AGRISCIENCE RESEARCH
response that allows plants to take in information about their environment and respond without changing their location. In this way, a given plant genotype can produce a different phenotype, or expressed characteristics like seed size, leaf shape or allocation of resources to the roots, when exposed to changes in environmental con- ditions. While this type of response is common, the im- plications on the reproductive success of the plant are poorly understood. Determining the consequences of phenotypic plasticity in plants is important for breeding new plants for different, challenging environments. In a preprint study published in September 2020, Harkess and colleagues used the common morning glory ( Ipomoea purpurea ) as a model system for un- derstanding the role of plasticity in the evolution of herbicide resistance 2 . By assembling a high quality genome and comparing gene expression in herbicide resistant morning glories to gene expression in morning glories receiving herbicides, the team identified a num- ber of genes that show plastic and evolved responses to herbicide. In contrast to similar studies in other organ- isms, these results suggest that gene expression chang- es in response to strong environmental change can be adaptive, meaning they improve the plant’s chance of survival. Harkess is also the lead investigator on an am- bitious Department of Energy (DOE) Joint Genome Institute (JGI) Community Science Program grant en- titled “The Brassicales Genome Initiative”. The Brassi- cales is a phenotypically diverse order of plants repre- sented by more than 4,700 species that display variation in traits relevant to the DOEmission. As part of the grant, Harkess is leading a 35-person international collabora- tive team tasked in generating 26 high quality genomes across all families in the Brassicales order of plants, including at least one member from each of the 16 un- derrepresented families of Brassicales. Harkess and his team selected pairs of species within each family that represent the presence or absence of four DOE-relevant traits: photosynthesis system, metabolite diversity, sex- ual reproduction, and woodiness. This highly collabora- tive and international team is showcasing the value of studying the genomes of plants that have evolved unique adaptations on the planet, and in particular, species that are not very well known.
The Harkess team identified a number of genes that show plastic and evolved responses to herbicide in morning glories.
His joint appointment at Auburn also allows Harkess to follow his other passion—educating the next generation of scientists about plant genomics and diversity. His position at Auburn will help develop a pipe- line for graduate student education at HudsonAlpha. Harkess is teaching a course in plant genomics at Auburn, which will feature a hands-on approach to learning practical bioinformatics and genome sequencing. Students will spend the semester work- ing in teams to assemble, annotate, and publish a plant genome manuscript, as a class, with the larger goal of reducing barriers to entry into graduate school and academic publishing. n
Harkess is passionate to educate the next generation of scientists about plant genomics and diversity.
2019-20 Research Report 37
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