TY - JOUR

T1 - Rhizosphere bacteria containing 1-aminocyclopropane-1-carboxylate deaminase increase growth and photosynthesis of pea plants under salt stress by limiting Na+ accumulation

AU - Wang, Qiyuan

AU - Dodd, Ian C.

AU - Belimov, Andrey A.

AU - Jiang, Fan

PY - 2016/1/6

Y1 - 2016/1/6

N2 - Although plant salt tolerance has been improved by soil inoculation with rhizobacteria containing the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase (which metabolises ACC, the immediate precursor of the phytohormone ethylene), it is not always clear whether ion homeostasis and plant water relations are affected. When pea (Pisum sativum L. cv. Alderman) was grown with 70 and 130 mM NaCl, the ACC-deaminase containing rhizobacterium Variovorax paradoxus 5C-2 increased total biomass by 25 and 54% respectively. Nutrient flow modelling showed that V. paradoxus 5C-2 increased K uptake and root to shoot K flow, but decreased Na flow and increased Na deposition in roots. Thus, shoot K+ : Na+ ratio increased following V. paradoxus 5C-2 inoculation. At 70 and 130 mM NaCl, rhizobacterial inoculation decreased stomatal resistance by 14 and 31% and decreased xylem balancing pressure by 7 and 21% respectively. Furthermore, rhizobacterial inoculation improved photosynthetic efficiency (F-v/F-m) by 12 and 19% and increased maximal electron transport rate (ETR) by 18 and 22% at 70 and 130 mM NaCl respectively. Thus V. paradoxus 5C-2 mitigates salt stress by improving water relations, ion homeostasis and photosynthesis of pea plants, and may provide an economic means of promoting growth of plants exposed to salt stress.

AB - Although plant salt tolerance has been improved by soil inoculation with rhizobacteria containing the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase (which metabolises ACC, the immediate precursor of the phytohormone ethylene), it is not always clear whether ion homeostasis and plant water relations are affected. When pea (Pisum sativum L. cv. Alderman) was grown with 70 and 130 mM NaCl, the ACC-deaminase containing rhizobacterium Variovorax paradoxus 5C-2 increased total biomass by 25 and 54% respectively. Nutrient flow modelling showed that V. paradoxus 5C-2 increased K uptake and root to shoot K flow, but decreased Na flow and increased Na deposition in roots. Thus, shoot K+ : Na+ ratio increased following V. paradoxus 5C-2 inoculation. At 70 and 130 mM NaCl, rhizobacterial inoculation decreased stomatal resistance by 14 and 31% and decreased xylem balancing pressure by 7 and 21% respectively. Furthermore, rhizobacterial inoculation improved photosynthetic efficiency (F-v/F-m) by 12 and 19% and increased maximal electron transport rate (ETR) by 18 and 22% at 70 and 130 mM NaCl respectively. Thus V. paradoxus 5C-2 mitigates salt stress by improving water relations, ion homeostasis and photosynthesis of pea plants, and may provide an economic means of promoting growth of plants exposed to salt stress.

KW - ion homeostasis

KW - maximal electron transport rate

KW - nutrient flow modelling

KW - photosynthetic efficiency

KW - water relations

KW - ACC-DEAMINASE

KW - SALINITY STRESS

KW - CHLOROPHYLL FLUORESCENCE

KW - PROMOTING ACTIVITY

KW - SODIUM-CHLORIDE

KW - TOMATO PLANTS

KW - PISUM-SATIVUM

KW - SHOOT GROWTH

KW - TOLERANCE

KW - RHIZOBACTERIA

U2 - 10.1071/FP15200

DO - 10.1071/FP15200

M3 - Journal article

VL - 43

SP - 161

EP - 172

JO - Functional Plant Biology

JF - Functional Plant Biology

SN - 1445-4408

IS - 2

ER -