Application of CRISPR/Cas system for genome editing in cotton.

Cotton holds immense economic potential owing to its premium quality fiber, oil, and protein contents. The ever-growing human population along with a global shift in climate requires a significant upsurge in cotton production. In the past years, conventional breeding tools were utilized to improve yield and quality through introgression of genes in elite cotton cultivars. The conventional breeding methods hold several limitations especially time-consuming, reliance on naturally available genetic variations, and extensive backcrossing. The modern plant breeding approaches especially modern genome editing technologies (GETs)can be utilized to achieve objectives within a limited time. The GETs including zinc-finger nucleases, transcription-activator-like effector nucleases, and clustered regularly interspaced palindromic repeats and CRISPR-associated proteins systems (CRISPR/Cas)-based technologies have been exploited in various crop improvement programs. The CRISPR/Cas system possesses immense potential owing to simplicity, competency, and versatility which lacks in other GETs. In cotton, the CRISPR/Cas system can help to enhance biotic and abiotic stress resistance, modify gene expression, and gene stacking of important traits with minimum chances of segregation. The transgene clean approach further enhances CRISPR acceptability, and plants can further utilized for selfing or backcrossing to improve traits under investigation. In this chapter, we highlight the avenues of research to utilize CRISPR/Cas system to combat biotic and abiotic stresses, fiber quality, plant architecture and flowering, epigenetic modifications, and gene stacking for economically important traits. Furthermore, the challenges associated with CRISPR application in cotton and its future prospects are addressed in detail.