基于RNA-Seq解析小桐子棉子糖代谢途径在干旱适应中的作用

Analysis of Roles of the Raffinose Metabolism Pathways in Adapatation of Jatropha curcas to Drought Stress Based on RNA-Seq

作为新兴的能源植物,小桐子所具备的耐贫瘠、种子含油量高、油质优良等特性使其受到广泛关注。本研究对小桐子幼苗进行10%PEG模拟干旱锻炼与空气干旱胁迫处理,以叶片样品进行RNA-Seq文库构建并基于Illumina Hiseq2000平台进行高通量测序,对差异表达基因进行鉴定和通路富集分析,发现糖代谢通路得到了显著富集。其中,肌醇半乳糖苷合成酶（inositol galactoside synthase,GS）和棉子糖合成酶（raffinose synthase,RS）作为棉子糖系列寡糖合成途径的2类关键酶,其家族成员的不同编码序列在干旱胁迫下呈现不同的表达模式。实时荧光定量（RT-q PCR）验证了两个酶基因家族关键成员对干旱处理的诱导响应,暗示了棉子糖合成途径参与了干旱锻炼和胁迫耐受性的形成,为进一步揭示小桐子抗旱性形成的分子机制及其基因工程改良奠定了坚实的理论基础。

Jatropha curcas L. has attracted wide attention as a new energy plant by the characteristics of its barren resistance, high seed oil content and good oil quality. In this study, Jatropha curcas seedlings were treated with10% PEG simulated drought hardening and air drought stress. RNA-Seq Libraries were constructed with leaf samples and high-throughput sequencing was carried out based on Illumina Hiseq2000 platform. Identification and enrichment analysis of the differentially expressed genes（DEG） indicated that the glucose metabolism pathways were significantly enriched. Among them, inositol galactoside synthase（GS） and rcarinose synthase（RS） acting as two kinds of key enzyme of raffinose oligosaccharide synthesis pathway, the different coding sequences of their family members showed different expression patterns during the drought treatment. Real-time PCR（RT-q PCR）results confirmed that the key isoforms of two enzyme gene families were induced by drought stress, and suggested that the raffinose synthesis pathway was involved in the response and formation of drought stress tolerance, which might establish a solid theoretical foundation for further revealing the molecular mechanism of drought-resistance formation and genetic engineering improvement of Jatropha curcas.