Cai Jianfa, Mo Xuelian, Wen Chenjin, Gao Zhen, Chen Xu, Xue Cheng
College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Horticultural Plant Biology and Metabolomics Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Int J Mol Sci. 2021 Dec 22;23(1):101. doi: 10.3390/ijms23010101.
Strawberry is a soft fruit with short postharvest life, due to a rapid loss of firmness. Pectin methylesterase (PME)-mediated cell wall remodeling is important to determine fruit firmness and softening. Previously, we have verified the essential role of in regulation of PME-mediated strawberry fruit softening. However, the regulatory network involved in PME-mediated fruit softening is still largely unknown. Here, we identified an R2R3-type MYB transcription factor FvMYB79, which activates the expression level of , thereby accelerating fruit softening. During fruit development, co-expressed with , and this co-expression pattern was opposite to the change of fruit firmness in the fruit of 'Ruegen' which significantly decreased during fruit developmental stages and suddenly became very low after the color turning stage. Via transient transformation, FvMYB79 could significantly increase the transcriptional level of , leading to a decrease of firmness and acceleration of fruit ripening. In addition, silencing of showed an insensitivity to ABA-induced fruit ripening, suggesting a possible involvement of in the ABA-dependent fruit softening process. Our findings suggest FvMYB79 acts as a novel regulator during strawberry ripening via transcriptional activation of , which provides a novel mechanism for improvement of strawberry fruit firmness.
草莓是一种采后寿命较短的软质果实，这是由于其硬度会迅速丧失。果胶甲酯酶（PME）介导的细胞壁重塑对于决定果实硬度和软化很重要。此前，我们已经证实了 在调控PME介导的草莓果实软化过程中的关键作用。然而，参与PME介导的果实软化的调控网络在很大程度上仍然未知。在此，我们鉴定出一个R2R3型MYB转录因子FvMYB79，它可激活 的表达水平，从而加速果实软化。在果实发育过程中， 与 共表达，且这种共表达模式与‘Ruegen’果实硬度的变化相反，‘Ruegen’果实在发育阶段硬度显著下降，在转色期后突然变得很低。通过瞬时转化，FvMYB79可显著提高 的转录水平，导致硬度降低并加速果实成熟。此外， 的沉默表现出对ABA诱导的果实成熟不敏感，这表明 可能参与了ABA依赖的果实软化过程。我们的研究结果表明，FvMYB79通过转录激活 在草莓成熟过程中作为一种新型调节因子发挥作用，这为改善草莓果实硬度提供了一种新机制。
