The population structure of Phytophthora infestans in China was studied and three mitochondrial haplotypes (Ia, IIa, IIb) were observed. Genetic analysis with 10 highly informative SSR markers identified 68 different genotypes, including three dominant clonal lineages. In the Chinese P. infestans population, the genotypes were strongly clustered according to their geographic origin. One of dominant clonal lineages was genetically similar to Blue_13, a dominant clonal lineage found in Europe since 2004. This is the first report of Blue_13 outside Europe. Only one mating type (A1) was found in the northern and southeastern provinces, but in southern and northwestern China both mating types were observed. The mating type ratio and SSR allele frequencies indicate that in China the sexual cycle of P. infestans is rare. These results emphasize that the migration of asexual propagules and the generation of subclonal variation are the dominant driving factors of the population structure of P. infestans in China. They may also have implications for the role of monitoring P. infestans populations in potato late blight management strategies in China.

During the jointing stage, the frost resistance of young ears (FRYE) was tested each day for the main stem, and also for the first, second and third tillers of the wheat cultivars Jinmai 47 and Jing 411. At the same time, the developmental progression of young ears (DPYE) of the same four shoots was also recorded each day. In the shoots of both cultivars, FRYE decreased as development advanced through the jointing stage. FRYE dropped off particularly sharply at the point when the anther connective tissue formation phase (ACFP) started. Shoots developing later, though with lower levels of soluble sugar, tended to suffer less from frost injury than those developing earlier. Frost resistance of 12 cultivars (six early‐ and six late‐maturing) was evaluated at ACFP. The results indicate that only one cultivar (Xin 11) is frost resistant, with no significant differences appearing among the other 11 cultivars. The results suggest that DPYE is an important factor affecting FRYE. Evaluation of frost resistance of wheat cultivars should thus be performed at the same phase to obtain a true measure of frost resistance. The early ACFP phase is suggested as being the most appropriate one for frost resistance evaluation.

The calcium-dependent protein kinases (CDPKs) are unique enzymes found only in plants, green algae, ciliates and apicomplexan parasites. In this study, a novel CDPK gene of Eimeria tenella, designed EtCDPK3, was cloned using rapid amplification of cDNA ends (RACE) based on the expressed sequence tag (EST). The entire cDNA of EtCDPK3 contained 1637 nucleotides encoding 433 amino acids and the deduced EtCDPK3 protein had canonical characteristic domains identified in other CDPKs, including a well-conserved amino-terminal kinase domain and a carboxy-terminal calmodulin-like structure with 4 EF-hand motifs for calcium binding. The expression profiles of the EtCDPK3 gene in different development stages were investigated by real-time quantitative PCR. Messenger RNA levels from the EtCDPK3 gene were higher in sporozoites than in other stages (unsporulated oocysts, sporulated oocysts and merozoites). Western blot analysis showed that rabbit antiserum against recombinant EtCDPK3 could recognize a native 49 kDa protein band of parasite. Indirect immunofluorescent antibody labelling revealed dispersed localization of EtCDPK3 during the first schizogony and intense specific staining. EtCDPK3 was located at the apical end of the sporozoites after early infection of DF-1 cells and the protein was highly expressed. Inhibition of EtCDPK3 function using specific antibodies reduced the ability of E. tenella to invade host cells. These results suggested that EtCDPK3 may be involved in invasion and survival of the parasite intracellular stages of E. tenella. Because this kinase family is absent from hosts, it represents a valid target that could be exploited for chemotherapy against Eimeria spp.

reported only rarely in North America in the states of New York, Ohio, and Wisconsin, and the province of Quebec (2,3,4). Although not likely to seriously affect the growth or survival of established trees, severe powdery mildew can detract from the aesthetic value of trees. Further, S. tulasnei might seriously damage small seedlings, and detection of this exotic pathogen in nurseries should restrict movement of stock. . Plant Dis. 98:282, 2014; published online as http:// dx.

