Peronosporaceae
From Wikipedia, the free encyclopedia
| iPeronosporaceae | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Scientific classification | ||||||||||
|
Peronosporaceae are a family of water moulds that contains 7 genera, comprising 600 species.
Nested within the peronosporaceae are the downy mildews and blue molds.
Contents |
[edit] Food
Peronosporaceae are obligate biotrophic plant pathogens, using the haustorial apparatus with most of its hosts being dicot.
[edit] Reproduction
Resting on top of the determinate sporangiospores, sporangia themselves are released in a similar manner to spores. They are also known as conidia.
The mitotic spore is borne externally, as would be expected.
The unusual case of direct germination is exemplified by Pseudoperonospora Peronospora and Bremia, which lack opercula on their sporangia.
[edit] Lifecycle
The lifecycle of peronosporaceae is comparable to the lifecycle of Oomycota.
[edit] Infection
This family creates infectious structures such as appressoria, primary vesicles, secondary vesicles, intracellular hyphae, and haustoria.
[edit] Economic Value
Peronosporaceae have parasitic mycorrhizal relationships with grape vines such as plasmopara viticola known as grape mildew, and phylloxera, forming root aphid.
They can be killed by the Millardet-Bordeaux mixture (CuSO4).
They are are saprotrophs of Peronospora tabacina (tobacco), releasing spores that are highly intolerant to desiccation, and light; so intolerant, that they are inviable after 4 days, reaching 50% viability after 1 day. Spore release is timed for the sunrise, when dew gathers, and moisture is ambient.
They are parasitic as bremia lactucae which forms on lettuce.
[edit] References
- C.J. Alexopolous, Charles W. Mims, M. Blackwell et. al., Introductory Mycology, 4th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN: 0-471-52229-5
