Differentiation of 1-aminocyclopropane-1-carboxylate (ACC) deaminase from its homologs is the key for identifying bacteria containing ACC deaminase

Abstract

1-Aminocyclopropane-1-carboxylate (ACC) deaminase-mediated reduction of ethylene generation in plants under abiotic stresses is a key mechanism by which bacteria can promote plant growth. Misidentification of ACC deaminase and the ACC deaminase structure gene (acdS) can lead to overestimation of the number of bacteria containing ACC deaminase and their function in ecosystems. Previous non-specific amplification of acdS homologs has led to an overestimation of the horizontal transfer of acdS genes. Here, we designed consensus-degenerate hybrid oligonucleotide primers (acdSf3, acdSr3 and acdSr4) based on differentiating the key residues in ACC deaminases from those of homologs for specific amplification of partial acdS genes. PCR amplification, sequencing and phylogenetic analysis identified acdS genes from a wide range of proteobacteria and actinobacteria. PCR amplification and a genomic search did not find the acdS gene in bacteria belonging to Pseudomonas stutzeri or in the genera Enterobacter, Klebsiella or Bacillus. We showed that differentiating the acdS gene and ACC deaminase from their homologs was crucial for the molecular identification of bacteria containing ACC deaminase and for understanding the evolution of the acdS gene. We provide an effective method for screening and identifying bacteria containing ACC deaminase.

Influences of Climate on Phyllosphere Endophytic Bacterial Communities of Wild Poplar

“…For instance, volatile organic compounds such as acetoin and butanediol elicits stomatal closure, helping the plant prevent water loss from transpiration (Cho et al, 2008) and improving drought tolerance (Saha and Bothast, 1999;Celińska and Grajek, 2009;Ji et al, 2011;Khalifa et al, 2016). In addition, Pseudomonas, Klebsiella, Erwinia, Serratia and Pantoea species are known to be ACC deaminase-producing bacteria and therefore able to regulate plant ethylene levels inducing tolerance to drought stress (Li et al, 2015;Saikia et al, 2018;Danish and Zafar-ul-Hye, 2019). Therefore, while climate and weather data had a limited impact on microbial community composition, community ASVs significantly correlated with environmental constraints such as vapor pressure deficit could enhance drought tolerance in plant inhabiting hot-dry environments.…”

Root ethylene mediates rhizosphere microbial community reconstruction when chemically detecting cyanide produced by neighbouring plants

“…To date, there is no evidence of direct interactions between Catenulispora sp. and plant phytohormones, but species belonging to Catenulisporaceae have been reported to act as plantassociated bacteria strengthening root colonization by producing the enzyme ACC deaminase, which controls the endogenous ethylene (ET) levels [68,69]. In addition to the increase in Catenulispora sp.…”

Rhizosphere pseudomonads as probiotics improving plant health

“…Plant growth may be actively promoted by microbial modifications of the location and levels of plant growth hormones. Roles for changed levels of the auxin, indole acetic acid (IAA), and ethylene in response to microbial production of the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase have been well documented (Glick, 1995(Glick, , 2012Glick et al, 2007;Li et al, 2015). The ACC deaminase destroys ACC, the precursor of ethylene, promoting enhanced growth through responses to IAA.…”