Comparisons indicated high sequence variability among known isolates with overall nucleotide sequence identities of 80 to 84%. A striking variable region was identified among the replicase protein

upstream of the RNA-dependent RNA polymerase (aa 1510–1590), which showed a 41–43% match with the corresponding region in other isolates. Phylogenetic analysis at the nucleotide level clustered the isolates find more into three groups, without any relation to geographical origin. Recombination analysis showed that the isolate is a recombinant with recombination sites spread throughout the genome, especially in the polymerase gene region (nt 4700–5400). Most recombination sites were bordered by an upstream region (5′) of GC-rich and downstream region (3′) of AU-rich sequences of similar Opaganib in vitro length. Correlation of recombination site with host type is discussed, and it was found that there were more interlineage recombinations in the apple host compared with intralineage recombinations. “
“Zoospores are major dispersal and infective propagules of pythiaceous species. Built upon a recently developed ‘wet-plate’ method, the objectives of this study

were to develop a better understanding about zoospore production biology. Four broth media and five incubation temperatures were evaluated with 12 isolates of Phytophthora nicotianae and 17 other pythiaceous species in this study. The ‘wet-plate’ method worked the best for heterothallic

MCE species, especially those isolates that do not produce chlamydospores. These species included Phytophthora citrophthora, P. nicotianae, Phytophthora palmivora and Phytophthora tropicalis. They readily produced 105–106 zoospores/ml. Overall, most species and isolates produced more zoospores with 20% clarified V8 broth than the other three media: rye, lima bean and carrot. The optimal temperature for nutrient-deprived culture without free-flowing water to produce sporangia typically is 5°C cooler than that for vegetative growth. Fresh and revived cultures are more prolific than those that had been subcultured multiple times. These findings will assist oomycete researchers, adding quality, productivity and efficiency to their future zoospore-based studies. “
“Pyricularia grisea is the most destructive and cosmopolitan fungal pathogen of rice and it can also cause disease on other agriculturally important cereals. We determined the number, location and interaction of quantitative trait loci (QTL) associated with resistance to P. grisea isolates obtained from rice (THL142 and THL222) and barley (TH16 and THL80) grown in Thailand. The isolates showed a spectrum of virulence when used to inoculate a series of differentials. We used a reference blast resistance mapping population of rice (IR64 × Azucena). IR64 was highly resistant, and Azucena was highly susceptible, to all four isolates. The numbers of resistant vs.