锥低磷胁迫响应基因的功能及代谢通路分析

Analysis of function and metabolic pathway of phosphorus-responsive genes of Castanopsis chinensis under low phosphorus stress

关键词:  锥, 低磷胁迫, 磷响应基因, 基因功能, 代谢通路

Key words:   Castanopsis chinensis, low phosphorus stress, phosphorus-reponsive genes, gene function, metabolic pathway

摘要:

磷是限制南亚热带常绿阔叶林植物生长的关键营养元素,研究森林群落中优势木本植物对低磷胁迫响应的内在分子机制具有重要意义。该文以鼎湖山20 hm²固定监测样地常绿阔叶林中优势种锥(Castanopsis chinensis)为研究对象,利用高通量测序技术结合生物信息学软件对锥基因组序列进行深入分析。结果表明:(1)完成了锥基因组参考序列的草图拼接,结合大样地土壤有效磷数据,共筛选出37个显著性磷响应基因,并对筛选出的锥磷响应基因进行GO功能注释分析,发现29个GO注释分类中属分子功能类的基因数最多,共有13条,所涉及的预测功能包括磷脂酶D活性、细胞色素c氧化酶活性、光电子传递、过氧化物酶活性等。(2)对锥磷响应基因进行KEGG富集分析,发现显著性富集的1条代谢通路为psbD基因参与调控的植物光合代谢途径。在锥生长期中,有众多基因与磷代谢相关,并参与调控多种生物途径。其中,psbD基因作为锥叶片主要的磷响应基因可通过调控光合作用来调节植物生长,但其功能有待今后进一步验证。

Abstract:

Phosphorus is the key nutrient factor for limiting the plant growth and production in subtropical evergreen broad-leaved forest. It is of great significance to study on the molecular mechanism of dominant species response to low phosphorus stress in the forest community. Castanopsis chinensis is the dominant species in 20 hm² lower subtropical evergreen broad-leaved forest plot in Dinghushan and plays very important role in forest community assembly and maintenance of biodiversity. In this study, high-throughput sequencing technology combined with bioinformatics softwares were used to deep analyze the genome sequence of C. chinensis. Sequencing quality was assessed by FastQC and clean data was demutiplexed by Stacks. The assembly of reference sequence of C. chinensis genome was preliminarily completed by dDocent and the fasta format file of genomic reference sequence totally contained 1 488 contig sequences including forward strand and reverse strand. Sequencing alignment was conducted by Bowtie2 and the individual sequence information was completely aligned to reference sequence. The results were as follows:(1)Pearson correlation analysis was performed using the data of soil available phosphorus content in Dinghushan plot with the result of sequence alignment matrix and the result showed that 37 significant phosphorus-responsive genes were detected. The GO function annotation analysis of the phosphorus-responsive genes found that among the 29 GO annotation classifications, there were 13 genes in the molecular functional class and the predicting functions included NAPE-specific phospholipase D activity, cytochrome-c oxidase activity, electron transporter and peroxidase activity.(2)The predicting function of 11 genes in the class of biological process class involved in RNA splicing, oxidative phosphorylation, photosynthetic electron transport in photosystem Ⅱ. Cellular component class contained nine genes, including chloroplast, integral component of membrane and photosystem Ⅱ. Moreover, the result of KEGG analysis showed that the KEGG terms of 37 genes were significantly enriched to the metabolic pathway of photosynthesis and psbD was the major gene participated in the regulatory process. This study reveals that many phosphorus-responsive genes are involved in the regulation of various biological pathways in the growth stage of C. chinensis under low phosphorus stress. psbD gene is a major phosphorus-responsive gene adjusting plant growth by regulating photosynthesis in leaves. The specific function of psbD gene in C. chinensis needs to be further vertified.