Day 1 :
U.S. Department of Agriculture
Time : 09:15-10:00
Present works in U.S. Department of Agriculture, Western Regional Research Center, Agricultural Research Service
The conventional source of hydroxy fatty acid (HFA) is from castor (Ricinus communis), 90% of castor oil is ricinoleic acid (18:1OH). Ricinoleic acid and its derivatives are used as raw materials for numerous industrial products, such as lubricants, plasticizers and surfactants. The production of castor oil, however, is hampered by the presence of the toxin ricin and hyper-allergic 2S albumins in its seed. Lesquerella (Physaria fendleri), being developed as a new industrial oilseed crop in the southwestern region of the United States, is valued for its HFA, lesquerolic acid (20:1OH), in seed. As lesquerella does not contain toxic compounds, its oil represents a safe source of HFA. To understand HFA synthesis and regulation in lesquerella, we investigated morphological and physiological changes, as well as temporal details of fatty acid composition and gene expression during seed development. Also we have developed the 1st lesquerella seed transcriptome that provides a global gene expression profile for identifying key targets for metabolic engineering in lesquerella. We found that the synthesis of 20:1OH is regulated largely by gene expression of PfKCS3. By suppressing the expression of PfKCS3 in leaquerella, 18:1OH was increased from wild-type (wt) 1% to 26% in transgenic seed oil. Castor oil has 90% 18:1OH which occupies all three sn positions of most TAGs, while lesquerella oil contains 60% 20:1OH mostly located at sn-1 and sn-3 of TAGs. In order to improve HFA levels in lesquerella seeds, a castor lysophosphatidic acid acyltransferase 2 gene (RcLPAT2) capable of acylating HFA to the sn-2 position of TAGs was introduced into lesquerella. Analysis of transgenic lesquerella seed TAGs showed that RcLPAT2 was able to incorporate HFA to the sn-2 position of TAG and consequently, oil accumulated more of TAGs with all three sn positions occupied by HFA. The results enhanced our understanding of plant lipid metabolism and provided invaluable guidance for future research not only for enhancing HFA content in lesquerella, but also for HFA production in other oilseed crops.
Professor University of Novi Sad Serbia
Time : 10.00-10.45
Faculty of Agriculture of the University of Novi Sad. Honorary Member for International Sunflower Association.
Global sunflower breeding can be divided into two periods. The first one, spanning 1910 to 1970, was when the Russian Empire and the USSR developed productive varieties with a high seed oil content, resistance to the dominant diseases, the sunflower moth, the broomrape races of the time, and broad adaptability. Also, during the same period, varieties were developed in Argentina that were suitable for the conditions of South America. The second period, from 1970 until the present, was marked by the discovery of sources of cytoplasmic male sterility and the restorer genes, which has enabled the use of the phenomenon of heterosis and the development of sunflower hybrids. This period is characterized by the establishment of important breeding programs in public institutions and private companies. The result of their work is the development of a large number of productive hybrids, which have helped the increase of the acreage in sunflower on a global scale and the increase of yields and their stability.Of all the field crops, the sunflower has the largest number of wild relatives within the genus Helianthus. There are diploid, tetraploid, and hexaploid wild sunflower species. Among them, the perennial species are more common than the annual ones. Using interspecific hybridization, a number of desirable traits have been incorporated into cultivated sunflower genotypes from the wild species. Especially of note is the contribution of the wild species to sunflower breeding for resistance to biotic and abiotic stresses. An important place in sunflower breeding belongs to spontaneous and induced mutations, the contribution of which has been manifested the most in the change of oil quality (fatty acids and tocopherols). High-oleic hybrids have been developed, as have been the hybrids with different types and levels of tocopherols (alpha, beta, gamma, and delta).