicing of dehydration stress tolerance in transgenic Arabidopsis plants. [2]
Regulatory metabolic networks in drought stress responses
Plants must adapt to drought stress to survive. The phytohormone abscisic acid (ABA) is produced under drought stress conditions and is important for the response to drought stress. The ABA level plays a crucial role within the response, and a number of other enzymes for ABA biosynthesis and catabolism are identified. Physiological studies have shown that several metabolites accumulate and performance as osmolytes under drought stress conditions. Many drought-inducible genes with various functions are identified, and transgenic plants that harbor these genes have shown increased tolerance to drought. [3]
Poly-γ-glutamic acid induces system tolerance to drought stress by promoting abscisic acid accumulation in Brassica napus L.
As a replacement plant biostimulant, poly-γ-glutamic acid (γ-PGA) could also be an efficient anti-drought agent which will efficiently alleviate the damage to plants under drought stress. during this study, the consequences of γ-PGA on the physiological responses of oilseed rape (Brassica napus L.) seedlings under drought stress were investigated using hydroponics. Growth and development of the rape seedlings were significantly inhibited during a polyethylene glycol-simulated drought environment. However, 12 d after application of γ-PGA under drought stress, the fresh weight, chlorophyll content, and relative water content of rape seedlings all markedly increased. Moreover, proline content and antioxidant enzyme activity were all markedly enhanced, and therefore the malondialdehyde content was significantly reduced in rape seedlings treated with γ-PGA. [4]
Genetic Parameters and Stress Tolerance Index for Quantitative Traits in Barley under Different Drought Stress Severities
To determine genetic parameters and drought resistance in barley, an experiment was conducted at Kafr El-Hamam Agricultural Research Station in Zagazig, El-Sharqiyah Governorate, Egypt. The fourteen and two checks genotypes were evaluated under a various set of conditions that ranged from non-stress condition to conditions with moderate to severe. The analysis of variance displayed that yield, and other studied traits were significantly suffering from seasons and genotypes. [5]
Reference
[1] Zhu, J.K., 2002. Salt and drought stress signal transduction in plants. Annual review of plant biology, 53(1), (Web Link)
[2] Shinozaki, K. and Yamaguchi-Shinozaki, K., 2007. Gene networks involved in drought stress response and tolerance. Journal of experimental botany, 58(2), (Web Link)
[3] Seki, M., Umezawa, T., Urano, K. and Shinozaki, K., 2007. Regulatory metabolic networks in drought stress responses. Current opinion in plant biology, 10(3), (Web Link)
[4] Poly-γ-glutamic acid induces system tolerance to drought stress by promoting abscisic acid accumulation in Brassica napus L.
Zongqi Xu, Junjie Ma, Peng Lei, Qian Wang, Xiaohai Feng & Hong Xu
Scientific Reports volume 10, (Web Link)
[5] F. El-Hashash, E. and M. Agwa, A. (2018) “Genetic Parameters and Stress Tolerance Index for Quantitative Traits in Barley under Different Drought Stress Severities”, Asian Journal of Research in Crop Science, 1(1), (Web Link)
