Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China; The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China; The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou, 310058, PR China.
Plant Physiol Biochem. 2019 Jun;139:731-737. doi: 10.1016/j.plaphy.2019.04.032. Epub 2019 Apr 26.
Many transcription factors (TFs), including NACs and MYBs, are involved in regulation of lignin biosynthesis during plant development and in responses to biotic and abiotic stresses. The lignin biosynthesis gene Ej4CL1 has been identified as a target for cold-induced TFs. We isolated a bHLH gene from loquat, EjbHLH1, the expression of which was negatively correlated with cold-induced fruit lignification. During low temperature storage (0 C), EjbHLH1 transcripts were stable but accumulated during low-temperature conditioning (LTC) treatment, an acclimation process that reduces lignification during subsequent storage at 0 C. Dual luciferase assays showed EjbHLH1 could repress Ej4CL1 promoter, but yeast one hybrid assay indicated EjbHLH1 is not able to bind to the Ej4CL1 promoter. Bimolecular fluorescence complementation (BIFC) indicated that EjbHLH1 could interact with EjAP2-1 and EjMYB2, two previously characterized fruit lignification related transcription factors and firefly luciferase complementation imaging assay indicated EjbHLH1, EjMYB2 and EjAP2-1 could form a ternary complex which enhanced repression of transcription from the Ej4CL1 promoter, reducing lignification at 0 C.
许多转录因子（TFs），包括 NAC 和 MYB，参与植物发育过程中木质素生物合成的调节以及对生物和非生物胁迫的响应。木质素生物合成基因 Ej4CL1 已被确定为冷诱导 TF 的靶标。我们从枇杷中分离出一个 bHLH 基因 EjbHLH1，其表达与冷诱导果实木质化呈负相关。在低温贮藏（0°C）期间，EjbHLH1 转录本稳定，但在低温驯化（LTC）处理期间积累，这是一个适应过程，可减少随后在 0°C 下贮藏时的木质化。双荧光素酶测定表明 EjbHLH1 可以抑制 Ej4CL1 启动子，但酵母单杂交测定表明 EjbHLH1 不能结合到 Ej4CL1 启动子上。双分子荧光互补（BIFC）表明 EjbHLH1 可以与 EjAP2-1 和 EjMYB2 相互作用，这两个因子是先前表征的与果实木质化相关的转录因子，萤火虫荧光互补成像测定表明 EjbHLH1、EjMYB2 和 EjAP2-1 可以形成三元复合物，从而增强对 Ej4CL1 启动子转录的抑制作用，减少 0°C 下的木质化。
