Genetic engineering approaches to understanding drought tolerance in plants

Abiotic stresses such as drought, salinity, frost, etc., affect plant yield manyfold. These stresses can decrease the plant yield of important major crops up to 50%. The abiotic stress-related genes or other transcription factors (TFs) have multiple functions, as it increases proline content, leads closing of stomata to decrease the transpiration rate, enhances the production of some important stress-related protective enzymes, etc. and hence increases abiotic stress tolerance. Many TFs and other stress-related genes have been identified and characterized and transformed to many important cultivated plants against drought and others abiotic stresses. The transformed plants show better morpho-biochemical and physiological performances than non-transgenic plants. Many genetically engineered plants have been developed against drought stress including wheat, rice, tomato, soybean, cotton and many more. The efficiently engineered clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9 (Cas9) system is now becoming a preferred choice of researchers to edit plant genomes for introgression natural resistance against a range of abiotic stresses. It leads genome editing by precise manure with minimal or no effect on growth and development of plants. Very limited reports are available to develop drought-tolerant plants using CRISPR/Cas9 system. Here we discuss transgenic plant technology and new [CRISPR Cas9 and Virus-Induced Gene Silencing (VIGS)] techniques to confer drought tolerance in important plant species.