potato

not annotated - annotated - LINNAEUS only

20173013

Streptomyces lacticiproducens sp. nov., a lactic acid-producing streptomycete isolated from the rhizosphere of tomato plants.

A novel actinomycete, designated strain GIMN4.001(T), was isolated from the rhizosphere of tomato plants grown in Guangzhou, China. The strain produced greyish white aerial mycelia, lactic acid and a large quantity of double diamond-shaped crystals on potato dextrose agar and yeast extract-malt extract agar. The colour of the substrate mycelium was not sensitive to pH. Microscopic observations revealed that strain GIMN4.001(T) produced verticillate chains of cylindrical spores. Chemotaxonomic data confirmed that strain GIMN4.001(T) belonged to the genus Streptomyces. Melanin pigments were not produced. No antibacterial activity was observed against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis or Candida albicans, but inhibitory activity was observed against Penicillium citrinum. 16S rRNA gene sequence analysis revealed that strain GIMN4.001(T) was related most closely to Streptomyces morookaense ATCC 19166(T) (98.9 % similarity) and Streptomyces lavenduligriseus ATCC 13306(T) (98.7 %). Levels of DNA-DNA relatedness between strain GIMN4.001(T) and the type strains of these species were low (14-20 %). Furthermore, strain GIMN4.001(T) could be differentiated from S. morookaense, S. lavenduligriseus and other closely related species of the genus Streptomyces based on morphological, physiological and biochemical characteristics. On the basis of its physiological and molecular properties, strain GIMN4.001(T) is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces lacticiproducens sp. nov. is proposed. The type strain is GIMN4.001(T) (=CCTCC M208214(T)=NRRL B-24800(T)).

20955222

Physiological and morphological adaptations in relation to water use efficiency in Mediterranean accessions of Solanum lycopersicum.

The physiological traits underlying the apparent drought resistance of 'Tomatiga de Ramellet' (TR) cultivars, a population of Mediterranean tomato cultivars with delayed fruit deterioration (DFD) phenotype and typically grown under non-irrigation conditions, are evaluated. Eight different tomato accessions were selected and included six TR accessions, one Mediterranean non-TR accession (NTR(M)) and a processing cultivar (NTR(O)). Among the TR accessions two leaf morphology types, normal divided leaves and potato-leaf, were selected. Plants were field grown under well-watered (WW) and water-stressed (WS) treatments, with 30 and 10% of soil water capacity, respectively. Accessions were clustered according to the leaf type and TR phenotype under WW and WS, respectively. Correlation among parameters under the different water treatments suggested that potential improvements in the intrinsic water-use efficiency (A(N)/g(s)) are possible without negative impacts on yield. Under WS TR accessions displayed higher A(N)/g(s), which was not due to differences in Rubisco-related parameters, but correlated with the ratio between the leaf mesophyll and stomatal conductances (g(m)/g(s)). The results confirm the existence of differential traits in the response to drought stress in Mediterranean accessions of tomato, and demonstrate that increases in the g(m)/g(s) ratio would allow improvements in A(N)/g(s) in horticultural crops.

20955812

Paralogous cyp51 genes in Fusarium graminearum mediate differential sensitivity to sterol demethylation inhibitors.

Analysis of the genome sequence of Fusarium graminearum revealed three paralogous cyp51 genes (designated cyp51A, -B, and -C) encoding 14-alpha demethylases in this fungus. Targeted gene disruption showed that the cyp51A, -B or -C disruption mutants were morphologically indistinguishable from the parent isolate on potato dextrose agar medium, which indicates that none of these genes is essential for mycelial growth. The sensitivity of cyp51A deletion mutants to seven sterol demethylation inhibitor (DMI) fungicides increased significantly compared to the parent strain, while sensitivity of cyp51C deletion mutants increased to some but not all DMIs. No change in DMI sensitivity was observed for cyp51B deletion mutants. The parental phenotypes of cyp51A and cyp51C deletion mutants were completely restored by genetic complementation with the wild-type cyp51A and cyp51C genes, respectively. The sensitivity of F. graminearum isolates increased significantly when subjected in vitro to a mixture of DMI fungicides triadimefon and tebuconazole as compared to the individual components. These results indicate that different DMI fungicides target different CYP51 proteins in F. graminearum and that a mixture of DMI fungicides can result in synergistic effects. Our findings have directly implications on chemical management strategies of plant diseases caused by Fusarium species.