Scientist improves biomass productivity of winter wheat, relevance for next-generation biofuels

Liuling Yan, a Chinese scientist working at Oklahoma State University’s Division of Agricultural Sciences and Natural Resources, is making major breakthroughs in wheat improvement. For his latest discoveries, which boost the yields of winter wheat, he used a DNA marker for a genomic region developed to select lines for biomass production that can be utilized as forage or as a supplemental biofuel feedstock. The findings make the economics of dual-purpose winter wheat more attractive and may result in higher biomass productivity - a fact with obvious consequences for second-generation biofuels which are made from residues such as straw.

Yan, who is recognized as world-class scientist with impressive accomplishments in the development and application of molecular genetics tools and techniques, is working in collaboration with Brett Carver, OSU Regents professor of wheat genetics and breeding. The team recently discovered a genome region that has a significant effect on the development process of winter wheat. The DNA marker for this genomic region was developed to select lines for biomass production.

This exciting find was achieved based on the genetic segregation of flowering time in a population generated from a cross between two winter cultivars, Jagger – a typical early flowering wheat variety – and 2174, a late-flowering wheat variety. David R. Porter, head of OSU’s department of plant and soil sciences

The Oklahoma Center for the Advancement of Science and Technology recently awarded $90,000 for two years to support Yan’s work in the cloning of this gene that is so beneficial to the dual purpose wheat in Oklahoma.

Complex genome
Yan is recognized worldwide in the scientific plant community as a leader in the cloning of genes from the large and ultra-complex genome of wheat. The wheat genome contains 16 billion base pairs, the DNA building block: that is five times the size of the human genome and approximately 120 times the genome size of Arabidopsis, the first plant to have its entire genome sequenced and a baseline model used for studying plant biology:
energy :: sustainability :: biomass :: bioenergy :: biofuels :: ethanol :: cellulose :: winter wheat :: genomics :: plant biology ::

Throw in the fact that wheat is a hexaploid species having three similar genomes and most people get lost in the science fairly quickly, says Mark Hodges, Oklahoma Wheat Commission executive director. The bottom line is that what Dr. Yan does is not easy, and Oklahoma is very fortunate to have him working on improvement of the state’s wheat crop, adds Hodges.

Economic boost
And by 'Oklahoma' he means all of Oklahoma is benefiting from Yan’s work, not just the state’s agricultural industry. "At August 15 prices, the cash price of an average crop in Oklahoma would be more than $900 million if we would have harvested a normal crop, which, of course, we weren’t able to manage this year because of the weather and other factors," Hodges said.

Hodges added that figure does not take into account the livestock or pounds-of-beef-produced aspects of wheat production and use. "In a normal year, wheat can easily account for more than $1.5 billion to the rural parts of the state, and eventually affects the entire state’s economic well-being," Hodges said.

USDA data – backed up by OSU research conducted by Division scientists – indicate the average increase of yield attributed to variety research is a half bushel per acre per year. "If you figure 30 bushels per acre in average yield and we increase that by a half bushel every year, at current prices that would be an increase of $3 per acre a year in return to the producer just in terms of the genetics," Hodges said. "Talk about providing a benefit."

A proud university
It is little wonder that the Proceedings of the National Academy of Sciences (PNAS) featured Yan on its cover when he cloned the third vernalization gene from wheat in 2006. The cover and open-access companion article reporting Yan’s findings made him the subject of considerable scientific attention. "PNAS is the premier science journal in the nation, actually the world", Porter said.

Vernalization requirement, long-term exposure to low temperatures to flower, is a common phenomenon in Oklahoma winter wheat varieties. "Revealing the vernalization genes in varieties would provide valuable information vital to our efforts to improve Oklahoma wheat, which in turn would provide direct and indirect benefits to Oklahoma’s agricultural industry and the state economy," Porter said.

Since Yan’s arrival in Oklahoma, he has taken his PNAS-published research one step further, by discovering key minute differences in the DNA of winter wheat varieties and their initiation of reproductive development.

"What this means to our wheat breeding program, and to the Oklahoma wheat producer, is that we’ll be able to tell with much greater confidence if a new variety can be grazed one to two weeks longer without sacrificing grain yield," Carver said. Just one more week of grazing could put an additional $3 per acre to $4 per acre in the producer's pocket.

"Yan’s our man," Carver said. "Yan’s type of research fits Oklahoma’s way of producing beef and wheat from one crop like a golf club fits Tiger Woods’ hands."

A native of China, Yan spent six years at the University of California-Davis prior to joining the OSU faculty. He was educated mainly in his native country but earned his doctoral degree in plant genetics in Australia.


Picture: Wheat field covered in snow, illustrating the adaptation of this crop to cold temperatures. Yan discovered that one of the main vernalization (cold-temperature induction of flowering) genes in wheat, VRN3, is similar to Arabidopsis FLOWERING LOCUS T (FT). Gene expression levels of the barley and wheat FT genes are significantly higher in plants homozygous for the dominant Vrn3 allele (which promotes early flowering) than in plants homozygous for the recessive vrn3 allele (late flowering). The wheat and barley FT genes account for some of the natural variations in vernalization, providing new insights into the adaptive diversity of these important crops. Credit: Agripicture.

References:
L. Yan, et. al., "The wheat and barley vernalization gene VRN3 is an orthologue of FT", PNAS | December 19, 2006, vol. 103, no. 51, pp. 19581-19586, DOI: 10.1073/pnas.0607142103

Oklahoma State University, Division of Agricultural Sciences and Natural Resources: OSU wheat breeder’s genetic code-breaking means dollars to Oklahoma and region - August 16, 2007.