title: Rhizosphere bacteria containing 1-aminocyclopropane-1-carboxylate deaminase increase yield of plants grown in drying soil via both local and systemic hormone signalling.
abstract: Decreased soil water availability can stimulate production of the plant hormone ethylene and inhibit plant growth. Strategies aimed at decreasing stress ethylene evolution might attenuate its negative effects. An environmentally benign (nonchemical) method of modifying crop ethylene relations - soil inoculation with a natural root-associated bacterium Variovorax paradoxus 5C-2 (containing the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase that degrades the ethylene precursor ACC), was assessed with pea (Pisum sativum) plants grown in drying soil. Inoculation with V. paradoxus 5C-2, but not with a transposome mutant with massively decreased ACC deaminase activity, improved growth, yield and water-use efficiency of droughted peas. Systemic effects of V. paradoxus 5C-2 included an amplified soil drying-induced increase of xylem abscisic acid (ABA) concentration, but an attenuated soil drying-induced increase of xylem ACC concentration. A local bacterial effect was increased nodulation by symbiotic nitrogen-fixing bacteria, which prevented a drought-induced decrease in nodulation and seed nitrogen content. Successfully deploying a single bacterial gene in the rhizosphere increased yield and nutritive value of plants grown in drying soil, via both local and systemic hormone signalling. Such bacteria may provide an easily realized, economic means of sustaining crop yields and using irrigation water more efficiently in dryland agriculture.
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Belimov
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Dodd
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: Nikos
authors.initials: N
authors.lastname: Hontzeas
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: Julian C
authors.initials: JC
authors.lastname: Theobald
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: Vera I
authors.initials: VI
authors.lastname: Safronova
authors.affiliation: All-Russia Research Institute for Agricultural Microbiology, Podbelskogo Sh. 3, Pushkin-8, 196608, St. Petersburg, Russian Federation;The Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK;Department of Biology, University of Waterloo, Waterloo, Canada, ON N2L 3G1.
authors.forename: William J
authors.initials: WJ
authors.lastname: Davies
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000064:Acclimatization; D019755:Carbon-Carbon Lyases / Q000235:genetics / Q000378:metabolism*; D003681:Dehydration; D005030:Ethylenes / Q000378:metabolism; D018532:Pisum sativum / Q000254:growth & development* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism; D012230:Rhizobiaceae / Q000235:genetics / Q000378:metabolism*; D012987:Soil
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D012987:Soil; D000040:Abscisic Acid; C036216:ethylene; C033634:1-aminocyclopropane-1-carboxylate deaminase; D019755:Carbon-Carbon Lyases