Najam Waris Zaidi

Trichoderma Species as Abiotic Stress Relievers in Plants

Abstract Drought, flood, soil salinity/sodicity or extreme temperatures are responsible for adverse effects on plant growth and production. More precisely, drought, flood and salinity are the major causes of crop loss worldwide. These stresses are likely to get further aggravated in near future due to climate change. A wide range of adaptations and mitigation strategies are required to cope with such impacts. Trichoderma species, one of the most widely used microbes for the biocontrol of plant diseases, are known to alter the response of plants to abiotic stresses. There is need to exploit its unique properties of genetic diversity, ubiquity, tolerance to extremities, its interaction with crop plants and develop methods for its effective disposition in agriculture production to cope with climate change induced stresses. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes especially Trichoderma species for improving plant stress tolerance and sustainable production of food crops. Subsequently, isolation of genes from this biocontrol agent and their further transfer to a plant genome may result in a significant improvement in plant tolerance to biotic or abiotic stresses. Here, we have described the role of Trichoderma species in alleviating adverse effects of abiotic stresses in plants and providing abiotic stress tolerance. A putative mechanism of stress tolerance by Trichoderma species has also been covered. Since Trichoderma alone may not be enough to provide required degree of protection against abiotic stresses like drought, soil salinity or flooding, there is need to explore the possibility of exploiting the microbes along with the plant gene (i.e. abiotic stress tolerant varieties) for the more effective abiotic stress management.

No yield penalty under favorable conditions paving the way for successful adoption of flood tolerant rice

Flooding is one of the major constraints for rice production in rainfed lowlands, especially in years and areas of high rainfall. Incorporating the Sub1 (Submergence1) gene into high yielding popular varieties has proven to be the most feasible approach to sustain rice production in submergence-prone areas. Introgression of this QTL into popular varieties has resulted in considerable improvement in yield after flooding. However, its impact under non-flooded conditions or years have not been thoroughly evaluated which is important for the farmers to accept and adopt any new version of their popular varieties. The present study was carried out to evaluate the effect of Sub1 on grain yield of rice in different genetic backgrounds, under non-submergence conditions, over years and locations. The study was carried out using head to head trials in farmer’s fields, which enable the farmers to more accurately compare the performance of Sub1 varieties with their recurrent parents under own management. The data generated from different head to head trials revealed that the grain yield of Sub1 varieties was either statistically similar or higher than their non-Sub1 counterparts under non-submergence conditions. Thus, Sub1 rice varieties show no instance of yield penalty of the introgressed gene.