Publications

4742

A novel halophilic actinomycete, designated strain YIM 93223T, was isolated from a salt lake in Xinjiang Province, north-west China, and was subjected to a polyphasic taxonomic study. The isolate grew at 25–45 °C, at pH 6–8 and in the presence of 1–15 % (w/v) NaCl; no growth was observed in the absence of NaCl. Strain YIM 93223T contained meso-diaminopimelic acid, glutamic acid and alanine as cell-wall amino acids, and glucose and galactose as major whole-cell-wall sugars. Major fatty acids were iso-C16 : 0, C16 : 0 and C16 : 1 ω7c/iso-C15 : 0 2-OH. MK-8(H4) was the predominant menaquinone. The genomic DNA G+C content was 66.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 93223T belongs to the genus Amycolatopsis. It shared highest 16S rRNA gene sequence similarity with Amycolatopsis palatopharyngis 1BDZT (96.6 %) and Amycolatopsis marina Ms392AT (96.4 %), but lower values (94.5–96.2 %) with the type strains of other recognized species of the genus Amycolatopsis. On the basis of the data from this polyphasic study, strain YIM 93223T is considered to represent a novel species of the genus Amycolatopsis, for which the name Amycolatopsis halophila sp. nov. is proposed. The type strain is YIM 93223T (=DSM 45216T =KCTC 19403T).

Carrot (Daucus carota) plants with symptoms resembling those of carrot psyllid (Trioza apicalis) damage (3,4) were observed in 14 commercial fields in southern Finland in August 2008; all cultivars grown were affected at approximately 5 to 35% symptomatic plants per field. T. apicalis, a pest of carrots in northern and central Europe, can cause up to 100% crop loss (3,4). Symptoms on affected plants included leaf curling, yellow and purple discoloration of leaves, stunted growth of shoots and roots, and proliferation of secondary roots (3,4). Given recent association of liberibacter with several annual crops affected by psyllids (1,2), an investigation on whether this bacterium is associated with symptoms of psyllid damage on carrots was conducted. Total DNA was extracted from petiole tissue of 20 symptomatic and 18 asymptomatic plants (cv. Maestro, Nanda, Nipomo, Nerac, and Fontana) sampled from 10 psyllid-infested fields in southern Finland, as well as 15 plants (cv. Primecut, Cheyenne, and Triple Play) grown from seed in an insect-free greenhouse, with the cetyltrimethylammoniumbromide (CTAB) method (2). DNA was also extracted from 10 carrot roots (cv. Nantura) of plants continuously exposed to field-collected carrot psyllid colonies in the laboratory. DNA samples were tested by PCR using primer pairs OA2/OI2c and CL514F/R to amplify a portion of 16S rDNA and rplJ/rplL ribosomal protein genes, respectively, of “Candidatus Liberibacter solanacearum” (1,2). A 1,168 bp 16S rDNA fragment was detected in DNA from 1 asymptomatic and 16 symptomatic plants and a 669 bp rplJ/rplL fragment was amplified from DNA from 19 symptomatic and 6 asymptomatic plants, indicating presence of liberibacter. DNA from all 10 root samples yielded similar amplicons with both primer pairs. DNA from all the greenhouse carrot plants yielded no amplicon. Amplicons from DNA from three petioles and three roots with each primer pair were cloned (pCR2.1-TOPO; Invitrogen, Carlsbad, CA) and three clones of each of the 12 amplicons were sequenced (MCLAB, San Francisco, CA). BLAST analysis of the 16S rDNA consensus sequences from petiole and root tissues (GenBank Accession Nos. GU373049 and GU373048, respectively) showed 99.9% identity to those of “Ca. L. solanacearum” amplified from Capsicum annuum (FJ957896) and Solanum lycopersicum (FJ957897) from Mexico, and “Ca. L. psyllaurous” from potato psyllids (EU812559). The rplJ/rplL consensus sequences from petioles and roots (GenBank Accession Nos. GU373051 and GU373050, respectively) were 97.9% identical to the analogous rplJ/rplL “Ca. L. solanacearum” ribosomal protein gene sequence from solanaceous crops in New Zealand (EU834131) and to “Ca. Liberibacter” sp. sequence from zebra chip-affected potatoes in California (FJ498803). To our knowledge, this is the first report of “Ca. L. solanacearum” associated with a nonsolanaceous species and the first report of this pathogen outside of North and Central America and New Zealand (1,2). References: (1) L. W. Liefting et al. Plant Dis. 93:208, 2009. (2) J. E. Munyaneza et al. Plant Dis. 93:552, 2009. (3) G. Nehlin et al. J. Chem. Ecol. 20:771, 1994. (4) A. Nissinen et al. Entomol. Exp. Appl. 125:277, 2007.

