Table2_Molecular and physiological responses of two quinoa genotypes to drought stress.XLSX

Quinoa is an important economic food crop. However, quinoa seedlings are susceptible to drought stress, and the molecular mechanism of drought tolerance remains unclear. In this study, we compared transcriptomic and physiological analyses of drought-tolerant (L1) and susceptible (HZ1) genotypes exposed to 20% PEG for 3 and 9 days at seedling stage. Compared with HZ1, drought stress had less damage to photosynthetic system, and the contents of SOD, POD and CAT were higher and the contents of H2O2 and O2−were lower in L1 leaves. Based on the RNA-seq method, we identified 2423, 11856, 1138 and 3903 (HZ1-C3-VS-T3, HZ1-C9-vs-T9, L1-C3-vs-T3 and L1-C9-vs-T9) annotated DEGs. Go enrichment was shown in terms of Biological Process: DEGs involved in biological processes such as metabolic process, cellular process, and single-organism process were most abundant in all four comparison treatments. In Molecular Function: the molecular functions of catalytic activity, binding and transporter activity have the most DEGs in all four processes. Cellular Component: membrane, membrane part, and cell have the most DEGs in each of the four processes. These DEGs include AP2/ERF, MYB, bHLH, b-ZIP, WRKY, HD-ZIP, NAC, C3h and MADS, which encode transcription factors. In addition, the MAPK pathway, starch and sucrose metabolism, phenylpropanoid biosynthesis and plant hormone signal transduction were significantly induced under drought stress, among them, G-hydrolases-66, G-hydrolases-81, G-hydrolases-78, Su-synthase-02, Su-synthase-04, Su-synthase-06, BRI1-20 and bHLH17 were all downregulated at two drought stress points in two genotypes, PP2C01, PP2C03, PP2C05-PP2C07, PP2C10, F-box01 and F-box02 were upregulated at two drought stress points in two genotypes. These results agree with the physiological responses and RNA-seq results. Collectively, these findings may lead to a better understanding of drought tolerance, and some of the important DEGs detected in this study could be targeted for future research. And our results will provide a comprehensive basis for the molecular network that mediates drought tolerance in quinoa seedlings and promote the breeding of drought-resistant quinoa varieties.

藜麦（Quinoa）是一种重要的经济粮食作物。然而，藜麦幼苗易受干旱胁迫影响，其耐旱的分子机制仍不明确。本研究对苗期经20%聚乙二醇（PEG）处理3天和9天的耐旱基因型（L1）与敏感基因型（HZ1）开展了转录组学与生理学对比分析。与HZ1相比，干旱胁迫对L1叶片光合系统的损伤更小，且其超氧化物歧化酶（SOD）、过氧化物酶（POD）与过氧化氢酶（CAT）的活性更高，过氧化氢（H₂O₂）与超氧阴离子（O₂·⁻）的含量更低。本研究基于RNA测序（RNA-seq）技术，共鉴定出2423、11856、1138和3903个注释后的差异表达基因（DEGs），对应比较组分别为HZ1-C3-VS-T3、HZ1-C9-vs-T9、L1-C3-vs-T3及L1-C9-vs-T9。基因本体论（GO）富集分析结果显示：在全部4组比较处理中，参与代谢过程、细胞过程及单有机体过程等生物过程的差异表达基因数量最多；在分子功能层面，催化活性、结合作用及转运蛋白活性相关的差异表达基因在4个比较组中占比最高；在细胞组分方面，细胞膜、细胞膜组分及细胞相关的差异表达基因在4个比较组中均为数量最多。这些差异表达基因包含AP2/ERF、MYB、bHLH、b-ZIP、WRKY、HD-ZIP、NAC、C3h及MADS等转录因子编码家族。此外，丝裂原活化蛋白激酶（MAPK）通路、淀粉与蔗糖代谢、苯丙烷生物合成及植物激素信号转导过程在干旱胁迫下显著富集。其中，G-水解酶66（G-hydrolases-66）、G-水解酶81（G-hydrolases-81）、G-水解酶78（G-hydrolases-78）、蔗糖合酶02（Su-synthase-02）、蔗糖合酶04（Su-synthase-04）、蔗糖合酶06（Su-synthase-06）、BRI1-20及bHLH17在两个基因型的两个干旱胁迫时间点均呈下调表达；而蛋白磷酸酶2C 01（PP2C01）、蛋白磷酸酶2C 03（PP2C03）、蛋白磷酸酶2C 05至蛋白磷酸酶2C 07（PP2C05-PP2C07）、蛋白磷酸酶2C 10（PP2C10）、F-box蛋白01（F-box01）及F-box蛋白02（F-box02）则在两个基因型的两个干旱胁迫时间点均呈上调表达。上述结果与生理响应及RNA-seq分析结果相符。综上，本研究结果可为深入解析藜麦耐旱机制提供参考，本研究中鉴定出的部分关键差异表达基因可作为未来研究的靶标。同时，本研究结果可为介导藜麦幼苗耐旱性的分子调控网络提供全面的理论依据，并有助于推动抗旱藜麦品种的育种工作。