Isolation and selection of plant growth promoting rhizobacteria from wedelia trilobata (L.) A.S. hitchcock rhizosphere

Abstract

The objective of this research was to isolate plant growth promoting rhizobacteria from Wedelia trilobata (L.) A.S. Hitchcock rhizosphere, and preliminarily test their plant growth promoting properties such as nitrogen fixation, siderophore production, phosphate solubilization and indole-3-acetic acid production. Forty-seven bacterial isolates were obtained including 26 isolates of gram positive, 18 isolates of gram negative and 3 isolates of actinobacteria. After that 8 isolates (including BWTM1_MSU, BWTM2_MSU, BWTM5_MSU, BWTM6_MSU, BWWM6_MSU, BWWM8_MSU, BWWM9_MSU and BWWM16_MSU) were selected for studying on root colonization and plant growth promoting properties under aseptic condition. The results showed that BWTM5_MSU had the evident on the promotion of plant growth with the most percentage of rice seed germination (63.33%), high level of root and shoot length with 6.11 cm and 3.89 cm, respectively. As a result, the root and shoot fresh weight was as high as 9.56 mg and 11.33 mg, respectively. It also correlated with the highest production of indole-3-acetic acid up to 421.29 ug/ml. The root colonization was studied by counting rhizobacteria isolate BWTM5_MSU from rice rhizoplane and rhizosphere with presented bacterial number at 9.67x106 CFU/g root and 1.64x10 10 CFU/g soil, respectively.