Important innate differences in determining symbiotic responsiveness in host and non-hosts of arbuscular mycorrhiza

Shalini Vasan,David Cahill,Alok Adholeya,Divya Srivastava,Pushplata Prasad Singh

doi:10.1038/s41598-021-93626-6

Shalini Vasan, David Cahill + Show 3 more

Open Access

https://doi.org/10.1038/s41598-021-93626-6

Copy DOI

Abstract

Genetic components that regulate arbuscular mycorrhizal (AM) interactions in hosts and non-hosts are not completely known. Comparative transcriptomic analysis was combined with phylogenetic studies to identify the factors that distinguish AM host from non-host. Mycorrhized host, non-mycorrhized host and non-host cultivars of tomato (Solanum lycopersicum) were subjected to RNA seq analysis. The top 10 differentially expressed genes were subjected to extensive in silico phylogenetic analysis along with 10 more candidate genes that have been previously reported for AM-plant interactions. Seven distantly related hosts and four non-hosts were selected to identify structural differences in selected gene/protein candidates. The screened genes/proteins were subjected to MEME, CODEML and DIVERGE analysis to identify evolutionary patterns that differentiate hosts from non-hosts. Based on the results, candidate genes were categorized as highly influenced (SYMRK and CCaMK), moderately influenced and minimally influenced by evolutionary constraints. We propose that the amino acid and nucleotide changes specific to non-hosts are likely to correspond to aberrations in functionality towards AM symbiosis. This study paves way for future research aimed at understanding innate differences in genetic make-up of AM hosts and non-hosts, in addition to the theory of gene losses from the “AM-symbiotic toolkit”.

Highlights

Genetic components that regulate arbuscular mycorrhizal (AM) interactions in hosts and non-hosts are not completely known
Exhaustive in silico analysis have further enabled identification of fungal and plant targets involved in governing the symbiotic functioning[21,22,23], provided insights into the common symbiotic signalling pathway (CSSP)[24,25] and allowed large-scale analysis of gene loss and gene conservation in distantly related non-hosts and hosts to establish mycorrhizal symbiosis[11,18,26,27]
Grafter did not show any signs of colonization with AM fungus Rhizophagus irregularis was selected as the AM non-host for this study

Summary

Introduction

Genetic components that regulate arbuscular mycorrhizal (AM) interactions in hosts and non-hosts are not completely known. Exhaustive in silico analysis have further enabled identification of fungal and plant targets involved in governing the symbiotic functioning[21,22,23], provided insights into the common symbiotic signalling pathway (CSSP)[24,25] and allowed large-scale analysis of gene loss and gene conservation in distantly related non-hosts and hosts to establish mycorrhizal symbiosis[11,18,26,27]. The novel findings led to a series of further investigations wherein the concept of ‘independent losses’ of AM symbiosis-specific genes in non-hosts came into c onsideration[28,29] This was proposed to be the reason for the inability of non-hosts to form AM associations

Objectives

Methods

Results

Discussion

Conclusion