Recently, a paper titled "The miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN (PmSBP ) transcription factor regulates the flowering time by binding to the promoter of SUPPRESSOR OF OVEREXPRESSION OF CO1 (PmSOC1 ) in Prunus mume " written by the research team led by Professor Zhang Qixiang of School of Landscape Architecture was published online in International Journal of Molecular Sciences(IF="6.208).
Prunus mume, a famous perennial ornamental plant and fruit tree in Asia, blooms in winter or early spring in the Yangtze River area. The flowering time directly determines its ornamental and economic value, so it is of great significance to study the molecular mechanism of flowering time. SQUAMOSA PROMOTER BINDING PROTEIN (SBP), often regulated by miR156, is an important flowering regulator, although its function is unknown in P. mume. Here, 11 miR156 precursors were analyzed and located in five chromosomes of the P. mume genome. The expression pattern showed that PmSBP1/6 was negatively correlated with miR156. The promoters of PmSBP1/6 were specifically expressed in the apical meristem. Overexpression of PmSBP1/6 in tobacco promoted flowering and changed the length ratio of pistil and stamen. Moreover, PmSBP1 also affected the number and vitality of pollen and reduced the fertility of transgenic tobacco. Furthermore, ectopic expression of PmSBP1/6 caused up-regulated expression of endogenous SUPPRESSOR OF OVEREXPRESSION OF CO1 (NtSOC1). The yeast-one hybrid assay showed that PmSBP1 was bonded to the promoters of PmSOC1s. In conclusion, a miR156-PmSBP1-PmSOC1s pathway was formed to participate in the regulation of flowering time in P. mume, which provided references for the molecular mechanism of flowering time regulation and molecular breeding of P. mume.
Professor Zhang Qixiang and senior engineer Wang Jia are the corresponding authors of the paper, and Doctor Yong Xue, who is also the teacher of College of Landscape Architechture, Sichuan Agriculture University, is the first author. The paper is supported by the Fundamental Research Funds for the Central Universities, R&D Program of Beijing Municipal Education Commission and Special Found for Beijing Common Construction Project.