Abstract Detail

Comparative Genomics/Transcriptomics

Melton, Anthony [1], Navock, Kara [2], Ellestad, Paige [3], Martinez, Peggy [2], Morales, Walker [2], Milliken, Erin [2], Serpe, Marcelo [4], Novak, Stephen [5], Buerki, Sven [6].

A drought GxE experiment reveals patterns of differential expression and drought tolerance genes in Artemisia tridentata (big sagebrush; Asteraceae).

Anthropogenic climate change is driving increased drought and high temperatures across the globe. Due to shifts in climate, western North America has been experiencing persistent mega-drought for over two decades. This extreme climate change is a clear danger to native plant communities. Artemisia tridentata (Asteraceae) is an endemic keystone shrub of the imperiled western North American sagebrush steppe ecosystems. The range of Artemisia tridentata covers much of western North America and features a variety of climatic gradients, such as differing precipitation regimes, with annual monsoons breaking the drought season in the south and earlier onsetting, longer droughts in the north. A drought Genotype×Environment experiment including half-sibs from mother plants collected from two geographically and climatically distinct populations, one without an annual monsoon season within the A. tridentata range (IDT3 from Idaho) and one with an annual monsoon season (UTT2 from Utah), was conducted to induce drought stress for transcriptomic analyses. RNASeq and gene expression analyses were performed to identify differentially expressed genes (DEGs) using a computational pipeline including Trinity, Trinotate, bowtie2, samtools, and the R package ‘edgeR’, and GO Enrichment analysis via the GO Consortium/PantherDB online portal. Comparisons of tissue (leaf and root), treatment (well-watered control and drought-stressed), and population (IDT3 and UTT2) were made. Interestingly, far greater drought-stress induced DEGs were identified in samples of the UTT2 population than the IDT3 population for both leaf and root tissues (e.g., 17,268 vs 2,584 and 10,662 vs 3,136 upregulated DEGs, respectively). This indicates that the IDT3 population is more canalized in response, exhibiting a conservative ‘bet-hedging’ strategy, while the UTT2 population has greater response to drought due to adaptations to greater seasonality of precipitation within and between years from the annual monsoons. Response differences in tissues were also identified, with greatest transcriptional response for IDT3 occuring in the roots (2,584 leaf DEGs versus 3,136 root DEGs, with 392 being up-regulated in both tissues), while the greatest for UTT2 occurring in the leaves (17,268 leaf DEGs versus 10,662 root DEGs, with 5,278 being up-regulated in both tissues). This work demonstrates that populations of Artemisia tridentata are likely locally adapted to their respective precipitation regimes, having great implications for conservation and reseeding efforts in light of rapid environmental changes.

1 - Boise State University, 10391 W Henrys Lake Dr, Boise, ID, 83709, United States
2 - Boise State University
3 - 8725 W Dewitt Ct, Boise, ID, 83704, United States
4 - Boise State University, Dept. Of Biological Sciences, 1910 University Drive, Boise, ID, 83725, United States
5 - Boise State University, Department Of Biological Sciences, 1910 University Dr., Science 107, Boise, ID, 83725, United States
6 - Boise State University, Dept. Of Biological Sciences, 1910 University Drive, Boise, ID, 83725

Keywords:
sagebrush
gene expression
drought.

Presentation Type: Oral Paper
Number: CGT1006
Abstract ID:681
Candidate for Awards:Margaret Menzel Award