| Potato (Solanum tuberosum) is one of the most important crops grown in Washington State. In 2011, Washington growers raised 160,000 acres of potatoes with an average yield of 615 CWT per acre, 98 CWT total, with a farm gate value of over ;My research reproduced this phenotype under controlled conditions and demonstrated the tuber/seed transmission and proved modified Koch's postulates. Moreover, PVS infection resulted in similar severe symptoms in late blight resistant (LBR) breeding line LBR4106 (A95053-61). To better understand this phenomenon and to characterize PVS at biological and molecular levels, the complete nucleotide sequence of the PVS isolates from Defender and LBR4106 were determined. In my studies, Nicotiana occidentalis-37B was recognized as a good biological indicator for identifying severe phenotypes of PVS. Host response studies of PVS were done by screening LBR breeding lines, selected commercial cultivars, and the pedigree of LBR breeding lines. The results indicated LBR potatoes appear to be susceptible to PVS infection. To further investigate the potential interactions between these two pathogens and the resulting response, detached leaves of Defender and Ranger Russet were inoculated with P. infestans and/or PVS. The amount of sporulation and the extent of lesion expansion were measured to estimate the severity of late blight. The incidence of late blight increased with PVS infection in Defender suggesting potential interaction between PVS and Defender impacting the outcome to break late blight resistance. The genetic diversity studying of PVS was also carried out by analysis PVS isolates on the world wide basis. The results indicated a broad genetic diversity and multiple phenotypes of PVS. Furthermore, a full-length PVS clone was established for using reverse genetic approaches to identify the molecular determinant(s) in the PVS genome that are responsible for the differential responses in potato genotypes. |
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