Research

Plants integrate a spectacular amount of environmental data on time scales bridging minutes (e.g. passing clouds can alter available light) to seasons (temperature and water availability) to decades (climate trends, including anthropogenic change). A plant’s life history – its lifespan and when and how often it reproduces — dictates the extent to which it must respond to cues at these different temporal scales. Life history variation represents compromises between biomass allocation, survivorship risks, and subsequent fitness benefits (Lundgren and Des Marais 2020).

The Des Marais Lab has developed the grass genus Brachypodium as a model system for studying the impact of temporal environmental heterogeneity on the evolution of life history strategies (Des Marais & Juenger 2016). These issues are not merely academic – relative allocation of resources to biomass and reproduction are central to agricultural output. We are working with the US DOE Joint Genome Institute to develop genomic resources to study the physiological and developmental control of annual vs perennial life history strategies in Brachypodium. Current projects include understanding genetic correlations among developmental and ecophysioligcal traits in perennial and annual species, identifying the molecular and environmental control of seasonal changes in growth and resource allocation, and determining the environmental context of perennial and annual species using niche modeling. Our work on life history evolution is supported, in part, by the MIT Jameel Water and Food Systems Lab.

Our collaborators on this project are Daniel Woods, Jill Preston, Pilar Catalan, Bruno Contreras-Moreira, John Vogel, Alistair Rogers, and Pat Edger.

Understanding how and why individuals and species respond differently to environmental cues is paramount for predicting how natural and agricultural systems will be impacted by climate change. When variation in response can be attributed to genetic differences among individuals within a species, it is called genotype by environment interaction, or GxE. We have shown that GxE is pervasive in plant-environment interactions and is caused by several different genetic architectures (Des Marais et al. AREES 2013). The Des Marais Lab integrates detailed ecophysiological measurements with genomic data to draw functional connections between the molecular and whole-plant scale (e.g. Des Marais et al 2012 Plant Cell, 2014 PNAS).

Work on GxE in the Lab is generously supported by the National Science Foundation; please reach out if you are interested in opportunities to join this project as a PhD student.

Response to environmental cues is a genome-wide phenomenon; much of this response is coordinated at the level of gene transcription. We are interested in characterizing both the trans-acting (Des Marais et al. 2015 MBE) and cis-acting (Lasky et al. 2014 MBE) variants which drive natural variation in transcriptional responses. With collaborators, the Des Maras Lab is using tools from network theory to understand how topological features of gene regulatory networks shape the evolution of environmental response (Des Marais et al. 2017. Proc Roy Sci). Current areas of inquiry include developing methods to detect GxE in the topology of regulatory network, and using patterns of network GxE to improve strategies for plant improvement.

Collaborators on this project include Caroline Uhler and Sam Scarpino. Our work on gene regulatory evolution is generously supported by the National Science Foundation; please reach out if you are interested in opportunities to join this project as a PhD student.

Climate change is dramatically altering the way that plants acquire and allocate resources, including carbon, water, and soil-derived nutrients. Building on our long-standing interest in water use efficiency (Des Marais et al. 2012, 2016, 2017) we have recently expanded our research towards understanding how plants co-optimize plant carbon and nitrogen status under variable environments. We are specifically addressing the molecular control of nutrient uptake under key dimensions of climate change: elevated atmospheric CO2 and temperature. Our motivation for this work arises from the need to reduce inputs of industrial fertilizer to agricultural lands while simultaneously ensuring a resilient food stream in the face of a rapidly changing earth system.

Our work on plant ecophysiology is generously supported by the MIT Climate Grand Challenge Initiative and by the Robert and Ardis James Foundation. Collaborators on this project include Chris Voigt, Benedetto Marelli, Kris Prather, Mary Gehring, Tavneet Suri, and Antoine Allanore.