Root bacterial endophytes confer drought resistance and enhance expression and activity of a vacuolar H+ -pumping pyrophosphatase in pepper plants
KAUST DepartmentRed Sea Research Center (RSRC)
Biological and Environmental Sciences and Engineering (BESE) Division
Environmental Science and Engineering Program
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AbstractIt has been previously shown that the transgenic overexpression of the plant root vacuolar proton pumps H+ -ATPase (V-ATPase) and H+ -PPase (V-PPase) confer tolerance to drought. Since plant-root endophytic bacteria can also promote drought tolerance, we hypothesize that such promotion can be associated to the enhancement of the host vacuolar proton pumps expression and activity. To test this hypothesis, we selected two endophytic bacteria endowed with an array of in vitro plant growth promoting traits. Their genome sequences confirmed the presence of traits previously shown to confer drought resistance to plants, such as the synthesis of nitric oxide and of organic volatile organic compounds. We used the two strains on pepper (Capsicuum annuum L.) because of its high sensitivity to drought. Under drought conditions, both strains stimulated a larger root system and enhanced the leaves' photosynthetic activity. By testing the expression and activity of the vacuolar proton pumps, H+ -ATPase (V-ATPase) and H+ -PPase (V-PPase), we found that bacterial colonization enhanced V-PPase only. We conclude that the enhanced expression and activity of V-PPase can be favoured by the colonization of drought-tolerance-inducing bacterial endophytes. This article is protected by copyright. All rights reserved.
CitationVigani G, Rolli E, Marasco R, Dell’Orto M, Michoud G, et al. (2018) Root bacterial endophytes confer drought resistance and enhance expression and activity of a vacuolar H+ -pumping pyrophosphatase in pepper plants. Environmental Microbiology. Available: http://dx.doi.org/10.1111/1462-2920.14272.
SponsorsThe authors declare an absence of competing financial interests. This research was supported by funding from the Italian MIUR FIRB project no. RBIN047MBH “Strategy to improve crop productivity under water stress”, the EU project BIODESERT (European Community’s Seventh Framework Programme CSA-SA REGPOT-2008-2) under grant agreement no. 245746, and King Abdullah University of Science and Technology (KAUST) baseline research funds to DD. ER acknowledges support from Università degli Studi di Milano, DeFENS, Regione Lombardia (contract ‘Dote Ricerca’). The authors thank (i) Dr. Vasco Meneghini for support with the confocal microscopy analysis and interpretation, and a critical reading of the manuscript; (ii) Dr. Umberto Fascio at the Centro Interdipartimentale di Microscopia Applicata of the University of Milan for technical support with the confocal microscope; (iii) Dr. M. Maeshima of Nagoya University, Nagoya, Japan, for the kind gift of antibodies against V-ATPase and V-PPase; (iv) Dr. Bessem Chouaia of the University of Milan for the help in the bacterial genome assembly and (v) Dr. Alessia Perego and Dr. Patrizia Zaccheo of the University of Milan and (vi) Dr. Marco Fusi of King Abdullah University of Science and Technology for assistance with the statistical analysis; (vii) Francesco Della Valle of King Abdullah University of Science and Technology for help in critical revision of the manuscript. The authors declare that they have no conflict of interest.