The mechanism involved in enhancing the biological control efficacy ofRhodotorula mucilaginosawith salicylic acid to postharvest green mold decay of oranges

The main postharvest pathogen of citrus fruit isPenicillium digitatum. The present study looked at the role ofRhodotorula mucilaginosaenhanced with 0.2 mM salicylic acid (SA) on pH, lignin content accumulation and growth dynamics as a resistance mechanism againstP.digitatumin orange fruit. Our findings revealed that the increase in lignin content at 20 degrees C storage temperature resulted in the significant decrease (P <= 0.05) in the lesion diameter in fruit treated withR.mucilaginosaenhanced with or without 0.2 mM SA compared to the untreated fruit (control). In addition, the pH values of the fruit treated withR.mucilaginosaenhanced with or without 0.2 mM SA were 4.43 +/- 0.07 and 4.15 +/- 0.11, respectively, around the infection site compared to the untreated group. Moreover, the in vivo trial showed that the addition of 0.2 mM SA to the antagonist augmented its growth, and subdued substantially the hyphae and spore germination ofP.digitatumin vitro. Also, lower levels of malondialdehyde (MDA) and hydrogen peroxide (H(2)O(2))content were observed in fruit treated with the antagonist enhanced with or without 0.2 mM SA compared to the control. The results established that pH, lignin content accumulation and growth of the yeast played a significant role in the control of green mold decay of orange fruit.