Identification and genomic characterization of a novel HIV-1 unique recombinant form (CRF01_AE/CRF07_BC) in Zhejiang Province, China.

Mutation and recombination are important mechanisms leading to the frequent evolution and genetic diversity of viruses as HIV-1. In this study, we identified the near full-length genomic characterization of a novel HIV-1 unique recombinant form (URF) strain (Sample ID: ZJ20202195/ZJ/CHN/2020, hereafter referred to as ZJ20202195) isolated during the HIV-1 molecular surveillance in 2020 in Zhejiang Province, China, through different recombination analysis tools and phylogenetic analysis. Our results amply proved that the near full-length genome (NFLG) sequence of ZJ20202195 was a novel HIV-1 unique recombinant form (URF) consisting of CRF01_AE and CRF07_BC subtype, and delimited three recombinant segments, of which the Segment I (HXB2:776-5559 nucleotide (nt)) and Segment III (HXB2:6224-9412 nt) were mainly originated from CRF01_AE cluster g4a strains prevalent in China and Segment II (HXB2:5560-6223 nt) was from CRF07_BC subtype. Overall, our findings provide insight and a scientific basis in the genetic diversity and accurate determination of HIV-1 recombinant strains in China.

Transfer of Bacillus mucilaginosus and Bacillus edaphicus to the genus Paenibacillus as Paenibacillus mucilaginosus comb. nov. and Paenibacillus edaphicus comb. nov.

Bacillus mucilaginosus and Bacillus edaphicus were reclassified based on their 16S rRNA and gyrB gene sequences, DNA-DNA hybridization, fatty acid methyl esters and other taxonomic characteristics. Phylogenetic analysis based on 16S rRNA and gyrB gene sequences indicated that strains of B. mucilaginosus and B. edaphicus were members of the genus Paenibacillus, with over 90.4 % and 70.3 % sequence similarity, respectively. Their DNA G+C contents were 54.5-56.8 mol%. The DNA-DNA relatedness values of B. edaphicus VKPM B-7517(T) with B. mucilaginosus KNP414 and B. mucilaginosus CGMCC 1.236 were 89.2 % and 88.7 %, respectively. The major isoprenoid quinone of B. mucilaginosus and B. edaphicus was MK-7 (94.1-95.7 %). The peptidoglycan type was A1gamma (meso-diaminopimelic acid) and the major polar lipids were phosphatidylglycerol and diphosphatidylglycerol. The major fatty acids were anteiso-C(15 : 0), C(16 : 1)omega11c and C(16 : 0). Phenotypic features and fatty acid profiles supported the similarity of B. mucilaginosus and B. edaphicus to Paenibacillus validus CCTCC 95016(T) and confirmed their relationship with members of the genus Paenibacillus. Therefore, it is proposed that Bacillus mucilaginosus and Bacillus edaphicus be transferred to the genus Paenibacillus as Paenibacillus mucilaginosus comb. nov. (type strain HSCC 1605(T)=VKPM B-7519(T)=VKM B-1480D(T)=CIP 105815(T)=KCTC 3870(T)) and Paenibacillus edaphicus comb. nov. (type strain VKPM B-7517(T)=DSM 12974(T)=CIP 105814(T)), respectively.

Isolation and characterization of endophytic and rhizosphere bacterial antagonists of soft rot pathogen from Pinellia ternata.

Pinellia ternata, a traditional Chinese herb that has been used in China for over 1000 years, is susceptible to a soft rot disease, which may cause major loss of yield. The use of bacteria as potential antagonists against Pectobacterium carotovorum SXR1, the causal agent of the disease on P. ternata, was evaluated. Altogether, 1107 candidate bacteria were isolated from the rhizosphere and surface-sterilized plants of P. ternata. In Petri dish tests, 55 isolates inhibited the growth of strain SXR1, and 21 of these reduced the disease development on P. ternata slices by over 50%. Four selected antagonists significantly reduced the disease incidence on tissue culture seedlings, and also prevented the disease on the transplants. Agonist P-Y2-2 yielded a good prevention level of 81.9%. The four antagonists rapidly colonized the tissue culture seedlings and transplants, whereas greater populations of the antagonists (10(7)-10(9) CFU g(-1) fresh tissues) were observed in the seedlings and in the preinoculated transplants than in those inoculated during transplanting. The use of pathogen-free tissue culture seedlings pre-inoculated with antagonist may provide a strategy for production of P. ternata plantlets resistant to soft rot disease. This is the first report on the efficacy of biocontrol agents against pathogens on P. ternata.