Objective To explore the function of BRL3 gene in flower development of Jatropha curcas.

Method  The full-length cDNA sequence of JcBRL3 gene was obtained by RACE PCR. The prokaryotic expression system was used to induce the expression of JcBRL3 gene. The expression products were identified by mass spectrometry using LC-MS/MS. The structure and basic physicochemical properties of the protein were analyzed by bioinformatics. The relative expression levels of JcBRL3 gene during the key stages of flower development of Jatropha curcas were analyzed by qRT-PCR. The overexpression JcBRL3 gene was transformed into tobacco by leaf plate method to analyze the influence of overexpression of JcBRL3 gene on the morphology and structure of tobacco flowers.

Result The length of the open reading frame of JcBRL3 gene was 3 618 bp and encoded 1 205 amino acids. The results of mass spectrometry showed that the expression of this gene encoded a JcBRL3 protein. Protein structure analysis showed that JcBRL3 protein was a transmembrane protein with multiple leucine-rich repeats and conserved repeats: LxxLxLxxN/CxL. qRT-PCR analysis showed that the expression of JcBRL3 in female flowers reached the highest level at mononuclear embryo sac stage, and in male flowers reached the highest level at pollen grain maturation stage, which was significantly higher than at any other stage. The morphological structure analysis of transgenic tobacco flower showed that the stigma position of transgenic tobacco was lower than that of anther, and the malformation rate of pollen grains was lower.

Conclusion JcBRL3 protein is a LRR-RLK, which is a membrane protein. JcBRL3 gene may participate in the development process of female flower mononuclear embryo sac stage and pollen grain maturation of male flower and promote filament elongation in Jatropha curcas.