Arthrobacter pityocampae sp. nov., isolated from Thaumetopoea pityocampa (Lep., Thaumetopoeidae)

A bacterium (strain Tp2T) was isolated from a caterpillar of the pine processionary moth, Thaumetopoea pityocampa (Den. & Schiff.) (Lepidoptera: Thaumetopoeidae), a destructive pine forest pest. The bacterium is a Gram-stain-positive, red-pigmented coccus, oxidase-negative, nitrate-reducing, non-motile and non-spore-forming. Strain Tp2T was subjected to a taxonomic study using polyphasic approach that included morphological and biochemical characterizations, 16S rRNA gene sequence analysis, DNA–DNA hybridization, DNA G+C content analysis, comparative fatty acid profiles, and analyses of quinones and polar lipids. The 16S rRNA gene sequence of strain Tp2T revealed that Arthrobacter agilis DSM 20550T was the closest known strain (98 % 16S rRNA gene sequence similarity). DNA–DNA hybridization of A. agilis DSM 20550T and strain Tp2T resulted in a DNA–DNA relatedness value of 11.9 % (20.2 % reciprocal). The DNA base composition of strain Tp2T was 69.5 mol%, which is consistent with the other recognized members of Actinobacteria that have a high G+C content in their genome. The polar lipid pattern of strain Tp2T consisted of diphosphatidylglycerol (major), phosphatidylglycerol and phosphatidylinositol and unknown glycolipids. The cellular fatty acids were anteiso C15 : 0 and anteiso C17 : 0 and the major menaquinone was MK-9(II-H2). The peptidoglycan type was A3α with an l-Lys–l-Thr–l-Ala3 interpeptide bridge. The above-mentioned characterization qualifies strain Tp2T as genotypically and phenotypically distinct from closely related species of the genus Arthrobacter with validly published names. Strain Tp2T is therefore proposed to represent a novel species of the genus Arthrobacter, described as Arthrobacter pityocampae sp. nov. The type strain is Tp2T ( = DSM 21719T = NCCB 100254T).