Plant growth-promoting traits of biocontrol potential bacteria isolated from rice rhizosphere

Abstract

Seven isolates of bacteria (SRI-156, SRI-158, SRI-178, SRI-211, SRI-229, SRI-305 and SRI-360) were earlier reported by us as having potential for biocontrol of charcoal rot of sorghum and plant growth promotion (PGP) of the plant. In the present study, the seven isolates were characterized for their physiological traits (tolerance to salinity, pH, temperature and resistance to antibiotics and fungicides) and further evaluated in the field for their PGP of rice. All the seven isolates were able to grow at pH values between 5 and 13, in NaCl concentrations of up to 8% (except SRI-156 and SRI-360), temperatures between 20 and 40°C and were resistant to ampicillin (>100 ppm; except SRI-158 and SRI-178) but sensitive (<10 ppm) to chloramphenicol, kanamycin, nalidixic acid, streptomycin (except SRI-156 and SRI-211) and tetracycline. They were tolerant to fungicides benlate and captan, except SRI-158 and SRI-178, bavistin and sensitive to thiram (except SRI-156 and SRI-211) at field application level. In the field, four of the seven isolates (SRI-158, SRI-211, SRI-229 and SRI-360) significantly enhanced the tiller numbers, stover and grain yields, total dry matter, root length, volume and dry weight over the un-inoculated control. In the rhizosphere soil at harvest, all the isolates significantly enhanced microbial biomass carbon (except SRI-156), microbial biomass nitrogen and dehydrogenase activity (up to 33%, 36% and 39%, respectively) and total N, available P and% organic carbon (up to 10%, 38% and 10%, respectively) compared to the control. This investigation further confirms that the SRI isolates have PGP properties.

Plant growth-promotion and biofortification of chickpea and pigeonpea through inoculation of biocontrol potential bacteria, isolated from organic soils

“…The bacterial strains studied (SRI-156, SRI-158, SRI-178, SRI-211, SRI-229, SRI-305 and SRI-360) in the present study were earlier demonstrated by us for biocontrol potential against M. phaseolina , which causes charcoal rot in sorghum, and PGP potentials in sorghum and rice (Gopalakrishnan et al 2011, 2012). In the present study, the seven bacteria were further evaluated for their PGP and biofortification traits on grain legumes such as chickpea and pigeonpea.…”

“…The selected seven bacteria were also able to grow at pH levels between 5 and 13, temperatures between 20 and 40 °C and salinity (NaCl) up to 6% under in vitro conditions and thus have the ability to survive under harsh environments such as saline and acidic to alkaline soils (Gopalakrishnan et al 2012). The interaction between native or introduced soil bacteria and roots and their possible impacts on plant growth have been extensively reported by Birkhofer et al (2008) and Uphoff et al (2009).…”

“…Seven bacteria isolated from rhizosphere of SRI organic fields, SRI-156 ( P. plecoglossicida ; NCBI accession: JQ247008), SRI-158 ( B. antiquum ; NCBI accession: JQ247009), SRI-178 ( B. altitudinis ; NCBI accession: JQ247010), SRI-211 ( E. ludwigii ; NCBI accession: JQ247011), SRI-229 (E. ludwigii ; NCBI accession: JQ247012), SRI-305 ( A. tandoii ; NCBI accession: JQ247013) and SRI-360 ( P. monteilii ; NCBI accession: JQ247014), reported previously as potential for biocontrol and PGP traits in sorghum and rice by us (Gopalakrishnan et al 2011, 2012), were further investigated in this study.…”

“…and PGP in sorghum and rice (Gopalakrishnan et al 2011, 2012). The major objectives of the present study were to further evaluate the PGP and biofortification potentials of the seven bacteria on grain legumes such as chickpea and pigeonpea.…”

Economies of scope: context of agriculture, small family farmers and sustainability

“…All these improve the micro ecosystem that enhances the condition for better plant protection and better agriculture (Collettte et al 2011, Rupela 2011. Similarly, scientific experiments in recent years in India prove the above points (Gopalakrishnan et al 2012, Panneerselvam et al 2013. A large number of research studies across India also lead to the same conclusion that productivity and efficiency in agriculture lay in sustainable agriculture practices (Shiva 1993, Alvares 2009, Nayak 2012a, 2012b, CRIDA 2013, and Nayak 2014a, 2014b, 2014c.…”