3rd Edition Of Plant Science and Molecular Biology World Conference 2026

Abstract

Lettuce is one of the most popular leafy greens in salads and has been facing problems with food waste, disease, and pathogen outbreaks. These issues are heavily influenced by the microbiome community on leaf surfaces. The dynamics of leaf trait– microbiome and interspecies microbial interactions influence product quality, growth, food waste, and consumer safety; therefore, understanding their roles in agricultural systems is necessary. In this study, we investigated the effects of lettuce genotypes, leaf hydrophobicity, stomata, and epidermal cells on the microbiome, and how these factors affect lettuce shelf life. Using a diverse lettuce panel of 498 accessions and 24 commercial varieties from Salinas (2020) and El Centro (2021) field trials, we analysed bacterial communities via 16S rRNA sequencing and linked them to lettuce genotypes and phenotypes.
The most common bacterial families identified were Morganellaceae, Erwiniaceae, Pseudomonadaceae, Bacillaceae, and Enterobacteriaceae. Leaf surface traits affecting bacterial abundance and diversity included stomatal length and width, stomatal index, and leaf hydrophobicity. Overall, species diversity was negatively correlated with stomatal size, hydrophobicity, and stomatal index. Stomatal size and density were correlated with Corynebacteriaceae, Alcaligenaceae, Morganellaceae, and Erwiniaceae, while leaf hydrophobicity—which influences shelf life—was correlated with Propionibacteriaceae, Pseudomonadaceae, Erwiniaceae, and Morganellaceae. Genome-wide association studies (GWAS) were conducted on leaf surface traits and co-mapped with bacterial taxa abundance as extended phenotypes to identify candidate genes underlying the effects of leaf surface traits on bacterial communities and their impacts on postharvest quality and food safety. These findings highlight the importance of leaf surface traits in shaping microbiome diversity and abundance, which may influence growth, disease resistance, shelf life, and food safety in lettuce.