Postharvest anthracnose, caused by the fungus Colletotrichum gloeosporioides, is one of the most important postharvest diseases of mangoes worldwide. Bacillus siamensis (B. siamensis), as a biocontrol bacteria, has significant effects on inhibiting disease and improving the quality of fruits and vegetables. In this study, pre-storage application of B. siamensis significantly induced disease resistance and decreased disease index (DI) of stored mango fruit. To investigate the induction mechanisms of B. siamensis, comparative transcriptome analysis of mango fruit samples during the storage were established. In total, 234,808 unique transcripts were assembled and 56,704 differentially expressed genes (DEGs) were identified by comparative transcriptome analysis. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs showed that most of the DEGs involved in plant-pathogen interaction, plant hormone signal transduction, and biosynthesis of resistant substances were enriched. Fourteen DEGs related to disease-resistance were validated by qRT-PCR, which well corresponded to the FPKM value obtained from the transcriptome data. These results indicate that B. siamensis treatment may act to induce disease resistance of mango fruit by affecting multiple pathways. These findings not only reveal the transcriptional regulatory mechanisms that govern postharvest disease, but also develop a biological strategy to maintain quality of post-harvest mango fruit.

Regulation of fruit ripening is one of the most important topics in postharvest storage. Effects of 1-methylcyclopropene (1-MCP) greatly depend on the responsiveness of fruit cultivar to this molecule. Although 1-MCP has been used in postharvest preservation of many fruit species, its effects on ripening process, including ethylene production, and softening of banana, mango, and papaya are still not very clear. In the present study, we comparatively investigated the effects of 1-MCP fumigation treatment (1 μL L⁻¹ for 20 h) on ripening behavior and texture qualities of the three fruits during storage at 15 °C. Results showed that 1-MCP treatment not only suppressed the production but also delayed the peak points of ethylene in banana and mango. However, it only significantly delayed the emergence of peak, but didn’t suppress the production of ethylene in papaya. Meanwhile, 1-MCP treated papayas showed the lowest malondialdehyde (MDA) content, cell membrane permeability (CMP) and activities of polygalacturonase (PG) and cellulose (CX), accompanied by the highest firmness and protopectin content. Furthermore, 1-MCP treatment slowed down the changes of pulp cell structure in three kinds of fruit. Thus, the findings suggest that postharvest application of 1-MCP has potential in banana and mango fruits due to both prolonging storage-life and ensuring the texture quality, whereas it is not suitable for papaya fruit because of the abnormal softening and the poor texture.