Institute of Vegetable Crop, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Laboratory for Genetic Improvement of High Efficiency Horticultural Crops in Jiangsu Province, Nanjing 210014, China.
Int J Mol Sci. 2023 Jun 3;24(11):9725. doi: 10.3390/ijms24119725.
Drought is among the most challenging environmental restrictions to tomatoes (Solanum lycopersi-cum), which causes dehydration of the tissues and results in massive loss of yield. Breeding for dehydration-tolerant tomatoes is a pressing issue as a result of global climate change that leads to increased duration and frequency of droughts. However, the key genes involved in dehydration response and tolerance in tomato are not widely known, and genes that can be targeted for dehydration-tolerant tomato breeding remains to be discovered. Here, we compared phenotypes and transcriptomic profiles of tomato leaves between control and dehydration conditions. We show that dehydration decreased the relative water content of tomato leaves after 2 h of dehydration treatment; however, it promoted the malondialdehyde (MDA) content and ion leakage ratio after 4 h and 12 h of dehydration, respectively. Moreover, dehydration stress triggered oxidative stress as we detected significant increases in HO and O levels. Simultaneously, dehydration enhanced the activities of antioxidant enzymes including peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and phenylalanine ammonia-lyase (PAL). Genome-wide RNA sequencing of tomato leaves treated with or without dehydration (control) identified 8116 and 5670 differentially expressed genes (DEGs) after 2 h and 4 h of dehydration, respectively. These DEGs included genes involved in translation, photosynthesis, stress response, and cytoplasmic translation. We then focused specifically on DEGs annotated as transcription factors (TFs). RNA-seq analysis identified 742 TFs as DEGs by comparing samples dehydrated for 2 h with 0 h control, while among all the DEGs detected after 4 h of dehydration, only 499 of them were TFs. Furthermore, we performed real-time quantitative PCR analyses and validated expression patterns of 31 differentially expressed TFs of NAC, AP2/ERF, MYB, bHLH, bZIP, WRKY, and HB families. In addition, the transcriptomic data revealed that expression levels of six drought-responsive marker genes were upregulated by de-hydration treatment. Collectively, our findings not only provide a solid foundation for further functional characterization of dehydration-responsive TFs in tomatoes but may also benefit the improvement of dehydration/drought tolerance in tomatoes in the future.
干旱是番茄（Solanum lycopersi-cum）面临的最具挑战性的环境限制之一，它会导致组织脱水，从而导致大量减产。由于全球气候变化导致干旱持续时间和频率增加，培育耐旱番茄成为当务之急。然而，番茄中参与脱水响应和耐受的关键基因尚未广泛知晓，能够针对耐旱番茄培育的基因仍有待发现。在这里，我们比较了对照和脱水条件下番茄叶片的表型和转录组谱。我们发现，在脱水处理 2 小时后，番茄叶片的相对含水量降低；然而，它分别在脱水 4 小时和 12 小时后促进了丙二醛（MDA）含量和离子泄漏率的增加。此外，脱水胁迫引发了氧化应激，因为我们检测到 HO 和 O 水平显著升高。同时，脱水增强了抗氧化酶的活性，包括过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和苯丙氨酸解氨酶（PAL）。对经或未经脱水（对照）处理的番茄叶片进行全基因组 RNA 测序，分别在脱水 2 小时和 4 小时后鉴定出 8116 个和 5670 个差异表达基因（DEGs）。这些 DEGs 包括参与翻译、光合作用、应激反应和细胞质翻译的基因。然后，我们特别关注注释为转录因子（TF）的 DEGs。通过比较 2 小时脱水与 0 小时对照的样本，RNA-seq 分析鉴定出 742 个 TF 为 DEGs，而在 4 小时脱水后检测到的所有 DEGs 中，只有 499 个是 TF。此外，我们进行了实时定量 PCR 分析，并验证了 NAC、AP2/ERF、MYB、bHLH、bZIP、WRKY 和 HB 家族 31 个差异表达 TF 的表达模式。此外，转录组数据显示，六个干旱响应标记基因的表达水平在脱水处理后上调。总之，我们的研究结果不仅为进一步研究番茄中脱水响应 TF 的功能特性提供了坚实的基础，而且可能有助于未来提高番茄的脱水/耐旱性。
