Abiotic stress is the major threat confronted by modern-day agriculture. Salinity is one of the major abiotic stresses that influence geographical distribution, survival, and productivity of various crops across the globe. Plants perceive salt stress cues and communicate specific signals, which lead to the initiation of defence response against it. Stress signalling involves the transporters, which are critical for water transport and ion homeostasis. Various cytoplasmic components like calcium and kinases are critical for any type of signalling within the cell which elicits molecular responses. Stress signalling instils regulatory proteins and transcription factors (TFs), which induce stress-responsive genes. In this review, we discuss the role of ion transporters, protein kinases, and TFs in plants to overcome the salt stress. Understanding stress responses by components collectively will enhance our ability in understanding the underlying mechanism, which could be utilized for crop improvement strategies for achieving food security.

No abstract

Plants being sessile are always exposed to various environmental stresses, and to overcome these stresses, modifications at the epigenetic level can prove vital for their long-term survival. Epigenomics refers to the large-scale study of epigenetic marks on the genome, which include covalent modifications of histone tails (acetylation, methylation, phosphorylation, ubiquitination, and the small RNA machinery). Studies based on epigenetics have evolved over the years especially in understanding the mechanisms at transcriptional and posttranscriptional levels in plants against various environmental stimuli. Epigenomic changes in plants through induced methylation of specific genes that lead to changes in their expression can help to overcome various stress conditions. Recent studies suggested that epigenomics has a significant potential for crop improvement in plants. By the induction and modulation of various cellular processes like DNA methylation, histone modification, and biogenesis of noncoding RNAs, the plant genome can be activated which can help in achieving a quicker response against various plant stresses. Epigenetic modifications in plants allow them to adjust under varied environmental stresses by modulating their phenotypic plasticity and at the same time ensure the quality and yield of crops. The plasticity of the epigenome helps to adapt the plants during pre- and postdevelopmental processes. The variation in DNA methylation in different organisms exhibits variable phenotypic responses. The epigenetic changes also occur sequentially in the genome. Various studies indicated that environmentally stimulated epimutations produce variable responses especially in differentially methylated regions (DMR) that play a major role in the management of stress conditions in plants. Besides, it has been observed that environmental stresses cause specific changes in the epigenome that are closely associated with phenotypic modifications. However, the relationship between epigenetic modifications and phenotypic plasticity is still debatable. In this review, we will be discussing the role of various factors that allow epigenetic changes to modulate phenotypic plasticity against various abiotic stress in plants.

Environmental variations caused by global climate change significantly affect plant yield and productivity. Because water scarcity is one of the most significant risks to agriculture’s future, improving the performance of plants to cope with water stress is critical. Our research scrutinized the impact of melatonin application on the photosynthetic machinery, photosynthetic physiology, root system, osmoprotectant accumulation, and oxidative stress in tomato plants during drought. The results showed that melatonin-treated tomato plants had remarkably higher water levels, gas exchange activities, root system morphological parameters (average diameter, root activity, root forks, projected area, root crossings, root volume, root surface area, root length, root tips, and root numbers), osmoprotectant (proline, trehalose, fructose, sucrose, and GB) accumulation, and transcript levels of the photosynthetic genes SlPsb28, SlPetF, SlPsbP, SlPsbQ, SlPetE, and SlPsbW. In addition, melatonin effectively maintained the plants’ photosynthetic physiology. Moreover, melatonin treatment maintained the soluble protein content and antioxidant capacity during drought. Melatonin application also resulted in membrane stability, evidenced by less electrolyte leakage and lower H2O2, MDA, and O2− levels in the drought-stress environment. Additionally, melatonin application enhanced the antioxidant defense enzymes and antioxidant-stress-resistance-related gene (SlCAT1, SlAPX, SlGR, SlDHAR, SlPOD, and SOD) transcript levels in plants. These outcomes imply that the impacts of melatonin treatment on improving drought resistance could be ascribed to the mitigation of photosynthetic function inhibition, the enhancement of the water status, and the alleviation of oxidative stress in tomato plants. Our study findings reveal new and incredible aspects of the response of melatonin-treated tomato plants to drought stress and provide a list of candidate targets for increasing plant tolerance to the drought-stress environment.

No abstract

No abstract

Millets hold an immense assurance for food safety and nourishment amid ever-rising agricultural expenses and climate alterations. They are healthful, have supplementary wellbeing profit and need remarkably fewer effort overheads for crop growing. These characters draw attention to millets as a plant of preference for the humankind in the course of emergent alarm about environmental changes. Millets have the prospect to provide biomass and thus bioenergy, reduced carbon emission, carbon footprint and sustainable modern agriculture. As the rate of expansion in budding countries is increasing day by day, the scarcity of energy is a big panic and there is a mounting turn in the direction and rehearsal of waste and biomass as an energy source. Globally, at least 20% of total irrigated land has been injured by salt and 1.5 million hectares is taken away of cultivation every year. Thus, in future, we will have a requirement of efficient crops and utilisation of marginal lands for agriculture. Millet is an answer to the efficient crop. Plants are subjected to various environmental pressures (high/low temperature, heavy metal, salinity, pesticides, etc.) as well as biotic stresses (virus, bacteria, fungi, etc.) and millets are not an exception to it. Millets are categorised as glycophytes and can tolerate average salt threshold of about 6 (EC e ) (dS/m) with some variation from specie to specie. Increase in the salt concentrations can lead to retarded growth and development, thus need for mitigants arise to reduce such stresses. Some mitigants to overcome the stress levels include proline, polyamine and betaines, Na 2 SeO 3 , H 2 S, KNO 3 , Mg(NO 3 ) 2 , etc.

Pea is an important legume crop because of its higher bioactive compounds, and its seeds are famous as functional foods. However, the yield of pea is still limited because of multiple biotic and abiotic stresses which prevailed during the growth period. Saline conditions significantly hamper pea growth, yield, and quality among abiotic stresses. Salicylic acid is effective for the activation of oxidative, non-oxidative, osmolytes, and metabolites. Hence, the present study was conducted at exogenous application of salicylic acid (control, 1 µM, 2 µM, and 3 µM) to mitigate the adverse effects of salt stress (control, 25 mM, 50 mM, and 100 mM NaCl) in pea plants grown in the year 2019–2020. The aim of the present study was to evaluate pea performance under saline conditions by salicylic acid sprays. Pea growth and yield were significantly decreased at 100 mM NaCl compared with the control and other salinity levels. Moreover, the growth and yield of pea were improved under exogenous application of salicylic acid treatment at 3 µM than others. Quality traits, i.e., carotenoids, ascorbic acid, and phenolic content, were decreased at 100 mM NaCl, and these quality traits were significantly improved under salicylic acid treatment of 3 µM. Chlorophyll a, chlorophyll b, total chlorophyll, photosynthesis, and stomatal conductance were reduced at 100 mM NaCl. In contrast, photosynthetic pigments, photosynthesis, and stomatal conductance were enhanced at 3 µM salicylic acid. The increases in SOD, CAT, POD, and APX were observed at 100 mM NaCl and 3 µM salicylic acid. The current study proved that exogenous application of salicylic acid concentrations had the potential to mitigate the salinity’s adverse effects by maintaining the physiological and metabolic activities of pea plants.