Comparative susceptibility of peanut genetically engineered for sclerotinia blight resistance to non-target peanut pathogens

Field trials were conducted from 2006 to 2008 at the Tidewater Agricultural Research and Extension Center (TAREC) in Suffolk, Virginia to determine whether Blight Blocker transgenic peanut lines showed possible increased or decreased susceptibility to common peanut pathogens. Disease susceptibility was evaluated for seven transgenic lines containing a barley oxalate oxidase gene and their corresponding parental cultivars (Perry, Wilson, NC 7). In addition to Sclerotinia blight, the peanut diseases evaluated included: i) early leaf spot caused by Cercospora arachidicola, ii) Cylindrocladium black rot caused by Cylindrocladium parasiticum, iii) southern stem rot caused by Sclerotium rolfsii, iv) tomato spotted wilt virus, and v) aflatoxin levels in seeds caused by Aspergillus flavus or A. parasiticus. Results demonstrated that the susceptibility of Blight Blocker transgenic lines to common peanut pathogens was similar to that of non-transgenic cultivars, while transgenic lines provided resistance to Sclerotinia blight caused by S. minor. Transgenic lines consistently provided high levels of resistance to S. minor in all three years, however, the barley oxalate oxidase had little or no effect on the disease susceptibility to other organisms on peanut. The results of this research should provide additional evidence needed to petition for deregulation of Blight Blocker peanut lines.