Chaste tree(Vitex negundo var.heterophylla)witches’-broom was a new disease found in Mountain Taishan and the neighboring region.Phytoplasmal cells could be easily observed in the phloem sieve elements of diseased pl...Chaste tree(Vitex negundo var.heterophylla)witches’-broom was a new disease found in Mountain Taishan and the neighboring region.Phytoplasmal cells could be easily observed in the phloem sieve elements of diseased plants under electron microscope.The 16S rRNA gene of phytoplasma associated with this disease(CTWB)was amplified with nested-PCR with the universal primer pairs R16mF2/R16mR1 and R16F2n/R16R2.An amplified fragment of ca.1.2 kb was sequenced and subjected to identity and phylogenetic analyses.Phytoplasma CTWB shared identities of more than 99.0% with members of Aster yellows group(16SrI)in 16S rRNA genes.It had the highest identity of 99.8% with phytoplasmas associated with Maize bushy stunt(subgroup 16SrI-B),and clustered into a common branch with phytoplasmas of the subgroup in the phylogenetic tree constructed with 16S rRNA genes.These results indicated that CTWB belonged to subgroup B of Candidatus Phytoplasma asteris(16SrI-B).展开更多
采用平板对峙法与灰色关联度分析法从小麦和苹果根际土壤中筛选出对小麦纹枯病(Rhizoctonia cerealis)和小麦根腐病(Bipolaris sorokiniana)具有良好拮抗作用的放线菌,并依据菌落形态和培养特征、生理生化特性及16S r DNA序列分析等进...采用平板对峙法与灰色关联度分析法从小麦和苹果根际土壤中筛选出对小麦纹枯病(Rhizoctonia cerealis)和小麦根腐病(Bipolaris sorokiniana)具有良好拮抗作用的放线菌,并依据菌落形态和培养特征、生理生化特性及16S r DNA序列分析等进行鉴定。结果表明,菌株FX-H-51抑菌效果显著,对不利生长环境有良好的耐受性。形态学与分子鉴定结果表明,菌株FX-H-51为海棠链霉菌(Streptomyces spectabilis)。展开更多
文摘Chaste tree(Vitex negundo var.heterophylla)witches’-broom was a new disease found in Mountain Taishan and the neighboring region.Phytoplasmal cells could be easily observed in the phloem sieve elements of diseased plants under electron microscope.The 16S rRNA gene of phytoplasma associated with this disease(CTWB)was amplified with nested-PCR with the universal primer pairs R16mF2/R16mR1 and R16F2n/R16R2.An amplified fragment of ca.1.2 kb was sequenced and subjected to identity and phylogenetic analyses.Phytoplasma CTWB shared identities of more than 99.0% with members of Aster yellows group(16SrI)in 16S rRNA genes.It had the highest identity of 99.8% with phytoplasmas associated with Maize bushy stunt(subgroup 16SrI-B),and clustered into a common branch with phytoplasmas of the subgroup in the phylogenetic tree constructed with 16S rRNA genes.These results indicated that CTWB belonged to subgroup B of Candidatus Phytoplasma asteris(16SrI-B).