A Gram-negative, aerobic, rod-shaped bacterium, designated strain CL-33T, was isolated from the encrusting pore coral Montipora aequituberculata collected from seawater off the coast of southern Taiwan. 16S rRNA gene sequence analysis showed that the strain clustered closely with Endozoicomonas elysicola MKT110T (96.7 % similarity). The novel strain required NaCl for growth and exhibited optimal growth at 25 °C and in the presence of 2–3 % NaCl. Predominant cellular fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 39.6 %), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 32.8 %) and C16 : 0 (12.0 %). The DNA G+C content of strain CL-33T was 50.0 mol%. The results of physiological and biochemical tests allowed the clear phenotypic differentiation of this isolate from E. elysicola. It is evident from the genotypic, phenotypic and chemotaxonomic data presented that strain CL-33T represents a novel species of the genus Endozoicomonas, for which the name Endozoicomonas montiporae sp. nov. is proposed. The type strain is CL-33T (=LMG 24815T =BCRC 17933T).

In August 2008, 30% of tomato (Solanum lycopersicum) plants in plots in Lubbock County, Texas showed yellowing, lateral stem dieback, upward leaf curling, enlargement of stems, adventitious roots, and swollen nodes. Yellowing in leaves was similar to that seen with zebra chip disease (ZC) of potato that was confirmed in a potato field 112 km away in July 2008 and was associated with a ‘Candidatus Liberibacter’ species (1), similar to findings earlier in 2008 in New Zealand and California (2,3). Tissue from four symptomatic plants of cv. Spitfire and two of cv. Celebrity were collected and DNA was extracted from midribs and petioles with a FastDNA Spin Kit (Qbiogene, Inc., Carlsbad, CA,). PCR amplification was done with 16S rRNA gene primers OA2 and OI2c, which are specific for “Ca. Liberibacter solanacearum” from potato and tomato and amplify a 1.1-kb fragment of the 16S rRNA gene of this new species (1,3). Amplicons of 1.1 kb were obtained from all samples and these were sequenced in both orientations (McLab, San Francisco, CA). Sequences of the 16S rRNA gene were identical for both Spitfire and Celebrity and were submitted to the NCBI as GenBank Accession Nos. FJ939136 and FJ939137, respectively. On the basis of a BLAST search, sequence alignments revealed 99.9% identity with a new species of ‘Ca. Liberibacter’ from potato (EU884128 and EU884129) in Texas (1); 99.7% identity with the new species “Ca. Liberibacter solanacearum” described from potato and tomato (3) in New Zealand (EU849020 and EU834130, respectively) and from the potato psyllid Bactericera cockerelli in California (2) (EU812559, EU812556); 97% identity with ‘Ca L. asiaticus’ from citrus in Malaysia (EU224393) and 94% identity with both ‘Ca. L. africanus’ and ‘Ca. L. americanus’ from citrus (EU921620 and AY742824, respectively). A neighbor-joining cladogram constructed using the 16S rRNA gene fragments delineated four clusters corresponding to each species, and these sequences clustered with “Ca. L. solanacearum”. A second PCR analysis was conducted with the CL514F/CL514R primer pair, which amplifies a sequence from the rplJ and rplL ribosomal protein genes of “Ca. L. solanacearum”. The resulting 669-bp products were 100% identical to a sequence reported from tomato in Mexico (FJ498807). This sequence was submitted to NCBI (GU169328). ZC, a disease causing losses to the potato industry, is associated with a ‘Candidatus Liberibacter’ species (1–3) and was reported in Central America and Mexico in the 1990s, in Texas in 2000, and more recently in other states in the United States (4). In 2008, a “Ca. Liberibacter solanacearum” was detected on Capsicum annuum, S. betaceum, and Physalis peruviana in New Zealand (3). Several studies have shown that the potato psyllid, B. cockerelli, is a potential vector for this pathogen (2,4). To our knowledge, this is the first report of “Ca. Liberibacter solanacearum” in field tomatoes showing ZC-like foliar disease symptoms in the United States. References: (1). J. A. Abad et al. Plant Dis. 93:108, 2009 (2) A. K. Hansen et al. Appl. Environ. Microbiol. 74:5862, 2008. (3) L. W. Liefting et al. Plant Dis. 93:208, 2009. (4) G. A. Secor et al. Plant Dis. 93:574, 2009.