Distinct metabolic profiling is correlated with bisexual flowers formation resulting from exogenous ethephon induction in melon (Cucumis melo L.)

Abstract

Melon (Cucumis melo L.) is an agronomically important vegetable. Most cultivars of melon are andromonoecious and bisexual flowers only emerged from the leaf axil of lateral branches. However, the regulatory mechanism contributing to the occurrence of bisexual flowers were still obscure. In this study, ethephon was applied in two common cultivars of melon. In control without ethephon treatment, no bisexual flower was made in the main stem. However, 6.56 ± 1.42 and 6.63 ± 0.55 bisexual flowers were respectively induced in main stem of ‘Yangjiaocui-QX’ and ‘Lvbao’ after ethephon treatment, and induced bisexual flowers distributed in 12–20 nodes of main stem. During the formation of bisexual flowers, 41 metabolites were significantly up-regulated and 98 metabolites were significantly down-regulated. According to the KEGG enrichment analysis of 139 different metabolites, a total of 30 pathways were mapped and KEGG terms of “Phenylalanine, tyrosine and tryptophan biosynthesis”, “Phenylalanine metabolism” and “Flavone and flavonol biosynthesis” were significantly enriched. In three significantly enriched KEGG terms, shikimic acid, L-tryptophan, L-phenylalanine, and kaempferol were significantly up-regulated while L-tyrosine, 4-hydroxycinnami acid and luteolin were significantly down-regulated in ET compared to CK. Different metabolites were also classified depend on major class features and 14 classes were acquired. The results of metabonomics and endogenous hormone identification indicated that ethylene could enhance the concentration of salicylic acid, methyl jasmonate, ABA and IAA. This study provided an important theoretical foundation for inducing bisexual flowers in main stem and breeding new varieties of melon in future.

Identification of key genes promoting stamen formation induced by silver nitrate in gynoecious melon

“…(2009) reported that the expression of WIP1 (wound inducible protein1) led to carpel abortion, resulting in the development of unisexual male flowers, and found that ACS‐7 and WIP1 interact to control the development of male, female, and hermaphrodite flowers in melon. Sex determination in melon is mainly controlled by the andromonoecious gene CmACS‐7 (Adnane et al., 2008), the gynoecious gene CmWIP1 (Antoine et al., 2009), and the androecious gene CmACS11 (Fang et al., 2022). CmACS‐7 is a andromonoecious gene that is expressed mainly in the carpel primordia of female and hermaphroditic flowers but does not accumulate in male flowers.…”

“…CmACS‐7 is a andromonoecious gene that is expressed mainly in the carpel primordia of female and hermaphroditic flowers but does not accumulate in male flowers. It plays an important role in the prevention of stamen development in female flowers (Fang et al., 2022). In addition, CmACS11 is also strongly expressed in the phloem of female and hermaphroditic, but not male, buds and is required for carpel development.…”