EjMYB8 Transcriptionally Regulates Flesh Lignification in Loquat Fruit.
EjMYB8 Transcriptionally Regulates Flesh Lignification in Loquat Fruit.
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EjMYB8转录调控枇杷果实的果肉木质化
DOI：
10.1371/journal.pone.0154399
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Chen KS
中科院分区：
文献类型：
--
作者：
Wang WQ;Zhang J;Ge H;Li SJ;Li X;Yin XR;Grierson D;Chen KS
木质素代谢的转录调控机制在模式植物和木本植物中得到了广泛的研究，但在经历木质化的果实如枇杷中却很少。在此，基于RNA-seq分离了12个EjMYB基因，设计为EjMYB 3 -14。结果表明，低温（0°C）处理能显著诱导木质素含量较高的果实中EjMYB 8和EjMYB 9的表达，而低温处理（LTC）和热处理（HT）均能减轻果实木质化，抑制EjMYB 8和EjMYB 9的表达。双荧光素酶分析表明，EjMYB 8，而不是EjMYB 9，可以反式激活木质素相关基因EjPAL 1，Ej 4CL 1和Ej 4CL 5的启动子。酵母单杂交实验表明EjMYB 8与Ej 4CL 1启动子物理结合。此外，EjMYB 8的推定功能通过在两种N.烟草和枇杷叶中木质素含量增加。此外，EjMYB 8与先前分离的EjMYB 1的组合对Ej 4CL 1启动子产生了强烈的反式激活作用，表明EjMYB 8是枇杷果实木质化的一种新的调控因子。
Transcriptional regulatory mechanisms underlying lignin metabolism have been widely studied in model plants and woody trees, but seldom in fruits such as loquat, which undergo lignification. Here, twelve EjMYB genes, designed as EjMYB3-14, were isolated based on RNA-seq. Gene expression indicated that EjMYB8 and EjMYB9 were significantly induced in fruit with higher lignin content resulting from storage at low temperature (0°C), while two treatments (low temperature conditioning, LTC; heat treatment, HT) both alleviated fruit lignification and inhibited EjMYB8 and EjMYB9 expression. Dual-luciferase assays indicated that EjMYB8, but not EjMYB9, could trans-activate promoters of lignin-related genes EjPAL1, Ej4CL1 and Ej4CL5. Yeast one-hybrid assay indicated that EjMYB8 physically bind to Ej4CL1 promoter. Furthermore, the putative functions of EjMYB8 were verified using transient over-expression in both N. tabacum and loquat leaves, which increased lignin content. Moreover, combination of EjMYB8 and previously isolated EjMYB1 generated strong trans-activation effects on the Ej4CL1 promoter, indicating that EjMYB8 is a novel regulator of loquat fruit lignification.