Drought and heat stress mediated activation of lipid signaling in plants: a critical review

Lipids are a principal component of plasma membrane, acting as a protective barrier between the cell and its surroundings. Abiotic stresses such as drought and temperature induce various lipid-dependent signaling responses, and the membrane lipids respond differently to environmental challenges. Recent studies have revealed that lipids serve as signal mediators forreducing stress responses in plant cells and activating defense systems. Signaling lipids, such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, and N-acylethanolamines, are generated in response to stress. Membrane lipids are essential for maintaining the lamellar stack of chloroplasts and stabilizing chloroplast membranes under stress. However, the effects of lipid signaling targets in plants are not fully understood. This review focuses on the synthesis of various signaling lipids and their roles in abiotic stress tolerance responses, providing an essential perspective for further investigation into the interactions between plant lipids and abiotic stress

<span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Growth response modulation by putrescine in Indian mustard <i style="mso-bidi-font-style:normal">Brassica juncea</i> L. under multiple stress</span>

262-270Plants, in general, are put to various kinds of stress, biotic and abiotic, both natural and manmade. Infestation by insect pests and diseases, and extreme conditions such as salinity, temperature, etc., as well as heavy metal contamination affect their growth performance. Here, we studied the impact of salinity and heavy metal pollution on the growth performance of Indian Mustard Brassica juncea L. and its amelioration by the diamine, putrescine, a known media supplement. We evaluated the putrescine (Put) modulation potential on multiple stress effect in 7-day old Indian mustard. The germination, seedlings length and photosynthetic pigments decline under salinity and metal (Cd/Pb) stress condition, alone or in combination, were checked by putrescine. The stress induced increase in root-shoot ratio, RNA and total amino acids content, as well as Na+/K+ ratio in leaf tissues were also comparatively less. The increased endogenous Cd/Pb accumulation in plants exposed to either metal further elevated under salinity was also found decelerated. However, the multiple stressed seedlings showed increase in glutathione content, which was further elevated with putrescine application. The increase in protein contents in leaf under single or combined stresses in the presence of putrescine could be a qualitative change. The differential changes in parameters examined here resulted in improved growth (>10%) suggests stress mitigation by the putrescine up to an extent

Effect of cadaverine on <i style="mso-bidi-font-style: normal">Brassica juncea</i> (L.) under multiple stress

758-763The cadaverine (Cad), an organic diamine was examined for its response on growth in salinity and metal stressed B. juncea cv RH-30 vis-à-vis compared the response of ammonium nitrate. The Cad (1 mM) application ameliorated the effect caused by salinity and metal stress on seed germination and plant growth. The plant growth recovery (dry biomass accumulation) was dependent on stress and diamine type. The higher growth recovery potential of Cad under both stresses was due to elevation in photosynthetic pigments, nitrate reductase activity and organic nitrogen as well as soluble protein, It is inferred that growth in stressed seedlings was mediated by Cad through lowering endogenous Cd/Pb and Na+/K+ level in leaf and shoot tissues

Mapping the ‘early salinity response’ triggered proteome adaptation in contrasting rice genotypes using iTRAQ approach

Abstract Background To delineate the adaptive mechanisms operative under salinity stress, it is essential to study plant responses at the very early stages of stress which are very crucial for governing plant survival and adaptation. We believe that it is the initial perception and response phase which sets the foundation for stress adaptation in rice seedlings where plants can be considered to be in a state of osmotic shock and ion buildup. Results An isobaric Tags for Relative and Absolute Quantitation (iTRAQ) approach was used to analyze the pre-existing differences as well as the very early salt shock responsive changes in the proteome of seedlings of contrasting rice genotypes, viz salt-sensitive IR64 and salt-tolerant Pokkali. In response to a quick salt shock, shoots of IR64 exhibited hyperaccumulation of Na+, whereas in Pokkali, these ions accumulated more in roots. Interestingly, we could find 86 proteins to be differentially expressed in shoots of Pokkali seedlings under non-stress conditions whereas under stress, 63 proteins were differentially expressed in Pokkali shoots in comparison to IR64. However, only, 40 proteins under non-stress and eight proteins under stress were differentially expressed in Pokkali roots. A higher abundance of proteins involved in photosynthesis (such as, oxygen evolving enhancer proteins OEE1 & OEE3, PsbP) and stress tolerance (such as, ascorbate peroxidase, superoxide dismutase, peptidyl-prolyl cis-trans isomerases and glyoxalase II), was observed in shoots of Pokkali in comparison to IR64. In response to salinity, selected proteins such as, ribulose bisphosphate carboxylase/oxygenase activase, remained elevated in Pokkali shoots. Glutamate dehydrogenase - an enzyme which serves as an important link between Krebs cycle and metabolism of amino acids was found to be highly induced in Pokkali in response to stress. Similarly, other enzymes such as peroxidases and triose phosphate isomerase (TPI) were also altered in roots in response to stress. Conclusion We conclude that Pokkali rice seedlings are primed to face stress conditions where the proteins otherwise induced under stress in IR64, are naturally expressed in high abundance. Through specific alterations in its proteome, this proactive stress machinery contributes towards the observed salinity tolerance in this wild rice germplasm

Drought and heat stress mediated activation of lipid signaling in plants: a critical review

Lipids are a principal component of plasma membrane, acting as a protective barrier between the cell and its surroundings. Abiotic stresses such as drought and temperature induce various lipid-dependent signaling responses, and the membrane lipids respond differently to environmental challenges. Recent studies have revealed that lipids serve as signal mediators forreducing stress responses in plant cells and activating defense systems. Signaling lipids, such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, and N-acylethanolamines, are generated in response to stress. Membrane lipids are essential for maintaining the lamellar stack of chloroplasts and stabilizing chloroplast membranes under stress. However, the effects of lipid signaling targets in plants are not fully understood. This review focuses on the synthesis of various signaling lipids and their roles in abiotic stress tolerance responses, providing an essential perspective for further investigation into the interactions between plant lipids and abiotic stress

