Abstract:[Background] Post-harvest diseases are a major factor restricting the industrialization of tropical fruit commodities. [Objective] To screen efficient biological inhibitors for maintaining the post-harvest storage quality of Syzygium samarangense by identifying the post-harvest rot-causing pathogens. [Methods] The main pathogens on the fruit surface of S. samarangense ‘Daye’ were isolated by the tissue isolation and identified by Koch’s postulates, morphological observation and ITS sequence homology analysis. The efficient inhibitors against the pathogens were screened by in vitro and in vivo experiments. [Results] Five species of pathogenic fungi were isolated and identified as Lasiodiplodia rubropurpurea, Colletotrichum fructicola, Fusarium equiseti, Pestalotiopsis microspora, and Neopestalotiopsis clavispora, respectively. F. equiseti was discovered to cause fruit rot in Syzygium samarangense. The results of in vitro experiments showed that 0.3 g/L caffeic acid (CA) had the highest inhibition rates on the five species of pathogenic fungi, followed by salicylic acid, and p-coumaric acid had the weakest inhibitory effects. The results of in vivo experiments showed that the treatment with CA maintained the hardness, retarded the decomposition of flocculent soft matter, maintained high content of vitamin C and titratable acid, and decreased the accumulation rate of malondialdehyde in the fruits of S. samarangense ‘Daye’. In addition, CA reduced the cell membrane permeability and delayed the membrane lipid peroxidation, being conducive to maintaining the storage quality of post-harvest fruits of S. samarangense ‘Daye’. [Conclusion] Five species of pathogens were isolated and identified from the post-harvest fruits of S. samarangense ‘Daye’, and the biological inhibitors were screened out. The results provide a theoretical basis for the biocontrol of diseases affecting the post-harvest fruits of S. samarangense.
