Changes in cell wall characteristics and expression of MiERF12, MiERF109-like, and MiERF113 during mango softening

Abstract

Mango fruit softening is the primary reason for the reduction in shelf life and the subsequent decrease in market value. In this study, we investigated the roles of ethylene response factor (ERF) in regulating mango fruit softening in response to 1-methylcyclopropene (1-MCP) and ethylene (ETH) treatments was investigated. The action mechanism of the cellular microstructure, key structural components of the cell wall, cell wall metabolizing enzymes, and the ERF were evaluated. Results showed that mango softening was induced by ETH and inhibited by 1-MCP. ETH treatment caused cellular microstructural changes, including cell wall thinning and distortion, while 1-MCP treatment preserved cell wall integrity. Biochemical and molecular assays indicated that 1-MCP and ETH regulated fruit softening by altering cell wall polysaccharide fractions, cell wall degrading enzyme activities (pectate lyase, pectin methylesterase, β-galactosidase, cellulase) and their gene expression (MiPLY8, MiPME3, Miβ-CAL, MiPG2). Meanwhile, ETH strongly induced the expression of MiERF12, MiERF021-like, MiERF109-like, and MiERF113. Virus-induced gene silencing (VIGS) results indicated MiERF109-like and MiERF113 promoted mango fruit softening, whereas MiERF12 inhibited softening. These findings emphasize that MiERF12, MiERF109-like and MiERF113 could play an important role in regulating postharvest ripening and softening of mango, and clarify the potential association of ERFs with cell wall metabolism and structure in mango.