A novel mutation inTFL1homolog sustaining determinate growth in cucumber (Cucumis sativusL.)

摘要

Key message BSA-seq combined with whole-genome resequencing map-based cloning delimited the cucumberdet-novellocus into a 44.5 kb region in chromosome 6 harboring a putative candidate gene encoding a phosphatidylethanolamine-binding protein (CsCEN). Determinate and indeterminate growth habits of cucumber can affect plant architecture and crop yield. TheTERMINAL FLOWER 1(TFL1) controls determinate/indeterminate growth inArabidopsis. In this study, a novel mutation in cucumberTFL1homolog (CsCEN) has shown to regulate determinate growth and product of terminal flowers in cucumber (Cucumis sativusL.), which is similar to the function ofCsTFL1as previously reported. Genetic analysis in two determinate genotypes (D226 and D082) and indeterminate genotype (CCMC) revealed that a single recessive gene is responsible for this determinate growth trait. With the combination of BSA-seq and whole-genome resequencing, the locus ofdeterminate-novel(det-novel) trait was mapped to a 44.5 kb genomic region in chromosome 6. Sequence alignment identified one non-synonymous SNP mutation (A to T) in the third exon ofCsCEN, resulting in an amino acid substitution (Thr to Pro), suggesting that determinate growth might be controlled by a novel geneCsCEN(Csa6G152360) which differed from the reportedCsTFL1gene. TheCsCENexpression level in shoot apexes and axillary buds was significantly lower in D226 compared to CCMC, suggesting its essential role in sustaining indeterminate growth habit. Identification and characterization of theCsCENin the present study provide a new insight into plant architecture modification and development of cucumber cultivars suited to mechanized production system.