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

Abstract

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.