Wenyingzhuangia marina gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from a recirculating mariculture system.

A Gram-stain-negative, strictly aerobic and heterotrophic bacterial strain, designed strain D1(T), was isolated from a recirculating mariculture system in Tianjin, China. Its taxonomic position was determined using a polyphasic approach. Cells of strain D1(T) were non-flagellated short rods, 0.3-0.5 µm wide and 0.5-1.0 µm long. Growth was observed at 15-30 °C (optimum, 25 °C), at pH 5.5-9.0 (optimum, pH 6.5-7.0) and in the presence of 1-8% (w/v) NaCl (optimum, 2-3 %). Cells contained carotenoid pigments but not flexirubin-type pigments. Strain D1(T) contained MK-6 as the sole menaquinone and phosphatidylethanolamine (PE) as the sole phospholipid and four unidentified lipids. The major cellular fatty acids (>10%) were iso-C15 : 0 (23.2 %), iso-C17 : 0 3-OH (15.2%), C(16 : 1)ω7c/C(16 : 1)ω6c (14.3%), iso-C(15 : 0) 3-OH (13.5%) and iso-C15 : 1 G (10.8%). 16S rRNA gene sequence analyses indicated that strain D1(T) belonged to the family Flavobacteriaceae and showed closest phylogenetic relationship to the genus Lutibacter, with highest sequence similarity to Lutibacter aestuarii MA-My1(T) (92.2%). The DNA G+C content of strain D1(T) was 35.9 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain D1(T) was considered to represent a novel species in a new genus of the family Flavobacteriaceae, for which the name Wenyingzhuangia marina gen. nov., sp. nov. is proposed. The type strain of the type species is D1(T) ( = CGMCC 1.12162(T) = JCM 18494(T)).

Photobacterium aquae sp. nov., isolated from a recirculating mariculture system.

A Gram-staining-negative, heterotrophic, facultatively anaerobic bacterium, designated AE6(T), was isolated from a grouper (Epinephelus malabaricas) culture tank in a recirculating mariculture system located in Tianjin, China. Strain AE6(T) was able to grow at 15-40 °C (optimum, 30-35 °C), at pH 5.5-10.0 (optimum, pH 7.0-7.5) and in the presence of 0.5-7% (w/v) NaCl (optimum, 2-3%). It contained Q-8 as the predominant respiratory quinone, phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) as the major polar lipids and C(16 : 1)ω7c/C(16 : 1)ω6c (40.4%), C(18 : 1)ω7c (15.5%) and C(16 : 0) (13.5%) as the predominant cellular fatty acids. The genomic DNA G+C content was 47.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain AE6(T) belonged to the genus Photobacterium (94.2-96.8% of 16S rRNA gene sequence similarity) and formed a distinct phylogenetic lineage within the genus and exhibited the highest sequence similarity to Photobacterium aphoticum CECT 7614(T) (96.8%). Multilocus sequence analysis (MLSA) using four loci (gyrB, rpoA, pyrH and recA) also revealed that strain AE6(T) was phylogenetically related to the genus Photobacterium. Based on the phylogenetic, chemotaxonomic and phenotypic evidence, strain AE6(T) is considered to represent a novel species of the genus Photobacterium, for which the name Photobacterium aquae sp. nov. is proposed. The type strain is AE6(T) ( = CGMCC 1.12159(T) = JCM 18480(T)).

Cotton gene expression profiles in resistant Gossypium hirsutum cv. Zhongzhimian KV1 responding to Verticillium dahliae strain V991 infection.

Verticillium wilt of cotton (Gossypium hirsutum) is a widespread and destructive disease that is caused by the soil-borne fungus pathogen Verticillium dahliae (V. dahliae). To study the molecular mechanism in wilt tolerance, suppression subtractive hybridization (SSH) and dot blot techniques were used to identify the specifically expressed genes in a superior wilt-resistant cotton cultivar (G. hirsutum cv. Zhongzhimian KV1) after inoculation with pathogen. cDNAs from the root tissues of Zhongzhimian KV1 inoculated with V. dahliae strain V991 or water mock were used to construct the libraries that contain 4800 clones. Based on the results from dot blot analysis, 147 clones were clearly induced by V. dahliae and selected from the SSH libraries for sequencing. A total of 92 up-regulated and 7 down-regulated non-redundant expressed sequences tags (ESTs) were identified as disease responsive genes and classified into 9 functional groups. Two important clues regarding wilt-resistant G. hirsutum were obtained from this study. One was Bet v 1 family; the other was UbI gene family that may play an important role in the defense reaction against Verticillium wilt. The result from real-time quantitative reverse transcription polymerase chain reaction showed that these genes were activated quickly and transiently after inoculation with V. dahliae.