Mitochondrial heteroplasmy for the cytochrome b gene Controls the level of strobilurin resistance in the apple powdery mildew fungus Podosphaera leucotricha (Ell. & Ev.) E.S. Salmon

2006 ◽  
Vol 113 (6) ◽  
pp. 259-266 ◽  
Author(s):  
S. S. Lesemann ◽  
S. Schimpke ◽  
F. Dunemann ◽  
H. B. Deising
Keyword(s):  
Powdery Mildew ◽  
Cytochrome B ◽  
Cytochrome B Gene ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Mitochondrial Heteroplasmy

scholarly journals Development and ultrastructure observations of secondary hyphae of Podosphaera leucotricha on apple cultivars of varying susceptibility to powdery mildew

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 425-428
Author(s):  
E. Rakhimova
Keyword(s):  
Electron Microscopy ◽  
Powdery Mildew ◽  
Light And Electron Microscopy ◽  
Dense Material ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Full Complement ◽  
Apple Cultivars ◽  
Host Parasite

The development and ultrastructure feature of secondary hyphae of Podosphaera leucotricha were studied using light and electron microscopy. The percentage of development and length of secondary hyphae, differed in compatible and incompatible combinations. In compatible host-parasite combinations, hyphal cells of powdery mildew fungus contained a full complement of fungal organelles. There were differences of hyphal ultrastructure in compatible and incompatible host-parasite combinations, the main one was the appearance of dense material inside the nucleus, in the cytoplasm, and a few mitochondria.

scholarly journals Occurrence and Molecular Characterization of Strobilurin Resistance in Cucumber Powdery Mildew and Downy Mildew

2001 ◽  
Vol 91 (12) ◽  
pp. 1166-1171 ◽  
Author(s):  
H. Ishii ◽  
B. A. Fraaije ◽  
T. Sugiyama ◽  
K. Noguchi ◽  
K. Nishimura ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Downy Mildew ◽  
Cytochrome B ◽  
Rapid Development ◽  
Single Point ◽  
Cytochrome B Gene ◽  
Single Point Mutation ◽  
Mitochondrial Cytochrome B ◽  
Control Failure ◽  
Pathogen Dna

Between 1998 and 1999, control failure of powdery mildew (Podosphaera fusca) and downy mildew (Pseudoperonospora cubensis) by the strobilurin fungicides azoxystrobin and kresoxim-methyl was observed in cucumber-growing areas of Japan. Results from inoculation tests carried out on intact cucumber plants and leaf disks clearly showed the distribution of pathogen isolates highly resistant to azoxystrobin and kresoximmethyl. Fragments of the fungicide-targeted mitochondrial cytochrome b gene were polymerase chain reaction amplified from total pathogen DNA and their sequences analyzed to elucidate the molecular mechanism of resistance. A single point mutation (GGT to GCT) in the cytochrome b gene, resulting in substitution of glycine by alanine at position 143, was found in resistant isolates of downy mildew. This substitution in cytochrome b seemed to result in high resistance to strobilurins in this pathogen. The same mutation was found in some but not all resistant isolates of powdery mildew. This study suggests that a mutation at position 143 in the target-encoding gene, resulting in an amino acid substitution, was probably a major cause of the rapid development of high strobilurin resistance in these two pathogens.

scholarly journals First Report of Powdery Mildew on Pyrus calleryana Caused by Podosphaera leucotricha

Plant Disease ◽  
2008 ◽  
Vol 92 (1) ◽  
pp. 176-176 ◽  
Author(s):  
L. Vajna ◽  
L. Kiss
Keyword(s):  
Powdery Mildew ◽  
Urban Areas ◽  
Its Sequence ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
First Report ◽  
Host Genus ◽  
Pyrus Calleryana ◽  
Single Leaf ◽  
Leaf Surfaces

Callery pear (Pyrus calleryana Decne.) is native to Asia and its varieties are planted as ornamentals in urban areas worldwide. It is also used as a source of resistance to fireblight in some breeding programs. In April 2007, symptoms of powdery mildew infection were observed on the foliage of almost every P. calleryana cv. Chanticleer tree planted along a 1.5-km road in Budapest, Hungary. These trees were planted 5 to 6 years ago and were the first callery pears used as ornamentals in Hungary. Powdery mildew infections were also detected on P. calleryana trees planted in other parts of the city. White powdery mildew mycelium appeared on the lower and sometimes upper leaf surfaces, especially on young shoots, and caused chlorotic spots on the upper leaf surfaces and severe distortions of leaves. The spread of the infection was monitored between April and August of 2007 in several sample sites. More than 100 trees that were examined became heavily infected by May 2007. Powdery mildew conidiophores were typical of the genus Oidium subgen. Fibroidium, the anamorph of the teleomorph genus Podosphaera (2). Conidia developed in chains, contained fibrosin bodies, germinated at one of their ends with germ tubes terminating in unlobed appressoria, and measured 16 to 27 × 10 to 15 μm. Hyphal appressoria were nipple shaped or inconspicuous. The teleomorph was not found. To precisely identify the pathogen, DNA was extracted from conidia collected with a sterile brush from a single leaf using a Qiagen DNeasy Plant Kit (Hilden, Germany), and the internal transcribed spacer (ITS) sequence of the ribosomal DNA was amplified and determined as described by Szentiványi et al. (3). The ITS sequence, deposited in GenBank under Accession No. EU148597, was identical to those determined in Podosphaera leucotricha (Ell. & Ev.) Salmon collected from apple in Australia (GenBank Accession No. AF073353) and Canada (GenBank Accession No. AY157844) and also from pear in Canada (GenBank Accession No. AY157845). Thus, the pathogen was identified as Podosphaera leucotricha on the basis of the host genus, morphology of the anamorph, and ITS sequence. Specimens were deposited under Accession No. BPI878262 at the U.S. National Fungus Collection. To our knowledge, Podosphaera leucotricha has not been reported on P. calleryana in any parts of the world so far. An Oidium sp. infecting this plant in Australia was listed by Amano (1), but the exact identity of that fungus is not known. Thus, this is the first report of an identified powdery mildew fungus on P. calleryana. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun et al. Pages 13-55 in: The Powdery Mildews: A Comprehensive Treatise. R. R Bélanger et al., eds. American Phytopathological Society, St Paul, MN, 2002. (3) O. Szentiványi et al. Mycol. Res. 109:429, 2005.

