A Gram-negative, aerobic and non-motile rod, designated Y4 T , was isolated from a cucumber leaf from Pinggu District, east Beijing, PR China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Y4T was most closely related to Luteimonas aquatica RIB1-20 T (96.7 % 16S rRNA gene sequence similarity). DNA-DNA relatedness between strain Y4 T and L.aquatica RIB1-20 T was 42.5±3.9 %. The predominant fatty acids were iso-C 15 : 0 , iso-C 17 : 1 v9c, iso-C 16 : 0 and iso-C 17 : 0 . The major ubiquinone was Q-8. The DNA G+C content of the type strain was 69.9 mol%. Based on the evidence above, strain Y4 T represents a novel species of the genus Luteimonas, for which the name Luteimonas cucumeris sp. nov. is proposed. The type strain is Y4 T (5CGMCC 1.10821The genus Luteimonas, in the family Xanthomonadaceae of the class Gammaproteobacteria, was first described by A yellow rod, designated Y4 T , was isolated from a cucumber leaf collected from Pinggu District, east Beijing, PR China, during the blossoming stage in May 2009. The leaf was surface sterilized (Rubini et al., 2005) and a sample of crushed tissue was incubated on nutrient agar (NA; Difco) at 30 u C for 3 days and a pure culture of strain Y4T was obtained after subcultivation. Strain Y4 T was routinely cultivated on NA at 30 uC and preserved in 25 % (w/v) glycerol at 280 u C.Cells were grown for 72 h and observed by light microscopy (61000; Olympus) and transmission electron microscopy (JEM-1400; JEOL) to ascertain their morphology and size. Motility was examined by the hanging drop method (Mackie & McCartney, 1989). The Gram-reaction was determined by using non-staining KOH method, as described by Powers (1995). Poly-b-hydroxybutyrate granule accumulation was tested by staining with Sudan black (Baomanbio) and observation by light microscopy. Tests for catalase, oxidase and hydrolysis of casein, gelatin, starch, DNA and Tweens 20 and 60 were performed according to the methods of Smibert & Krieg (1994). Growth at 15, 20, 25, 30, 37, 42 and 45 u C was assessed in nutrient broth (NB; Difco). Growth at pH 4-10 (at intervals of one pH unit) was determined by measuring the OD 600 of cultures in NB adjusted with appropriate biological buffers (Chung et al., 1995) prior to sterilization. Growth with 0, 0.5 and 1.0-10.0 % (w/v) NaCl (at intervals of 1.0 %) was tested in NB prepared according to the formula of the Difco medium. Anaerobic growth was determined after incubation in an anaerobic chamber (Thermo). Strain Y4T was a Gramnegative, aerobic, and non-motile rod. Poly-b-hydroxybutyrate granules were not accumulated. The isolate was able to grow on NA, tryptic soy agar (TSA; BD, Difco) and R2A agar (BD Difco). After 72 h at 30 u C on NA, cells were 0.5-0.6 mm wide and 2.0-3.0 mm long and colonies were approximately 1.5-2.0 mm in diameter, yellow and round with umbonate elevations and smooth edges. Strain Y4T was able to grow at 20-40 u C, at pH 6.0-8.0 and with 0-3 % NaCl. The optimum growth conditions were 30 u C, pH 7.0 and 0 % NaCl. The...

No abstract