So far 19 genera of downy mildews have been described, of which seven are parasitic to grasses. Here, we introduce a new genus, Baobabopsis, to accommodate two distinctive downy mildews, B. donbarrettii sp. nov., collected on Perotis rara in northern Australia, and B. enneapogonis sp. nov., collected on Enneapogon spp. in western and central Australia. Baobabopsis donbarrettii produced both oos...

Downy mildews and root and foliar rots caused by Phytophthora are among the most destructive plant pathogens and therefore have attracted considerable attention during the past two decades. Although it has been realized that a close phylogenetic relationship exists, so far sharp distinction has been made between the obligate biotrophic downy mildews and the hemibiotrophic Phytophthora. In the s...

Phylogenetic relationships between thirteen species of downy mildew and 103 species of Phytophthora (plant-pathogenic oomycetes) were investigated with two nuclear and four mitochondrial loci, using several likelihood-based approaches. Three Phytophthora taxa and all downy mildew taxa were excluded from the previously recognized subgeneric clades of Phytophthora, though all were strongly suppor...

Pathogens belonging to the Oomycota, a group of heterokont, fungal-like organisms, are amongst the most notorious pathogens in agriculture. In particular, the obligate biotrophic downy mildews and the hemibiotrophic members of the genus Phytophthora are responsible for a huge variety of destructive diseases, including sudden oak death caused by P. ramorum, potato late blight caused by P. infest...

medicinal plants are infected by fungal diseases. a four years survey indicated that, there are various fungal infections in roots and shoots of several medicinal plants that grown in isfahan. lavender (lavandula angustifolia), rosemarry (rosmarinus officinalis) and viper’s bugloss (borago officinalis) plants were infected by fusarium oxysporum and f. solani on roots, showing wilting and eventu...

Fungal spores are continuously deposited on the leaf surfaces by wind impaction, sedimentation and rain wash-out from the atmosphere and splash-dispersal. They reside and act as asymptomatic mutualists, benign commensals or latent pathogens. A slight imbalance in this relation can lead to pathogenic phase of the fungi, resulting in a variety of symptoms on leaves viz. discoloration, blight, soo...

Biotrophic eukaryotic plant pathogens require a living host for their growth and form an intimate haustorial interface with parasitized cells. Evolution to biotrophy occurred independently in fungal rusts and powdery mildews, and in oomycete white rusts and downy mildews. Biotroph evolution and molecular mechanisms of biotrophy are poorly understood. It has been proposed, but not shown, that ob...

Mitochondrially encoded cox2 sequences were used to infer evolutionary relationships of downy mildew and white rust taxa in a data set of 36 peronosporomycete isolates. The data set of 599 aligned nucleotides was analysed using neighbor joining, maximum parsimony, and maximum likelihood. These phylogenetic analyses did not infer separate monophyletic orders for the Pythiales versus downy mildew...