Sequencing and analysis of transcriptome to reveal regulation of gene expression in Salvia miltiorrhiza under moderate drought stress / 中草药

ABSTRACT

Objective: To analyze the molecular mechanism of different tissues of Salvia miltiorrhiza in response to moderate drought stress by transcriptome sequencing. Methods: The roots and leaves of 4-month-old S. miltiorrhiza from moderate drought stressed group and control group (the relative water content in soil was 55%-60% and 75%-80%, respectively) were used as the test material. And the transcriptome sequencing analysis was carried out by using Illumina HiSeq 2000. After obtaining transcriptome data, gene function annotation, differentially expressed genes (DEGs) screening and and co-expression network analysis were performed. Results: A total of 58 085 Unigenes were obtained by transcriptome sequencing. Among them, 28 846 Unigenes were annotated, and there were 1 853 and 1 457 DEGs in roots and leaves, respectively. The GO enrichment results showed that the DEGs of the roots and leaves were both significantly enriched in metabolic process, stimulus response, cell structure, and catalytic activity, etc. The KEGG pathway analysis showed that DEGs in roots were significantly enriched in DNA replication, plant hormone signal transduction, plant-pathogen interaction, and carotenoid biosynthesis, etc. And the DEGs in leaves were mainly concentrated in amino acids, alkaloids, and phenylpropanoid biosynthesis. The genes of key enzymes involved in phenylpropanoid and terpenoid biosynthesis were up-regulated by moderate drought stress, which might be the basis for accelerating the accumulation of active ingredients in leaves and roots of S. miltiorrhiza. AP2 /ERF, bHLH, bZIP, WRKY, and MYB transcription factors were significantly differentially expressed in roots and leaves. Gene co-expression network analysis predicted transcription factors that may be involved in regulating the expression of terpenoid genes under moderate drought stress. Conclusion: The high-throughput transcriptome sequencing revealed the regulatory characteristics of moderate drought stress on gene expression in different tissues of S. miltiorrhiza, which could provide scientific basis for further research on the biosynthesis mechanism of medicinal components of S. miltiorrhiza and reasonable irrigation in cultivation.