Postharvest microbiota dynamics of mango fruit stem-end
Stem-end rots (SER) develop in mango fruit during fruit ripening and cause significant losses. SERs are caused by pathogenic fungi (e.g. Colletotrichum gloeosporioides, Alternaria alternata, Lasiodiplodia theobromae, Neofusicoccum, Dothiorella, Phomopsis mangiferae, and others) that endophytically colonize fruit stem during fruit development in the orchard and remain quiescent until the onset of fruit ripening. This work was conducted to characterize the endophytic microbiota in mango fruit stems and study the effect of different preharvest treatments on the composition of endophytic microbiological community in the stem-end tissue of the stored fruit. Microscopic observations showed that during the quiescent stage fungi colonize the phloem of fruit stem-end, and after switching to the pathogenic stage, they colonize the fruit parenchyma surrounding the stem, causing SER. Our initial results show that fungicide spray at the orchard during flowering, in March, could significantly change the endophytic community and reduce postharvest SER in September. Interestingly, fruits that were subjected to high light in the orchard developed less SER after storage. These fruits accumulated anthocyanins leading to red color peel, which was correlated with resistance to SER. Additionally, we show that harvesting 'Shelly' mango fruit with a short stem significantly reduced the occurrence of postharvest SER in comparison to fruit harvested without the stem. At harvest, the endophytic community was similar between fruit that were harvested with or without the stem. However, after cold storage and shelf-life the community of the fruits that were harvested without the stem shifted to a more pathogenic community, while the microorganism community of the fruit that was harvested with the stem contained mostly yeast. Collectively, our results show that pre- and postharvest treatments significantly modify the microbial community in the stem-end and therefore could reduce postharvest SERs.
Diskin, S., Lurie, S., Feygenberg, O., Maurer, D., Droby, S., Prusky, D. and Alkan, N. (2021). Postharvest microbiota dynamics of mango fruit stem-end. Acta Hortic. 1323, 195-200
endophyte, stem-end rot, anthocyanin, fungicide spray, harvesting methods