Fungal microbiome shifts on avocado fruit associated with a combination of postharvest chemical and physical interventions

Aim of the Study The aim was to characterize the baseline microbial population of the avocado carposphere and understand shifts in community structure from the harvest to ready-to-eat stages. Methods and Results The changes in surface or stem-end (SE) fungal microbiomes at the postharvest stage of avocado fruit were studied using next-generation sequencing of the internal transcribed spacer region. Avocado fructoplane and SE pulp fungal richness differed significantly between postharvest stages with a decline following prochloraz dip treatments. Known postharvest decay-causing genera, Colletotrichum, Fusarium, Alternaria, Epicoccum, Penicillium and Neofusicoccum were detected, with Papiliotrema, Meyerozyma and Aureobasidium confirmed as the most dominant potentially beneficial genera. Postharvest interventions such as prochloraz had a negative non-target effect on the presence of Papiliotrema flavescens on the avocado fructoplane. Conclusion Our findings reveal a core community of beneficial and pathogenic taxa in the avocado fructoplane and further highlight the reduction of pathogenic fungi as a consequence of fungicide use. Significance and Impact of the Study The current study provides important baseline data for further exploration of fungal population shifts in avocado fruit driven by chemical (fungicide) as well as physical (cold storage) interventions.