THE EFFECTS OF EXTENDED EXPOSURE TO ZEA MAYS L. BORDER CELLS WITH TOTAL ASSOCIATED EXUDATES ON THE MOTILITY AND BACTERIAL ATTRACTION ABILITIES OF CAENORHABDITIS ELEGANS

Author

Melissa Ruiz

Date of Award

2020

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Clore, Amy

Area of Concentration

Biology

Abstract

Nematodes, including Caenorhabditis elegans, become temporarily paralyzed (quiescent) when exposed to root border cells and their total associated exudates (BCTAE) from Zea mays, Sorghum bicolor, and Pisum sativum. C. elegans can excrete exudates to attract consumable bacteria. However, it is unknown whether quiescence induces lasting effects on C. elegans’ motility and their ability to attract bacteria; knowing its potential effects may allow insight into the rhizosphere’s trophic and non-trophic interactions. To investigate, two chemotaxis assays were conducted to evaluate the chemotactic responses of a.) C. elegans to Zea mays BCTAE and then b.) Pseudomonas putida – a gram-negative bacterium with chemotaxis capabilities – to C. elegans exudates. The Z. mays BCTAE assay involved placing root tips on agarose plates containing C. elegans and examining the nematode responses via video capture. Gravid adults were not paralyzed, but eggs were laid in BCTAE areas, so the general motility of the hatchlings was quantified digitally. The P. putida assay involved making agarose plugs containing C. elegans exudates from worms exposed and not exposed to BCTAE for 24 hours, then introducing Syto 9-stained bacteria to the plugs; the bacterial distributions were then observed under a fluorescent microscope. P. putida was unaffected by the BCTAE-exposed exudates in contrast to the observed chemotaxis toward the positive control plugs. There was no significant difference in overall nematode motility from BCTAE exposure in the plate assay, although quiescence was seen in BCTAE-exposed C. elegans in liquid cultures. The fact that no bacterial chemotaxis towards BCTAE-exposed nematode exudates was observed could suggest that BCTAE affects C. elegans’ ability to attract bacteria. This mechanism may represent another mode of nematode inhibition by root tips.

Recommended Citation

Ruiz, Melissa, "THE EFFECTS OF EXTENDED EXPOSURE TO ZEA MAYS L. BORDER CELLS WITH TOTAL ASSOCIATED EXUDATES ON THE MOTILITY AND BACTERIAL ATTRACTION ABILITIES OF CAENORHABDITIS ELEGANS" (2020). Theses & ETDs. 5992.
https://digitalcommons.ncf.edu/theses_etds/5992