Genetic control of compound leaf development in mungbean (Vigna radiata L.). Vigna radiata

Many studies suggest that there are distinct regulatory processes to control the compound leaf development in different clades of legumes. Loss of function of the LEAFY (LFY) orthologs results in reduction of leaf complexity to different degrees in inverted repeat-lacking clade (IRLC) and non-IRLC species. To further understand the role of LFY orthologs and molecular mechanism in compound leaf development in non-IRLC plants, we studied leaf developmental processes and characterized unifoliate leaf (un), a classical mutant in mungbean (Vigna radiata L.), with a complete conversion of compound leaves into simple leaves. Our analysis revealed that UN encodes the mungbean LFY ortholog and plays a significant role in leaf development. RNA in situ hybridization results shown that two STM-like KNOXI gens expressed in compound leaf primordia in mungbean and Lotus japonicus. Furthermore, genetic interaction and gene expression analysis shown that initiation of lateral leaflet primordia in heptafoliate leaflets1 (hel1) mutants involves regulatory processes mediated by the LFY ortholog and STM/BP-like KNOXI function in mungbean. Our results suggested that HEL1 is a key factor coordinating two regulatory processes in the control of compound leaf development in mungbean and related non-IRLC legumes.