Ginger (Zingiber officinale Roscoe) is an important commercial crop planted on more than 13,000 ha annually in Anqiu city, Shandong Province, China. From 2010 to 2011, the incidence of Pythium soft rot disease on cv. Laiwu Big Ginger reached 40 to 75% in Anqiu and yield losses of up to 60% were observed. The disease symptoms included brown spots on ginger rhizomes followed by soft rot, stems and leaves above ground becoming withered and yellow, and water soaking on the collar region. The soft rot did not produce offensive odors, which is different from bacterial rots (2). Forty symptomatic rhizomes were sampled from eight farms. Martin's method (1) was used to isolate the pathogen. Ten pieces from each rhizome were washed with sterile distilled water for 30 s and plated on Martin's selective medium at 26°C in a chamber without light. Colonies grew with cottony aerial mycelium. Main hyphae were 5.7 to 9.6 μm wide. Globose sporangia consisting of terminal complexes of swollen hyphal branches were 11.4 to 18.3 μm wide. The average diameter of zoospores was 9.2 μm. The oogonia were globose and smooth, with a diameter of 21 to 33 μm. The sequences of the rRNA gene internal transcribed spacer (ITS) regions 1 and 2 and the 5.8S gene of five isolates were amplified using primers ITS1 and ITS4 (4), and the nucleotide sequence was the same as isolate No. 2, which was deposited in GenBank (Accession No. KC594034). A BLAST search showed 99% identity with Pythium aphanidermatum strain 11-R-8 (Accession No. JQ898455.1). Pathogenicity tests of five isolates were carried out in a greenhouse. Sixty plants (cv. Laiwu Big Ginger) were grown for 30 days in plastic pots (diameter 20 cm) in sandy soil (pH 5.48) and inoculated. Ten plants were used as untreated controls. Five isolates were grown on Martin's liquid medium for 72 h and the spores were harvested in sterile distilled water. Aqueous spore suspensions of the five isolates were adjusted with deionized water to 1 × 108 CFU/ml and injected with a syringe into the soil around the rhizome of the plants. Plants were then placed in the greenhouse at 24 to 26°C and assessed for rhizome rot on the 14th day after inoculation. The inoculated isolates were recovered from the diseased rhizomes, confirming their pathogenicity. To our knowledge, this is the first report of ginger Pythium soft rot caused by P. aphanidermatum in China. Ginger Pythium soft rot caused by P. myriotylum is reported in Taiwan (3). References: (1) F. N. Martin. Page 39 in: The Genus Pythium. American Phytopathological Society, St. Paul, MN, 1992. (2) E. E. Trujillo. Diseases of Ginger (Zingiber officinale) in Hawaii, Circular 62, Hawaii Agricultural Experiment Station, University of Hawaii, December 1964. (3) P. H. Wang. Lett. Appl. Microbiol. 36:116, 2003. (4) T. J. White. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

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Carrot (Daucus carota L. subsp. sativus [Hoffm.] Arcang.) is an im portant vegetable in Serbia, where it is grown on nearly 8,000 ha. In Au gust 2012, -1 ,5 0 0 ha o f carrot fields were inspected in southern Backa in North Serbia. In nearly 40% o f the fields, severe foliar and stem symptoms characteristic o f cercospora leaf spot o f carrot, caused by Cercospora carotae (Pass.) Solheim (3), were observed. Lesions on stems were ob long, elliptical, and more or less sunken, while those on the leaves were amphigenous, subcircular, light brown in the center, and surrounded by a dark brown margin. Conidiophores emerging from the lesions formed very loose tufts but sometimes were solitary. Conidiophores were simple and straight to subflexuous with a bulbous base (17 to 37 x 3 to 5 pm). Conidia were 58 to 102 x 2 to 4 pm, solitary, cylindrical to narrowly-obclavate, and hyaline to subhyaline with 2 to 6 septa. To obtain monosporial isolates, the conidia from one lesion were placed on water agar plates at 25°C in the dark for 24 h, after which single germinated conidia were selected and each placed on a petti dish containing potato dextrose agar (PDA). To confirm pathogenicity o f three o f the isolates, Koch's postulates were tested on carrot seedlings (3-true-leaf stage of growth) o f a Nantes cultivar, SP-80, with 12 plants tested/isolate and 12 non-inoculated plants used as a control treatment. The leaves were atomized until runoff with the appropri ate C. carotae spore suspension (104 conidia/ml sterilized water), while