Molecular cloning and functional analysis of Chinese bayberry MrSPL4 that enhances growth and flowering in transgenic tobacco.

Chinese bayberry () is an important tree in South China, with its fruit being of nutritional and high economic value. In this study, early ripening (ZJ), medium ripening (BQ) and late ripening (DK) varieties were used as test materials. Young leaves of ZJ, BQ and DK in the floral bud morphological differentiation periods were selected for transcriptome sequencing to excavate earliness related genes. A total of 4,538 differentially expressed genes were detected. Based on clustering analysis and comparisons with genes reportedly related to flowering in , 25 homologous genes were identified. Of these, one gene named was determined, with its expression down-regulated in DK but up-regulated in ZJ and BQ. contained SBP domain and the target site of miR156, and its total and CDS length were 1,664 bp and 555 bp respectively. The overexpression vector of (35S::35S::-pCambia2301-KY) was further constructed and successfully transfected into tobacco to obtain -positive plants. Based on the results of qRT-PCR, the relative expression of was up regulated by 3,862.0-5,938.4 times. Additionally, the height of -positive plants was also significantly higher than that of wild-type (WT), with the bud stage occurring 12 days earlier. Altogether, this study identified an important gene - in Chinese bayberry, which enhanced growth and flowering, which provided important theoretical basis for early-mature breeding of Chinese bayberry.