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E-GEOD-78101 - Effect of drought on herbivore-induced plant gene expression: Population comparison for range limit inferences
Released on 19 February 2016, last updated on 27 February 2016
Low elevation “trailing edge” range margin populations typically face increases in both abiotic and biotic stressors that may contribute to range limit development. We hypothesize that selection may act on ABA and JA signaling pathways for more stable expression needed for range expansion, but that antagonistic crosstalk prevents their simultaneous co-option. To test this hypothesis, we compared high and low elevation populations of Boechera stricta that have diverged for constitutive levels of glucosinolate defenses and root:shoot ratios; neither population has high levels of both traits. If constraints imposed by antagonistic signaling underlies this divergence, one would predict that high constitutive levels of traits would coincide with lower plasticity. To test this prediction, we compared the genetically diverged populations in a double challenge drought-herbivory growth chamber experiment. Although a glucosinolate defense response to the generalist insect herbivore Spodoptera exigua was attenuated under drought conditions, the plastic defense response did not differ significantly between populations. Similarly, although several potential drought tolerance traits were measured, only stomata aperture behavior, as measured by carbon isotope ratio, was less plastic as predicted in the high elevation population. However, RNAseq results on a small subset of plants indicated differential expression of relevant genes between populations as predicted. We suggest that the ambiguity in our results comes from a weaker link between the pathways and the functional traits compared to transcripts. Examination of four different treatments on two different populations
RNA-seq of coding RNA
Gunbharpur Singh Gill <Gunbharpur.Gill@yellowjackets.bhsu.edu>, Abdelali Barakat, David H Siemens, Riston Haugen, Steven L Matzner