Genome-wide identification of the Catharanthus roseus receptor-like kinase 1-Like (CrRLK1L) gene family in rubber dandelion (Taraxacum kok-saghyz Rodin) and functional characterization of TkFER in growth and pollen development

Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) kinases are integral to various physiological processes in plants, including developmental regulation and adaptation to both biotic and abiotic stresses. Taraxacum kok-saghyz (TKS), commonly known as the rubber dandelion, serves as a crucial alternative supply for natural rubber. Nevertheless, the functional characterization of CrRLK1L members in TKS has yet to be elucidated. This study discovered fourteen CrRLK1L genes ( TkCrRLK1L1 – TkCrRLK1L14 ) in TKS. Among them, the FERONIA ( FER ) homolog, TkCrRLK1L2 (designated TkFER ), exhibited substantial expression in various tissues, including the latex. It could fully complement the vegetative growth defects and partially rescue the reduced sterility in the Arabidopsis mutant fer-4 . Furthermore, knockout or overexpression of TkFER in TKS caused drastically abnormal growth in the transgenic plants, whereas the heterozygous mutant lines of TkFER showed defects in pollen viability. Moreover, TkFER could form a homodimer and could interact with TkCrRLK1L6 and TkRALF8. These results suggest that the TkFER has conserved biochemical functions and is involved in growth, reproduction, and possibly also rubber production in TKS, as it is expressed in the latex, providing foundational information for further studies into the molecular processes governing growth, reproduction, and rubber production in TKS. • 14 TkCrRLK1L genes were identified in the genome of Taraxacum kok-saghyz (TKS). • TkFER could rescue growth and fertility defects in Arabidopsis fer-4 mutants. • Both mutation and overexpression of TkFER caused severely abnormal growth in TKS. • Heterozygous mutant lines of TkFER showed defects in pollen viability. • TkFER forms homodimers and interacts with TkCrRLK1L6 and TkRALF8.