Seed endophytes of malting barley from different locations are shaped differently and are associated with malt quality traits

Authors: Ajayi, Oyeyemi; Mahalingam, Ramamurthy

Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2025
Publication Date: 2/5/2025
Citation: Ajayi, O.O., Mahalingam, R. 2025. Seed endophytes of malting barley from different locations are shaped differently and are associated with malt quality traits. BMC Plant Biology. 151(2025). https://doi.org/10.1101/2024.05.12.593598.
DOI: https://doi.org/10.1101/2024.05.12.593598

Interpretive Summary: Plant seeds are home to diverse microbes. However, little is known about the relationships between microbes and malting and how the composition of the microbes contributes to crop health. To this end, we investigated the microbes in barley seed of three recommended barley genotypes grown in different locations and associated them with malt quality traits like barley protein, diastatic power, malt extract, etc. Increased abundance and diversity of these microbes were negatively correlated with malt quality traits and may suggest that more abundant microbes in the seed may negatively impact malt quality. In relation to the composition of the seed microbes and how that may impact crop health, we observed that both beneficial and pathogenic microbes cohabit the seed and may have evolved to sustain crop health. These results contribute to our understanding of the function of microbes in relation to malting and crop health.

Technical Abstract: Maximizing microbial functions for improving crop performance requires better understanding of the important drivers of plant-associated microbiomes. However, it remains unclear the forces that shapes microbial structure and assembly, and how plant seed-microbiome interactions impact grain quality. In this work, we characterized the seed endophytic microbial communities of malting barley from different geographical locations and investigated associations between microbial (bacterial and fungal) species diversity and malt quality traits. Host genotype, location, and interactions (genotype x location) significantly impacted the seed endophytic microbial communities. Taxonomic composition analysis identified the most abundant genera for bacterial and fungal communities to be Bacillus (belonging to phylum Firmicutes) and Blumeria (belonging to phylum Ascomycota), respectively. We observed that a greater proportion of bacterial amplicon sequence variants (bacterial ASVs) were shared across genotypes and across locations while the greater proportion of the fungal ASVs were unique to each genotype and location. Association analysis showed a significant negative correlation between bacterial alpha diversity indices (Faith PD and Shannon indices) and malt quality traits for barley protein (BP), free amino nitrogen (FAN), diastatic power (DP) and alpha amylase (AA), while fungal alpha diversity (Shannon and Simpson) showed significant negative relationship with ß-D-glucan content. In addition, some bacterial and fungal genera were significantly associated with malt extract (ME) -a key trait for maltsters and brewers. We conclude that barley genotype, location, and their interactions shape the seed endophytic microbiome and is key to microbiome manipulation and management during barley production and/or malting.