Genome-wide analysis of CrRLK1L gene family in Gossypium and identification of candidate CrRLK1L genes related to fiber development.

Members of the CrRLK1L family, a subgroup of the receptor-like kinase (RLK) gene family, are thought to act as sensors for the integrity of the cell wall and regulators of polar elongation. To better understand the various functions in fiber development, we conducted genome-wide identification and characterization analyses of CrRLK1L family in cotton. Here 44, 40, and 79 CrRLK1L genes were identified from three cotton species: diploid G. raimondii (D5), diploid G. arboreum (A2), and tetraploid G. hirsutum TM-1 (AD1), respectively. The 44 CrRLK1Ls in G. raimondii were anchored to the 12 chromosomes unevenly and were classified into six groups (I-VI), with group II and group IV being further divided into two subgroups (groups IIa and IIb, and IVa and IVb, respectively). These CrRLK1Ls displayed a highly regular pattern of developmental and spatial regulation in cotton. Using the transcriptome data of five chromosomal segment introgression lines (CSILs) and the physical integration of CrRLK1Ls with the quantitative trait loci (QTLs) related to fiber quality traits, we revealed that six CrRLK1L genes were highly associated with fiber development. This study brings new insights into the integrated genome-wide identification of CrRLK1Ls in cotton and provides references for the genetic improvement of cotton fiber.