The Molecular Plant Breeding Laboratory
One of the major challenges facing agriculture is feeding an exponentially growing worldpopulation, which is expected to exceed 9.3 billion by 2050, with limited resources andunfavorable environmental conditions. This multifactorial challenge is not confined solely toincreasing productivity, but rather, includes goals such as improved nutritional quality andincreased food safety. These factors are an important consideration in order to improve thehealth of the general public. Insect and pest control are important issues as well. At the PeeDee Research and Education Center (PDREC) we are engaged in finding solutions to these major agricultural problems by utilizing molecular breeding approaches.
I) Development of nutritionally enhanced, allergen-free or non-immunogenic crops
Dietary disorders which include sensitivity, intolerance, and allergenicity to a food or ingredient are conditions in which the immune system mistakenly recognizes food as a threat, triggers an immune response. Indigestible protein segments called “peptides” are often responsible for such reactions. Symptoms and the severity of the immune response vary indifferent individuals. The sensitivity to a food, however, may increase or decrease within an individual depending on exposure to various environmental factors.
These factors include exposure to infectious agents or major changes in dietary patterns, both of which can affect gut microbiota. In general, exposure of susceptible individuals to immunogenic foods also enhances their vulnerability to other disorders such as diabetes and some forms of cancer. Eight foods, dubbed the “Big Eight”, have been recognized as major allergens by the US Food and Drug Administration (FDA). Soybean, peanut, and wheat are included in the Big Eight and are also three of the major food crops grown in South Carolina. In 2016, over 420,000 acres of soybean, 110,000 acres of peanut, and 60,000 acres of wheat were grown in the state. Collectively, food-borne disorders affect 12% of the US population, which is nearly 15 million individuals (8% children and 4% adults). This means that about 1 in 13 children, under the age of 18, is affected by a food allergy. The average cost to support children in the US with such allergies is nearly $25 billion per annum.
Given the magnitude of the problem we sought 1) to find hypoallergenic peanut genotypes within the USDA peanut germplasm collection. This is being done in collaboration with Dr. Dan Anco of the Edisto REC, Dr. Wonkeun Park of the PDREC, and Dr. Shyam Tallury of the USDA-ARS. This activity is supported by the SC Peanut Board. 2) to develop allergen-free soybean mutants by applying conventional breeding approaches. This research is performed in collaboration with Dr. Ben Fallen of the PDREC and Dr. Dil Thavarajah of Clemson University. 3) to develop celiac-safe wheat genotypes using transgenic, non-transgenic, and genome-editing approaches. This is being done in cooperation with Dr. Nii Ankrah and Dr. Richard Koenig of Washington State University (Pullman) and Drs. Hong Luo, Charles Rice, and Nishanth Tharayil of Clemson University. This activity is supported by a grant from the Life Sciences Discovery Fund (LSDF).
II) Increasing genetic diversity in cotton germplasm and identification of cotton genotypes with annual growth habit
Both of these research projects were developed in view of increasing cotton productivity. The first project aims to increase the frequency of genetic recombination during gametogenesis in order to facilitate the exchange of genetic material between distantly related chromosomes. This will allow for the enhancement of genetic diversity in upland cotton. This project is done in collaboration with Dr. Todd Campbell of the USDA-ARS and Dr. Chris Saski of the Clemson University Genomics Institute (CUGI).
The second project is an effort to channel metabolites from source tissue to sink tissue (cotton bolls) by selecting for plants with a determinate or annual growth habit. This project is performed in collaboration with Dr. Mike Jones of the PDREC and Dr. Chris Saski of the CUGI. Both projects are supported by Cotton Incorporated.
III) Development of a novel eco-friendly pesticide to control sugarcane aphid, a major insect pest of sorghum
Sorghum production has been severely affected by the sugarcane aphid, which has devastated sorghum fields in the Southeast with yield losses up to 70%. Utilizing the recent advances in the field of RNA interference, and taking leads from the industry, genes targeted by major chemical pesticides are targeted instead by double-stranded RNA molecules. This research is performed in collaboration with Dr. Francis-Reay Jones of the PDREC and is supported by Bayer Crop Science.
IV) Breeding for recurrent flowering in rose and peach
Seasonal flowering and a long juvenile phase are inversely related and present a major problem in the breeding of woody perennials. Both of these traits are controlled by two major floral regulators, TERMINAL FLOWER (TFL) and FLOWERING LOCUS T (FT). In order to reduce the juvenile phase and develop recurrent flowering rose and peach genotypes, we decided to finetune the expression levels of these two flowering genes. This research is performed in collaboration with Dr. Ksenija Gasic of Clemson University.