Salt Tolerant Bacillus Strains Improve Plant Growth Traits and Regulation of Phytohormones in Wheat under Salinity Stress

Abstract

Soil salinity is a major constraint adversely affecting agricultural crops including wheat worldwide. The use of plant growth promoting rhizobacteria (PGPR) to alleviate salt stress in crops has attracted the focus of many researchers due to its safe and eco-friendly nature. The current study aimed to study the genetic potential of high halophilic Bacillus strains, isolated from the rhizosphere in the extreme environment of the Qinghai–Tibetan plateau region of China, to reduce salt stress in wheat plants. The genetic analysis of high halophilic strains, NMCN1, LLCG23, and moderate halophilic stain, FZB42, revealed their key genetic features that play an important role in salt stress, osmotic regulation, signal transduction and membrane transport. Consequently, the expression of predicted salt stress-related genes were upregulated in the halophilic strains upon NaCl treatments 10, 16 and 18%, as compared with control. The halophilic strains also induced a stress response in wheat plants through the regulation of lipid peroxidation, abscisic acid and proline in a very efficient manner. Furthermore, NMCN1 and LLCG23 significantly enhanced wheat growth parameters in terms of physiological traits, i.e., fresh weight 31.2% and 29.7%, dry weight 28.6% and 27.3%, shoot length 34.2% and 31.3% and root length 32.4% and 30.2%, respectively, as compared to control plants under high NaCl concentration (200 mmol). The Bacillus strains NMCN1 and LLCG23 efficiently modulated phytohormones, leading to the substantial enhancement of plant tolerance towards salt stress. Therefore, we concluded that NMCN1 and LLCG23 contain a plethora of genetic features enabling them to combat with salt stress, which could be widely used in different bio-formulations to obtain high crop production in saline conditions.

Broad‐spectrum antagonistic potential of Bacillus spp. volatiles against Rhizoctonia solani and Xanthomonas oryzae pv. oryzae

“…Additionally, compared to the control, PDC (38.5%), BDH (41.5%), 1,2-BIT (42.0%), and MIX-VOCs (58.2%) all considerably reduced the activity of MDA. Similar findings were reported by Liang et al (2022) and Ayaz et al (2022), who found that in circumstances of VOC stress, antioxidant enzymes were greatly enhanced and MDA concentration dramatically decreased with the use of Bacillus and synthetic VOCs (Ayaz et al 2021;Liang et al 2022).…”

“…In addition, the cell shrinks due to the evacuation of its cytoplasmic contents and the disappearance of its cytoplasmic organelles. (43.5,39.7,46.5,and 51.1%) and POD (23.5,21.1,24.4,and 25.9%), respectively, as compared to control, which agrees with (Ayaz et al 2022). The activities of CAT (26.2,28.6,29.5,and 33.5%),APX (39.4,37.8,39.5,and 42.5%), and H 2 O 2 (38.4, 41.5, 45.4, and 51.0%) were similar to those of control according to earlier research (Ali et al 2022a).…”

Physiological and molecular insight of microbial biostimulants for sustainable agriculture

“…Application of both inoculants significantly downregulated the expression of ABA- response element ( ABARE ), 4-Hydroxy-2-nonenal ( 4-HNE ), whereas the P5CS gene was found to be upregulated. This clearly illustrates that these halophilic microbes regulate key stress signaling pathways (ABA synthesis, MDA and proline production) that subsequently lowered the effect of stress ( Ayaz et al., 2022 ). From the cited literature ( Table 1 ), it is evident that PGPR could alleviate salt stress by improving soil health, nutrient uptake, hormone production, antioxidant activity, and stress- responsive genes.…”

Screening and Characterization of Potential Plant Growth-Promoting Endophytes of Wheat (Triticum aestivum)

“…PGPR traits; antagonistic bacteria; Tritium aestivum; 16s rRNA 2 Wheat (Triticum aestivum) is grown in 17% of farmland globally and provides about 82% of the protein source and 80% of the calories for the global population [2][3][4]. It is grown annually on around 220 million hectares area and approximately 775 metric tons of yield is reported in the world per year [5].…”