Microbiological Insights into the Stress-Alleviating Property of an Endophytic Bacillus altitudinis WR10 in Wheat under Low-Phosphorus and High-Salinity Stresses

Abstract

An indole–3–acetic acid producing Bacillus altitudinis WR10 was previously isolated from the root of wheat (Triticum aestivum L.). In this study, the strain WR10 was used for relieving abiotic stresses in wheat under low phosphorus and high saline in hydroponic co-culture models. Significantly, strain WR10 improved wheat seed relative germination rate under salinity stress (200/400 mM NaCl) and the root dry weight in wheat seedlings under phosphorus stress (10 μM KH2PO3) when insoluble phosphates are available. To provide insights into its abiotic stress-alleviating properties, the strain was characterized further. WR10 grows well under different culture conditions. Particularly, WR10 resists salt (12% NaCl) and hydrolyzes both inorganic and organic insoluble phosphates. WR10 uses many plant-derived substrates as sole carbon and energy sources. It produces catalase, amylase, phosphatase, phytase, reductase, and 1–aminocyclopropane–1–carboxylate (ACC) deaminase. In addition, WR10 possesses long peritrichous flagella, and its biofilm formation, as well as phytase production, is induced by abiotic stresses. Overall, the salinity-alleviating property of WR10 in wheat can be attributed to its inherent tolerance to NaCl, formation of biofilm, and production of enzymes, like catalase, amylase, and ACC deaminase. Meanwhile, B. altitudinis WR10 reduces low-phosphorus stress in wheat by production of phosphatases and phytases in the presence of insoluble phosphates.

Functional Genetic Diversity and Plant Growth Promoting Potential of Polyphosphate Accumulating Bacteria in Soil

“…We also found improved P-content in plants treated with bacterial strains compared with uninoculated stressed plants. Yue et al ( 53 ) reported improved productivity of wheat by mediating phosphate availability to the plants under stress conditions through phosphatase enzymes activity. Similarly, NBRI RAR inoculated plants showed approximately similar P level under both control and salinity conditions ( Table 2 ), presumably due to its higher alkaline and acidic phosphatase activity in both conditions (Table S3; https://github.com/ssrivastava-nbri/Supplementary-file/blob/main/Supplementary%20file.pdf ).…”

Microbial-Assisted Wheat Iron Biofortification Using Endophytic Bacillus altitudinis WR10

“…In this study, we used an endophytic bacterium, B. altitudinis WR10, because it has a strong ability to absorb Fe and improves the ability of wheat to tolerate Fe ( 27 ). In addition, the strain produces siderophores and secretes phytase ( 28 ). These properties made the strain a good candidate for assisting wheat Fe biofortification for three reasons at least.…”

“…Phytate is widely recognized as anti-nutritional because of the strong binding potential with minerals, including Fe and Zn ( 47 ). Strain WR10 produces phytases that effectively degrade phytate ( 28 ). Therefore, the content of phytate can be decreased after inoculation with WR10; however, this data suggest that this is not true in grains ( Supplementary Table 4 ), and, as reported in AMF, the positive effect of WR10 on plant Fe accumulation may also be modulated by wheat genotypes, soil pH, texture, and nutrient concentration, as well as agronomic practices, such as N and P fertilization ( 46 , 48 ).…”

“…For pathogenicity analysis, the Virulence Factors Database (VFDB, www.mgc.ac.cn/cgi-bin/VFs/v5/main.cgi?fun=VFanalyzer ) and the PathogenFinder ( https://cge.cbs.dtu.dk/services/PathogenFinder ) web-based tools were searched using the reference genome of B. altitudinis GR8 ( 31 , 32 ). Strain GR8 has the highest identity in a marker gene gyrB of B. altitudinis WR10 ( 28 ).…”

“…One of them, B. altitudinis WR10, has a strong ability to absorb Fe and improves the ability of wheat to tolerate Fe by upregulating the expression of wheat genes encoding ferritin ( 27 ). The strain has high phytase activity, produces siderophores, and forms biofilm ( 28 ). Therefore, this study was planned to inoculate wheat with this strain using different methods (such as soaking or spraying) to increase Fe content in wheat grains and achieve WR10-assisted Fe biofortification in wheat.…”