CURRENT PROJECTS
Our crops are already showing the adverse impacts of climate change. Year to year yield instabilities are now regular outcomes for crops as the frequency of adverse weather events has increased. However, some extremophile plants like Eutrema salsugineum are closely related to major crops but these species have adapted to highly stressful environmental conditions in their native habitat. In the Yukon territory of Canada, E. salsugineum plants frequently experience periods of drought, typically grow (and thrive) on soil that is low in key nutrients, and plants are regularly exposed to extreme changes in temperature. The physiological and metabolic responses and the underlying genomic determinants regulating stress tolerance traits for this plant are topics that we study. We use a variety of strategies ranging from phenotypic measurements to transcriptome and/or metabolic profiling to identify and characterize how these plants cope with adverse conditions. We believe that extremophytes can guide our selection for traits that can be used to improve our crops, traits that can stabilize yields by making our crops more tolerant to the deleterious environmental conditions they experience in the field.
A plant adapted to extreme environmental conditions -
• freezing temperatures
• high salinity
• drought
• low nutrients
Eutrema’s “Xtreme” habitat led to a plant ideally suited for identifying traits for improving nutrient use by crops and tolerance to drought, freezing, and salt.
Projects currently underway
1. Nutrient use by extremophiles plants:
Plants accumulate organic solutes when experiencing drought, some well known “osmoprotectants” include the amino acid proline or carbohydrates like sorbitol or pinitol. Previously, we used GC mass spectrometry to profile metabolites accumulated by E. salsugineum salt-stressed in growth cabinets and plants growing at field sites in the Yukon, Canada. Surprisingly, we found cabinet-grown plants accumulated proline while field-grown plants had negligible proline but high levels of carbohydrates (Guevara et al, 2012). This told us that E. salsugineum shows plasticity with respect to osmotic solutes needed for osmotic adjustment. Is nutrient use for other essential elements also plastic or is nitrogen use exceptional with respect to flexibility? This led us to study phosphorus use by Yukon E. salsugineum, and our work suggests that this species does not show plasticity with respect to use of this nutrient, rather is fixed to conservatively use this nutrient (Velasco et al., 2016). Current work compares the use of phosphorous by two E. salsugineum ecotypes, one found in Shandong, China and the other from the Yukon.
From: Velasco et al. 2016 Plant, Cell & Environment 39: 1818
2. Genetic basis for drought tolerance:
We have profiled transcriptomes of E. salsugineum plants exposed to a progressive drought exposure protocol (MacLeod et al., 2015). These profiles are being used to further characterize the drought tolerance features of the Yukon E. salsugineum ecotype and how these tolerance traits are distinguished from the drought avoidance behaviour of the Shandong ecotype.
3. Long non-coding RNAs: do they play a role in stress tolerance for the extremophyte E. salsugineum?
Long non-coding (lnc) RNAs are an enigmatic class of gene products that are only now receiving greater attention in plants. We have devised an ensemble machine learning approach (CREMA; Simopoulos et al., 2018) to help identify putative lncRNAs. This tool also ranks transcribed products by providing an estimated likelihood that they are lncRNAs. We are now in a position to identify stress responsive lncRNAs and assess the role(s) these products may play in the adaptation of E. salsugineum to the extreme conditions in its native habitat.