Integrated RNA-seq and snRNA-seq analysis identifies PR10 tandem gene cluster governing early defense against Fusarium wilt in sea island cotton

Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum 7 (FOV7), poses a major threat to the production of elite Sea Island cotton ( Gossypium barbadense ). To uncover the molecular basis of defense FOV7 in cotton, we employed RNA sequencing to identify numerous differentially expressed genes across various stages of infection. Subsequent K-means clustering and weighted gene co-expression network analysis revealed a core module significantly enriched in defense response and abscisic acid-activated signaling pathways. A detailed examination of the gene distribution within these pathways identified 10 out of 50 genes as members of the Pathogenesis-Related 10 ( PR10 ) gene family. Evolutionary analysis of these PR10 genes uncovered a tandemly-expanded gene cluster located on chromosome 10 of the D sub-genome. In addition, root cell type maps constructed via single-nucleus RNA sequencing (snRNA-seq) enabled pinpointing FOV7 response in the root epidermis, where GbD_PR10.11 was identified as a specifically activated sentinel. Our work, by logically progressing from genome-wide patterns to a single gene in a single cell type, not only deciphers a key component of the cotton-pathogen arms race but also delivers a high-confidence target for engineering frontline resistance.