Variability of isolated colonies in bean nodulating Rhizobium strains before and after exposure to high temperature

Brazilian Journal of Microbiology

Rui Raposeiras²  Patrícia P. Pinto²  Raul V.m. Passos²  Lucy Seldin¹  Edilson Paiva¹  M. Rita Scotti²  Nadja M.h. Sá² 

[1] ,Universidade Federal de Minas Gerais Instituto de Ciências Biológicas Departamento de Botânica BH ,Brasil

关键词: Rhizobium tropici;    Rhizobium leguminosarum bv. phaseoli;    bean plants;    high temperature;    cerrado soils;    Rhizobium tropici;    Rhizobium leguminosarum bv. phaseoli;    feijoeiro;    solos de cerrado;    temperatura elevada;   

DOI  :  10.1590/S1517-83822002000200010

来源: SciELO

【 摘 要 】

Irregular response to bean plants to Rhizobium inoculation has been attributed to among other factors, low competitive ability, low N2 fixation efficiency and genetic instability of the symbiont. This genetic instability caused by high rates of genomic rearrangements and/or plasmid deletions can be accentuated by high temperatures. This fact may limit the utilization of these strains as inoculants, especially in tropical soils. In this study, the variability of isolated colonies derived from effective R. leguminosarum bv. phaseoli (SLP1.3 and BR 10.026) and R tropici (SLA2.2 and BR322) strains was evaluated before and after exposure to high temperatures (four consecutive thermal shocks at 45ºC). This evaluation involved plant dry matter analysis of inoculated plants and genotypic (plasmid profile and genomic patterns via RAPD) analysis of the Rhizobium strains. The results evidenced that high temperature improve the natural performance variability especially between isolated colonies from R. leguminosarum bv. phaseoli strains. The plasmid profile of isolated colonies from R. tropici strains were identical regardless of temperature treatment whereas isolated colonies from R. leguminosarum bv. phaseoli alterations were detected especially after the thermal treatment. The genomic patterns generated by AP-PCR showed more alterations and genetic variation in isolated colonies from R. leguminosarum bv. phaseoli strains indicating that R. tropici strains are more stable and lower affected by high temperature.

【 授权许可】

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