GREENHOUSE TESTING OF TRANSGENIC PEANUT FOR RESISTANCE TO SCLEROTINIA MINOR

Authors: Chamberlin, Kelly; PAYTON, MARK - OKLA STATE UNIVERSITY; Melouk, Hassan

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2004
Publication Date: 6/1/2005
Citation: Chenault, K.D., Payton, M.E., Melouk, H.A. 2003. Greenhouse testing of transgenic peanut for resistance to Sclerotinia minor. Peanut Science. 30(2):116-120.

Interpretive Summary: Fungal diseases of peanut such as Sclerotinia blight are responsible for increased production costs and yield losses of up to 50% for peanut producers in the Southwest, North Carolina and Virginia. Only a few cultivars with moderate disease resistance have been developed through traditional breeding practices. One such cultivar, SW Runner, is extremely yresistant to Sclerotinia blight but produces small, undesirable seed. There is an urgent need for developing peanut cultivars that are not only resistant to a broad spectrum of fungal pathogens, but also produce desirable seed. Anti-fungal traits have been introduced into Okrun, a popular peanut cultivar that produces desirable seed but is susceptible to Sclerotinia blight. In this study, plant lines possessing these traits were evaluated in the greenhouse for resistance to the fungus causing Sclerotinia blight. While most plant lines were not distinguishable from the susceptible cultivar in their response to fungal infection, several lines did show an increased resistance to Sclerotinia blight. In particular, plant line 133 produces seed that shells and grades similar to the cultivar Okrun and demonstrates a level of resistance to fungal infection similar to that of the moderately resistant cultivar SW Runner. The production and commercial release of such peanut lines with quality yield and increased fungal resistance would be extremely beneficial to the peanut industry. These studies will facilitate the screening of such potentially economically important peanut lines.

Technical Abstract: Fungal diseases of peanut, such as Sclerotinia blight caused by Sclerotinia minor, are responsible for increased production costs and yield losses of up to 50% for peanut producers in the Southwest, North Carolina and Virginia. A few cultivars with moderate disease resistance, such as Southwest Runner, have been developed through traditional breeding practices. There is an urgent need for developing peanut cultivars that are resistant to the broad spectrum of fungal pathogens that pose a recurring threat to peanut health. Transgenic peanut plant lines containing anti-fungal genes have been produced from somatic embryos of the susceptible cultivar Okrun, and have been tested under greenhouse conditions for resistance to S. minor by inoculation with a mycelial plug. Disease symptoms, such as lesion length and vascular collapse were recorded for transgenic peanut, non-transgenic Okrun, and Southwest Runner plants. The reaction of the majority of transgenic peanut lines to S. minor infection was indistinguishable from that of the susceptible cultivar Okrun. However, three transgenic lines did show a significant increase in resistance to S. minor compared to the cultivar Okrun, and one line in particular demonstrated levels of resistance comparable to the moderately resistant cultivar Southwest Runner.