Abstract Detail

Comparative Genomics/Transcriptomics

Webster, Rebecca [1].

Detecting Differential Gene Expression Linked to Foraging Behavior in Cuscuta harperi.

Cuscuta, common name Dodder, are leafless, rootless, flowering holoparasitic vines related to Morning Glories. Upon germination, Dodder seedlings forage for potential hosts by circling as they lengthen and only have a few days to locate and attach to a suitable photosynthetic plant. Once attached to a suitable host the parasite extracts nutrients from the host's vascular system and grows rapidly. Seedlings are able to detect gradients of volatile organic compounds (VOCs) emitted by potential hosts to either grow away from unsuitable hosts or towards a preferred host while foraging (Runyon et al. 2006). The genetic mechanisms responsible for VOC recognition, foraging behavior, and growth response are currently unknown. Harper's Dodder (Cuscuta harperi) is a rare species endemic to sandstone and granite outcrops in Georgia and Alabama that shows a high degree of selectivity for preferred hosts (Rogers 2017) and possesses a relatively small, fully sequenced genome, making it an ideal species for investigating genetics of foraging behavior.Our overarching goal for this research is to identify the genetic mechanisms involved in volatile organic compound (VOC) recognition and foraging behavior in Harper's Dodder by comparing gene expression between Cuscuta harperi seedlings exposed to differing experimental conditions. 36 Cuscuta harperi seedlings were exposed to either a preferred host (Liatris microcephala), a non-preferred host (Danthonia sericea), or a control, and tissue samples were flash frozen to preserve transcriptome activity during uniform times of either 0.5hrs, 2 hrs, or 6hrs after seedling exposure to VOCs. A sufficient quantity of high-quality RNA was successfully isolated from the collected samples, and the messenger RNA (mRNA) was converted into a complementary DNA (cDNA) library suitable for high-throughput sequencing Illumina DNA sequencing. Resulting sequence data will then be used to compare changes in seedling gene expression across different time intervals of VOC exposure and changes in gene expression between seedlings exposed to unsuitable versus preferred host VOCs. Results of these trials will help elucidate the genetic mechanisms involved in VOC recognition, foraging behavior, and host selection in C. harperi and closely related Cuscuta species, some of which are known to cause extensive agricultural damage. _{Runyon, JB, MC Mescher and CM DeMoraes. 2006. Volatile Chemical Cues Guide Host Location and Host Selection by Parasitic Plants. Science, 313: 1964-1967. Rogers, B.N. 2017. Population Genetics and Host Specificity of a Rare Parasitic Plant, Cuscuta harperi. Masters Thesis. Kennesaw State University.}

1 - Kennesaw State University, Department of Ecology, Evolution, and Organismal Biology, 1000 Chastain Road, Kennesaw, Ga, 30144, USA

Keywords:
Next generation sequencing
Illumina
Dodder
Cuscuta
Holoparasite
VOC Recognition
Foraging Behavior.

Presentation Type: Poster
Session: P, Comparative Genomics and Transcriptomics
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PGT001
Abstract ID:70
Candidate for Awards:None