Improved Phosphorus (P) Uptake and Yield of Rainfed Wheat Fed with P Fertilizer by Drought-Tolerant Phosphate-Solubilizing Fluorescent Pseudomonads Strains: a Field Study in Drylands

Abstract

Application of phosphate-solubilizing bacteria (PSB) to improve phosphorus (P) nutrition of plants under conditions of P deficit in soil has been frequently studied in controlled conditions. However, little research attention has been paid to studying the combined effects of PSB and P fertilizer on improving P uptake and yield of rainfed wheat plant under natural conditions in arid and semi-arid regions including drylands. Field experiments were arranged in a randomized complete block design with a 3 × 4 × 2 × 2 factorial arrangement of treatments with three replications during years 2017-2018 (Y1) and 2018-2019 (Y2) (at four fields) at two various locations (Qazvin and Zanjan). Experimental treatments included P fertilizer factor at three levels: no fertilizer (P0), triple superphosphate (TSP) fertilizer at 10 kg P ha −1 (P10), and TSP fertilizer at 20 kg P ha −1 (P20) and four variants of PSB factor: no inoculation (B0), inoculation with Pseudomonas baetica B21 (B1), inoculation with Pseudomonas helmanticensis B30 (B2), and co-inoculation with B21 and B30 (B3). The results of this study showed that the growth indices and P nutrition of rainfed wheat in dryland fields were affected by the time and location of planting. The application of 20 kg P ha −1 and single inoculation and coinoculation of wheat with bacterial strains had a significant (p ≤ 0.05) impact on reduced electrolyte leakage. However, the application of 20 kg P ha −1 and single inoculation and co-inoculation of wheat with strains B21 and B30 showed a significant (p ≤ 0.05) effect on increased relative water content, chlorophyll index, proline content, plant height, shoot dry weight, thousand grain weight, and the concentration of shoot and grain P. As a result, application of 20 kg P ha −1 and single inoculation and coinoculation of wheat with strains B21 and B30 increased grain yield by 63, 43, 52, and 58%, respectively. However, the pattern of these fluctuations differed in different years and locations. The significant enhancement of biomass parameters and grain yield of rainfed wheat by co-inoculation of PSB in combination with 20 kg P ha −1 strongly supports the use of Pseudomonas strains as a biofertilizer for improving the wheat growth and grain yield in rainfed farming systems. The results of this study also highlight the importance of simultaneous introduction of phosphate fertilizer and PSB for improving plant performance under drought stress.

Effect of Exogenously Applied Jasmonic Acid and Kinetin on Drought Tolerance of Wheat Cultivars Based on Morpho-Physiological Evaluation

“…Some researchers advocate that, under conditions of waterdeficit stress, plant accumulated proline to protect itself from its negative effects or to help preserve osmotic potential, eliminating free ROS radicals, protecting macromolecules from denaturation, and regulating cellular pH (Shirmohammadi et al 2020). In the present study, under drought stress conditions, proline content in leaves of sensitive cultivars accumulated more than tolerant ones, and exogenous application of both hormones supplied proline content in leaves of the sensitive cultivar.…”

Improved salinity and dust stress tolerance in the desert halophyte Haloxylon aphyllum by halotolerant plant growth-promoting rhizobacteria

“…These bacteria may also decrease the production of abscisic acid (Naz et al, 2009 ); in this way, they reduce the negative effects of stress on stomatal conductance, photosynthesis, and plant sensitivity to water deficiency (Etesami and Beattie, 2018 ). It seems that the plants inoculated with the bacterial strains have the ability to change the structure of the lateral root system and increase RWC (Bertrand et al, 2015 ; Shirmohammadi et al, 2020 ). Increased leaf RWC under stress in plants inoculated with PGPB has also been reported in other studies (Ilyas et al, 2020 ; Shilev, 2020 ).…”

Increase in yield, leaf nutrient, and profitability of soybean co-inoculated with Bacillus strains and Arbuscular mycorrhizal fungi

“…In field experiments with phosphate solubilizing microorganisms and phosphate fertilization on wheat yield, Shirmohammadi et al (2020) stated that the best results occur when phosphate fertilization is associated with microorganisms. In corn inoculated with Bacillus strains, Sousa et al (2020) stated that the results are better with the association of phosphate fertilization since the bacteria enhance the effect of phosphate fertilizer.…”

“…Studies have shown the ability of benefic microorganisms to promote plant development, specifically Pseudomonas in wheat and soybean (Afzal et al, 2010;Karimzadeh et al, 2020;Shirmohammadi et al, 2020), Bacillus strains on millet, corn and oil palm (Ribeiro et al, 2018;Lima et al, 2020, Sousa et al, 2020, Trichoderma in soybean (Bononi et al, 2020), arbuscular mycorrhiza in rice, corn and tomato (Zhang et al, 2016;Saia et al, 2020), among others. Also, these microorganisms, in most cases, are of the "multifunctional" type and can bring benefits to plants through multiple mechanisms of direct and indirect stimulation (Sobral et al, 2018;Silva et al, 2020), with the capacity to fix atmospheric nitrogen (Döbereiner, 1997), potassium solubilization (Basak et al, 2022), siderophore production (Yadav et al, 2020) and mitigation of biotic and abiotic stresses (Leite et al, 2019;Wang et al, 2020;Oliveira et al, 2021).…”