Chen Hao, Qiu Shaoxin, Chen Yuanping, Li Jiqin, Xu Tingyu, Zhong Pingzhan, Shao Xiuhong, Xu Shihuan, Ma Zhuwen, Huang Zhenrui, Pan Xiaoying
Guangdong Key Laboratory for Crops Genetic Improvement, Crops Research Institute, Guangdong Academy of Agricultural Sciences (GAAS), Guangdong Provincial Engineering & Technology Research Center for Tobacco Breeding and Comprehensive Utilization, Guangzhou, China.
College of Agronomy, South China Agricultural University, Guangzhou, China.
Front Plant Sci. 2024 Jul 22;15:1425944. doi: 10.3389/fpls.2024.1425944. eCollection 2024.
Heat stress is a prevalent factor that significantly damages crops, especially with the ongoing global warming and increasing frequency of extreme weather events. Tobacco is particularly sensitive to temperature fluctuations, experiencing reduced yield and quality under high temperatures. However, the underlying molecular mechanisms of heat resistance in tobacco remain poorly understood. This study comprehensively analyzed biochemical, transcriptomic, and metabolomic responses to heat stress on the root and shoot of the tobacco cultivar K326 compared to control conditions. Heat stress significantly increased the activities of antioxidant enzymes (CAT, POD, and SOD) and levels of osmotic mediators (soluble sugars, sucrose, and proline) in the shoot. Furthermore, transcriptome analysis identified 13,176 differentially expressed genes (DEGs) in the root (6,129 up-regulated and 7,047 down-regulated) and 12,283 DEGs (6,621 up-regulated and 5,662 down-regulated) in the shoot. The root had 24 enriched KEGG pathways, including phenylpropanoid metabolism, while the shoot had 32 significant pathways, such as galactose metabolism and MAPK signaling. The metabolomic data identified 647 metabolites in the root and 932 in the shoot, with carbohydrates and amino acids being the main categories. The root had 116 differentially abundant metabolites (DAMs) (107 up-regulated and 9 down-regulated), and the shoot contained 256 DAMs (251 up-regulated and 5 down-regulated). Joint transcriptome and metabolome analysis showed that galactose metabolism and starch and sucrose metabolism were co-enriched in both tissues. In contrast, amino sugar and nucleotide sugar metabolism was enriched in the root, and purine metabolism in the shoot. The purine metabolic pathway in the shoot can modulate the expression of MYB transcription factors by influencing ABA synthesis and signaling, thereby controlling the accumulation of HSPs, raffinose, sucrose, and trehalose to enhance heat tolerance. Furthermore, , an MYB transcription factor, enhances tolerance for heat stress in tobacco. This research offers a foundational framework for investigating and implementing heat-resistant genes and metabolic pathways in the root and shoot of tobacco seedlings.
热胁迫是一种普遍存在的因素，会对作物造成严重损害，尤其是在全球气候持续变暖和极端天气事件频率不断增加的情况下。烟草对温度波动特别敏感，在高温下产量和品质会下降。然而，烟草耐热性的潜在分子机制仍知之甚少。本研究全面分析了烟草品种K326的根和地上部分在热胁迫下与对照条件相比的生化、转录组和代谢组反应。热胁迫显著提高了地上部分抗氧化酶（CAT、POD和SOD）的活性以及渗透调节物质（可溶性糖、蔗糖和脯氨酸）的水平。此外，转录组分析在根中鉴定出13176个差异表达基因（DEGs）（6129个上调和7047个下调），在地上部分鉴定出12283个DEGs（6621个上调和5662个下调）。根中有24条富集的KEGG途径，包括苯丙烷代谢，而地上部分有32条显著途径，如半乳糖代谢和MAPK信号传导。代谢组数据在根中鉴定出647种代谢物，在地上部分鉴定出932种代谢物，碳水化合物和氨基酸是主要类别。根中有116种差异丰富代谢物（DAMs）（107个上调和9个下调），地上部分含有256种DAMs（251个上调和5个下调）。联合转录组和代谢组分析表明，半乳糖代谢以及淀粉和蔗糖代谢在两个组织中均共同富集。相比之下，氨基糖和核苷酸糖代谢在根中富集，嘌呤代谢在地上部分富集。地上部分的嘌呤代谢途径可通过影响ABA合成和信号传导来调节MYB转录因子的表达，从而控制HSPs、棉子糖、蔗糖和海藻糖的积累以增强耐热性。此外，一个MYB转录因子增强了烟草对热胁迫的耐受性。本研究为研究和应用烟草幼苗根和地上部分的耐热基因及代谢途径提供了基础框架。
