甜瓜果形基因CmSUN25-26-27a的鉴定和分子标记OA北大核心CSTPCD

[Objective]The purpose of this study is to explore the genes related to the shape of melon fruits in order to provide a theoretical basis for genetic improvement in melon fruit breeding.[Method]This study identified the CmSUN gene involved in melon fruit shape regulation through whole genome identification,phylogenetic analysis,and association analysis between expression levels and fruit shape.The sequence variation of this gene in natural populations is utilized to develop relevant molecu-lar markers.[Result]Through whole-genome identification and phylogenetic analysis,the CmSUN25-26-27a gene in the melon CmSUN family was identified.This gene shows significant expression in fe-male flowers on the day of flowering and its expression level in different fruit-shaped melons is positively correlated with the fruit shape index(FSI).Through sequence analysis of 200 natural populations.It was found that a SNP-Single Nucleotide Polymorphism(A/G)in the coding region of CmSUN25-26-27a gene,resulting in a non-synonymous mutation in the encoded amino acid.Melons with CmSUN25-26-27aA gene have significantly higher FSI than those with CmSUN25-26-27aG gene.This SNP site roughly divides thick-skinned melons into two types based on fruit shape:FSI＞1.5(A)and FSI＜1.5(G),and the dCAPS markers for distinguishing sweet melon shape are designed according to this SNP site.[Conclusion]CmSUN25-26-27a homologous genes play a significant role in regulating fruit shape in cucurbit crops.The expression level and sequence variations of this gene in melons are closely cor-related with melon fruit shape index(FSI).