# Bacterial diversity and composition on the rinds of specific melon cultivars and hybrids from across different growing regions in the United States

## TL;DR

This study explores how the bacterial communities on melon rinds vary by region, rind netting, and melon type to improve food safety and shelf-life.

## Contribution

The study identifies regional influence as a key driver of melon rind bacterial diversity over melon type or rind netting.

## Key findings

- Bacterial diversity on melon rinds is significantly influenced by growing region and rind netting.
- Melon bacterial communities cluster more by region than by melon variety.
- Non-netted melons share a core microbiome of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae.

## Abstract

The goal of this study was to characterize the bacterial diversity on different melon varieties grown in different regions of the US, and determine the influence that region, rind netting, and variety of melon has on the composition of the melon microbiome. Assessing the bacterial diversity of the microbiome on the melon rind can identify antagonistic and protagonistic bacteria for foodborne pathogens and spoilage organisms to improve melon safety, prolong shelf-life, and/or improve overall plant health. Bacterial community composition of melons (n = 603) grown in seven locations over a four-year period were used for 16S rRNA gene amplicon sequencing and analysis to identify bacterial diversity and constituents. Statistically significant differences in alpha diversity based on the rind netting and growing region (p < 0.01) were found among the melon samples. Principal Coordinate Analysis based on the Bray-Curtis dissimilarity distance matrix found that the melon bacterial communities clustered more by region rather than melon variety (R2 value: 0.09 & R2 value: 0.02 respectively). Taxonomic profiling among the growing regions found Enterobacteriaceae, Bacillaceae, Microbacteriaceae, and Pseudomonadaceae present on the different melon rinds at an abundance of ≥ 0.1%, but no specific core microbiome was found for netted melons. However, a core of Pseudomonadaceae, Bacillaceae, and Exiguobacteraceae were found for non-netted melons. The results of this study indicate that bacterial diversity is driven more by the region that the melons were grown in compared to rind netting or melon type. Establishing the foundation for regional differences could improve melon safety, shelf-life, and quality as well as the consumers’ health.