Sugars in an aqueous extract of the spent substrate of the mushroom Hypsizygus marmoreus induce defense responses in rice.

Plant defense responses are activated by various exogenous stimuli. We found that an aqueous extract of spent mushroom substrate used for the cultivation of Hypsizygus marmoreus induced defense responses in rice. Fractionation of the spent mushroom substrate extract indicated that the compounds responsible for this induction were neutral and hydrophilic molecules with molecular weights lower than 3 kDa.

Induction of defense responses by extracts of spent mushroom substrates in rice.

We investigated the effect of treatment with hot water extracts from the spent mushroom substrates (SMSs) of and on the resistance of rice leaves to infection. The spraying of the SMS extracts clearly suppressed the development of lesions caused by infection. The accumulation of phytoalexins momilactones A and B, oryzalexin A, and sakuranetin was markedly induced by the spraying of extracts.