RESUMO
Transgenic soybean is the most widely grown genetically modified crop in the world, with herbicide resistance being the major modified trait. Microbial community is one of the most important indicators for soil quality. The effects of glyphosate-resistant transgenic soybean and glyphosate application on rhizospheric bacteria and rhizobia still remained unknown. In this study, with the non-transgenic parent Zhongdou 32 as control (CK), we investigated the effects of the G10-epsps transgenic glyphosate-resistance soybean SHZD32-01 without or with glyphosate application (abbreviated as GR and GR+G, respectively) on rhizospheric bacteria and rhizobia at different growth stages of soybean in field. Compared with CK, GR and GR+G had effects on soil pH, total organic carbon, total nitrogen and ammonium contents at the seedling and mature stages. GR significantly increased the abundance and diversity of soil rhizospheric bacterial community at the podding stage. GR+G significantly increased the abundance of soil rhizospheric bacterial community at the podding stage but decreased its diversity at the seeding and podding stages. GR and GR+G changed the relative abundance of dominant bacteria populations. Proteobacteria, Acidobacteria, Bacteroidetes, Chloroflexi, Planctomycetes and Actinobacteria were generally the dominant ones among the three treatments across all growth stages. Furthermore, GR and GR+G changed the relative abundance of rhizobia but did not change that of soybean-nodulating rhizobia, Bradyrhizobium and Sinorhizobium. The relative abundance of rhizobia in GR+G was decreased significantly at the podding stage. The abundance of actinobacteria and rhizobia was mainly affected by soil pH. Glyphosate-resistant transgenic soybean without or with glyphosate application altered soil rhizospheric bacteria and rhizobia at the podding stage, but the effects disappeared along with the growth of soybean.
Assuntos
Glycine max/genética , Glicina/análogos & derivados , Plantas Geneticamente Modificadas , Microbiologia do Solo , Solo , Bactérias , Glicina/toxicidade , Rhizobium , GlifosatoRESUMO
Glyphosate inhibits the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) in the shikimate pathway. A mutant of EPSPS from Pantoea sp. was identified using site-directed mutagenesis (SDM). The mutant significantly improved glyphosate resistance. The mutant had mutations in three amino acids: Gly97 to Ala, Thr 98 to Ile and Pro 102 to Ser. These mutation sites in E.coli have been studied as significant active sites of glyphosate resistance. However, in our research they were found to jointly contribute to the improvement of glyphosate tolerance. In addition, the level of glyphosate tolerance in transgenic Arabidopsis confirmed the potentiality of the mutant in breeding glyphosate-resistant plants.
Assuntos
3-Fosfoshikimato 1-Carboxiviniltransferase/genética , Resistência a Herbicidas/genética , Pantoea/fisiologia , 3-Fosfoshikimato 1-Carboxiviniltransferase/antagonistas & inibidores , 3-Fosfoshikimato 1-Carboxiviniltransferase/química , Substituição de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Glicina/análogos & derivados , Glicina/farmacologia , Herbicidas/farmacologia , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Mutação , Pantoea/enzimologia , Pantoea/genética , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/genética , GlifosatoRESUMO
Soybean frogeye leaf spot is one of the main diseases in Heilongjiang province. Usually, under several physical races of Cerospora Sojina Hara existed condition, the inheritance of resistance to this disease is controlled by equal-effect polygene. While high resistant parent 'Dongnong 9674 and other sensitive parents were used to make the three resistance-sensitive combinations in this paper, the resistance to Cerospora Sojina Hara had appeared the significant major gene effect. When P1, P2, F1, F2, B1, and B2 six generations were used to study and estimate the gene effects, major genes of resistance to Cerospora Sojina Hara were identified and the genetic parameters were also estimated in three combinations. The inheritance of genes resistant to this disease was fitted to the major gene and polygene mixed inheritance model or two gene loci inheritance model. The estimation of genetic parameters indicated that the additive, dominance and epistasis effects were existed and played an important role in the resistance to Cerospora Sojina Hara. It is meaningful in soybean resistance breeding to frogeye leaf spot.
