Research Report 2019_20

Kankshita Swaminathan, PhD / Swaminathan Lab

Understanding the complex genomes of grasses with biofuel potential

The knowledge gained in this project will help research- ers breed for traits of interest in miscanthus and breed or modify plants to improve certain processes such as nutrient remobilization and the ability to bounce back after winter. Unraveling themysteries of themiscanthus rhizome is also a major goal of Swaminathan’s lab. Rhizomes are modified underground stems involved in nutrient stor- age and reproduction in these grasses. As the plant’s leaves die in the fall, nitrogen and other nutrients are sent to the rhizome, where they are stored underground over the winter. In the spring, that energy is taken up into other tissues as the plant grows, instead of going back into the soil, reducing the need for fertilizer. The rhizomes also produce new stems, allowing the plant to get bigger every year, and help with carbon storage. All of that makes miscanthus more sustainable, less costly to manage, and more environmentally friendly. Swaminathan is intrigued by what makes a stem be- come a storage organ. Her lab is working to understand the molecular mechanisms that direct the miscanthus rhizome to store complex carbohydrates while sugar- cane and sweet sorghum stems store sugar.

A lot of fuel is required to keep our country running. Americans consume an average of 390 million gallons of motor gasoline and 197 million gallons of aviation gas- oline, per day, to fuel planes, trains, and automobiles. There is a growing renewable energy movement aimed at reducing the production and use of petroleum-based fuels in favor of cleaner, more sustainable fuel sources. Bioenergy is a form of renewable energy derived from biomass to generate heat, electricity, renewable prod- ucts and liquid fuels for transportation. Biomass is an abundant, renewable, and sustainable resource that includes agricultural waste, algae, dedicated energy crops, and forestry residues. HudsonAlpha Faculty Investigator Kankshita Swaminathan, PhD, is passionate about improving bio- energy feedstock crops to increase their yields and im- prove their abilities to adapt to extreme environments such as poor soils and drought. Swaminathan’s lab works to sequence and understand complex genomes of perennial grasses with biofuel potential. Their research also focuses on understanding the genetics behind how perennial plants reproduce and how they capture and store nutrients to use year after year. One such plant that Swaminathan’s lab studies is the perennial grass miscanthus, a promising source of bio- mass. Miscanthus grasses is extremely adaptable and easy to grow. It can thrive on agriculturally unfavorable lands, requires limited fertilization, has a high tolerance for drought and cool temperatures, and uses the more efficient C4 form of photosynthesis. In October 2020, Swaminathan’s lab, along with several colleagues, pub- lished the full genome sequence of Miscanthus sinensis in Nature Communications 1 . The full genome sequence and accompanying genomic analysis of M. sinesis is the first for any type of miscanthus and are accordingly a valuable resource for researchers studying this plant and breeding it to improve biomass and other traits. In addition to the full genome sequence, the group also discovered important information on gene expres- sion in the leaves, stems, and rhizome of the grasses. Swaminathan’s lab led the gene expression efforts.

Toni Trieu and Shilpa Manjuna show off plant rhizomes

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HudsonAlpha Institute for Biotechnology

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