Cotton is regarded as a strategic agricultural commodity owing to its renewable and naturally derived fiber. With the escalating global demand for high-quality fiber, genetic improvement of fiber traits is a critical focus for sustaining and advancing the textile industry standards. The cotton GhJAZ2 gene encodes the Jasmonate ZIM-domain 2 protein, a known repressor in the jasmonic acid signaling pathway and negatively regulates fiber initiation. In this study, we designed a gRNA that simultaneously targets GhJAZ2 homologs and assembled it into the CRISPR vector (pHSE401). Subsequently, the construct (pHSE401-gRNA) was transformed into cotton (Gossypium hirsutum L.) using an Agrobacterium-mediated in planta transformation strategy, targeting the shoot apical meristem as the primary site of transformation. Sanger sequencing analysis revealed consistent single-base pair indels at the targeted site across both A and D sub-genomes, with edited T1 progenies showing both inherited and newly introduced indels at the targeted loci. Fiber analysis of edited lines compared to the control revealed a significant (p ) enhancement in lint percentage (≤13.74%) and fiber length (≤16.91%). This study demonstrated the effective application of CRISPR/Cas9 for targeted trait improvement in cotton, offering GhJAZ2-edited lines that can be advanced to develop transgene-free cultivars with improved fiber traits.
Saleem et al. (Sun,) studied this question.