1-Aminocyclopropane-1-carboxylate deaminase producers associated to maize and other Poaceae species

Marie-Lara Bouffaud,Sébastien Renoud,Daniel Muller,Audrey Dubost,Yvan Moënne-Loccoz

doi:10.1186/s40168-018-0503-7

Abstract

BackgroundComplex plant-microbe interactions have been established throughout evolutionary time, many of them with beneficial effects on the host in terms of plant growth, nutrition, or health. Some of the corresponding modes of action involve a modulation of plant hormonal balance, such as the deamination of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC). Despite its ecological importance, our understanding of ACC deamination is impaired by a lack of direct molecular tools. Here, we developed PCR primers to quantify the ACC deaminase gene acdS and its mRNA in soil communities and assessed acdS+ microorganisms colonizing maize and other Poaceae species.ResultsEffective acdS primers suitable for soil microbial communities were obtained, enabling recovery of bona fida acdS genes and transcripts of diverse genetic backgrounds. High numbers of acdS genes and transcripts were evidenced in the rhizosphere of Poaceae, and numbers fluctuated according to plant genotype. Illumina sequencing revealed taxonomic specificities of acdS+ microorganisms according to plant host. The phylogenetic distance between Poaceae genotypes correlated with acdS transcript numbers, but not with acdS gene numbers or the genetic distance between acdS functional groups.ConclusionThe development of acdS primers enabled the first direct analysis of ACC deaminase functional group in soil and showed that plant ability to interact with soil-inhabiting acdS+ microorganisms could also involve particular plant traits unrelated to the evolutionary history of Poaceae species.

Highlights

Complex plant-microbe interactions have been established throughout evolutionary time, many of them with beneficial effects on the host in terms of plant growth, nutrition, or health
The acdS gene encoding ACC deaminase is highly conserved among microorganisms and has been used to study the phylogeny and diversity of ACC deaminase producers [18,19,20] in bacteria and micro-eukaryotes
Validation of quantitative PCR (qPCR) and quantitative reverse-transcription PCR (qRT-PCR) tools We developed primer sets (Additional file 1: Table S1) to amplify acdS gene sequences in the acdS reference database constructed

Summary

Introduction

Complex plant-microbe interactions have been established throughout evolutionary time, many of them with beneficial effects on the host in terms of plant growth, nutrition, or health. Development, and health of macroorganisms are strongly influenced by the interactions they develop with their associated microbial community [1,2,3] These interactions often involve nutrient exchanges between partners, the host typically providing organic carbon [4,5,6,7] while microorganisms supply amino acids or mineral nutrients, which results from various processes such as nitrogen fixation or phosphorus solubilization [8]. Many of these interactions are complex and entail the exchange of molecular signals [2].

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