Figure 6.

MaMADS1 inhibits MaNAC083 expression and promotes ethylene biosynthesis. (A) MaMADS1 represses MaNAC083 promoter activity in a DLR assay in tobacco leaves. The left panel shows reporter and effector constructs schematically. For the empty vector with the ethylene biosynthesis gene promoter reporter, the LUC/REN ratio was set as 1. (B–F) Transient overexpression of MaMADS1 in banana fruit. (B) Banana fruit ripening transiently overexpresses MaMADS1 and empty vector. (C) Western blot showing MaMADS1 protein level in bananas transiently overexpressing empty vector and MaMADS1. Protein recognition used fruit pulp tissues from the injection area, with actin as a loading control. (D) CI, firmness, and ethylene production during the ripening process in MaMADS1-overexpressing and control banana fruit. (E) Relative expression of MaNAC083 in MaMADS1-overexpressing and control banana fruit. (F) MaACS1, MaACO1, MaACO4, MaACO5, and MaACO8 gene expression in MaMADS1-overexpressing and control bananas. (G–K) Transient silencing of MaMADS1 in banana fruit. (G) Appearance of banana fruit infiltrated with empty vector (control) and pTRV2-MaMADS1. (H) RT–qPCR showing MaMADS1 mRNA level in infiltrated banana fruit. (I) Changes in CI, firmness, and ethylene production in banana fruit as shown in (G). (J) Relative expression of MaNAC083 in banana fruit as shown in (G). (K) Expression of MaACS1, MaACO1, MaACO4, MaACO5, and MaACO8 in banana fruit as shown in (G). Error bars in (A, D, G, I) and (E, F, J, K) denote the standard error from six replicates and triplets, respectively. Student's t-test, ^**P < .01.