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Abstract Detail


Symbioses: Plant, Animal, and Microbe Interactions

Athukorala , Sarangi N.P. [1], Piercey-Normore, Michele D. [1].

In vitro resynthesis of C. rangiferina to identify the three early stages of resynthesis.

Reindeer lichens in the genus Cladonia (former genus Cladina) are the main winter diet for Caribou and Reindeer and form the dominant vegetation cover in northern ecosystems. Early gene regulation of the interaction between the algal and fungal symbionts initiates development of the lichen thallus, which may produce morphological variation in different growing conditions. The objectives of this study were 1) to examine the morphological development and identify the three early stages of in vitro resynthesis in the lichen C. rangiferina; 2) to study the regulation of certain recognition and defense related genes during above stages. The mycobiont and the photobiont of C. rangiferina were isolated from thallus fragments using standard procedures. The mycobiont was co-inoculated with a compatible (Asterochloris), and with a non-lichenized incompatible alga, (Chlorella). Using dissecting and light microscopic observations, the first three stages of resynthesis of C. rangiferina were identified. Twenty four hours post co-inoculation (PCI) was defined as the "pre-contact stage", while 8 days PCI and 21-29 days PCI were identified as "contact" and "growth together" stages respectively. Scanning Electron Microscopy was used to further observe the three stages identified above. After 24 hrs, no interaction was observed in both interactions (compatible or incompatible). During the "contact" stage, the mycobiont was growing towards cells of Asterochloris and making contacts with them by producing lateral branches. In contrast, no interaction was observed with Chlorella and both fungal hyphae and algal cells were growing independently. During the "growth together" stage, the mycobiont made hyphal networks between colonies of Asterochloris species, sometimes completely engulfing them. In addition, more frequent and prominent appressoria were observed as swellings on the hyphae. During this same stage, fast growth rate was observed in Chlorella while growth of the mycobiont had stopped or slowed down. Identification of the resynthesis stages of C. rangiferina is required before gene expression of the proteins involved in recognition and defense can be studied. Recognition and defense related gene expression coordinated with these resynthesis stages will also be described.

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1 - University of Manitoba, Biological Sciences, Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada

Keywords:
resynthesisstages
Cladonia rangiferina
Asterochloris sp
gene regulation
defense and recognition.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM
Number: PDB002
Abstract ID:476


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