Phylloplane bacteria increase seedling emergence, growth and yield of field-grown groundnut (Arachis hypogaea L.)

Abstract

Aim: To isolate and characterize groundnut-associated bacterial isolates for growth promotion of groundnut in field. Methods and Results: Three hundred and ninety-three groundnut-associated bacteria, representing the geocarposphere, phylloplane and rhizosphere, and endophytes were applied as seed treatment in greenhouse. Maximum increase in plant biomass (up to 26%) was observed following treatment with a rhizosphere isolate identified as Bacillus firmis GRS 123, and two phylloplane isolates Bacillus megaterium GPS 55 and Pseudomonas aeruginosa GPS 21. There was no correlation between the production of L L-tryptophan-derived auxins and growth promotion by the test isolates. Actively growing cells and peat formulations of GRS 123 and GPS 55, and actively growing cells of GPS 21, significantly increased the plant growth and pod yield (up to 19%) in field. Rifampicin-resistant mutants of GRS 123 and GPS 21 colonized the ecto-and endorhizospheres of groundnut, respectively, up to 100 days after sowing (DAS), whereas GPS 55 was recovered from both the habitats at 100 DAS. Conclusion: Seed bacterization with phylloplane isolates promoted groundnut growth indicating the possibility of isolating rhizosphere beneficial bacteria from different habitats. Significance and Impact of the Study: Identification of phylloplane bacteria as effective plant growthpromoting rhizobacteria (PGPR) broadens the spectrum of PGPR available for field application.

Genetic and functional diversities of bacterial communities in the rhizosphere of Arachis hypogaea

“…The two most common groundnut plant growth promoting rhizobacteria (PGPR) that enhance biomass, nitrogen and phosphorous uptake and cropyield are Pseudomonas and Bacillus sp. (Dey et al 2004;Saravanakumar and Samiyappan 2007;Kishore et al 2005). Until recently, most studies aiming for the isolation and identification of PGPR were based on cultivation and phenotypic characterization of bacterial isolates (Prosser et al 2006).…”

“…In rain-fed areas of Asia, soil fertility is an important constraint for high pod yields. The majority of the small-scale farmers in these regions are reluctant to invest in chemical fertilizers and other agrochemicals because of the unassured crop returns owing to the high incidence of fungal diseases and unpredictable monsoon (Kishore et al 2005). Besides, application of inorganic fertilizer debilitates the soil's physical and chemical status and drastically alters microbial diversity, which is vital to sustain the fertility of soil (Adesemoye and Kloepper 2009;Yang et al 2000).…”

Assessment of ecological diversity of rhizobacterial communities in vermicompost and analysis of their potential to improve plant growth

“…Patel et al (2011) also reported that strains MSC1 (Pseudomonas putida) and MSC4 (Pseudomonas pseudoalcaligens) showed increases in all vegetative parameters of chickpea under saline conditions. Similarly, enhancement of growth parameters of groundnut by pseudomomads has also been reported by a number of authors (e.g., Gupta et al 2002;Kishore et al 2005;Bhatia et al 2008). Recently, Stefan et al (2013) found that runner bean seed inoculation with two rhizobacterial strains resulted in an increase of photosynthetic activities, water-use efficiency and chlorophyll content along with their significant yield.…”

Gamma Irradiation and Autoclave Sterilization Peat and Compost as the Carrier for Rhizobial Inoculant Production

“…Even though the liquid form of rhizobial inoculants is applied in the production process more easily than solid form, the survival of rhizobial cell in liquid inoculants depends on strain of rhizobia and polymeric additive substance incorporated into liquid inoculants formulation (Tittabutr et al, 2007). Thus, solid inoculants, especially those using peat-based carrier, are still popular for biofertilizer inoculant production because peat could support the survival of bacteria in long term storage (Kishore et al, 2005;Okon & Labandera-Gonzalez, 1994). However, peat is limited in many countries including Thailand, so it is necessary to find carriers that are locally available for commercial scale production.…”