Co-application of bio-fertilizer and salicylic acid improves growth, photosynthetic pigments and stress tolerance in wheat under drought stress

Abstract

Drought stress hampers the growth and productivity of wheat crop worldwide. Thus far, different strategies have been proposed to improve drought tolerance in wheat but the combined application of plant growth-promoting rhizobacteria formulated bio-fertilizer (BF) and salicylic acid (SA) has not been thoroughly explored yet. Therefore, a pot experiment was conducted to observe the effect of SA, BF, and their combination on wheat plants under optimal and drought stress conditions. Seeds priming was done with BF (107 CFU mL−1). After 2 weeks of germination, SA (one mM) was applied as a foliar spray. Drought stress was applied by withholding water supply at three-leaf stage (30 d old plants) for the next 15 d until soil moisture dropped to 10%. Foliar application of SA increased the bacterial population of BF significantly compared to the sole application of BF under irrigated as well as drought stress conditions. Co-application of BF and foliar spray of SA induced drought tolerance in wheat plants by enhancing plant biomass, photosynthetic pigments, relative water content and osmolytes, and activities of the defense-related system. Plants treated with SA and BF together under drought stress had significantly increased leaf water status, Chl a, Chl b, and carotenoids synthesis by 238%, 125%, 167%, and 122%, respectively. Moreover, the co-application of SA and BF showed maximum SOD, POD, APX, and CAT activities by 165%, 85%, 156%, and 169% in the leaves while 153%, 86%, 116% and 200% in roots under drought stress. Similarly, the combined treatment exhibited a pronounced decrease in MDA content by 54% while increased production of proteins and proline by 145% and 149%, respectively. Our results showed that the co-application of SA and BF induced better drought tolerance as compared with the sole application of SA or BF. The results obtained herein suggest that combined application of BF and SA can be applied to the wheat crop to greatly improve drought tolerance in field conditions.

Genomic Features and Molecular Function of a Novel Stress-Tolerant Bacillus halotolerans Strain Isolated from an Extreme Environment

“…Phytopathogenic fungi severely reduce the yield of agricultural products, and the use of biological fertilizer offers a sustainable way of avoiding this problem [7]. The ability to produce diverse secondary metabolic compounds is the most outstanding biocontrol feature of the Bacillus species.…”

Volatile organic compounds produced by Pseudomonas pseudoalcaligenes alleviated drought stress by modulating defense system in maize (Zea mays L.)

“…Hence, we proposed that VOCs produced by P. pseudoalcaligenes induce a systemic response in maize plants against drought stress conditions. The positive impact of PGPR inoculation on drought stress mitigation on plants has already been reported in many studies (Amna et al, 2020;Azmat et al, 2020;Ghosh et al, 2018;Ilyas et al, 2020;Yasmin et al, 2017). Cho et al (2008) has demonstrated the role of bacterial VOCs (BVOCs) on drought stress mitigation in Arabidopsis thaliana.…”

“…Secondly, VOCs exposed seedlings further augmented the ROS scavenging machinery and exhibited higher activity of SOD, POD, CAT, APX, PPO, and PAL and reduced the drought stress than non‐exposed control. The role of PGPR in the alleviation of drought stress by augmenting the ROS scavenging enzyme system is well documented in the literature (Azmat et al, 2020; Ilyas et al, 2020; Khan et al, 2020; SkZ et al, 2018; Yasmin et al, 2017). However, for the first‐time current study showed BVOCs‐mediated alleviation of drought stress by modulating ROS scavenging machinery.…”

“…Water shortage generates stress in the cell membrane which induces permeability resulting in higher electrolyte leakage (EL) while higher malondialdehyde (MDA) induce the peroxidation of the lipid content of membrane. Generally, both EL and MDA indicate the cellular damage caused by the stress in plants (AbdElgawad et al, 2016; Azmat et al, 2020; Cao et al, 2017; Ilyas et al, 2020; Shi et al, 2017). Exposure of maize seedlings to drought stress exhibited elevated levels of EL, proline, and MDA content.…”

“…In cells, ROS are reduced or oxidized form of molecular oxygen (Azmat et al, 2020; Khan et al, 2020). The function of ROS in the cells is to regulate signal transductions processes as well as act as a toxic by‐product of aerobic metabolism (Khan et al, 2020).…”