GM cotton for stress environments

Abstract

Genetically modified (GM) insect-resistant (IR) and herbicide-tolerant (HT) cotton was released for commercial cultivation more than two decades ago. In 2018, GM cotton was planted on 24.8 million hectares worldwide. Rapid increase in GM cotton acreage is one of the indicators of the overall success of cotton biotechnology program. Environmental stresses like drought, salinity, heat, waterlogging, submergence, flooding, cold, freezing, oxidative stress, heavy metals, nutritional deficiency, etc. are limiting cotton yield from 50 to 70%. Multiple gene(s) control multiple abiotic stresses, making the situation more complex. Several genes and transcription factors regulating abiotic stress tolerance have been identified and cloned. Promising candidate genes were transformed into crop plants with significant improvement. Pyramiding of these genes is under investigation. Genome sequencing, transcriptomics, proteomics, and metabolomics have made it possible to study the expression of large number of genes at a global level. There are examples of transformation of individual genes into cotton under constitutive and stress-inducible promoters. Due to complex nature of traits, progress is very slow in developing abiotic stress-tolerant GM cotton. Genome editing and speed breeding tools could be used to develop GM cotton for stress environments. In this chapter, identification of genes and development of abiotic stress-tolerant GM cotton has been presented.