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The Golovinomyces cichoracearum complex is morphologically highly variable and causes powdery mildew on a wide range of Compositae, including Hieracium spp. and Lapsana communis. A comprehensive phylogenetic analysis of Golovinomyces, published in 2013, revealed that G. cichoracearum s. str. was confined to Scorzonera and Tragopogon spp. as hosts (Compositae, tribe Lactuceae, subtribe Scorzonerinae). To clarify the phylogeny and taxonomy of Golovinomyces on Hieracium spp. (Compositae, tribe Lactuceae, subtribe Hieraciinae), which is common in Asia and Europe, morphology and phylogenetic analyses of ITS + 28S rDNA sequences were conducted for 57 powdery mildew specimens of Hieracium spp. and Lapsana communis. Golovinomyces on Hieracium spp. in Asia and Europe, previously referred to as G. cichoracearum, is a previously undescribed, cryptic species, which is described here as Golovinomyces hieraciorum sp. nov. Since a sequence retrieved from a powdery mildew on Lapsana communis in Switzerland clustered in sister position to the G. hieraciorum clade, numerous German specimens identified as G. cichoracearum were included in the present examinations. All the re-examined collections of "G. cichoracearum" on L. communis were misidentified, and were shown to belong to Neoërysiphe nevoi or Podosphaera ergerontis-canadensis. [ABSTRACT FROM AUTHOR]

Xanthomonas oryzae pv. oryzicola is an important bacterial pathogen responsible for outbreaks of bacterial leaf streak (BLS) on rice, mostly occurring in Asia and parts of Africa. To better monitor epidemics and assess population structures, efficient tools that allow the precise identification and diagnosis of pathogenic populations are needed. In this study, we explored variable numbers of tandem repeats (VNTR) as a fast, reliable, and cost-effective molecular typing tool. Screening of three X. oryzae pv. oryzicola genome sequences (Philippine strain BLS256, Chinese strain GX01, and Malian strain MAI10) predicted 28 candidate VNTR loci. Primer pairs for polymerase chain reaction (PCR) amplification of all 28 loci were designed and applied to a panel of 20 X. oryzae pv. oryzicola strains originating from Asia and Africa. Sequencing of PCR amplicons revealed 25 robust and polymorphic VNTR loci that are shared among Asian and African X. oryzae pv. oryzicola strains. A dendrogram constructed from 25 VNTR loci indicated that most Asian strains are clearly discriminated from African strains. However, in agreement with previous reports, one strain from Mali is related to Asian strains, pointing to a possible introduction of Asian strains to the African continent. The new VNTR-based tool described here is useful for studies of population structures and epidemiological monitoring of X. oryzae pv. oryzicola. [ABSTRACT FROM AUTHOR]