Selected Research Outcomes
Basic plant science
The Jiming Jiang lab made a major discovery in 2014 when they found that maize centromeres expand by 100% in the genetic background of oat. This discovery led to a much larger finding of general importance to biology: the sizes of centromeres of all chromosomes in a single species are identical and are independent from chromosome size.
The Patrick Krysan lab published an article in the Breakthrough Technologies section of Plant Physiology describing a new method for performing mutation screening in plants, which greatly facilitates screening of plant materials for important and useful mutations. The technique they described was a new twist on an established method called TILLING. This method made it possible for one scientist to easily perform mutation screens that would have otherwise been too costly and time-consuming to do using the original process.
The Jiming Jiang lab is credited for developing several molecular cytogenetic techniques that are now widely used in the plant science community. The DNA fiber-fluorescence in situ hybridization (fiber-FISH)-based physical mapping effort was an essential part of the International Rice Genome Sequencing Project. Jiang was the only scientist who co-authored all six major papers associated with this project, including 3 in Nature and 1 in Science. His lab has made significant contributions to the sequencing of several important crop genomes, including potato, maize, and papaya.
Germplasm development, systematics, and breeding
The Shelley Jansky lab developed a very unique resource for potato breeding and genetics that is receiving widespread attention around the world; the first true diploid potato breeding population. This has led to the development of an recombinant inbred line population for potato, developed from a doubled monoploid x a self compatible inbred line, and has stimulated the interest of potato breeders around the world for new ways to improve this important food crop.
The Yiqun Weng lab conducted comparative genetic mapping between cucumber and melon, and established detailed syntenic relationships between seven cucumber and 12 melon chromosomes. They investigated chromosome synteny among cucumber, C. hystrix, and melon which allowed them to infer at least 59 chromosome rearrangement events that led to the evolution of the seven cucumber chromosomes, including five fusions, four 11 translocations, and 50 inversions. This remarkable piece of research demonstrated the genetic ancestry of cucumber, showing the importance of this wild species in the development of the cultivated crop.
Havey led efforts to develop marker-facilitated selection for virus resistances in vegetable crops. Mutations in eukaryotic initiation factor 4E were shown to condition resistance to Zucchini Yellow Mosaic Virus (ZYMV) in watermelon and a PCR-marker was developed for use by other scientists around the world. Tolerance in cucumber to Cucurbit Yellow Stunting Disorder Virus (CYSDV) was also identified and released, and molecular markers associated with geminivirus resistances in tomato were identified.
Spooner has led international efforts to deepen our knowledge of the evolution, domestication, and spread of the cultivated potato. Spooner has used morphological and molecular data to completely revise the taxonomy of cultivated potato (to four species, with S. tuberosum being the most widespread, diverse, and comprising many ploidy levels formerly recognized as distinct species). He demonstrated, for the first time, a single origin of cultivated potato, and placed the event in southern Peru. Further studies challenged a long-held hypothesis of the sole introductions of early European origins of potato solely from the high Andes, and showed origins from lowland Chile as well. These investigations have rewritten the taxonomy and origin of cultivated potato, revised the history of its spread outside of South America, and has redefined the diversity and taxonomy of cultivated potato. These studies are also helping guide genebank managers to the need for an integrated and comprehensive program for gathering wild potato species.
Molecular biology, crop physiology, and postharvest quality
Jiwan Palta’s program led an effort to understand mechanism of action of a natural lipid that acts as a bioregulator with to help improve the shelf life of fruits, flowers and vegetables. Palta and students discovered that a natural lipid lysophosphatidyl-ethanolamine (LPE) is not only able to accelerate ripening of cranberry but also prolong shelf life during storage. LPE has now been shown to be effective in a wide variety of fruits as well as prolonging the shelf life of cut flowers.
In collaboration with Jiming Jiang’s group, Dr. Paul Bethke’s group launched a major effort to reduce tuber reducing sugar and asparagine contents by specifically silencing potato genes using RNA interference (RNAi). They discovered that silencing the vacuolar acid invertase gene dramatically decreased tuber reducing sugar contents and significantly lowered the acrylamide content in potato chips processed from the silenced lines. Most importantly, they found that the silencing of this gene does not alter potato growth and development, which could inhibit commercialization of this methodology.
The Yiqun Weng lab sequenced and release the genome of the pickling cucumber inbred line Gy14, which is an important genomic resource for the cucurbit research community. The Weng lab systematically investigated the microsatellite sequences from the Gy14 draft genome. More than 83,000 microsatellite markers were developed and publicly available. This work is the first of its kind in cucurbit crops with large-scale development of microsatellite markers from whole genome sequences and presents a very valuable tool for molecular mapping and comparative studies in cucurbit crops. Basically, there are unlimited number of easy-to-use microsatellite markers for most marker-related studies by the cucumber (and other cucurbit crops) community.
Edible and ornamental crop management and sustainable production
Jiwan Palta’s research program led an effort to improve potato tuber internal quality and storage quality by increasing tuber calcium concentration. His early research showed that potato tubers derived calcium from the soil via the roots on the tubers and stolons. Since tubers are generally calcium deficient, this research demonstrated that potato tuber quality can be improved by providing calcium nutrition to the potato tubers during the bulking period. These findings led to the development of liquid fertilizers containing soluble calcium that could be injected into the irrigation water to deliver calcium to the tuber area at the top of the hill at the tuber bulking period. This research has also led to the development of practical means to improve the potato tuber internal quality. Several commercial liquid products containing calcium are being used by potato growers in Wisconsin and elsewhere.
The Jim Nienhuis lab has released a unique root rot resistant cultivar of snap beans called ‘Accelerate’ which combines desirable plant and pod characteristics with resistance to root rot pathogens. This snap bean cultivar was originally developed as a unique root rot resistant cultivar. However, the root rot resistance provided a unique opportunity to produce organic seeds which do not require insecticides and fungicide seed treatments.
The Julie Dawson lab has led efforts to develop unique partnerships in urban and regional food systems. In particular, a recent collaboration developed by Dawson engages chefs, farmers, plant breeders, and others in the farm to table movement to examine culinary quality of vegetables and initiate dialogue among these groups. This unique collective has enabled cross-talk among important players in the food system, fostering research and outreach partnerships and improving the quality of crops available to consumers.