Resumo

GARCIA BASTIDAS, NEVAR et al. Detection and Quantification of Spongospora subterranea f. sp. subterranea in Bait Plants and Potato Fields in Colombia using qPCR. Acta biol.Colomb. [online]. 2013, vol.18, n.1, pp.121-136. ISSN 0120-548X.

In recent years, potato crops (Solanum tuberosum, S. phureja) have been seriously affected by powdery scab; a disease caused by Spongospora subterranea f.sp. subterranea (Sss). In Colombia, asymptomatic detection of Sss has been achieved with bait plants, PCR of ITS regions and ELISA tests. Unfortunately, these techniques have low sensitivity and may require long processing times. In this work, Quantitative real time PCR (qPCR) was tested for detection of Sss using different sets of primers. Primers SsTQF1-SsTQR1, Spon421F-Spon494R and SscolF-SscolR (designed in this study), were tested using SYBR Green®, while primers SponFSponR were tested using the Taqman® probe SponP. Primers Spon421F-Spon494R were discarded due to lack of specificity. Standard curves were obtained from serial dilutions of cystosori. The 20 N. benthamiana and potato bait plants evaluated tested positive for Sss using primers SsTQF1-SsTQR1 (Ct: 10.57-29.34) and SscolF-SscolR (Ct: 14.39-34.08) and 19 samples were positive with primers SponF-SponR-SponP, with Ct values ranging between 15,63 and 38,93. Sss was detected in 17 out of 20 root samples from potato crops in La Unión (Antioquia) using primers SscolF-SscolR, with an estimated concentration of 6470 to 1,39x10¹⁰ cystosori/ mL. These results suggest high levels of Sss in the potato fields from this region and recall the importance of strengthening seed-certification programs in Colombia.

Palavras-chave : powdery scab; real time PCR; Solanum phureja; Solanum tuberosum.

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