芦竹茎对盐胁迫响应的转录组分析

Transcriptome analysis of Arundo donax stems under salt stress

【目的】丰富芦竹(Arundo donax)的耐盐基因资源并为分子育种提供帮助。【方法】对长势一致的“绿洲1号”芦竹分别用0、50、100、150和200 mmol/L NaCl盐溶液处理36 h,每个处理3次重复。收集相同部位的茎进行转录组测序和生物信息学分析,随机挑选5个差异表达基因进行qRT-PCR验证表达模式。【结果】对质控后的测序数据进行De novo组装,共产生971309个转录本,GC含量为47.14%,Unigene contigs的N50达到1126 bp,表明组装效果良好。对鉴定出的7305个差异表达基因进行GO与KEGG富集分析,结果表明“绿洲1号”茎主要通过氮代谢、离子转运、萜类合成、玉米素合成、亚油酸代谢、水杨酸生物合成和渗透调节物质等途径来响应盐胁迫。对差异表达基因进行筛选,共得到104个核心差异表达基因,其中差异倍数较大的88315_c0_g1_i1、1200_c2_g1_i1、13330_c0_g1_i8、46571_c0_g1_i7、3434_c0_g1_i11和713_c0_g1_i32基因可能在芦竹盐响应过程中发挥重要作用。转录因子的鉴定结果表明AP2/ERF-ERF、MYB-related和WRKY家族是盐响应过程中最重要的基因家族,并且这3种转录因子家族成员在响应盐胁迫时大部分呈上调状态,说明主要通过增加基因的表达发挥作用。qRT-PCR对5个差异表达基因表达模式的检测结果与RNA-seq结果基本一致,也说明转录组数据可靠。【结论】本研究鉴定了芦竹在响应盐胁迫过程中的重要基因和转录因子,为其今后的遗传改良工作奠定了坚实基础。

【Objective】The present paper aimed to enrich the salt tolerance gene resources of Arundo donax and provide help for molecular breeding.【Method】The‘LZ_No.1’A.donax with consistent growth were treated with 0,50,100,150 and 200 mmol/L NaCl salt solutions for 36 hours,and each treatment consisted of 3 replicates.Stems from the same site were collected for transcriptome sequencing and bioinformatics analysis.5 differentially expressed genes were randomly selected for qRT-PCR to verify the expression pattern.【Result】De novo assembly was performed on the sequencing data after quality control,and a total of 971309 transcripts were generated,with a GC content of 47.14%,and the N50 of Unigene contigs reached 1126 bp,indicating a good assembly effect.The 7305 differentially expressed genes identified were subjected to GO and KEGG enrichment analysis,and the results showed that stems of‘LZ_No.1’responded to salt stress mainly through nitrogen metabolism,ion transport,terpenoid synthesis,zeatin synthesis,linoleic acid metabolism,salicylic acid biosynthesis and osmotic regulator substances.The differentially expressed genes were screened,and a total of 104 core differentially expressed genes were obtained,of which 88315_c0_g1_i1,1200_c2_g1_i1,13330_c0_g1_i8,46571_c0_g1_i7,3434_c0_g1_i11 and 713_c0_g1_i32 genes with large differential multiples may play an important role in the response to the salt.The identification of transcription factors indicated that AP2/ERF-ERF family,MYB-related family and WRKY family were the most important gene families in salt response,and most of these three transcription factor family members were up-regulated in response to salt stress,indicating that they mainly worked by increasing the expression of genes.The detection results of the five differentially expressed genes by qRT-PCR were basically consistent with the RNA-seq results,which also demonstrated the reliability of the transcriptome data.【Conclusion】The study identifies important genes and transcription factors of A.donax in response to salt stress,which can lay a solid foundation for its future genetic improvement work.