Intercellular colonization and growth promoting effects of Methylobacterium sp. with plant-growth regulators on rice (Oryza sativa L. Cv CO-43).
The Methylobacterium sp. strain NPFM-SB3, isolated from Sesbania rostrata stem nodules possessed nitrogenase activity and nodA genes. Pure culture of NPFM-SB3 strain produced indole-3-acetic acid, cytokinins and on inoculation to rice plants resulted in numerous lateral roots. Inoculation of synthetic auxins 2,4-dichlorophenoxy acetic acid, naphthalene acetic acid or flavonoids naringenin and dihydroxy-4-methoxyisoflavone individually or to bacterial inoculated rice seedlings improved the plant growth and lateral root formation under hydroponic condition. The formation of nodule-like structure and nitrogenase activity which is purely auxin dependent was observed in 2,4-dichlorophenoxy acetic acid treatments to Methylobacterium sp. NPFM-SB3 inoculated rice plants. The rhizobia entered through fissures formed due to lateral root emergence and spread intercellularly in the nodular structures concluded that the effect of 2,4-dichlorophenoxy acetic acid treatment for rice seedlings grown under gnotobiotic conditions is to create a niche in which these bacteria can grow.
Senthilkumar
M
M
Department of Agricultural Microbiology, Horticultural College and Research Institute, Tamilnadu Agricultural University, Periyakulam 625 604, Tamilnadu, India. senthiltnj@rediffmail.com
Madhaiyan
M
M
Sundaram
Sp
S
Kannaiyan
S
S
D001426:Bacterial Proteins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D020580:Methylobacterium / Q000254:growth & development* / Q000378:metabolism; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000378:metabolism; D012275:Oryza / Q000254:growth & development* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology
D001426:Bacterial Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D009591:Nitrogenase