Impact of Pseudomonas Plecoglossicida AVP1, Plant Growth Promoting Rhizobacteria on Growth and Physiological Attributes in Chilli

Abstract

Plant growth-promoting rhizobacteria (PGPR) are known for their significant role in agriculture systems. But little is known about their effect on high-energy reactions of photosynthesis and transpiration. Pseudomonas plecoglossicida AVP1, isolated from chilli (Capsicum annum L), was used to evaluate its efficacy on chilli.  P. plecoglossicida AVP1 strain showed significantly high levels of phosphate solubilisation (845ppm/ml), IAA (66±0.49 μg/ml) and Ammonia production (55 ± 0.67μg/ml) and maximum acid phosphatase activity (0.176 IU/ml) at pH 3.0 and pH 3.4 after the optimization of growth conditions. The strain AVPI also increased the fresh weight (109.82%), root length (16%), and shoot length (56.44%) at 4 and 8 weeks of growth compared to untreated control. Physiological attributes were analysed using the ADC Bio-scientific Le pro-system (33292). The 8-weeks-old untreated seedlings showed 0.55 µmol/m2/s of Transpiration (E), 230.5 ppm of Internal carbon(Ci), 0.027 µmol/m2/s of stomatal conductance(gs) and 2.01 µmol /m2/s and seedlings treated with AVP1 strain increased the gs and A by 100% and 93.73%. In contrast, E and Ci production was not significant among treatments. Our results suggest that P. plecoglossicida AVP1 stimulates the stomatal conductance (gs), a regulator of gas exchange of CO2 and water, and allows the plant to increase CO2 uptake and assimilation, thereby subsequently enhanced the photosynthesis (A). We hypothesized that these attributes increased the plant growth of chilli.