MaMPK19, a key gene enhancing cold resistance by activating the CBF pathway in banana

MPKs play an essential part role in the process of plant low temperature stress. In this study, the specific inhibitor SB203580 of MPK was used to spray banana leaves and MaMPK19 was overexpressed in N.benthamiana and banana to explore the effect of MaMPK19 on cold resistance and the regulation mode of downstream genes. Additionally, we optimized the method of genetic transformation of banana laying the foundation for the establishment of an efficient genetic transformation system. The results showed that 40 μmol L⁻¹ SB203580 could significantly reduce the expression of MaMPK19 and MaCBFs, as well as weaken the cold resistance of banana at 4 °C. After agrobacterium tumefaciens infection, the regeneration rates of adventitious buds in ‘Tianbao’, ‘Brazilian’ and‘Indonesia’ (Musa spp. AAA Group, Cavendish) reached 10.43%, 15.81% and 14.23%, respectively. And the positive rates reached 10.71%, 2.25% and 6.94%, respectively. Overexpression of MaMPK19 enhanced the cold resistance of N.benthamiana and bananas. MaMPK19 promoted the expression of MaICE1, MaDREB1D and MaCOR413. Furthermore, MaMPK19 increased POD activity and the content of ABA and JA. Our study highlights the importance of MaMPK19 in improving the cold resistance of bananas and provides a reference for biological breeding.