Maps of Miscanthus genome offer insight into grass evolution

May 15, 2012
University of Illinois crop sciences professor and Energy Biosciences Institute program leader Stephen Moose and his colleagues mapped the Miscanthus sinensis genome, a first step towards a full genome sequence. Credit: L. Brian Stauffer

Miscanthus grasses are used in gardens, burned for heat and energy, and converted into liquid fuels. They also belong to a prominent grass family that includes corn, sorghum and sugarcane. Two new, independently produced chromosome maps of Miscanthus sinensis (an ornamental that likely is a parent of Miscanthus giganteus, a biofuels crop) are a first step toward sequencing the M. sinensis genome. The studies reveal how a new plant species with distinctive traits can arise as a result of chromosome duplications and fusions.

The two studies were published this year: The first, led by the company Ceres, appeared in the journal PLoS ONE; the second, from a team led by researchers at the University of Illinois, is in the journal BMC Genomics. The data, materials, methods and used in the latter study are available to the public for further research.

Before this work, scientists knew that M. sinensis had a base set of 19 and was closely related to sorghum, which has a base set of 10. (Humans have a base set of 23). But without a map and sequence of the Miscanthus genome, researchers who hope to maximize yields or discover which genes give Miscanthus its desirable traits are working in the dark, said Stephen Moose, a University of Illinois professor and Energy Biosciences Institute program leader who led the study.

Moose and his colleagues used information gleaned from the sugarcane genome to develop hundreds of genetic markers to target specific regions of the M. sinensis genome. Then they crossed two M. sinensis plants and grew 221 offspring in the lab. By comparing how the genetic markers from each parent were sorted in the offspring, the team reconstructed 19 "linkage groups" corresponding to the 19 chromosomes of Miscanthus. This rough map of the chromosomes is a first step toward a Miscanthus genome, Moose said.

The researchers also used the sorghum genome as a comparative reference. Their analysis indicated thatM. sinensis arose as a result of a duplication of the sorghum genome, with a later fusion of some chromosome parts.

"Some plants will duplicate their genomes and then there's some sorting that goes on," Moose said. "Sometimes whole chromosomes are lost and sometimes there are fusions." Once there are two copies of each chromosome in a base set, each will proceed along its own evolutionary trajectory. "Often what will happen is even though there are two (versions of the same chromosome), one of them will start to deteriorate over time," Moose said. "Some positions and some genes will win out over the others."

Genome duplications may undermine the viability of a plant or give it an advantage. One immediate advantage of doubling, tripling or otherwise duplicating the genome is that it increases the size of the plant, or of certain plant parts, Moose said.

"Humans have selected for these traits," he said. "Strawberries, for example, are octoploids; they have eight chromosome sets. Sugarcane has eight sets, and it's bigger (than its wild cousins)."

Moose and his colleagues were surprised to find a high degree of similarity between the Miscanthus and sorghum genomes.

"I would say that for about 90 percent of the Miscanthus markers, their chromosomal order corresponds to what is known for ," he said.

The new findings and the eventual publication of the Miscanthus genome will help scientists understand the evolution of grasses and the genetic mechanisms that give them some of their useful traits, such as cold tolerance, Moose said.

The BMC Genomics team also included researchers from the University of California, Berkeley; the Polish Academy of Sciences; the department of plant biology at the University of Illinois; the Department of Energy Joint Institute; and the National Institute of Horticultural and Herbal Science, in South Korea. Moose is an affiliate of the Institute for Genomic Biology at Illinois.

Explore further: Plant engineered for more efficient photosynthesis

Related Stories

Key discovered to cold tolerance in corn

Aug 29, 2008

Demand for corn -- the world's number one feed grain and a staple food for many -- is outstripping supply, resulting in large price increases that are forecast to continue over the next several years. If corn's intolerance ...

Doubling a gene in corn results in giant biomass

Mar 02, 2009

University of Illinois plant geneticist Stephen Moose has developed a corn plant with enormous potential for biomass, literally. It yields corn that would make good silage, Moose said, due to a greater number of leaves and ...

Recommended for you

For legume plants, a new route from shoot to root

51 minutes ago

A new study shows that legume plants regulate their symbiotic relationship with soil bacteria by using cytokinins—signaling molecules— that are transmitted through the plant structure from leaves into the roots to control ...

Controlling the transition between generations

20 hours ago

Rafal Ciosk and his group at the FMI have identified an important regulator of the transition from germ cell to embryonic cell. LIN-41 prevents the premature onset of embryonic transcription in oocytes poised ...

User comments : 0