Changes in root microbiome during wheat evolution

Somayeh Gholizadeh,Seyed Abolghasem Mohammadi,Ghasem Hosseini Salekdeh

doi:10.1186/s12866-022-02467-4

Abstract

BackgroundAlthough coevolutionary signatures of host-microbe interactions are considered to engineer the healthy microbiome of humans, little is known about the changes in root-microbiome during plant evolution. To understand how the composition of the wheat and its ancestral species microbiome have changed over the evolutionary processes, we performed a 16S rRNA metagenomic analysis on rhizobacterial communities associated with a phylogenetic framework of four Triticum species T. urartu, T. turgidum, T. durum, and T. aestivum along with their ancestral species Aegilops speltoides, and Ae. tauschii during vegetative and reproductive stages.ResultsIn this study, we illustrated that the genome contents of wild species Aegilops speltoides and Ae. tauschii can be significant factors determining the composition of root-associated bacterial communities in domesticated bread wheat. Although it was found that domestication and modern breeding practices might have had a significant impact on microbiome-plant interactions especially at the reproductive stage, we observed an extensive and selective control by wheat genotypes on associated rhizobacterial communities at the same time. Our data also showed a strong genotypic variation within species of T. aestivum and Ae. tauschii, suggesting potential breeding targets for plants surveyed.ConclusionsThis study performed with different genotypes of Triticum and Aegilops species is the first study showing that the genome contents of Ae. speltoides and Ae. tauschii along with domestication-related changes can be significant factors determining the composition of root-associated bacterial communities in bread wheat. It is also indirect evidence that shows a very extensive range of host traits and genes are probably involved in host-microbe interactions. Therefore, understanding the wheat root-associated microbiome needs to take into consideration of its polygenetic mosaic nature.

Highlights

Coevolutionary signatures of host-microbe interactions are considered to engineer the healthy microbiome of humans, little is known about the changes in root-microbiome during plant evolution
The rhizosphere is influenced by the plant developmental stage in wheat At first, we visualized the Bray-Curtis distances between samples using principal coordinates analysis (PCoA) to investigate the dissimilarity between sample types across two plant growth stages
Considering rhizobacterial communities at the reproductive stage, we presented that the rhizosphere communities of cultivated species aestivum and durum and wild species T. turgidum were more similar to Ae. speltoides than other wild diploid relatives when comparing the value of their pairwise community composition dissimilarity

Summary

Introduction

Coevolutionary signatures of host-microbe interactions are considered to engineer the healthy microbiome of humans, little is known about the changes in root-microbiome during plant evolution. To understand how the composition of the wheat and its ancestral species microbiome have changed over the evolutionary processes, we performed a 16S rRNA metagenomic analysis on rhizobacterial communities associated with a phylogenetic framework of four Triticum species T. urartu, T. turgidum, T. durum, and T. aestivum along with their ancestral species Aegilops speltoides, and Ae. tauschii during vegetative and reproductive stages. Understanding how the composition of the host species microbiome has changed over the evolutionary processes requires the inclusion of the microbiomes of phylogenetic outgroups (i.e., wild and close species) into analyses of plant microbiomes. A correlation between host phylogenetic distances and the clustering of rhizosphere microbiome was reported for Poaceae species [10], Brassica napus [11], different species from monocots and dicots [12], but not for distant relatives of Arabidopsis [13]. Distinct rhizobacterial communities were observed between domesticated plants and their wild ancestors in barley [17], maize [18], wheat [19], Agave [20], and common bean [21] compared with their respective wild ancestors

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