کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2026358 1070027 2007 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
New insights into the origins and evolution of rhizobia that nodulate common bean (Phaseolus vulgaris) in Brazil
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش خاک شناسی
پیش نمایش صفحه اول مقاله
New insights into the origins and evolution of rhizobia that nodulate common bean (Phaseolus vulgaris) in Brazil
چکیده انگلیسی

It is generally accepted that there are two major centers of genetic diversification of common beans (Phaseolus vulgaris L.): the Mesoamerican (Mexico, Colombia, Ecuador and north of Peru, probably the primary center), and the Andean (southern Peru to north of Argentina) centers. Wild common bean is not found in Brazil, but it has been grown in the country throughout recorded history. Common bean establishes symbiotic associations with a wide range of rhizobial strains and Rhizobium etli is the dominant microsymbiont at both centers of genetic diversification. In contrast, R. tropici, originally recovered from common bean in Colombia, has been found to be the dominant species nodulating field-grown common-bean plants in Brazil. However, a recent study using soil dilutions as inocula has shown surprisingly high counts of R. etli in two Brazilian ecosystems. In the present study, RFLP-PCR analyses of nodABC and nifH genes of 43 of those Brazilian R. etli strains revealed unexpected homogeneity in their banding patterns. The Brazilian R. etli strains were closely similar in 16S rRNA sequences and in nodABC and nifH RFLP-PCR profiles to the Mexican strain CFN 42T, and were quite distinct from R. etli and R. leguminosarum strains of European origin, supporting the hypothesis that Brazilian common bean and their rhizobia are of Mesoamerican origin, and could have arrived in Brazil in pre-colonial times. R. tropici may have been introduced to Brazilian soils later, or it may be a symbiont of other indigenous legume species and, due to its tolerance to acidic soils and high temperature conditions became the predominant microsymbiont of common bean.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Soil Biology and Biochemistry - Volume 39, Issue 4, April 2007, Pages 867–876
نویسندگان
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