ABSTRACT
A novel strain, 1433T, was isolated from leaves of Chinese red pepper (Huajiao, Zanthoxylum bungeanum Maxim) collected from Gansu province in northwestern China, and was characterised by a polyphasic approach. Cells of strain 1433T were observed to be Gram-stain positive, aerobic, asporogenous, rod shaped, motile and to have peritrichous flagella. The strain was observed to grow at a range of temperatures and pH, 4-45 °C (optimum 28-32 °C) and 6.0-10.0 (optimum pH 6.0-7.0), respectively. Growth was found to occur in the presence of 0-7% (w/v) NaCl [optimum 0-3% (w/v)]. The G+C content of the genomic DNA was determined to be 41.9 mol% and the cell wall peptidoglycan found to contain meso-diaminopimelic acid. The predominant menaquinone was identified as MK-7 and the major polar lipids as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified polar lipid and three unidentified phospholipids. The major cellular fatty acids were identified as iso-C15:0 (31.6%), anteiso-C15:0 (26.9%) and iso-C14:0 (17.1%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 1433T is a member of the genus Bacillus and is closely related to Bacillus aryabhattai DSM 21047T (99.4% sequence similarity) and Bacillus megaterium DSM 32T (99.2%). DNA-DNA relatedness of the novel strain 1433T with B. aryabhattai DSM 21047T and B. megaterium DSM 32T was 33.8 ± 2.8% and 28.9 ± 3.4%, respectively. On the basis of the polyphasic evidence presented, strain 1433T is considered to represent a novel species of the genus Bacillus, for which we propose the name Bacillus zanthoxyli sp. nov. The type strain is 1433T (= CCTCC AB 2016326T = KCTC33730T).
Subject(s)
Bacillus/classification , Bacillus/physiology , Phylogeny , Zanthoxylum/microbiology , Bacillus/chemistry , Bacillus/genetics , Base Composition , Cell Wall/chemistry , China , Flagella , Nucleic Acid Hybridization , Plant Leaves/microbiology , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Species SpecificityABSTRACT
A total of 287 agricultural soil samples collected from 26 provinces or autonomous regions of China were tested on their ability to suppress the conidial germination of nine biocontrol fungal agents. These soil samples showed great differences in the degree to inhibit the germination of conidia (22.8% < mean inhibition rate < 97.5%), but all exhibited fungistatic activities above the moderate levels (mean inhibition rate > 50%) to most of tested fungi. Ten soil samples that have stronger fungistatic intensity (germination inhibition rate > 68.3%) to the target fungi, Trichoderma viride and Paecilomyces lilacinus, were selected to evaluate their soil actinobacteria involved fungistasis in soil. Of the 1,000 isolates from those soil samples, 345 actinobacteria exhibited fungistatic activity to conidial germination of T. viride and P. lilacinus with germination inhibition rates higher than 10%. Sequences encoding 16S rRNA gene of the 345 actinobacteria were analyzed by ARDRA and resulted 44 different ARDRA types. Fifty-six isolates, at least one from each unique ARDRA type, were selected for 16S rDNA sequencing and phylogenetic analysis. Results indicated that the actinobacteria involved in the soil fungistasis had close phylogenetic relationship with the members of Sterptomycetaceae, Microbacteriaceae, Micrococcaceae, and Nocardiacea.
