Ecology, Evolution, Behavior and Systematics

A novel Gram-stain-positive, rod shaped and anaerobic bacterium, designated as W6T, was isolated from Shengli oilfield in China. Strain W6T was observed to grow from 20 to 45 °C with pH 6.5–9.0 (optimally at 40 °C and pH of 7.5) and without addition of NaCl. The major cellular fatty acids were iso-C15 : 0 (29.1%), C14 : 0 (27.0%) and C16 : 0 (12.2%), and the main polar lipids were lipids (L) and aminolipids (AL). The DNA G+C content is 42.9 mol%. Based on 16S rRNA gene sequence analysis, strain W6T showed highest similarities to Tissierella creatinini DSM 9508T (94.9%) and Soehngenia saccharolytica DSM 12858T (94.1%). The morphological, physiological, biochemical, phylogenetic and phylogenomic analyses demonstrated strain W6T (CCAM 534T=DSM 28124T=CGMCC 1.5291T) represents a novel species in a new genus, for which the name Gudongella oleilytica gen. nov. sp. nov. is proposed. The family Tissierellaceae is proposed as a new family containing the genera Anaerosalibacter , Gudongella, Keratinibaculum , Soehngenia , Sporanaerobacter , Tepidimicrobium , Tissierella , Urmitella and species Clostridium ultunense based on the phylogenetic and phylogenomic analyses.

An obligately anaerobic, Gram-stain-positive and coccus-shaped bacterium, designated strain YH-panp20T, was isolated from pig faeces. Phylogenetic analysis based on 16S rRNA gene sequencing indicated that the isolate belongs to the family Erysipelotrichaceae , and is most closely related to Catenisphaera adipataccumulans KCTC 15517T (93.5 % sequence similarity), followed by Faecalitalea cylindroides KCTC 5815T (92.2 %), Faecalicoccus acidiformans KCTC 15521T (90.2 %) and Holdemanella biformis KCTC 5969T (89.6 %). Average nucleotide identity values between YH-panp20T and its closest relatives were lower than 71 %. The G+C content of the isolate was 38.4 mol%, and its cell-wall peptidoglycan was found to be of A1γ type and contained meso-diaminopimelic acid. The predominant fatty acids were C18 : 1 cis 9, C18 : 0 DMA and C16 : 0. The major end-products of glucose fermentation were lactate, acetate and formate. Therefore, based on the phenotypic, phylogenetic and chemotaxonomic properties, a novel genus and species, Absicoccus porci gen. nov., sp. nov., is proposed for isolate YH-panp20T (=KCTC 15747T=JCM 32769T).

AbstractPhytoplasmas are specialized small bacteria restricted to the phloem tissue and spread by hemipterans feeding on plant sieve tube elements. As for many other plant pathogens, it is known that phytoplasmas alter the chemistry of their hosts. Most research on phytoplasma-plant interactions focused on the induction of plant volatiles and phytohormones. Little is known about the influence of phytoplasma infections on the nutritional composition of phloem and consequences on vector behavior and development. The plum psyllid Cacopsylla pruni transmits ‘Candidatus Phytoplasma prunorum’, the causing agent of European Stone Fruit Yellows (ESFY). While several Prunus species are susceptible for psyllid feeding, they show different responses to the pathogen. We studied the possible modulation of plant-insect interactions by bacteria-induced changes in phloem sap chemistry. Therefore, we sampled phloem sap from phytoplasma-infected and non-infected Prunus persica and Prunus insititia plants, which differ in their susceptibility to ESFY and psyllid feeding. Furthermore, the feeding behavior and development of C. pruni nymphs was compared on infected and non-infected P. persica and P. insititia plants. Phytoplasma infection did not affect phloem consumption by C. pruni nymphs nor their development time. In contrast, the study revealed significant differences between P. insititia and P. persica in terms of both phloem chemistry and feeding behavior of C. pruni nymphs. Phloem feeding phases were four times longer on P. insititia than on P. persica, resulting in a decreased development time and higher mortality of vector insects on P. persica plants. These findings explain the low infestation rates of peach cultivars with plum psyllids commonly found in field surveys.