Identification of a natural RcLOG1 allele linked to prickle development in Rose (Rosa spp.)

Roses, one of the most important ornamental crops, face challenges due to the presence of prickles. Recent studies have highlighted the important role of the LONELY GUY 1 (LOG1) gene in prickle formation in the eggplant. The LOG (LONELY GUY) genes are involved in plant cytokinin biosynthesis, converting inactive cytokinin precursors into their active forms. This activation is essential for various physiological processes, including cell division, organogenesis, and stress responses. The current study identified and investigated the RcLOG genes and their involvement in prickle formation in roses. In this study, eight RcLOG genes were identified in rose, with coding sequence (CDS) lengths ranging from 648 to 921 bp, encoding proteins between 215 and 306 amino acids. qRT-PCR analysis revealed distinct expression patterns of RcLOG genes in prickled and prickle-less rose genotypes, suggested their involvement in prickle development. During prickle development, RcLOG1 expression was absent in prickle-less roses, while it was significantly upregulated in prickled roses. This indicated that RcLOG1 plays a crucial role in prickle formation, and its downregulation was likely responsible for the prickle-less phenotype. Interestingly, a single nucleotide polymorphism (SNP), Affx-86787307 (G/A), was identified in the seventh exon of RcLOG1. The homozygous AA genotype was associated with the prickle-less phenotype. This SNP was non-synonymous, and G to A transition resulted in an amino acid substitution from aspartic acid (D) to asparagine (N), which reduced the protein stability. In summary, the Affx-86787307-AA allele led to the incorporation of asparagine, potentially destabilizing the protein and contributing to the absence of prickles. These findings provide valuable insights into the molecular mechanisms underlying prickle development in roses and could facilitate the breeding of prickle-less rose varieties.