Abstract Detail

Conservation Biology

Vuruputoor, Vidya [1], BenJeddi, Sophia [1], Fetter, Karl [1], Wegrzyn, Jill [2].

Assessing genetic differences in hemlock resistance (Tsuga sp.) through comparative transcriptomics and metabolomics.

Covering over 1.3 million hectares, the eastern hemlocks (Tsuga canadensis) form an integral part of the forests of eastern North America. The hemlock woolly adelgid (HWA) was introduced to the North American continent through an infested Japanese ornamental and since the 1980s, has rapidly destroyed hemlock forests. Since its introduction, across eastern hemlock populations, the hemlock basal area declined from a mean of 56% of the total basal area to 46%. Given the current rate of destruction, most of the eastern and all of the Carolina hemlock populations will be infested by the HWA. Researchers have developed chemical and biological control strategies to combat the HWA, although these solutions are labor-intensive, expensive, and can negatively impact non-target species. Understanding the genetic variation within and among Tsuga species can help in leveraging innate host resistance against the HWA that exists in other species. The Chinese hemlock (T. chinensis), for example, is the most resistant to the HWA, followed by other Asian and western North American species, and the eastern and Carolina (T. caroliniana) hemlocks are the most susceptible species. The Chinese hemlock produces terpenoids that are hypothesized to deter aphids more readily than eastern or Carolina hemlocks. Certain individuals within eastern hemlock populations can tolerate HWA infestations, and developing HWA-tolerant populations has been a focus of recent research. Given the differential response, an underlying genetic signal likely drives tolerance. We collected needle samples of four individuals across six species (T. chinensis, T. canadensis, T. sieboldii, T. heterophylla, T. caroliniana, T. ulleungensis - 24 individuals in total) and performed targeted GC/MS profiles for five terpenoids, of which isobornyl acetate is claimed to be an attractant of the HWA, and the other four terpenoids act as HWA deterrents. We found significant differences in the production of isobornyl acetate across the species, and within the susceptible individuals sampled, there was a considerable amount of variation in the concentration of isobornyl acetate. We coupled this study with differential expression analysis of needle and branch tissue of the same individuals from Harvard’s Arnold Arboretum to examine differences in the expression of genes involved in terpene-producing pathways. This study provides insights into the molecular mechanisms as well as variation across and within members of the Tsuga genus.

1 - University of Connecticut, Department of Ecology and Evolutionary Biology, 75 N. Eagleville Road, , Unit 3043, Storrs, CT, 06269-3043, United States
2 - University Of Connecticut, EEB, 67 N. Eagleville Road, Unit 3124, Storrs, CT, 06269, United States

hemlock woolly adelgid.

Presentation Type: Oral Paper
Number: CB1004
Abstract ID:663
Candidate for Awards:None

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