Drought response of Mucuna pruriens (L.) DC. inoculated with ACC deaminase and IAA producing rhizobacteria

Abstract

Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Complete Genome Sequence of Enterobacter roggenkampii ED5, a Nitrogen Fixing Plant Growth Promoting Endophytic Bacterium With Biocontrol and Stress Tolerance Properties, Isolated From Sugarcane Root

“…Drought and heavy metal stress greatly decrease crop yield (Khan et al, 2018;Kang et al, 2020). Drought is the leading reason for preventive crop production over massive areas of the Earth (Saleem et al, 2018), and estimated to cause severe plant growth difficulties for above 50% of the arable lands in 2050 (Vinocur and Altman, 2005;Kasim et al, 2013). However, heavy metal recognized as a principal hazard in many terrestrial ecosystems globally (Shahid et al, 2015).…”

Plant Growth Promoting Rhizobacterial Mitigation of Drought Stress in Crop Plants: Implications for Sustainable Agriculture

“…The growth of the plants was enhanced by increasing the biomass of the crops four times when compared to the un-inoculated controls, as well as contributed significantly to reduced levels of ethylene in the stressed plants The growth of the plants was enhanced by increasing the biomass of the crops four times over compared to the un-inoculated controls, as well as contributed significantly to reduced levels of ethylene in the stressed plants [101,102]. Since the study of Mayak et al [101], other authors have used ACC deaminase producing PGPR to promote crop production and reduce yield losses in crops exposed to water stress [75,86,89,91,92]. This was documented in a recent study in which Pseudomonas fluorescens DR7 and Pseudomonas fluorescens D11 with high ACC deaminase activities (24.56 ± 2.24 µmol α-KB mg protein −1 h −1 and 39.40 ± 0.68 µmol α-KB mg protein −1 h −1 ) significantly (p < 0.05) enhanced the germination of foxtail millet (13.68%-141.82%) at water potentials of −0.49 MPa and −1.03 Mpa (enhancement of 13.68% and 141.28%), respectively [89].…”

Plant Growth-Promoting Rhizobacteria Isolated from Degraded Habitat Enhance Drought Tolerance of Acacia (Acacia abyssinica Hochst. ex Benth.) Seedlings

“…Drought increases the demand for irrigation, which already comprises 70% of global water consumption [ 7 ]. Plants have evolved different mechanisms to mitigate DS that include a series of molecular, cellular, and physiological adaptations [ 8 , 9 ]. All DS-associated problems result in loss of soil microbial diversity, soil fertility, and aggravate competition for nutrients.…”