Integrated Biochemical Profiling of Drought Stress Responses and Plant Growth-Promoting Rhizobacterial Activity
Keywords:
Drought Stress, Plant Growth-Promoting Rhizobacteria, Biochemical Profiling, Oxidative Stress, Plant Stress ToleranceAbstract
Physiological, biochemical and oxidative changes caused by drought stress have a negative impact on plant growth. The present study aimed at studying the biochemical changes caused by the drought and the possible role of plant growth promoting rhizobacteria (PGPR) in enhancing the response of tomato plants under water stress conditions. Experimental data were used for biochemical indicators, physiological characteristics and bacterial growth promoting activities in drought and PGPR associated treatments. The exposure to drought caused an increase in proline level by 122.97%, lipid peroxidation by 134.25%, a decrease in ascorbic acid level by 56.65% and a decrease of soluble sugars level by 32.40%. Shoot biomass and relative water content were greatly reduced under severe drought, suggesting reduced plant growth and hydration. The indole-3-acid (IAA) production and phosphate-solubilizing activity of rhizobacterial isolates varied. The use of PGPR-based treatments led to higher levels of chlorophyll, lower levels of proline accumulation and enhanced root growth than did uninoculated plants under drought stress. The findings indicated that the responses observed in PGPR could help to reduce the drought stress by biochemical and physiological changes. But, standardized experiments and validated statistical analyses are needed to validate microbial effectiveness and mechanisms.
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