Colonization and Maize Growth Promotion Induced by Phosphate Solubilizing Bacterial Isolates

Area of Science:

• Agricultural Microbiology
• Plant Nutrition
• Soil Science

Background:

• Phosphorus deficiency limits maize production in China.
• Phosphate-solubilizing bacteria (PSB) convert insoluble phosphorus into plant-available forms.
• PSB utilize acidification, chelation, and exchange reactions for phosphate solubilization.

Purpose of the Study:

• Isolate and identify PSB from maize rhizosphere.
• Evaluate the P-solubilizing capacity of isolated strains.
• Assess the plant growth-promoting potential of PSB, particularly strain B1.

Main Methods:

• Isolation and 16S rRNA sequencing for bacterial identification.
• In vitro assessment of inorganic and organic phosphorus solubilization.
• Confocal laser scanning microscopy (CLSM) for bacterial colonization studies.
• Evaluation of plant growth parameters (root/shoot length, dry weight) and nutrient content (P, N).

Main Results:

• Six bacterial strains (Paenibacillus sp. B1, Pseudomonas sp. B10, B14, SX1, SX2, and Sphingobium sp. SX14) were identified.
• All strains solubilized inorganic P; B1 and B10 also solubilized organic P.
• Most strains produced indole-3-acetic acid (IAA); B1 and SX14 showed highest levels.
• Strain B1 significantly increased root length, shoot/total dry weight, and P/N uptake.

Conclusions:

• Bacterial strain B1 effectively promotes maize growth and nutrient uptake.
• B1 colonizes maize roots and can form spores for enhanced survival.
• B1 demonstrates potential as a sustainable bio-fertilizer for improving agricultural sustainability.