Chao Yuehui, Xie Lijuan, Yuan Jianbo, Guo Tao, Li Yinruizhi, Liu Fengqi, Han Liebao
1Turfgrass Research Institute, College of Forestry, Beijing Forestry University, Beijing, 100083 China.
2School of Applied Chemistry and Biotechnology, Shenzhen Polytechnic, Shenzhen, 518055 China.
Physiol Mol Biol Plants. 2018 Sep;24(5):753-765. doi: 10.1007/s12298-018-0562-z. Epub 2018 Jun 18.
Red clover ( L.) is an important cool-season legume plant, which is used as forage. Leaf senescence is a critical developmental process that negatively affects plant quality and yield. The regulatory mechanism of leaf senescence has been studied, and genes involved in leaf senescence have been cloned and characterized in many plants. However, those works mainly focused on model plants. Information about regulatory pathways and the genes involved in leaf senescence in red clover is very sparse. In this study, to better understand leaf senescence in red clover, transcriptome analysis of mature and senescent leaves was investigated using RNA-Seq. A total of about 35,067 genes were identified, and 481 genes were differentially expressed in mature and senescent leaves. Some identified differentially expressed genes showed similar expression patterns as those involved in leaf senescence in other species, such as Arabidopsis, and rice. Differentially expressed genes were confirmed by quantitative real-time PCR (qRT-PCR). Genes involved in signal transduction, transportation and metabolism of plant hormones, transcription factors and plant senescence were upregulated, while the downregulated genes were primarily involved in nutrient cycling, lipid/carbohydrate metabolism, hormone response and other processes. There were 64 differentially expressed transcription factor genes identified by RNA-Seq, including ERF, WRKY, bHLH, MYB and NAC. A total of 90 genes involved in biosynthesis, metabolism and transduction of plant hormones, including abscisic acid, jasmonic acid, cyokinin, brassinosteroid, salicylic acid and ethylene, were identified. Furthermore, 207 genes with direct roles in leaf senescence were demonstrated, such as senescence-associated genes. These genes were associated with senescence in other plants. Transcriptome analysis of mature and senescent leaves in red clover provides a large number of differentially expressed genes. Further analysis and identification of senescence-associated genes can provide new insight into the regulatory mechanisms of leaf development and senescence in legume plant and red clover.
红车轴草（Trifolium pratense L.）是一种重要的冷季豆科植物，用作饲料。叶片衰老 是一个关键的发育过程，会对植物品质和产量产生负面影响。叶片衰老的调控机制已得到研究，许多植物中参与叶片衰老的基因也已被克隆和鉴定。然而，这些工作主要集中在模式植物上。关于红车轴草叶片衰老调控途径及相关基因的信息非常稀少。在本研究中，为了更好地了解红车轴草的叶片衰老，利用RNA测序对成熟叶和衰老叶进行了转录组分析。共鉴定出约35067个基因，其中481个基因在成熟叶和衰老叶中差异表达。一些鉴定出的差异表达基因表现出与拟南芥和水稻等其他物种中参与叶片衰老的基因相似的表达模式。通过定量实时PCR（qRT-PCR）对差异表达基因进行了验证。参与植物激素信号转导、运输和代谢、转录因子和植物衰老的基因上调，而下调基因主要参与营养循环、脂质/碳水化合物代谢、激素应答和其他过程。通过RNA测序鉴定出64个差异表达的转录因子基因，包括ERF、WRKY、bHLH、MYB和NAC。共鉴定出90个参与植物激素生物合成、代谢和转导的基因，包括脱落酸、茉莉酸、细胞分裂素、油菜素内酯、水杨酸和乙烯。此外，还证实了207个在叶片衰老中起直接作用的基因，如衰老相关基因。这些基因与其他植物的衰老相关。红车轴草成熟叶和衰老叶的转录组分析提供了大量差异表达基因。进一步分析和鉴定衰老相关基因可为豆科植物和红车轴草叶片发育和衰老的调控机制提供新的见解。
