中国农业科学 ›› 2019, Vol. 52 ›› Issue (12): 2079-2091.doi: 10.3864/j.issn.0578-1752.2019.12.006

• 植物保护 • 上一篇    下一篇

基于转录-代谢联合分析哈茨木霉ACCC32527 对NaCl胁迫的分子调节

向杰,陈敬师,夏鑫鑫,刘快,李世贵,顾金刚()   

  1. 中国农业科学院农业资源与农业区划研究所农业农村部农业微生物资源收集保藏重点实验室,北京100081
  • 收稿日期:2019-01-21 接受日期:2019-03-18 出版日期:2019-06-16 发布日期:2019-06-22
  • 通讯作者: 顾金刚
  • 作者简介:向杰,E-mail: 18801076480@163.com。
  • 基金资助:
    国家重点研发计划(2017YFD0200604-5)

Molecular Regulation of Trichoderma harzianum ACCC32527 Response to NaCl Based on Transcriptome and Metabolome Analysis

XIANG Jie,CHEN JingShi,XIA XinXin,LIU Kuai,LI ShiGui,GU JinGang()   

  1. Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081
  • Received:2019-01-21 Accepted:2019-03-18 Online:2019-06-16 Published:2019-06-22
  • Contact: JinGang GU

摘要:

【目的】 通过NaCl胁迫下哈茨木霉(Trichoderma harzianum)ACCC32527差异转录组和代谢组数据分析,挖掘关键功能型差异表达基因(DEG)及次级代谢产物。【方法】 采用RNA-seq和GC-TOF-MS技术分别完成0(T1)、0.4(T2)、0.6(T3)mol?L -1 NaCl胁迫下哈茨木霉ACCC32527的差异表达基因和次级代谢产物检测,利用相关软件及数据库(GO、COG、KEGG pathway等)完成对差异表达基因(|log2fold change)|>1 & FDR<0.01)和次级代谢产物(P-value≤0.05 & VIP>1)的筛选、注释和分类,并进行RT-qPCR验证。 【结果】 NaCl胁迫处理后,ACCC32527的生长受到抑制,繁殖速率明显降低,并在该条件下分别获得T1 vs T2和T1 vs T3比较组637、1 570个DEG,获得DEG的16种表达模式,包括9种上调表达模式(950 gene)、3种下调表达模式(662 gene)和4种不规则表达模式(309 gene),共有的GO功能分类为催化活性、结合、细胞器、细胞膜部分、细胞膜、细胞部分、细胞、单组织过程和代谢过程,且占主要比例,约为61%—94%,其中处理前后基因比例差异较大的分类为催化活性。KEGG代谢通路富集分析发现,不同NaCl浓度处理下的DEG富集到的代谢通路种类及数量存在较大差异,分别有225和535个差异基因富集于20条KEGG通路,包括代谢通路、抗生素的合成和次级代谢产物合成, 其中T2和T3处理下核糖体的生物合成途径分别有12个和18个相关基因受到抑制。从NaCl胁迫下差异转录组中筛选出活性氧清除、离子转运和细胞壁及胞外结构等共73个相关基因,并且多数为上调表达基因。另外,差异代谢组学分析表明,T3处理下,胞内小分子代谢物出现明显变化,累积量增加的代谢产物有30种,包括氨基酸及其衍生物、糖类及其衍生物和醇类,而减少的代谢物有53种,涉及脂肪酸和有机酸等。其中,甘油是已知的真菌重要渗透保护物,T3处理下ACCC32527胞内甘油水平提高,可参与细胞的渗透调节,维持渗透压平衡。RT-qPCR验证了7个差异表达显著基因,虽然在表达量上存在一定的差异,但表达趋势与RNA-seq分析结果基本一致,表明转录组测序结果的可靠性。【结论】 NaCl胁迫引起哈茨木霉ACCC32527大量基因及次级代谢产物变化,获得了与NaCl胁迫调节相关基因和代谢产物,这些机制共同作用减少盐离子对细胞的毒害作用,研究结果可为研究木霉菌的耐盐机理提供重要信息。

关键词: NaCl, 哈茨木霉, 转录组, 代谢组, 耐盐机理

Abstract:

【Objective】The objective of this study is to mine the key functional differentially expressed genes (DEGs) and secondary metabolites by analyzing the data of Trichoderma harzianum ACCC32527 differential transcriptomes and metabolomes under NaCl stress.【Method】The transcriptomes and metabolomes of ACCC32527 with the treatment of 0 (T1), 0.4 (T2), 0.6 (T3) mol?L -1 NaCl were performed by RNA-seq and GC-TOF-MS, respectively, and the annotation, screening and classification of DEGs (|log2fold change|>1 & FDR<0.01) and secondary metabolites (P-value≤0.05 & VIP>1) were completed by related softwares and databases (GO, COG and KEGG pathway). Finally, RT-qPCR was conducted to validate RNA-seq data.【Result】In this study, after NaCl stress treatments, the growth of ACCC32527 was inhibited and the reproductive rate was significantly decreased, 637 and 1 570 DEGs were screened from the T1 vs T2 and T1 vs T3 comparison groups, respectively. Trend analysis result showed that 1 921 DEGs were assigned to 16 significant expression patterns, including 9 up-regulated trends (950 genes), 3 down-regulated trends (662 genes) and 4 irregular trends (309 genes). GO enrichment analysis result showed that each tread was shared by catalytic activity, binding, organelle, cell membrane part, cell membrane, cell part, cell, single-organism process and metabolic process, and accounted for 61%-94%. Among them, the classification with great difference in gene proportion before and after treatment was catalytic activity. The enrichment analysis of KEGG metabolic pathway displayed that the classification and numbers of pathways treated with different NaCl concentrations were significantly different, there were 225 and 535 DEGs enriched in 20 KEGG pathways, respectively, including metabolic pathways, biosynthesis of antibiotics, biosynthesis of secondary metabolites and so on. Among them, 12 and 18 related genes of ribosome biosynthesis pathway were suppressed under T2 and T3 treatments, respectively. A total of 73 genes were screened from the DEGs including ROS scavenging, ion transport and cell wall structure, and most of them were up-regulated. In addition, intracellular small molecule metabolites showed significant change in response to NaCl stress, and there were 30 metabolites with increased accumulation, including amino acids and their derivatives, sugars and their derivatives and alcohols, while 53 metabolites were reduced including fatty acids and organic acids. Among them, glycerol, a known important osmoregulation substance of fungi, was increased under T3 treatment, which may be involved in the process of cell osmotic adjustment. RT-qPCR verified the expression changes of 7 DEGs, which were consistent with the RNA-seq analysis, indicating the reliability of transcriptome sequencing results.【Conclusion】Under NaCl stress, a large number of genes and secondary metabolites of T. harzianum ACCC32527 were changed, which were related to NaCl stress regulation. These processes act together to reduce the toxic effect to the cells, and the results can provide important information for the study of salt-tolerant mechanism of Trichoderma spp..

Key words: NaCl, Trichoderma harzianum, transcriptome, metabolome, salt-tolerant mechanism