State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticultural Science, South China Agricultural University, Guangzhou 510642, China.
Key Laboratory of Plant Hormones and Development Regulation of Chongqing, School of Life Sciences, Chongqing University, Chongqing 400044, China.
Cell Rep. 2023 Aug 29;42(8):112832. doi: 10.1016/j.celrep.2023.112832. Epub 2023 Jul 25.
The mitogen-activated protein kinase (MAPK) cascade consisting of MKKK, MKK, and MPK plays an indispensable role in various plant physiological processes. Previously, we showed that phosphorylation of MabZIP21 by MaMPK6-3 is involved in banana fruit ripening, but the regulatory mechanism by which MKK controls banana fruit ripening remains unclear. Here, ripening-induced MaMKK1 from banana fruit is characterized, and transiently overexpressing and silencing of MaMKK1 in banana fruit accelerates and inhibits fruit ripening, respectively, possibly by influencing phosphorylation and activity of MPK. MaMKK1 interacts with and phosphorylates MaMPK6-3 and MaMPK11-4 mainly at the pTEpY residues, resulting in MPK activation. MaMPK11-4 phosphorylates MabZIP21 to elevate its transcriptional activation ability. Transgenic tomato fruit expressing MabZIP21 ripen quickly with a concomitant increase in MabZIP21 phosphorylation. Additionally, MabZIP21 activates MaMPK11-4 and MaMKK1 transcription to form a regulatory feedback loop. Collectively, here we report a regulatory pathway of the MaMPK6-3/11-4-MabZIP21 module in controlling banana fruit ripening.
由 MKKK、MKK 和 MPK 组成的丝裂原活化蛋白激酶 (MAPK) 级联反应在各种植物生理过程中起着不可或缺的作用。先前，我们表明 MabZIP21 由 MaMPK6-3 磷酸化参与香蕉果实成熟，但 MKK 控制香蕉果实成熟的调控机制仍不清楚。在这里，我们对成熟诱导的香蕉果实 MaMKK1 进行了表征，并在香蕉果实中瞬时过表达和沉默 MaMKK1，分别加速和抑制果实成熟，可能通过影响 MPK 的磷酸化和活性。MaMKK1 与 MaMPK6-3 和 MaMPK11-4 相互作用并主要在 pTEpY 残基上磷酸化 MaMPK6-3 和 MaMPK11-4，导致 MPK 激活。MaMPK11-4 磷酸化 MabZIP21 以提高其转录激活能力。表达 MabZIP21 的转基因番茄果实成熟迅速，同时 MabZIP21 磷酸化增加。此外，MabZIP21 激活 MaMPK11-4 和 MaMKK1 转录，形成调节反馈回路。总之，在这里我们报告了 MaMPK6-3/11-4-MabZIP21 模块调控香蕉果实成熟的调控途径。
