Abstract Detail

Poster Session

Martin, W. Wallace [1], Warren, Alyssa M. [1].

A New Basal Oomycete with Isogamous Sexual Reproduction.

An unusual oomycete was isolated from moribund simuliid adults collected from a Virginia stream.  The organism produces large contorted hyphae in a variety of common media and mostly endobiotic growth when dead insects are used as a food source.  In asexual reproduction portions of hyphae are converted into elongate zoosporangia by the formation of septa.  Zoosporogenesis is similar to that reported for Crypticola (Atkinsiella) entomophaga in which a contraction of zoosporangial protoplasm to the center is followed by slow cleavage of flagellated cells.  Following a period of swarming within the zoosporangium, the biflagellate zoospores are released through one or more narrow discharge tubes.  An unusual form of sexual reproduction has been observed that bears some superficial resemblance to that occurring in conjugating green algae.  In older cultures portions of elongate hyphae may be converted into many rounded and thin-walled isogametes.  In some cases in which two hyphae are in close proximity, fertilization tubes are produced by gametes of one hypha which pass through the walls of both hyphae and contact gametes in the adjacent hypha.  The fertilized gametes contained in the “receiving” hypha develop into thick-walled cells with eccentric content.  In addition to a “scalariform” pattern of sexuality, gametes in one region of a hypha may develop fertilization tubes that pass laterally to fertilize gametes in another region of the same hypha.   A preliminary study comparing the SSU and LSU rDNA of this organism with other oomycetes has revealed that it is most closely related to Apodachyla and Atkinsiella dubia.

1 - Randolph-Macon College, Department of Biology, P.O. Box 5005, Ashland, VA, 23005, USA

Keywords:
Oomycetes
Basal Oomycetes
Isogamy
Atkinsiella
Apodachlya.

Presentation Type: Offered Paper - Poster
Session: P3
Location: Lincoln Room/Kellogg Hotel and Conference Center
Date: Monday, June 9th, 2014
Time: 8:00 PM
Number: P3001
Abstract ID:211
Candidate for Awards:None