Putrescine Mitigates High Temperature Effects by Modulating Morpho-Physiological and Biochemical Attributes in Brassica juncea Seedlings

A variety of environmental issues are affecting crops all across the world, but rising temperatures are posing the greatest threat. High temperature has been found to drastically inhibit seedling emergence and cause leaf necrosis at the seedling stage, which results in poor plant stand and significantly decreased yields. Polyamines (PAs) are positively charged, low-molecular-weight aliphatic nitrogenous bases present in all living organisms and are involved in various biological processes in plant growth and development, including senescence and response to different abiotic stresses. Putrescine (Put) functions as a master growth regulator that promotes optimal plant development and greater stress tolerance. Here, the current study aimed to elucidate how Put (1 mM) functions in reducing the negative impacts of high temperature on four varieties of Brassica juncea (RH-1707, RH-1708, RH-1566 and RH-1999-42). Exposure of plants to high temperature resulted in decrease in growth parameters, chlorophyll content and relative water content. Simultaneously, increases were found in antioxidant enzymes, electrolyte leakage, lipid peroxidation, hydrogen peroxide content and stomatal density. High temperature more significantly affected varieties RH-1707 and RH-1708, while RH-1566 and RH-1999-42 showed lesser effects. Exogenous application of Put mitigated the negative impacts of high temperature by enhancing growth, chlorophyll content, relative water content and antioxidant enzyme activities and, simultaneously, it reduces oxidative damage and stomatal density. This study specifies that varieties RH-1707 and RH-1708 are sensitive whereas RH-1566 and RH-1999-42 are tolerant of high temperature and provides an insight into the effectiveness of Put in mitigating the effects of high temperature to a significant extent in B. juncea seedlings

Drought-Induced Morpho-Physiological, Biochemical, Metabolite Responses and Protein Profiling of Chickpea (Cicer arietinum L.)

The chickpea (Cicer arieitnum L.) is an important food legume crop of the family Fabaceae with high protein levels that is widely grown in rainfed areas prone to drought stress. It is a self-pollinated cool season crop with a true diploid (2n = 16) nature. It is relatively cheap and a high source of protein. About 90% of the chickpea crop is grown by the use of residual moisture in the soil without depending on irrigation. In the present study, two varieties of chickpea, namely ICC 4958 and HC-6, were grown under three field capacities (FC) (100% FC, 50% FC and 25% FC). Samples were taken three times, i.e., 15, 30 and 45 days after sowing (DAS). Parameters such as morphological, physiological, biochemical, metabolite and protein profiling of the two varieties were completed. Morphological parameters such as shoot length (14.2%), number of branches (20.7%), number of leaves (17.5%) and yield (56%) declined as the drought level increased and other characteristics such as root length (9.7%), number of flowers (24.5%) and number of pods (34.4%) increased as drought stress progressed. Physiological parameters such as relative water content (RWC) (13.5%), cell membrane stability (CMS) (29.6%) and chlorophyll content decreased, whereas electrolyte conductivity (EC) (38%) increased in both the varieties as field capacity decreased. Biochemical parameters such as proline (54.75%), sugar (15.2%), glycine betaine (32.25%), superoxide dismutase (SOD) (49.5%), catalase (CAT) (50.5%), ascorbate peroxidase (APX) (44.9%) and glutathione reductase (GR) (49%) increased as drought stress increased. Metabolite analyses of, for example, MDA (malondialdehyde) content (30.5%), total anthocyanin (36.3%), flavonoid content (26%) and phenolic content (29.5%) increased as drought progressed. We also performed protein profiling of the two varieties using SDS-PAGE (sodium dodecyl-sulfate polyacrylamide gel electrophoresis) to differentiate the expression analysis of the two varieties

Genetic Analysis for Resistance to Sclerotinia Stem Rot, Yield and Its Component Traits in Indian Mustard [<i>Brassica juncea</i> (L.) Czern & Coss.]

Understanding the mode of gene action that controls seed yield and Sclerotinia stem rot resistance in Indian mustard is critical for boosting yield potential. In a line × tester mating design, ten susceptible lines and four resistant testers were used to conduct genetic analysis. The significance of general combining ability (GCA) and specific combining ability (SCA) variances revealed that both additive and non-additive gene actions were involved in the inheritance of Sclerotinia stem rot resistance and yield attributing traits. In addition to 1000-seed weight and number of primary and secondary branches/plant, the genotypes RH 1569 (line) and DRMR 2035 (tester) appeared to be the strongest general combiners for Sclerotinia stem rot resistance. RH 1657 × EC 597317 was the only cross among several that demonstrated a significant desired SCA value for Sclerotinia rot resistance. Regarding SCA effects for yield and component traits, the cross RH 1658 × EC 597328 performed best, with a non-significant but acceptable negative SCA effect for resistance. DRMR 2035, RH 1222-28, RH 1569, RH 1599-41, RH 1657, RH 1658, and EC 597328 are promising genotypes to use as parents in future heterosis breeding and for obtaining populations with high yield potential and greater resistance to Sclerotinia stem rot disease in Indian mustard, based on GCA effects of parents, per se performance, and SCA effects of hybrids. Days to 50% flowering, number of primary branches/plant, main shoot length, and 1000-seed weight all had a high genotypic coefficient of variability (GCV), broad-sense heritability (h2bs), and genetic advance as percent of the mean (GAM) values, as well as significant and desirable correlations and direct effects on seed yield. As a result, these traits have been recognized as the most critical selection criterion for Indian mustard breeding programs