Venturia inaequalis
Description and significance
Venturia inaequalis is type of fungi that causes plant disease. Spring is the time V. inaequalis starts its life cycle. During springtime, V. inaequalis spores spread out into the air and attack the apple tree by penetrating apple’s waxy cuticle to cause scab. V. inaequalis is a typical apple scab pathogen. V. inaequalis has seven haploid chromosome.
Genome structure
Venturia inaequalis could undergo sexual reproduction to provide raw material for develop new resistant gene. Venturia inaequalis capable to develop new resistant gene. For example, Vf fungicide resistant gene. A new fungicide resistant gene was found in 2004 named Vr2 gene
Cell structure and metabolism
Venturia inaequalis has multicellular structure. It undergo parasitic life cycle to apple trees. mature spores release in spring and begins the infection to apple tree. Then secondary spores develop on the surface of infected tissue throughout spring and summer. When the spore touch the surface of apple, a germ tube is form and it penetrates the waxy surface. Asexually reproduce secondary spores between the waxy surface and epidermal tissue to germinate the fresh area.
Ecology
Natural Host: V. inaequalis is parasitic to apple tree and other closely related species. V. inaequalis itself and infected apple are not harmful to human. V. inaequalis causes common apple disease apple scab. Large economic loss in apple plantation causes by apple scab.
Pathology
How does V. inaequalis life cycle parasite to plants Even though V. inaequalis infection cycle starts in the springtime, V. inaequalis was stored in fallen fruits or leaves as immature pseudothecia during the winter. In the winter, sexual reproduction takes place; aeciospores are produced and are able to release in rainy springtime. When Venturia inaequalis contact the surface of the plants, a germ tube is form and it penetrates the surface. Between the cuticle and epidermal tissue, a fungal mycelium is formed. Venturia inaequalis then develop asexually to new generation of conidial spores and germinate the tree. The secondary infection keeps on going throughout the summer and stop when leaves and fruit fall from the host tree.
Current Research
Localized Melanization of Appressoria Is Required for Pathogenicity of Venturia inaequalis This paper investigates the path that Venturia inaequalis infect apple trees. The formation of appressoria is required for Venturia inaequalis to form a melanized appressorial ring structure (MARS)to attach to the leaf surface to form a fungus-plant like interface. Such a process is believed to be required for Venturia inaequalis to penetrate the cuticle.
Subdivision and genetic structure of four populations of Venturia inaequalis in Switzerland This paper investigates the subdivision and genetic structure of four populations of Venturia inaequalis in Europe. The migration of the population was study to predict the speed of new specie of Venturia inaequalis to overcome resistance. Venturia inaequalis could undergo sexual reproduction to provide raw material for develop new resistant gene. Random amplified polymorphic DNA (RAPD) was used as markers to calculate the haploid stage diversity based on allele frequencies. It is expected to have new pathogen spread out from their original places.
Managing Resistance of Venturia inaequalis to the Strobilurin Fungicides This paper investigates on the study of reduce resistance of Venturia inaequalis to the strobilurin Fungicides. Venturia inaequalis was becoming more and more resistant to fungicide in the past year and caused large-scale crop losses due to apple scab. In this study, strobilurin fungicides were examined at their highest and lowest labeled rates. The result suggested that high strobilurin rate were superior to low rate mixture in term of anti-resistance properties.
References
- (1)Fungal Disease Apple scab Venturia inaequalis (http://urbanext.illinois.edu/hortanswers/detailproblem.cfm?PathogenID=3)
- (2)Venturia inaequalis (http://eol.org/pages/1029739/details)
- (3)Ulrike Steiner and Erich-Christian Oerke, Institute of Crop Science and Resource Conservation, Phytomedicine, University of Bonn, Nussallee 9, D-53115 Bonn, German, "Localized Melanization of Appressoria Is Required for Pathogenicity of Venturia inaequalis", October 2007, Volume 97, Number 10, Pages 1222-1230, DOI: 10.1094/PHYTO-97-10-1222
- (4)Isabel Tenzer1 and Cesare Gessler, Journal European Journal of Plant Pathology Publisher Springer Netherlands ISSN0929-1873 (Print) 1573-8469 (Online) IssueVolume 103, Number 6 / August, 1997, DOI10.1023/A:1008636913211 Pages565-571 Subject Collection Biomedical and Life Sciences SpringerLink Date Tuesday, November 02, 2004
- (5)William W. Turechek and Wolfram Köller, Turechek, W. W., and Köller, W. 2004. Managing resistance of Venturia inaequalis to the strobilurin fungicides. Online. Plant Health Progress doi:10.1094/PHP-2004-0908-01-RS.