Symbioses: Plant, Animal, and Microbe Interactions
Hirsch, Ann M. , Hernandez, Monica , Mojica, Miguel C. , Pablo, Erin J. , Yashar, Cheryl M. , Angus, Annette A. .
The Quest for a Host Plant for the Nitrogen-Fixing, Nodulating Beta-Proteobacterium, Burkholderia tuberum.
Burkholderia tuberum STM678, a member of the beta-Proteobacteriaceae, was originally isolated from nodules of an indigenous South African legume and has not only nif, but also nod genes, which were previously assumed to be present only in Rhizobiaceae (alpha-proteobacteria). Although isolated from Aspalanthus caronosa nodules, inoculation studies have demonstrated that STM678 does not re-nodulate this plant (1). However, B. tuberum STM678 initiated ineffective (Fix-) nodules on Macroptilium atropurpureum (siratro) (1) or nitrogen-fixing (Fix+) nodules on five different species of another South African legume genus Cyclopia (2). We wanted to find a legume host that was easier to grow and obtain than Cyclopia, so we pursued nodulation studies on other species of Aspalathus as well as the African genera Lebeckia and Rhynchosia and found that either no nodules or Fix- nodules developed. Elliot et al. (2) found in their studies that Fix- nodules formed on cowpea (Vigna unguiculata L.) and bean (Phaseolus vulgaris L.), and following the suggestions of J. Cabellero-Mellado (Cuernavaca, Mexico) and Felix Dakora (South Africa), we analyzed the responses of different bean and cowpea cultivars to B. tuberum inoculation. Because they are important crop plants in both Mexico and southern African, significantly more genomic and genetics resources exist for bean and cowpea than for other potential hosts for Burkholderia tuberum. We will present our studies of bean and cowpea nodulation in response to B. tuberum STM678 in this paper. 1. Moulin L, Mundive A, Dreyfus B, Boivin-Masson C (2001) Nature 411:948-950. 2. Elliot GN, Chen W-M, Bontemps C, Chou J-C, Young JPW, Sprent JI, James EK (2007) Ann Bot 100:1403-1411.
The four middle authors are undergraduates as UCLA. M. Mojica, E. Pablo, and C. Yashar did part of this work during the winter quarter in an undergraduate laboratory (MCDB 150L) that I teach. M. Hernandez is enrolled as a student research project participant (MCDB 99). Burkholderia tuberum has the potential of serving as an inoculum for legume crops in drought-stricken areas.
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1 - UCLA, Dept. of MCD Biology and Mol Biol Institute, 405 Hilgard Avenue, Los Angeles, California, 90095, USA
2 - University of Californa-Los Angeles, Dept. of Mol. Cell & Develop. Biology, Los Angeles, CA
Presentation Type: Oral Paper:Papers for Topics
Location: 552A/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 2:00 PM