4463

242 دكتري

دكتري

اصلاح نباتات - ژنتيك مولكولي و مهندسي ژنتيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده كشاورزي

1387

شانزده، 192، [8]،[II]ص: مصور، جدول، نمودار

ص.ع به: فارسي و انگليسي

مسعود بهار، قدرت الله سعيدي

ابوالقاسم محمدي، ماركو باتزيكلوپو

88/2/22

امير لكزيان، بهروز شيران، فرشيد نوربخش

مهندسي كشاورزي

ID242 دكتري

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

194AbstractAlfalfa Medicago sativa as an autotetraploid allogamous and important foragelegume develops symbiotic association with its bacterial symbioant Sinorhizobiummeliloti To determine diversity of Sinorhizobium strains nodulating Iranian alfalfagenotypes Sinorhizobium populations from eight different Iranian sites were sampledusing two Iranian Hamadani and Nikshahri and an American Kodi alfalfa cultivarsas trap host plants A total of 982 rhizobial strains were isolated and species wereidentified showing large prevalence of S meliloti over S medicae Analysis of salttolerance and melanin production revealed high diversity among strains whereassignificant differences were not observed between groups of strains isolated fromdifferent sites and cultivars Nine S meliloti strains were indexed as rhizopine isolatesusing specific primers designed from rhizopine catabolism gene mocA and GC MSanalysis Analysis of molecular variance AMOVA based on BOX PCR data indicatedthat most of the total molecular variance was attributable to divergence among strainsisolated from the same sites and cultivars Competitiveness and ability of two chosenstrains of S meliloti to nodulate three local populations Hamedani Yazdi Nikshahri and an American cultivar Kodi of alfalfa were examined Simultaneously inter andintra genetic relationship of the nodulating plants were analyzed using microsatellitemarkers Based on the results the proportion of strain 5A1 with rhizopine catabolismand melanin production activity was relatively higher than others in the nodules formedin all the cultivars Key Words Diversity Rhizopine Medicago sativa Sinorhizobium meliloti S medicae CompetitivenessIntroductionAlfalfa Medicago sativa L is believed to have originated in north western of Iran andhas a long history of coexistence with its bacterial symbiont Sinorhizobium in soils ofIran but little is known about diversity of Sinorhizobium strains nodulating Iranianalfalfa genotypes The study of genetic diversity in bacterial population is carried outwith different DNA fingerprinting techniques among the most utilized are those basedon the distribution of repetitive DNA REP and ERIC sequences in the genomes of anumber of gram negative soil bacteria These have been studied and reported to behighly specific for each strain suggesting that the REP and ERIC PCR methods areuseful for the identification and classification of bacterial strains includingSinorhizobium 3 Despite the considerable capacity for nitrogen fixation the abundance of rhizobia inalfalfa growing area does not necessarily result in yield increases Evidences suggestthat the success of this symbiosis is influenced by the dynamics of indigenous rhizobialpopulations their survival and competitiveness along with several factors such aslocation host cultivar and individual plant genotypes sown in the soil 2 Response andadaptation to environmental stresses is also a complex phenomenon that likely affectsSinorhizobium alfalfa partnership Many Rhizobium species produce melanin pigments when grown on complete media Increasing levels of melanin production are obtained when bacteria are grown in thepresence of L tyrosine and Cu2 CuSO4 suggesting that tyrosinase may be involved inthis process The range of melanin production in rhizobia has been characterized

مسعود بهار، قدرت الله سعيدي

ابوالقاسم محمدي، ماركو باتزيكلوپو

امير لكزيان، بهروز شيران، فرشيد نوربخش