Studies on Effect of PGPR on Wheat (Triticum aestivum L.) for Mitigation of Water Stress

Author: Tanvi N. Parnate, Achyut A. Bharose, Mahendra S. Dudhare and Ramesh N. Dhawale

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Abstract

Wheat (Triticum aestivum) is one of the world's most important staple crops, is significantly impacted by water stress, which hinders its growth and productivity globally. Various strategies have been developed to mitigate water stress, but the use of PGPR-based formulation remains underexplored. This study aimed to assess the morphological and biochemical differences between wheat genotypes (HI1636, GW513, HI8823, and MP1358) under water stress and those treated with PGPR. The experiment involved treatments: 1) normal irrigation, 2) water-stressed, and 3) water stress with seed inoculation of Bacillus subtilis and Pseudomonas fluorescens separately. Ten morphological and two biochemical parameters were analysed, revealing significant changes in traits like germination percentage, plant height, productive tillers, root length, relative water content (RWC), chlorophyll index, proline accumulation, and grain yield. Water stress significantly reduced grain yield, with MP1358's yield declining by 55.1% from 20.65 g to 9.31 g. Notably, root length increased in HI8823 under stress, demonstrating a 60.44% increase, suggesting adaptive responses. Chlorophyll content decreased under water stress, particularly in HI1636 (51.6% reduction). Proline content rose significantly in GW513, indicating stress acclimatization. PGPR demonstrated notable enhancements in the growth and physiological parameters of the wheat genotypes. In the case of HI8823, chlorophyll levels increased from 1.893 mg/g (normal) to 2.766 mg/g with Bacillus subtilis, marking an enhancement of 46.24%. HI1636's grain yield improved from 8.84 g (water stress) to 16.76 g when treated with Pseudomonas fluorescens, indicating an increase of approximately 89.80%. Among the genotypes, HI1636 and MP1358 showed good stress tolerance, especially when treated with Bacillus subtilis and Pseudomonas fluorescens, improving yield, RWC, and proline accumulation. On the other hand, GW513 and HI8823 were more susceptible to water stress, exhibiting significant declines in yield, RWC, and chlorophyll content, even though inoculation provided partial recovery

Keywords

Triticum aestivum, water stress, PGPR, Bacillus subtilis, Pseudomonas fluorescens

Conclusion

HI1636 and MP1358 demonstrated good stress tolerance, especially when inoculated with Bacillus subtilis and Pseudomonas fluorescens, improving yield, RWC, and proline accumulation. Pseudomonas fluorescens showed a stronger overall recovery for grain yield and proline accumulation, helping HI1636 return to near normal performance. In MP1358, Bacillus subtilis had a stronger positive impact on proline content and grain yield recovery for MP1358. Pseudomonas fluorescens led to full recovery and even improvement in chlorophyll content, indicating a positive effect on photosynthetic activity. Both PGPR-treatments helped to recover RWC, with Bacillus subtilis showing a slightly better effect. GW513 and HI8823 showed susceptibility to water stress, with significant reductions in key traits like yield, RWC, and chlorophyll content under stress, despite partial recovery with inoculation. Genotype GW513 under Bacillus subtilis showed better recovery in grain yield and RWC, improving overall plant performance under stress. Pseudomonas fluorescens helped significantly improve chlorophyll content and proline accumulation but was less effective for yield recovery, while HI8823 under Bacillus subtilis was better for maintaining RWC and chlorophyll content under stress, while Pseudomonas fluorescens improved grain yield and proline accumulation, despite negatively affecting chlorophyll. Despite the positive impacts of PGPR, some genotypes (particularly GW513 and HI8823) exhibited incomplete recovery, especially in terms of RWC and yield, indicating continued susceptibility to water stress even with PGPR inoculation. Water stress severely affected key phenotypic traits, leading to reductions in chlorophyll content, grain yield, RWC, and overall plant growth in all four genotypes. Although inoculation with PGPR like Bacillus subtilis and. Pseudomonas fluorescens helped mitigate some of the negative effects, full recovery to normal conditions was not achieved. Pseudomonas fluorescens was generally more effective than Bacillus subtilis in enhancing stress tolerance, but genotypes like GW513 still struggled under stress, particularly in terms of water retention and yield

References

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How to cite this article

Tanvi N. Parnate, Achyut A. Bharose, Mahendra S. Dudhare and Ramesh N. Dhawale (2024). Studies on Effect of PGPR on Wheat (Triticum aestivum L.) for Mitigation of Water Stress. Biological Forum – An International Journal, 16(10): 109-116