Genetic variability analysis of human papillomavirus 58: Novel sublineage identification and persistent infection association.

This study aims to characterize the genetic variability of HPV58, identify novel lineages and sublineages, and explore the association between persistent/multiple HPV58 infections and genetic variation. In this study, samples from 124 women with HPV58 infection in Eastern China were collected and 81 isolates of E6 and L1 full-length genes were successfully amplified from 55 samples. We evaluated the diversity of genetic variants and performed correlation analyses between genetic variability and pathology, vaccination, multiple infections, and persistent infections. Among the E6 and L1 gene sequences collected, the dominant prevailing sublineages were A1 (46.2%) and A2 (23.1%). In addition, we found two potential novel sublineages denoted as the A4 and A5 sublineage. A total of 50 nucleotide substitutions, including 28 synonymous substitutions and 22 nonsynonymous substitutions, were observed in the E6 and L1 genes. Among them, variants with A388C/K93N substitutions in the E6 gene correlated with persistent infection (≥1 and ≥2 years) (p < 0.005), and C307T/C66C was associated with persistent infection (≥2 years) (p < 0.005). Notably, two mutations above were detected in the isolate from the patient with breakthrough vaccine infection. Our study found two novel sublineages and sites of genetic variability in multiple and persistent infection variants. In addition, we identified two mutational sites associated with persistent infection. This study provides new insight into the clinical characteristics of HPV 58 genetic variations and offers new ideas for research on next-generation vaccines in Eastern China.

Independent Evolution with the Gene Flux Originating from Multiple Xanthomonas Species Explains Genomic Heterogeneity in Xanthomonas perforans.

Xanthomonas perforans is the predominant pathogen responsible for bacterial leaf spot of tomato and X. euvesicatoria for that of pepper in the southeast United States. Previous studies have indicated significant changes in the X. perforans population collected from Florida tomato fields over the span of 2 decades, including a shift in race and diversification into three phylogenetic groups driven by genome-wide homologous-recombination events derived from X. euvesicatoria In our sampling of Xanthomonas strains associated with bacterial spot disease in Alabama, we were readily able to isolate X. perforans from symptomatic pepper plants grown in several Alabama counties, indicating a recent shift in the host range of the pathogen. To investigate the diversity of these pepper-pathogenic strains and their relation to populations associated with tomatoes grown in the southeast United States, we sequenced the genomes of eight X. perforans strains isolated from tomatoes and peppers grown in Alabama and compared them with previously published genome data available from GenBank. Surprisingly, reconstruction of the X. perforans core genome revealed the presence of two novel genetic groups in Alabama that each harbored a different transcription activation-like effector (TALE). While one TALE, AvrHah1, was associated with an emergent lineage pathogenic to both tomato and pepper, the other was identified as a new class within the AvrBs3 family, here designated PthXp1, and was associated with enhanced symptom development on tomato. Examination of patterns of homologous recombination across the larger X. euvesicatoria species complex revealed a dynamic pattern of gene flow, with multiple donors of Xanthomonas spp. associated with diverse hosts of isolation.IMPORTANCE Bacterial leaf spot of tomato and pepper is an endemic plant disease with a global distribution. In this study, we investigated the evolutionary processes leading to the emergence of novel X. perforans lineages identified in Alabama. While one lineage was isolated from symptomatic tomato and pepper plants, confirming the host range expansion of X. perforans, the other lineage was isolated from tomato and acquired a novel transcription activation-like effector, here designated PthXp1. Functional analysis of PthXp1 indicated that it does not induce Bs4-mediated resistance in tomato and contributes to virulence, providing an adaptive advantage to strains on tomato. Our findings also show that different phylogenetic groups of the pathogen have experienced independent recombination events originating from multiple Xanthomonas species. This suggests a continuous gene flux between related xanthomonads associated with diverse plant hosts that results in the emergence of novel pathogen lineages and associated phenotypes, including host range.

Insights on Lulworthiales Inhabiting the Mediterranean Sea and Description of Three Novel Species of the Genus Paralulworthia.

The order Lulworthiales, with its sole family Lulworthiaceae, consists of strictly marine genera found on a wide range of substrates such as seagrasses, seaweeds, and seafoam. Twenty-one unidentified Lulworthiales were isolated in previous surveys aimed at broadening our understanding of the biodiversity hosted in the Mediterranean Sea. Here, these organisms, mostly found in association with Posidonia oceanica and with submerged woods, were examined using thorough multi-locus phylogenetic analyses and morphological observations. Maximum-likelihood and Bayesian phylogeny based on nrITS, nrSSU, nrLSU, and four protein-coding genes led to the introduction of three novel species of the genus Paralulworthia: P. candida, P. elbensis, and P. mediterranea. Once again, the marine environment is a confirmed huge reservoir of novel fungal lineages with an under-investigated biotechnological potential waiting to be explored.

Yogsothoth knorrus gen. n., sp. n. and Y. carteri sp. n. (Yogsothothidae fam. n., Haptista, Centroplasthelida), with Notes on Evolution and Systematics of Centrohelids.

Two closely related new species of centrohelid heliozoans with unusual morphology were studied with light and electron microscopy. Sequences of the 18S rRNA gene were also obtained and secondary structure of 18S rRNA molecule reconstructed. The cells, covered with inner siliceous plate scales formed colonies. The entire colony was surrounded with a thick layer of external scales. Inner scales were tabulate and had a patternless surface, except for the presence of an axial rib. Outer scales had a boat-like (Yogsothoth knorrus gen. nov., sp. nov.) or pot-like (Yogsothoth carteri sp. nov.) shape with an axial rib and numerous conical papillae on the scale surface. Analysis of 18S rRNA gene sequences robustly placed the new taxa within centrohelids, but not in any existing family. Scaled Yogsothoth represents a genetically divergent closest outgroup of Acanthocystida, branching after the supposedly primary non-scaled Marophrys, and together with acanthocystids, forming the novel taxon Panacanthocystida. Reconstruction of presumptive 18S rRNA secondary structure reveals interspecific differences in expansion segments 7 and 9 of Yogsothoth. Analysis of 18S rRNA secondary structure of other centrohelids allowed identification of length increases characteristic for Panacanthocystida location and reconstruction of 18S rRNA elongation in the course of the evolution of this group.

Ecological and evolutionary significance of novel protist lineages.

Environmental molecular surveys targeting protist diversity have unveiled novel and uncultured lineages in a variety of ecosystems, ranging from completely new high-rank lineages, to new taxa moderately related to previously described organisms. The ecological roles of some of these novel taxa have been studied, showing that in certain habitats they may be responsible for critical environmental processes. Moreover, from an evolutionary perspective they still need to be included in a more accurate and wider understanding of the eukaryotic tree of life. These seminal discoveries promoted the development and use of a wide range of more in-depth culture-independent approaches to access this diversity, from metabarcoding and metagenomics to single cell genomics and FISH. Nonetheless, culturing using classical or innovative approaches is also essential to better characterize this new diversity. Ecologists and evolutionary biologists now face the challenge of apprehending the significance of this new diversity within the eukaryotic tree of life.