Bacterial wilt of ginger (Zingiber officinale), caused by Ralstonia solanacearum (Rs), has emerged as an important disease of ginger production in Thailand and throughout Asia. Real-time PCR assays were developed for detection of Rs in ginger rhizomes. A unique 329-bp DNA fragment from Rs biovar 4 from ginger was identified using amplified fragment length polymorphisms, and the nucleotide sequence was determined. PCR primer and probe sequences were designed for real-time PCR assays and screened against 86 strains of Rs. The primers RSAF1 and RSAR1 and probe RSP1 were shown to react with all strains of Rs race 1 biovars 3 and 4 but not biovars 1 and 2. Real-time TaqMan® PCR protocols were developed for two real-time PCR platforms, the ABI 7700 sequence detection system (Applied Biosystems, Foster City, Calif.) and the portable Smart Cycler (Cepheid, Sunnyvale, Calif.). A comparison between classical real-time PCR and real-time BIO-PCR protocols, using 15 asymptomatic ginger rhizomes collected from different fields and markets, showed that 13 and 9 were positive by standard PCR and BIO-PCR, respectively. This is the first description of a real-time PCR assay capable of detecting Rs in asymptomatic ginger rhizomes and the first report of Rs in asymptomatic ginger rhizomes being sold in markets in Thailand.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Plant Science