scholarly journals Phenotypic Characterization and Molecular Phylogenetic Relationship of Erysiphe necator Infecting Grapes (Vitis vinifera)

2019 ◽  
pp. 1-10
Author(s):  
Marimuthu Karthick ◽  
Ayyanar Kamalakannan ◽  
Varagur Ganesan Malathi ◽  
Vaikuntavasan Paranidharan ◽  
Uthandi Sivakumar ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Cytochrome B ◽  
Tamil Nadu ◽  
Gene Segment ◽  
Cytochrome B Gene ◽  
Phenotypic Characterization ◽  
Infected Leaf ◽  
Cyt B ◽  
Erysiphe Necator ◽  
Microscopic Studies

Grapes powdery mildew is caused by the most destructive pathogen Erysiphe necator leading to severe yield losses around the world.  In order to study the phenotypic and molecular characters, the powdery mildew infected leaf samples were collected from eight different places in Coimbatore and Theni districts in the state of Tamil Nadu India. The identity of the pathogen as E. necator was established by microscopic studies and the isolates were further confirmed molecularly by amplification of Internal transcribed spacer (ITS) and Cytochrome b gene (Cyt b). Further molecular confirmation was obtained by characterizing Cytochrome b. An amplicon size of ~ 367 and ~ 470 bp were obtained from amplification with Uncin144 and Uncin511 and Cyt b F and Cyt b R gene primers respectively. The identity for cyt b gene segment was 96 to 98%, similarity with E. necator isolates deposited in NCBI genbank (KY418048.1, KY418049.1). A phylogenetic tree was constructed on the basis of nucleotide sequence of cytochrome b gene of the study isolates as well as E. necator and other Erysiphe species in NCBI database. From the tree it was evident that the study isolates from Tamil Nadu, India were very distinct from other E. necator isolates deposited in NCBI genbank database.

scholarly journals Peach Rusty Spot Is Caused by the Apple Powdery Mildew Fungus, Podosphaera leucotricha

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 719-724 ◽  
Author(s):  
Tünde Jankovics ◽  
Nenad Dolovac ◽  
Aleksandra Bulajić ◽  
Branka Krstić ◽  
Thierry Pascal ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Prunus Persica ◽  
Causal Agent ◽  
Podosphaera Leucotricha ◽  
Powdery Mildew Fungus ◽  
Peach Fruit ◽  
Internal Transcribed Spacer Sequences ◽  
Necrotic Spots ◽  
Polymerase Chain ◽  
Powdery Mildew Pathogen

Peach rusty spot, an economically important disease of peach (Prunus persica var. persica), appears as necrotic spots on fruit. The etiology of the disease is still not well understood, although it has long been suspected that the causal agent is the apple powdery mildew pathogen, Podosphaera leucotricha. This work confirmed this hypothesis based on cross-inoculation experiments and analysis of rDNA internal transcribed spacer sequences polymerase chain reaction amplified from rusty spot and peach powdery mildew lesions. Cross-inoculations of apple and peach leaves with P. leucotricha and P. pannosa, the causal agent of peach powdery mildew, showed that (i) young peach fruit, up to 5 cm in diameter, developed symptoms typical of rusty spot following inoculation with P. leucotricha; (ii) leaves of ‘Jonagold’ apple seedlings developed powdery mildew infections when inoculated by touching young rusty spot lesions to their surfaces; (iii) P. leucotricha sporulated on young peach fruit up to 5 cm in diameter; and (iv) peach leaves and young shoots were not susceptible to P. leucotricha, whereas P. pannosa infected all the green parts of peach. A field experiment revealed that there was only a 2- to 3-week period of time during early peach fruit development when the epidermis was susceptible to P. leucotricha. An outcome of this study is that now a clear distinction can be made between the symptoms caused by P. pannosa and P. leucotricha on peach.

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