An Assessment of Nested PCR to Detect Phytoplasmas in Imported Dormant Buds and Internodal Tissues of Quarantined Tree Fruit Germ Plasm

Abstract

Nested polymerase chain reaction (PCR) assays were evaluated for use on a routine basis in a quarantine program to detect phytoplasmas in dormant fruit tree scionwood collected during the winter season. Phytoplasmas associated with peach yellow leaf roll, Western X, apricot chlorotic leaf roll, plum leptonecrosis, and apple proliferation diseases were detected in all known infected sources. Phytoplasmas in Prunus spp. were readily detected in both dormant bud and internodal tissues. Use of nested PCR versus a single primer pair resulted in electrophoresed PCR products that were easier to interpret. The nested PCR procedure has replaced 3-year tests with grafts on sensitive indicators to detect this group of pathogens.

Distribution patterns of mulberry dwarf phytoplasma in reproductive organs, winter buds, and roots of mulberry trees

“…(Seemüller et al 1998), western X-phytoplasma of Prunus spp. (Waterworth and Mock 1999), and pear decline phytoplasma of pear trees (Garcia-Chapa et al 2003). Our results also suggest that winter buds are important as an overwintering site for MD phytoplasma.…”

Impacts of Molecular Diagnostic Technologies on Plant Disease Management

“…Detection of some pathogens using traditional techniques that are serology-based is often limited to certain months of the year and to certain parts of the plant (72). PCR detection facilitates reliable testing at any time of year since the sensitivity of the test allows detection of the pathogen in most tissue including dormant woody material (71,173). This ability to reliably detect pathogens in dormant budwood should contribute significantly to preventing the spread of pathogens because of the increased sensitivity and reduction of time imported germplasm spends in quarantine (173).…”

“…PCR detection facilitates reliable testing at any time of year since the sensitivity of the test allows detection of the pathogen in most tissue including dormant woody material (71,173). This ability to reliably detect pathogens in dormant budwood should contribute significantly to preventing the spread of pathogens because of the increased sensitivity and reduction of time imported germplasm spends in quarantine (173). Increased sensitivity has also been achieved by taking advantage of the synergies derived from combining technologies.…”

“…In the case of specific detection of Erwinia carotovora subsp. atroseptica, regions of repetitive DNA were identified and labeled to produce very specific probes (173). This level of specificity is essential for proper management and control of the related diseases.…”

Amarelo da ameixeira: caracterização molecular do fitoplasma e modelo de colonização do hospedeiro

“…Em relação a 'Candidatus Phytoplasma pronurum', 'Candidatus Phytoplasma pyri' e 'Candidatus Phytoplasma mali', resultados obtidos por diversos autores são concordantes com a proposição de Garcia-Chapa et al (2003), uma vez que estes fitoplasmas permanecem na parte aérea de ameixeira, damasqueiro, pereira e macieira durante o período de dormência, ao passo que os mesmos persistem durante o ano todo nas raízes (SEEMÜLLER et al, 1998;JARAUSCH et al, 1999;ERREA et al, 2002;WATERWORTH;MOCK, 1999). No Brasil, estudos foram realizados na cultura do milho para as doenças causadas por espiroplasma (enfezamento pálido) e fitoplasma (enfezamento vermelho), onde constataram que a incidência e os danos causados por essas doenças são influenciados pelo clima, principalmente por temperaturas elevadas, em torno de 27/18 ºC e de 31/25ºC (dia/noite) (NAULT, 1980;OLIVEIRA et al, 2005).…”