Functional characterization of AbHog1 protein and its mediation of energy metabolism in regulating oxidative stress in Agaricus bisporus

Agaricus bisporus ( A. bisporus ) is highly susceptible to postharvest oxidative stress, which accelerates browning, tissue softening, and nutritional decline, resulting in shortened shelf life and substantial economic losses. CO 2 (6 %) modified atmosphere storage has been established to induce moderate oxidative stress, which subsequently activated the Hog1-MAPK pathway and thereby delayed quality deterioration. However, the specific regulatory role of AbHog1, the core kinase of this pathway, has yet to be fully elucidated. In this study, the downstream targets of the mitogen-activated protein kinase AbHog1 involved in the oxidative stress response were investigated. Results showed that oxidative stress treatment significantly attenuated postharvest browning and tissue softening. AbHog1 phosphorylation levels remained elevated during the mid-to-late storage period, suggesting that oxidative stress strengthened antioxidant defenses and maintained cellular homeostasis via persistent activation of the Hog1-MAPK signaling pathway. Utilizing AbHog1 as a bait, potential interacting targets were screened using a yeast two-hybrid (Y2H) system. Subsequent results confirmed that AbHog1 specifically interacted with the mitochondrial protein AbNsl through point-to-point Y2H, GST pull-down, and BiFC assays. Functional characterization via gene silencing and overexpression demonstrated that AbHog1 enhanced intracellular energy level by regulating the mitochondrial respiratory chain, thereby improving stress adaptability. These findings elucidated a novel AbHog1-AbNSL mediated regulatory mechanism governing postharvest quality deterioration in macrofungi, providing a precise molecular target for the development of targeted preservation strategies.