Table_1_Transcriptome and Co-expression Network Analyses Reveal Differential Gene Expression and Pathways in Response to Severe Drought Stress in Peanut (Arachis hypogaea L.).XLSX

Drought is one of the major abiotic stress factors limiting peanut production. It causes the loss of pod yield during the pod formation stage. Here, one previously identified drought-tolerant cultivar, “L422” of peanut, was stressed by drought (35 ± 5%) at pod formation stage for 5, 7, and 9 days. To analyze the drought effects on peanut, we conducted physiological and transcriptome analysis in leaves under well-watered (CK1, CK2, and CK3) and drought-stress conditions (T1, T2, and T3). By transcriptome analysis, 3,586, 6,730, and 8,054 differentially expressed genes (DEGs) were identified in “L422” at 5 days (CK1 vs T1), 7 days (CK2 vs T2), and 9 days (CK3 vs T3) of drought stress, respectively, and 2,846 genes were common DEGs among the three-time points. Furthermore, the result of weighted gene co-expression network analysis (WGCNA) revealed one significant module that was closely correlated between drought stress and physiological data. A total of 1,313 significantly up-/down-regulated genes, including 61 transcription factors, were identified in the module at three-time points throughout the drought stress stage. Additionally, six vital metabolic pathways, namely, “MAPK signaling pathway-plant,” “flavonoid biosynthesis,” “starch and sucrose metabolism,” “phenylpropanoid biosynthesis,” “glutathione metabolism,” and “plant hormone signal transduction” were enriched in “L422” under severe drought stress. Nine genes responding to drought tolerance were selected for quantitative real-time PCR (qRT-PCR) verification and the results agreed with transcriptional profile data, which reveals the reliability and accuracy of transcriptome data. Taken together, these findings could lead to a better understanding of drought tolerance and facilitate the breeding of drought-resistant peanut cultivars.

干旱是限制花生生产的主要非生物胁迫因子之一，其在荚果形成阶段会造成荚果产量损失。本研究以已鉴定的耐旱花生品种“L422”为材料，在荚果形成阶段对其施以相对含水量35±5%的干旱胁迫，处理时长分别为5天、7天及9天。为解析干旱胁迫对花生的影响，本研究对正常供水（CK1、CK2、CK3）与干旱胁迫（T1、T2、T3）条件下的花生叶片开展了生理指标与转录组分析。经转录组分析，在干旱胁迫第5天（CK1 vs T1）、第7天（CK2 vs T2）及第9天（CK3 vs T3）的“L422”中分别鉴定出3586、6730和8054个差异表达基因（differentially expressed genes, DEGs），其中2846个基因为三个时间点共有的差异表达基因。此外，加权基因共表达网络分析（weighted gene co-expression network analysis, WGCNA）结果显示，存在一个与干旱胁迫及生理数据显著相关的关键模块。在该模块的干旱胁迫全程三个时间点中，共鉴定出1313个显著上调/下调的基因，其中包含61个转录因子。进一步分析发现，“MAPK信号通路-植物”“黄酮类生物合成”“淀粉与蔗糖代谢”“苯丙烷类生物合成”“谷胱甘肽代谢”及“植物激素信号转导”这6条重要代谢通路在重度干旱胁迫下的“L422”中显著富集。本研究选取9个与耐旱性相关的基因进行实时荧光定量PCR（quantitative real-time PCR, qRT-PCR）验证，结果与转录组表达谱数据高度吻合，证实了转录组数据的可靠性与准确性。综上，本研究结果有助于加深对花生耐旱机制的理解，并可助力耐旱花生品种的选育工作。