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Molecular Geneticist New Dimension to Sunflower Research

Monday, September 2, 2002
filed under: Research and Development

A New Dimension to Sunflower Research:

USDA Molecular Geneticist Jinguo Hu

Sunflower research at the USDA Northern Crop Science Laboratory in Fargo, N.D. now has a new dimension, with the addition of molecular geneticist Jinguo Hu. He joined the sunflower research staff in Fargo last spring, his permanent position funded through a special Congressional appropriation.

Hu has an MS in agronomy from Huazhong (Central China) Agricultural University, and a Ph.D in genetics from the University of California, Davis. Hu has conducted research on plant breeding and genetics for the past 24 years. During the last 12 years, he has been primarily engaged in genome mapping and DNA-based marker development and applications.

Most recently, Hu was a research scientist for Unilever-Lipton Tomato Technology Center, Stockton, Calif., a private company where Hu applied molecular techniques to the breeding of processing tomato varieties for resistance to multiple diseases and for improved quality.

At the USDA lab in Fargo, Hu is identifying genes through genetic markings that provide particular production or quality traits to the plant. Once the gene or genes have been marked, researchers can test the gene presence in the laboratory in newly emerged sunflower plants. This will eliminate the need to screen hundreds of plants, thus bringing greater efficiency to the quest for improved sunflower hybrid traits.

There are three primary areas to Hu’s research:

1) Sunflower genomics (structural and functional, gene expression profiling, gene discovery).

2) Application of molecular techniques to the genetic improvement of sunflower, including characterizing germplasm, marker-assisted breeding, and seed quality assurance.

3) Cooperating with other USDA scientists in Fargo on various sunflower research projects, including:

•Collaboration with biochemist and research leader Brady Vick to explore the genetic basis of fatty acids synthesis, and develop DNA markers for breeding.

•Collaboration with research geneticist Jerry Miller to determine the molecular basis of sulfonylurea (SU) resistance in sunflower.

•Collaboration with plant pathologist Tom Gulya to develop DNA Markers for downy mildew resistance.

•Collaboration with research botanist Gerald Seiler to survey DNA similarities and differences among wild species of sunflower.

•Collaboration with research geneticist Chao-Chien Jan to expand the USDA sunflower genetic map.

Miller says some genetic traits, such as Sclerotinia resistance and low saturated fatty acids, are very hard (and expensive) to research in the greenhouse. And other genetic traits, such as sunflower midge resistance, can be difficult to evaluate in field plots. “Midge never occurs consistently in a field nursery,” he says. “So how do you find a resistant gene when you don’t have an environment that will allow you to detect whether or not you have the presence or absence of a gene?”

That’s where Hu’s research is valuable: he can evaluate the presence or absence of genes molecularly, right in his lab. “He can study the DNA of a plant and using molecular markers, determine whether or not a gene is present, and distribute that information to the seed industry to use in their own breeding programs,” says Miller. “It’s intellectual property developed and released for companies to use on a DNA level, rather than on the level of germplasm or a hybrid.”

Miller says Hu’s research will help provide a valuable resource to public and private breeding programs: time. “Evaluating wild sunflower species for downy mildew resistance, for example, takes a long time and a lot of effort to transfer to cultivated species. If Dr. Hu can take a piece of DNA from a wild species and tell me ‘this is the same gene you already have in a given line,’ or ‘no, this is a gene that is entirely different,’ it would save both myself and seed companies a tremendous amount of research work.”

DNA like the English Alphabet

Hu would tell you that DNA is much like the English alphabet—they are both codes. Thus, his research as a molecular geneticist is similar to that of someone who studies the structure and use of language.

For example, if you didn’t understand the English language, you wouldn’t be able to comprehend what the letters “s-u-n-f-l-o-w-e-r” mean in that particular order, or differentiate the word from other words that contain the same letters as “sunflower.” Just as the alphabet is our code for putting letters into words and words into language, DNA is a genetic code for the proteins that form all living things. Proteins are essentially the work force in both plant and animal cells, responsible for making new cells and destroying old or diseased cells, creating energy and growth, and transporting chemicals needed for healthy living between cells.

The ingredients of a protein are amino acids, each with a code letter for easier identification. There are only four letters in the DNA code: A (adenine), G (guanine), cytosine (C) and thymine (T) for every living being, be it plants or animals. Thus, for example, while a sunflower plant and a blackbird have the same four letters in their genetic code, The DNA sequence of those letters is different, in the same way that the spelling and meaning of a word lies in the sequence of alphabet letters.

Much of Hu’s research as a molecular geneticist is to scan the DNA code of sunflower, and identify desirable traits such as stronger downy mildew resistance and better oil quality, using molecular markers to identify where a particular trait is located within a sunflower plant’s genetic makeup. The process of using molecular markers is not the same as biotechnology: Molecular markers are essentially a tremendously accurate means of “fingerprinting” germplasm, enabling Hu and his research colleagues to follow traits or genetic makeup in the course of natural sunflower breeding efforts. Then, based on the pattern revealed by these markers, to select crosses for better hybrids through conventional breeding methods. – Tracy Sayler

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