Identification of major-effect QTL CmFpl3.1 controlling fruit pedicel length in melon (Cucumis melo L.)

Abstract

Fruit pedicel length (FPL) is among the most important traits associated with melon (Cucumis melo L.), impacting their appearance and management. Melon pedicels are also utilized in the preparation of certain traditional Chinese medicine formulations. Herein, we analyzed a melon parental lines with long and short pedicles (M125 and X055, respectively), and found that the primary differences between these lines included changes in both cell number and cytokinin content in the fruit pedicel. This study is the first to report that the CmFpl3.1 is associated with the regulation of melon pedicel length, and we were able to narrow this locus to an 89 Kb region containing 10 genes on chromosome 3 via bulk segregant analysis (BSA) and quantitative trait loci (QTL) analysis. Microscopy, qPCR, functional annotation, and gene sequence alignment studies further led us to identify MELO3C010972, which encodes cytokinin oxidase, as a candidate gene of CmFpl3.1 likely to regulate melon FPL. Furthermore, the concomitant cleave amplified polymorphic sequence (CAPS) marker genotyping data sets from 95 germplasm accessions strongly supported a role for MELO3C010972 as a regulator of FPL variability. In conclusion, our results offer new insights regarding the mechanistic basis for FPL determination, offering a foundation for future breeding programs or efforts to understand the mechanisms governing melon FPL development.