Draft
Potato Genome Based on Unique Potato Variety
Blacksburg,
Va. The Potato Genome Sequencing Consortium (PGSC), an international
team of scientists from industry and academia in 14 countries, has
released a draft sequence of the potato genome with the help of
a Virginia Tech researcher.
Richard
Veilleux, professor of horticulture in the College of Agriculture
and Life Sciences (www.cals.vt.edu/), contributed a unique phureja
type of potato variety that accelerated the development of a blueprint
for one of the world's most important food crops. Widely anticipated
to assist scientists in improving the yield, quality, nutritional
value, and disease resistance of potato varieties, the genome sequence
will reduce the 10-12 years plant breeders need to develop new varieties
today.
"The
potato genome sequence will allow you to locate genes for any type
of trait you want," Veilleux said.
Each
copy of the potato genome consists of a dozen chromosomes and has
a length of approximately 840 million base pairs, making it a medium-sized
plant genome. Most lines of potato, such as the widely cultivated
Solanum tuberosum, have four slightly different copies of the genome
that can be traced to parents and grandparents, with some recombination
occurring during sexual cycles. Although the PGSC began sequencing
a potato species with such a complex genome, researchers turned
to Veilleux for a unique line with only one copy of the genome (known
as a "monoploid") to simplify and complement their work.
Veilleux
has spent more than 25 years of his career investigating homozygous
varieties of potatoes to create hybrid lines. An organism is homozygous
when identical alleles of each gene are present in both chromosomes
that pair during cell division. Homozygous organisms have less genetic
information to analyze during the genome sequencing process, and
they pass biological traits to all subsequent generations, making
them "true-breeding organisms." On the other hand, most
potato species are heterozygous i.e., different alleles occupy
the same gene position.
"The
consortium turned to me for a homozygous line of potato," Veilleux
explained. "Because potato suffers from 'inbreeding depression,'
the weaker homozygous lines of potato are relatively rare and not
cultivated in most parts of the world."
Thanks
to a new computer program developed by the Beijing Genomics Institute,
the potato genome assembly, which is publicly available on the PGSC
website (www.potatogenome.net/), covers 95 percent of potato genes.
Over the next six months, PGSC members will update the genome with
an annotation of the genes, an analysis of when and where they are
switched on and off, and a review of specific suites of genes critical
to potato production. Research teams around the world are working
to complete genome sequences for other plants in the Solanaceae
family, which includes tomato, eggplant, petunia, tobacco, and pepper.
Suzanne
Piovano, a lab specialist in the Department of Horticulture, has
worked with Veilleux for the duration of his potato breeding research
at Virginia Tech. Under Veilleux's supervision, 21 graduate students
have earned their degrees based on some aspect of potato genetics.
###
The
PGSC news release is available at http://www.potatogenome.net/images/2/2e/PGSC_Press_Release_0909.pdf
Nationally
ranked among the top research institutions of its kind, Virginia
Tech's College of Agriculture and Life Sciences focuses on the science
and business of living systems through learning, discovery, and
engagement. The college's comprehensive curriculum gives more than
2,400 students in a dozen academic departments a balanced education
that ranges from food and fiber production to economics to human
health. Students learn from the world's leading agricultural scientists,
who bring the latest science and technology into the
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