基于转录组测序对干旱胁迫下马铃薯块茎中淀粉和蔗糖代谢途径相关基因的差异表达分析

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干旱胁迫下,碳水化合物作为一种信号分子对作物的生长发育和生态适应性进行调控。为探究马铃薯(Solanum tuberosum)块茎响应干旱胁迫的分子机制,本研究以马铃薯‘合作88’为试验材料,采用Illumina HiSeq 2500测序技术对不同程度干旱胁迫下的马铃薯块茎样本进行转录组测序,对获得的差异表达基因进行注释,进一步筛选与淀粉和蔗糖代谢途径相关的酶基因,并随机选取5个基因进行实时定量PCR基因表达验证。不同程度干旱胁迫下马铃薯块茎中共有4476个基因上调表达,4490个基因下调表达,3种处理下共有的差异表达基因为164个。KEGG代谢通路注释结果表明碳水化合物代谢和氨基酸代谢途径中差异表达基因富集数量最多。筛选出5个参与淀粉和蔗糖代谢途径的关键酶基因(TPS11、SS、SPS2、BGLU12和BACOVA_02659),并随机选取CATHB1、CKA2F、GRXS17、PABN1和RFS2等5个基因进行实时定量PCR检测,转录组测序结果与实时定量PCR检测表达水平一致,证明转录组数据可靠。干旱胁迫下马铃薯块茎中参与调控淀粉和蔗糖代谢途径的基因有10个。研究结果有助于阐明马铃薯的差异表达基因在淀粉和蔗糖代谢途径中的分子机制,探索不同程度干旱胁迫下淀粉合成与分解、蔗糖分解以及葡萄糖合成的途径。

As a kind of signal molecule, carbohydrate regulates crop growth and development and ecological adaptation under drought stress. To explore the molecular mechanisms of potato(Solanum tuberosum) tuber responding to drought stress, the potato ′Cooperation 88′ was used as the experimental material in this study. Transcriptome sequencing was performed on potato tuber samples under diffe-rent degrees of drought stress by Illumina Hiseq 2500 sequencing technology and the obtained differentially expressed genes were annotated. The enzyme genes related to starch and sucrose metabolic pathways were further screened, and five genes were randomly selected for real-time quantitative PCR gene expression verification. A total of 4 476 genes were up-regulated and 4 490 genes were down-regulated in potato tuber under different degrees of drought stress. A total of 164 differentially expressed genes were found under the three treatments. KEGG metabolic pathway annotation suggested the enrichment of differentially expressed genes was the largest in carbohydrate metabolism and amino acid metabolism. Five key enzyme genes(SS, TPS11, SPS2, BGLU12 and BACOVA_02659) involved in the metabolic synthesis of starch and sucrose were screened out, and 5 genes including CATHB1, CKA2F, GRXS17, PABN1 and RFS2 were randomly selected for real-time quantitative PCR detection. Transcriptome sequencing results were consistent with the expression levels detected by real-time quantitative PCR, which proved the reliability of transcriptome data. Ten genes are involved in the regulation of starch and sucrose metabolic pathways in potato tubers under drought stress. The results can help to elucidate that molecular mechanisms of differentially expressed genes in starch and sucrose metabolism in potato, and explored the pathways of starch synthesis and decomposition, sucrose breakdown and glucose synthesis under different degrees of drought stress.