Fungal microbiome shifts of avocado fruit from flowering to the ready-to-eat stage

Mycobiomes are directly affected by pre- and postharvest practices that may impact fruit quality. The fungal diversity and composition associated with ‘Hass’ avocados from flowering to the ready-to-eat stage was investigated using Next-generation (Illumina) sequencing of the internal transcribed spacer (ITS1) during the 2017/2018 season. The study aimed at understanding epiphytic (fructoplane) and endophytic (stem-end pulp) microbiome dynamics with particular emphasis on the presence of the pathogenic and beneficial fungal genera. A total of 1374325 ITS sequences were generated in this study. Sequences belonging to the Colletotrichum (Colletotrichum gloeosporioides), Alternaria (Alternaria alternata) and Epicoccum (Epicoccum nigrum) genera were detected as the most dominant postharvest decay causing fungal genera throughout the study period. Other decay causing genera detected included Fusarium (Fusarium sp.), Mucor (Mucor racemosus) and Botryosphaeria (Botryosphaeria sp.). Meanwhile, Aureobasidium (Aureobasidium pullulans) was detected as the dominant potential beneficial fungal genus. Postharvest interventions such as the prochloraz dip treatment had a non-targeted effect on the presence of Aureobasidium pullulans populations both on the avocado fructoplane and in the stem-end pulp. Similarly, the prochloraz dip treatment resulted in a decline in fungal richness (ACE index). The current study provides important baseline data for further exploration of microbial population shifts in avocado fruit as a foundation in the development of effective anthracnose and stem-end rot in avocados.