Browsing by Author "Pietersen, Gerhard"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
- ItemDraft genome sequence of a “candidatus phytoplasma asteris” - related strain (aster yellows, subgroup 16SrI-B) from South Africa(American Society for Microbiology, 2019-04-25) Coetzee, Beatrix; Douglas-Smit, Nicoleen; Maree, Hans J.; Burger, Johan T.; Kruger, Kerstin; Pietersen, GerhardHere, we report the draft genome sequence of a phytoplasma discovered in grapevine. The genome size is 600,116 nucleotides (nt), with 597 predicted open reading frames. It is most similar to a maize bushy stunt phytoplasma of group 16SrI-B (aster yellows). The possible presence of a 3,833-nt plasmid was also noted.
- ItemMitochondrial genetic variation reveals phylogeographic structure and cryptic diversity in Trioza erytreae(Nature Research (part of Springer Nature), 2020) Ajene, Inusa; Pietersen, Gerhard; Van Asch, BarbaraTrioza erytreae is the main vector for ‘Candidatus Liberibacter africanus’, the causative agent of African Citrus Greening disease. The insect is widespread in Africa, and has recently disseminated to Southwestern Europe. This study aimed at generating reference mitogenome sequences for T. erytreae, as a background for future genetic diversity surveys. Complete mitochondrial sequences of three specimens collected in Ethiopia, Uganda and South Africa were recovered using Ion Torrent technology. The mitogenomes of T. erytreae from Uganda and Ethiopia were highly similar, and distinct from that found in South Africa. The phylogeographic structure of T. erytreae was assessed using genetic clustering and pairwise distances, based on a dataset of public COI sequences recorded as T. erytreae. The dataset revealed ten haplotypes with strong phylogeographic structure in Africa and Europe. Three haplotypes found in Kenya on Clausena anisata belonged to pairs separated by distances as high as 11.2%, and were basal to all other sequences. These results indicate that not all sequences identified as T. erytreae belong to the same species, and that some degree of specificity with different plant hosts is likely to exist. This study provides new baseline information on the diversity of T. erytreae, with potential implications for the epidemiology of African Citrus Greening disease.
- ItemThe structure and function of the global citrus rhizosphere microbiome(Nature Research (part of Springer Nature), 2018) Xu, Jin; Zhang, Yunzeng; Zhang, Pengfan; Trivedi, Pankaj; Riera, Nadia; Wang, Yayu; Liu, Xin; Fan, Guangyi; Tang, Jiliang; Coletta-Filho, Helvecio D.; Cubero, Jaime; Deng, Xiaoling; Ancona, Veronica; Lu, Zhanjun; Zhong, Balian; Roper, M. Caroline; Capote, Nieves; Catara, Vittoria; Pietersen, Gerhard; Verniere, Christian; Al-Sadi, Abdullah M.; Li, Lei; Yang, Fan; Xu, Xun; Wang, Jian; Yang, Huanming; Jin, Tao; Wang, NianCitrus is a globally important, perennial fruit crop whose rhizosphere microbiome is thought to play an important role in promoting citrus growth and health. Here, we report a comprehensive analysis of the structural and functional composition of the citrus rhizosphere microbiome. We use both amplicon and deep shotgun metagenomic sequencing of bulk soil and rhizosphere samples collected across distinct biogeographical regions from six continents. Predominant taxa include Proteobacteria, Actinobacteria, Acidobacteria and Bacteroidetes. The core citrus rhizosphere microbiome comprises Pseudomonas, Agrobacterium, Cupriavidus, Bradyrhizobium, Rhizobium, Mesorhizobium, Burkholderia, Cellvibrio, Sphingomonas, Variovorax and Paraburkholderia, some of which are potential plant beneficial microbes. We also identify over-represented microbial functional traits mediating plant-microbe and microbe-microbe interactions, nutrition acquisition and plant growth promotion in citrus rhizosphere. The results provide valuable information to guide microbial isolation and culturing and, potentially, to harness the power of the microbiome to improve plant production and health.