| Abstract Detail
Potato Genomics - Afternoon Huang, Sanwen [1], Xu, Jianfei [1], Xin, Cuihua [1], Vleeshouwers, Vivianne [2], van der Vossen, Edwin [2], Huigen, Dirkjan [2], Qu, Dongyu [1], Visser, Richard G.F. [2], Jacobsen, Evert [2]. High allelic diversity of the major late blight resistance complex in potato implicates a novel strategy for disease management. THE oomycete pathogen Phytophthora infestans was the cause of the Irish potato famine in 1845 and it is still a major global threat to the most important non-cereal crop potato. Since the beginning of the 20th century, great effort has been put into the introgression of single dominant resistance (R) genes from wild species, particularly from Solanum demissum. Although initially promising, these race-specific R genes (R1-R11) in the end only provided short-lived protection in the field when deployed separately. Despite the fact that single S. demissum derived R genes are not durable when introgressed into cultivated potato, it has been shown that this wild species displays a durable resistance at the population level under natural conditions at the Toluca Valley of Mexico, which is considered as a center of diversity of the pathogen. Here we demonstrate that eight of the eleven characterized late blight R specificities from S. demissum (R3 and, R5-11) are conferred by allelic versions of the major late blight resistance complex (MLB) on the short arm of chromosome 11. These unexpected findings suggest that the multiple allelism of this major complex locus is the natural mechanism for late blight control in wild S. demissum populations. The R3 haplotype has been well characterized and one of the two functional R genes (R3a and R3b) has been isolated. A physical map spanning about 3 Mb in the MLB has been constructed. Sequencing of several BACs revealed that all R gene-like sequences found in the region are homologs of the cloned R3a gene. Allele mining is being applied to isolate functional R genes in other haplotypes. Our final aims are to create R gene polyculture using GMO and to simulate the multiple allelism of the MLB for disease control.
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1 - Institute of Vegetables and Flowers, Chinese Academy of Agricultural S, No. 12 Zhongguancun Nandajie, Beijing, 100081, China
2 - Wageningen University, Graduate School Experimental Plant Sciences, Laboratory of Plant Breeding, Department of Plant Sciences, Droevendaalsesteeg 1, Wageningen, 6708PB, The Netherlands
Keywords:
Potato
Late Blight
R gene polyculture.
Session: SAT09-8
Location: Hall of Ideas Room I/Monona Terrace
Date: Wednesday, July 26th, 2006
Time: 4:00 PM
Abstract ID:345 |
