Search

Rice is the staple food for more than 3.5 billion people worldwide. The sensitivity of rice to heat, drought, and salinity is well documented. However, rice response to combinations of these stresses is not well understood. A contrasting set of rice genotypes for heat (N22, Gharib), drought (Moroberekan, Pusa 1121) and salinity (Pokkali, IR64) were selected to characterize their response under drought, and combination of drought with heat and salinity at the sensitive seedling stage. Sensitive genotypes (IR64, Pusa 1121, Gharib) recorded higher reactive oxygen species accumulation (20–40%), membrane damage (8–65%) and reduction in photosynthetic efficiency (10–23%) across the stress and stress combinations as compared to stress tolerant checks. On the contrary, N22 and Pokkali performed best under drought + heat, and drought + salinity combination, respectively. Moreover, gene expression pattern revealed the highest expression of catalase (CAT), ascorbate peroxidase (APX) and GATA28a in N22 under heat + drought, whereas the highest expression of CAT, APX, superoxide dismutase (SOD), DEHYDRIN, GATA28a and GATA28b in Pokkali under drought + salinity. Interestingly, the phenotypic variation and expression level of genes highlighted the role of different set of physiological traits and genes under drought and drought combination with heat and salinity stress. This study reveals that rice response to stress combinations was unique with rapid readjustment at physiological and molecular levels. Moreover, phenotypic changes under stress combinations showed substantial adaptive plasticity in rice, which warrant further investigations at molecular level. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-022-01162-y.

Rice, the most widely consumed staple food across the world, is threatened by multiple environmental challenges. Among them, salinity stress as a combination of osmotic and ionic stress, adversely influencing its production. Plant biologists are making concerted efforts to improve the tolerance of this crop against salinity stress. In this chapter, we present a detailed account of molecular response exhibited by the rice plant toward salinity during its distinct developmental stages. Alongside the signaling machinery working in the plant, there are complex circuitries of effector molecules such as stress proteins and metabolites playing significant roles to combat stress. We have summarized the recent progress primarily done in this area to understand the salinity stress signaling and the adaptive mechanisms in rice operative in response to stress. The diverse approaches being explored for the development of improved rice genotypes utilizing the “omics” tools are also presented.

A livelihood is sustainable when it can cope with and recover from stresses and shocks and maintain or enhance its capabilities and assets both now and in the future, while not undermining the natural resource base. The unique livelihood strategy makes rural people exclusive from other parts of any country. Uprising problem is common in similar regions, which need to be sorted out with a detailed perspective on people and their living condition. Finding indicators is a way to improve understanding of the livelihoods of poor people. It draws on the main factors that affect poor people's livelihoods and the typical relationships between these factors. It can be used in planning new development activities and in assessing the contribution that existing activities have made to sustaining livelihoods.