Harvesting Mango Fruit with a Short Stem-End Altered Endophytic Microbiome and Reduce Stem-End Rot

Abstract

Stem-end rot (SER) is a serious postharvest disease of mango fruit grown in semi-dry area. Pathogenic and non-pathogenic microorganisms endophytically colonize fruit stem-end. As fruit ripens, some pathogenic fungi switch from endophytic colonization to necrotrophic stage and cause SER. Various pre/post-treatments may alter the stem-end community and modify SER incidence. This study investigates the effects of harvesting mango with or without short stem-end on fruit antifungal and antioxidant activities, the endophytic microbiome, and SER during fruit storage. Our results show that harvesting mango with short stem significantly reduced SER during storage. At harvest, fruit harvested with or without stem exhibit a similar microorganisms community profile. However, after storage and shelf life, the community of fruit without stem shifted toward more SER-causing-pathogens, such as Lasiodiplodia, Dothiorella, and Alternaria, and separated from the community of fruit with stem. This change correlated to the high antifungal activity of stem extract that strongly inhibited both germination and growth of Lasiodiplodia theobromae and Alternaria alternata. Additionally, fruit that was harvested with stem displayed more antioxidant activity and less ROS. Altogether, these findings indicate that harvesting mango with short stem leads to higher antifungal and antioxidant activity, retaining a healthier microbial community and leading to reduced postharvest SER.

Double‐stranded RNA targeting fungal ergosterol biosynthesis pathway controls Botrytis cinerea and postharvest grey mould

“…The effect of dsRNA‐ERG on B . cinerea conidia germination was tested using an in vitro micro‐assay (Galsurker et al ., 2020 ; Gatto et al ., 2011 ). Conidia suspension (10 μL) was seeded on a glass slide, containing 0.2% Sabouraud maltose broth (SMB; 10 g Peptone (Difco), 40 g Maltose (Caisson labs, Smithfield, Utah, United States) per 1 L) and incubated in a humid petri dish for 24 h at room temperature.…”

“…The plates were incubated at room temperature and O.D measurement at 600 nm was taken every hour during 48–72 h using Synergy LX plate reader (BioTek, Winooski, Vermont). The absorbance of three wells of repeats was averaged together and was background‐corrected by subtracting the average absorbance of media alone at time zero (Galsurker et al ., 2020 ; Langvad, 1999 ). Growth inhibition percentage was calculated (O.D in control well − O.D in treatment well)/O.D in control well × 100) (Meletiadis et al ., 2003 ).…”

Stem-end rot in major tropical and sub-tropical fruit species

“…The earliest indicator of stem-end rot incidence at harvest was the infection level in peduncle tissue sampled 11 weeks after flowering (Johnson et al, 1991b). As the fruit ripens, some pathogenic fungi switch from endophytic colonization to necrotrophic stage and cause stem-end rot (Galsurker et al, 2020). Stem-end rot fungi are also found as endophytes in host tissue and can cause twig and branch dieback, cankers and fleck-spots on inflorescence and stem tissues.…”

Mango Endophyte and Epiphyte Microbiome Composition during Fruit Development and Post-Harvest Stages

“…Several studies have characterised diseases such as stem-end rot [13][14][15] and anthracnose of mango [16][17][18] at the pre-and post-harvest stage, assessed the pathogenicity of post-harvest fungal pathogens [19][20][21] and the efficacy of different post-harvest control strategies of stem-end rot [22][23][24][25] and anthracnose [26][27][28][29][30][31][32]. To date, microbial dynamics of mango fruit have only been studied at the post-harvest stage [33].…”