Steven Tanksley
When you first bite into a juicy ripe tomato, you probably aren’t thinking of
the multitude of genes that have to turn on and off in the right order to make
it both ripe and juicy, but someone is. Tomatoes are a crop with high economic
value and many different uses. There is thus scope for divergent breeding for
desirable traits, and a need to continually improve resistance to diseases. As
examples, Tanksley’s group has identified genes involved in developmental
control of “yellow stuffer” tomatoes, pear tomatoes, processing tomatoes,
tomatoes with different sized seeds, and tomatoes with resistance to several
diseases. Intensive molecular mapping (e.g. with RFLPs) to define markers has
greatly facilitated effective breeding strategies. Many of the traits involved
are the result of quantitative gene expression, and the Hageman Lecture will
focus on the molecular mechanisms involved.
Steven D. Tanksley began work with tomato genetics as a graduate student with
C.M. Rick, at UC-Davis in the late 1970s. Through his efforts, tomato rapidly
became the first dicot for which a genetic map could be connected to a physical
map of the 12 chromosomes. As molecular techniques became available, Tanksley
pioneered their application to further the study of tomatoes. His publication
list runs to a dozen pages with his recent research emphasis focused on three
areas: identifying key determinants of the change from wild plants with small
berries to the modern cultivated tomato which may be several hundred fold larger
in volume and diverse in shape, color and structure; developing comparative
genomics of other crops such as eggplant, potato, pepper, and petunia; devising
new molecular breeding techniques. All of these are based on his major
contributions to the sequencing and molecular genetic mapping of tomato, which
came to fruition in the early 1990s. Gene maps of the other solanaceous species
show large blocks of similarity, with interesting rearrangements of chromosome
segments from which evolutionary relationships can be seen.
Dr. Tanksley obtained his B.S. in Agronomy from Colorado State, and following
his PhD and post-doctoral at Davis, was an Assistant Professor at NMSU in Las
Cruces, prior to moving to Cornell in 1985. In 1995 he was appointed Liberty
Hyde Bailey Professor of Plant Breeding, in recognition of the eminent botanist
who preceded him. He was elected to the National Academy of Sciences in 1995,
and has received several international honors including the Alexander von
Humboldt Foundation Award in 1998, Martin Gibbs Medal of the ASPP in 1999, Wolf
Foundation Prize in Agriculture in 2004 and the Kumho Award in Plant Molecular
Biology and Technology in 2005. He also received an Outstanding Undergraduate
Mentor Award, and a number of recognitions for his contributions to genetics.
The Kumho Award was given in recognition of his many contributions including
cloning of Pto tomato locus, one of the earliest resistance genes to be cloned,
a kinase that provides a model paradigm for disease resistance.
The workshop will focus on use of wild species to introduce genes for novel
traits, particularly disease resistance. Tanksley’s group has worked with rice,
as well as tomatoes. As widely disparate as these two plants are in growth habit
and commercial product, they share in common the presence of wild relatives
harboring a wealth of useful genes. The challenge is integration of those genes
into valuable commercial cultivars without provoking concerns about GMOs.
Colloquium: "Use of wild genetic variation in plant improvement"