Taphrina deformans
Encyclopedia
Taphrina deformans is a fungus and plant pathogen, one of the causal agents of peach
leaf curl
, the other being a virus.
including P. amygdalus
(almond
) and P. persica
(peach
) . Infected leaves develop a whitish bloom as infection progresses. This color consists of asci
that break through the cuticle
of the leaf by way of lysis. One ascus contains eight ascospore
s that create conidia
, which are ejected in early summer and moved by rain and wind. It is believed that this fungus survives the winter by staying on the surface of the new host plant, such as on bark or buds. In the spring, new buds are infected by the conidia as the leaves come out of the buds. The disease does not occur every year as it requires a minimum of 3mm of rainfall followed by at least twelve days during which the developing conidia remain damp and at temperatures below 19 ̊C. The fungus has higher infection rates following cooler, damper winters.
Taphrina deformans hyphae growing in intercellular spaces secrete
polysaccharide
-degrading enzymes such as cellulase
causing partial dissolution of the host cell wall
. This process also results in changes in the plasma membrane.
T. Deformans produces the auxin
indoleacetic acid (IAA) from L-tryptophan via Indole-3-pyruvic acid (IPyA) and indole-3-acetaldehyde (IAAid). This process is thought to be responsible for the hyperplastic effect of the infection .
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
leaf curl
Leaf curl
Leaf curl is a plant disease caused by a fungus or virus and characterized by curling of leaves...
, the other being a virus.
Life Cycle
T.deformans infects species of the genus PrunusPrunus
Prunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, apricots and almonds. There are around 430 species spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament.-Botany:Members of the genus...
including P. amygdalus
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...
(almond
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...
) and P. persica
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
(peach
Peach
The peach tree is a deciduous tree growing to tall and 6 in. in diameter, belonging to the subfamily Prunoideae of the family Rosaceae. It bears an edible juicy fruit called a peach...
) . Infected leaves develop a whitish bloom as infection progresses. This color consists of asci
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
that break through the cuticle
Cuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
of the leaf by way of lysis. One ascus contains eight ascospore
Ascospore
An ascospore is a spore contained in an ascus or that was produced inside an ascus. This kind of spore is specific to fungi classified as ascomycetes ....
s that create conidia
Conidium
Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...
, which are ejected in early summer and moved by rain and wind. It is believed that this fungus survives the winter by staying on the surface of the new host plant, such as on bark or buds. In the spring, new buds are infected by the conidia as the leaves come out of the buds. The disease does not occur every year as it requires a minimum of 3mm of rainfall followed by at least twelve days during which the developing conidia remain damp and at temperatures below 19 ̊C. The fungus has higher infection rates following cooler, damper winters.
Taphrina deformans hyphae growing in intercellular spaces secrete
Secretion
Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...
polysaccharide
Polysaccharide
Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...
-degrading enzymes such as cellulase
Cellulase
400px|thumb|right|alt = Colored dice with checkered background|Ribbon representation of the Streptomyces lividans beta-1,4-endoglucanase catalytic domain - an example from the family 12 glycoside hydrolases...
causing partial dissolution of the host cell wall
Cell wall
The cell wall is the tough, usually flexible but sometimes fairly rigid layer that surrounds some types of cells. It is located outside the cell membrane and provides these cells with structural support and protection, and also acts as a filtering mechanism. A major function of the cell wall is to...
. This process also results in changes in the plasma membrane.
T. Deformans produces the auxin
Auxin
Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins have a cardinal role in coordination of many growth and behavioral processes in the plant's life cycle and are essential for plant body development. Auxins and their role in plant growth were first described by...
indoleacetic acid (IAA) from L-tryptophan via Indole-3-pyruvic acid (IPyA) and indole-3-acetaldehyde (IAAid). This process is thought to be responsible for the hyperplastic effect of the infection .
External links
- Taphrina deformans at Species Fungorumhttp://www.speciesfungorum.org/Names/GSDSpecies.asp?RecordID=234886
- Taphrina deformans at Fungal Databaseshttp://nt.ars-grin.gov/fungaldatabases/new_allView.cfm?whichone=all&thisName=Taphrina%20deformans&organismtype=Fungus&fromAllCount=yes