Aggregation of selected plant growth promoting Methylobacterium strains: role of cell surface components and hydrophobicity.
The bacterial cell surface plays a major role in the bacterial aggregation that in turn plays a positive role in affecting the bacterial dispersion and survival in soil and their ability to adhere to plant surfaces. Plant growth-promoting Methylobacterium strains, Methylobacterium goesingense CBMB5, Methylobacterium sp. CBMB12, Methylobacterium oryzae CBMB20, Methylobacterium fujisawaense CBMB37, M. oryzae CBMB110 and Methylobacterium suomiense CBMB120 were evaluated for aggregation efficiency. Aggregation occurred in all test strains under high C/N growth conditions, and the strain CBMB12 showed the highest aggregation of 53.4 % at 72 h. Disaggregation compound treatment studies revealed the role of protein-protein interaction in Methylobacterium strains except CBMB110 and CBMB120 strains, where a possible carbohydrate-protein interaction is suspected. Surface layer protein extraction by LiCl followed by SDS-PAGE analysis showed the presence of proteins at molecular weights ranging from 41 to 49 kDa. Methylobacterium strains under aggregated conditions showed increased hydrophobicity compared to the cells under standard grown conditions. A relatively higher hydrophobicity of 50.1 % as evident by the adhesion with xylene was observed with strain CBMB12 under aggregated condition. This study reports the aggregation ability in plant growth-promoting Methylobacterium strains and the possible involvement of cellular components and hydrophobicity in this phenomenon.
Department of Agricultural Chemistry, Chungbuk National University, Cheongju, Republic of Korea. mel_vin@sify.com
Manoharan Melvin
MM
Joe
Venkatakrishnan Sivaraj
VS
Saravanan
Tongmin
T
Sa
D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008565:Membrane Proteins / Q000378:metabolism; D020580:Methylobacterium / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010944:Plants / Q000382:microbiology; D013045:Species Specificity; D013997:Time Factors
D008565:Membrane Proteins