AUTHOR=Abideen Zainul , Cardinale Massimiliano , Zulfiqar Faisal , Koyro Hans-Werner , Rasool Sarwat Ghulam , Hessini Kamel , Darbali Walid , Zhao Fengliang , Siddique Kadambot H.M. 

TITLE=Seed Endophyte bacteria enhance drought stress tolerance in Hordeum vulgare by regulating, physiological characteristics, antioxidants and minerals uptake

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.980046

DOI=10.3389/fpls.2022.980046

ISSN=1664-462X

ABSTRACT=<p>Growth stimulating bacteria help remediate dry arid soil and plant stress. Here, <italic>Pseudomonas</italic> sp. and <italic>Pantoea</italic> sp. we used to study the stress ecology of <italic>Hordeum vulgare</italic> and the environmental impact of water deficit on soil characteristics, growth, photosynthesis apparatus, mineral acquisition and antioxidiant defense. Plants inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic> had significantly higher (about 2 folds) soil carbon flux (soil respiration), chlorophyll levels (18%), net photosynthetic rate (33% in <italic>Pantoea</italic> and 54% in <italic>Pseudomonas</italic>), (44%) stomatal conductance than uninoculated plants in stressed conditions. Both bacterial strains improved leaf growth (23-29%) and root development under well-watered conditions but reduced around (25%) root biomass under drought. Plants inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic> under drought also increased of about 27% leaf respiration and transpiration (48%) but decreased water use efficiency, photoinhibition (91%), and the risk of oxidative stress (ETR/A) (49%). Drought stress increased most of the studied antioxidant enzymatic activities in the plants inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic>, which reduce the membrane damage and protect plants form oxidative defenses. Drought stress increased K<sup>+</sup> acquisition around 50% in both shoots inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic> relative to non-stressed plants. Plants inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic> increased shoot Na<sup>+</sup> while root Na<sup>+</sup> only increased in plants inoculated with <italic>Pseudomonas</italic> in stressed conditions. Drought stress increased shoot Mg<sup>2+</sup> in plants inoculated with <italic>Pseudomonas</italic> or <italic>Pantoea</italic> but did not affect Ca<sup>2+</sup> relative to non-stressed plants. Drought stress increased about 70% K<sup>+</sup>/Na<sup>+</sup> ratio only in plants inoculated with <italic>Pseudomonas</italic> relative to non-stressed plants. Our results indicate that inoculating barley with the studied bacterial strains increases plant biomass and can therefore play a role in the environmental remediation of drylands for food production.</p>