Improvement of Drought Tolerance in Rice (Oryza sativa L.): Genetics, Genomic Tools, and the WRKY Gene Family

Abstract

Drought tolerance is an important quantitative trait with multipart phenotypes that are often further complicated by plant phenology. Different types of environmental stresses, such as high irradiance, high temperatures, nutrient deficiencies, and toxicities, may challenge crops simultaneously; therefore, breeding for drought tolerance is very complicated. Interdisciplinary researchers have been attempting to dissect and comprehend the mechanisms of plant tolerance to drought stress using various methods; however, the limited success of molecular breeding and physiological approaches suggests that we rethink our strategies. Recent genetic techniques and genomics tools coupled with advances in breeding methodologies and precise phenotyping will likely reveal candidate genes and metabolic pathways underlying drought tolerance in crops. The WRKY transcription factors are involved in different biological processes in plant development. This zinc (Zn) finger protein family, particularly members that respond to and mediate stress responses, is exclusively found in plants. A total of 89 WRKY genes in japonica and 97 WRKY genes in O. nivara (OnWRKY) have been identified and mapped onto individual chromosomes. To increase the drought tolerance of rice (Oryza sativa L.), research programs should address the problem using a multidisciplinary strategy, including the interaction of plant phenology and multiple stresses, and the combination of drought tolerance traits with different genetic and genomics approaches, such as microarrays, quantitative trait loci (QTLs), WRKY gene family members with roles in drought tolerance, and transgenic crops. This review discusses the newest advances in plant physiology for the exact phenotyping of plant responses to drought to update methods of analysing drought tolerance in rice. Finally, based on the physiological/morphological and molecular mechanisms found in resistant parent lines, a strategy is suggested to select a particular environment and adapt suitable germplasm to that environment.

Growth Performance and Antioxidant Enzyme Activities of Advanced Mutant Rice Genotypes under Drought Stress Condition

“…Increase in proline content helped to maintain tissue water status and avoid a reduction in cell damages induced by water deficit or drought stress. Accordingly, cell damage attributed to the reduction in active and reactive oxygen species [33]. The increase in proline under drought stress suggests that low water potential in plants had triggered proline accumulation.…”

Identification of main-effect quantitative trait loci (QTLs) for low-temperature stress tolerance germination- and early seedling vigor-related traits in rice (Oryza sativa L.)

“…In addition to that, several major biotic and abiotic stress factors significantly influence crop yield. Importantly, abiotic stresses such as drought, submergence, high temperature, cold/low temperature, and salinity directly or indirectly affect the physiological status of rice and negatively alter its overall genetic mechanisms and metabolism, often with negative impacts on yield (Wani et al 2016;Meena et al 2017;Abhinandan et al 2018;Sahebi et al 2018). More than 50% of plant productivity often becomes decreased by various abiotic stresses, which have effects individually or in combination, leading to an alteration in plant growth metabolism and development (Rejeb et al 2014;Singhal et al 2016).…”

Adaptation of Rice to the Nordic Climate Yields Potential for Rice Cultivation at Most Northerly Site and the Organic Production of Low-Arsenic and High-Protein Rice

“…Thus, paddy rice has come to meet the human food demand and to dominate as a staple food. However, there are several drawbacks associated with paddy rice: (i) cultivation of paddy rice is laborious (Food and Agricultural Organization of the United Nations (FAO), 2019; International Rice Research Institute, 2019); (ii) rice paddies require a good water supply (Sahebi et al, 2018;Mukamuhirwa et al, 2019); (iii) paddy rice agriculture produces the greenhouse gas methane (Su et al, 2015); and (iv) rice grains can contain high concentrations of metals if the cultivation environment or soil are polluted (Rahman et al, 2014;Singh et al, 2015;Awasthi et al, 2017;Chen et al, 2017;Norton, 2019).…”