Frindte Katharina, Maarastawi Sarah A, Lipski André, Hamacher Joachim, Knief Claudia
Molecular Biology of the Rhizosphere, Institute of Crop Science and Resource Conservation, University of Bonn, Nussallee 13, 53115 Bonn, Germany.
Food Microbiology and Hygiene, Institute of Nutritional and Food Sciences, University of Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany.
Int J Syst Evol Microbiol. 2017 Nov;67(11):4507-4514. doi: 10.1099/ijsem.0.002319. Epub 2017 Oct 6.
Three gammaproteobacterial methanotrophic strains (73a, 175 and 114) were isolated from stems of rice plants. All strains are Gram-negative, motile and grow on methane or methanol as sole carbon sources. They oxidize methane using the particulate methane monooxygenase. Strains 114 and 175 possess additionally a soluble methane monooxygenase. All strains contain significant amounts of the cellular fatty acids C16 : 0, C16 : 1ω6c and C16 : 1ω7c, typical for type Ib methanotrophs. Characteristic for strains 114 and 175 are high amounts of C14 : 0 and C16 : 1ω6c , while strain 73a contains high quantities of C16 : 1ω5c. 16S rRNA gene sequence analyses showed that strains 114 and 175 are most closely related to Methylomagnum ishizawai (≥99.6 % sequence identity). Strain 73a is representing a new genus within the family Methylococcaceae, most closely related to Methylococcus capsulatus (94.3 % sequence identity). Phylogenetic analysis of the PmoA sequence indicates that strain 73a represents rice paddy cluster I (RPCI), which has almost exclusively been detected in rice ecosystems. The G+C content of strain 73a is 61.0 mol%, while strains 114 and 175 have a G+C content of 63.3 mol%. Strain 73a (=LMG 29185, =VKM B-2986) represents the type strain of a novel species and genus, for which the name Methyloterricola oryzae gen. nov., sp. nov. is proposed and a description is provided. Strains 175 (=LMG 28717, VKM B-2989) and 114 are members of the species Methylomagnum ishizawai. This genus was so far only represented by one isolate, so an amended description of the species is given.
从水稻植株茎部分离出三株γ-变形菌纲甲烷营养菌株（73a、175和114）。所有菌株均为革兰氏阴性、具运动性，可利用甲烷或甲醇作为唯一碳源生长。它们利用颗粒性甲烷单加氧酶氧化甲烷。菌株114和175还拥有可溶性甲烷单加氧酶。所有菌株均含有大量细胞脂肪酸C16 : 0、C16 : 1ω6c和C16 : 1ω7c，这是Ib型甲烷营养菌的典型特征。菌株114和175的特征是含有大量的C14 : 0和C16 : 1ω6c，而菌株73a含有大量的C16 : 1ω5c。16S rRNA基因序列分析表明，菌株114和175与石泽甲基巨球菌关系最为密切（序列同一性≥99.6 %）。菌株73a代表甲基球菌科内的一个新属，与荚膜甲基球菌关系最为密切（序列同一性94.3 %）。对PmoA序列的系统发育分析表明，菌株73a代表稻田簇I（RPCI），几乎仅在水稻生态系统中被检测到。菌株73a的G+C含量为61.0 mol%，而菌株114和175的G+C含量为63.3 mol%。菌株73a（=LMG 29185，=VKM B-2986）代表一个新物种和新属的模式菌株，为此提出了新的名称甲基土栖稻菌属（Methyloterricola）、新种甲基土栖稻菌（Methyloterricola oryzae）并给出了描述。菌株175（=LMG 28717，VKM B-2989）和114是石泽甲基巨球菌的成员。该属迄今仅由一个分离株代表，因此给出了该物种的修订描述。
