Transcriptome sequencing dissection of the mechanisms underlying differential cold sensitivity in young and mature leaves of the tea plant (Camellia sinensis)
Transcriptome sequencing dissection of the mechanisms underlying differential cold sensitivity in young and mature leaves of the tea plant (Camellia sinensis)
复制标题
转录组测序解析茶树幼叶和成熟叶冷敏感性差异的机制
DOI：
10.1016/j.jplph.2018.03.017
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发表时间：
2018-05-01
影响因子：
4.3
通讯作者：
Yang, Ya-jun
中科院分区：
文献类型：
--
作者：
Li, Na-na;Yue, Chuan;Yang, Ya-jun
茶树原产于热带和亚热带地区，在寒冷的冬季和晚春霜冻期间经历了相当大的挑战。茶树经短期低温胁迫后，幼叶出现褐变，电解质渗漏显著增加，光系统II的最大光化学效率(F-v/F-m)显著降低。为了探讨茶树幼叶和成熟叶之间耐冷性差异的机制，我们利用Illumina RNA-Seq技术分析了茶树幼叶和成熟叶在20℃、4℃和0℃处理4h后的转录表达谱，获得了4570-7293万个RNA-Seq原始读数，然后从头组装成228,864个非基因，平均长度为601个核苷酸，N50为867个核苷酸。此外，通过对幼叶和成熟叶进行配对比较的Venn图分析，确定了差异表达的Uniges。基于基因本体论和京都百科全书的基因和基因组浓缩分析的功能分类表明，上调的差异表达基因主要与叶绿体和细胞膜的细胞组成术语、氧化还原过程的生物过程术语以及谷胱甘肽代谢和光合作用的途径术语有关，表明这些成分和途径可能与成熟叶片的抗寒性有关。相反，低温条件下幼叶中与细胞膜、类胡萝卜素代谢、光合作用和ROS解毒相关的基因表达受到抑制，可能导致细胞膜的解体和光合作用器官的氧化损伤。进一步的实时定量聚合酶链式反应检测验证了我们的RNA-Seq结果的可靠性。这项工作为了解茶树幼叶冷敏性的机制以及通过抗氧化酶的遗传操作选育抗霜性优良的茶树品种提供了有价值的信息。
The tea plant originated in tropical and subtropical regions and experiences considerable challenges during cold winters and late spring frosts. After short-term chilling stress, young leaves of tea plants exhibit browning, a significant increase in electrolyte leakage and a marked decrease in the maximal photochemical efficiency of photosystem II (F-v/F-m) compared with mature leaves. To identify the mechanisms underlying the different chilling tolerance between young and mature leaves of the tea plant, we used Illumina RNA-Seq technology to analyse the transcript expression profiles of young and mature leaves exposed to temperatures of 20 degrees C, 4 degrees C, and 0 degrees C for 4 h. A total of 45.70-72.93 million RNA-Seq raw reads were obtained and then de novo assembled into 228,864 unigenes with an average length of 601 bp and an N50 of 867 bp. In addition, the differentially expressed unigenes were identified via Venn diagram analyses for paired comparisons of young and mature leaves. Functional classifications based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the up-regulated differentially expressed genes were predominantly related to the cellular component terms of chloroplasts and cell membranes, the biological process term of oxidation-reduction process as well as the pathway terms of glutathione metabolism and photosynthesis, suggesting that these components and pathways may contribute to the cold hardiness of mature leaves. Conversely, the inhibited expression of genes related to cell membranes, carotenoid metabolism, photosynthesis, and ROS detoxification in young leaves under cold conditions might lead to the disintegration of cell membranes and oxidative damage to the photosynthetic apparatus. Further quantitative real-time PCR testing validated the reliability of our RNA-Seq results. This work provides valuable information for understanding the mechanisms underlying the cold susceptibility of young tea plant leaves and for breeding tea cultivars with superior frost resistance via the genetic manipulation of antioxidant enzymes.