聚球藻PCC7002 phoR基因的鉴定及其在磷稳态中的功能

IDENTIFICATION AND FUNCTION OF PHOR GENE INVOLVED IN PHOSPHORUS HOMEOSTASIS IN SYNECHOCOCCUS SP.PCC 7002

为探究蓝藻低磷适应机制,研究鉴定了海洋聚球藻PCC7002中可能的磷调控基因phoR(A2100),并通过生物信息学的方法对PhoR蛋白理化性质进行了分析,发现phoR基因长度为1296bp,编码431个氨基酸,PhoR蛋白由PAS、HisKA和HATPase_c三部分结构域组成,在不同蓝藻物种中序列较为保守。随后通过原核表达获得了PhoR重组蛋白,并制备其鼠源多克隆抗体,检测了PhoR在聚球藻PCC7002中缺磷诱导时的表达变化,证明PhoR蛋白在磷缺乏时大量诱导表达。为探究PhoR在聚球藻PCC7002中的生理功能,通过缺失突变获得了Mut-phoR突变株,并分析了其生理表型,发现Mut-phoR突变株在磷限制条件下出现显著的生长缺陷及光合作用的损伤,证明PhoR是聚球藻PCC7002适应低磷环境不可缺少的。研究结果为深入认识蓝藻的低磷适应分子机制提供了科学基础。

To explore the mechanism of phosphorus limitation adaptation in cyanobacteria,a possible phosphorus regulatory gene,phoR(A2100),was identified in Synechococcus sp.PCC 7002.The results of bioinformatics analysis showed that the length of phoR was 1296 bp,encoding 431 amino acids.PhoR comprises a PAS domain,a HisKA domain and a HATPase_c domain,with a theoretical isoelectric point of 5.20 and a predicted molecular weight of 49.58 kD.In addition,the sequence of PhoR is relatively conserved in different cyanobacteria species.Subsequently,the PhoR recombinant protein was expressed in E.coli,and a murine polyclonal antibody was prepared to detect the expression in Synechococcus sp.PCC 7002 under the phosphorus deprivation induction.The results indicated that the expression of PhoR was significantly induced in response to P deficiency.Then,we generated the Mut-phoR mutant strain through deletion mutagenesis and analyzed its physiological phenotype.It was found that Mut-phoR exhibited notable growth defects and impaired photosynthesis under phosphate limitation.This study provides a scientific basis for further understanding on the molecular mechanism of phosphate deficiency adaptation in cyanobacteria.