Table_1_Comparative Transcriptome and Proteome Analysis of Salt-Tolerant and Salt-Sensitive Sweet Potato and Overexpression of IbNAC7 Confers Salt Tolerance in Arabidopsis.xlsx

Salt stress is one of the major devastating factors affecting the growth and yield of almost all crops, including the crucial staple food crop sweet potato. To understand their molecular responses to salt stress, comparative transcriptome and proteome analysis of salt-tolerant cultivar Xushu 22 and salt-sensitive cultivar Xushu 32 were investigated. The results showed the two genotypes had distinct differences at the transcription level and translation level even without salt stress, while inconsistent expression between the transcriptome and proteome data was observed. A total of 16,396 differentially expressed genes (DEGs) and 727 differentially expressed proteins (DEPs) were identified. Wherein, 1,764 DEGs and 93 DEPs were specifically expressed in the tolerant genotype. Furthermore, the results revealed that the significantly upregulated genes were mainly related to the regulation of ion accumulation, stress signaling, transcriptional regulation, redox reactions, plant hormone signal transduction, and secondary metabolite accumulation, which may be involved in the response of sweet potato to salt stress and/or may determine the salt tolerance difference between the two genotypes. In addition, 1,618 differentially expressed regulatory genes were identified, including bZIP, bHLH, ERF, MYB, NAC, and WRKY. Strikingly, transgenic Arabidopsis overexpressing IbNAC7 displayed enhanced salt tolerance compared to WT plants, and higher catalase (CAT) activity, chlorophyll and proline contents, and lower malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation were detected in transgenic plants compared with that of WT under salt stress. Furthermore, RNA-seq and qRT-PCR analysis displayed that the expression of many stress-related genes was upregulated in transgenic plants. Collectively, these findings provide revealing insights into sweet potato molecular response to salt stress and underlie the complex salt tolerance mechanisms between genotypes, and IbNAC7 was shown as a promising candidate gene to enhance salt tolerance of sweet potato.

盐胁迫是影响几乎所有作物生长与产量的主要毁灭性因素之一，其中包括至关重要的主食作物甘薯。为解析作物对盐胁迫的分子响应，本研究针对耐盐品种徐薯22与盐敏感品种徐薯32开展了比较转录组（transcriptome）与蛋白质组（proteome）分析。结果显示，即使在无盐胁迫条件下，两个基因型材料在转录水平与翻译水平上均存在显著差异，且转录组与蛋白质组数据间的基因表达模式并不一致。本研究共鉴定得到16396个差异表达基因（differentially expressed genes, DEGs）与727个差异表达蛋白（differentially expressed proteins, DEPs），其中1764个差异表达基因与93个差异表达蛋白仅在耐盐基因型中特异性表达。进一步分析显示，显著上调的基因主要参与离子积累调控、胁迫信号传导、转录调控、氧化还原反应、植物激素信号转导以及次生代谢产物积累等过程，这些过程或参与甘薯对盐胁迫的响应，或决定两个品种间的耐盐性差异。此外，本研究共鉴定得到1618个差异表达调控基因，涵盖bZIP、bHLH、ERF、MYB、NAC与WRKY等转录因子家族。值得注意的是，过表达IbNAC7的转基因拟南芥相较于野生型（wild type, WT）植株展现出更强的耐盐性；在盐胁迫条件下，转基因植株的过氧化氢酶（catalase, CAT）活性、叶绿素与脯氨酸含量均更高，而丙二醛（malondialdehyde, MDA）含量与活性氧（reactive oxygen species, ROS）积累量则更低。此外，RNA-seq与实时荧光定量PCR（qRT-PCR）分析结果显示，转基因植株中众多胁迫相关基因的表达量均显著上调。综上，本研究结果为解析甘薯对盐胁迫的分子响应提供了全新见解，阐明了不同基因型间复杂的耐盐调控机制，同时证实IbNAC7是一个可用于提升甘薯耐盐性的极具潜力的候选基因。