Molecular detection of Erwinia psidii in guava plants under greenhouse and field conditions

作者：da Silva Claudenia Ferreira; Uesugi Carlos Hidemi; Bassay Blum Luiz Eduardo; dos Anjos Marques Abi Soares; da Silva Velloso Ferreira Marisa Alvares

来源：Ciencia Rural, 2016, 46(9): 1528-1534.

DOI：10.1590/0103-8478cr20151600

• BIO-PCR
• diagnosis
• guava bacterial blight
• PCR
• Psidium guajava

Erwinia psidii causes bacterial blight of guava (Psidium guajava), an important disease of this crop in Brazil. The pathogen affects branches and twigs of guava trees, reducing yield significantly. Bacterial dissemination often occurs through contaminated but asymptomatic propagating plant material. The objectives of this research were to evaluate the use of BIO-PCR and conventional PCR to detect E. psidii in inoculated guava plants grown in a greenhouse and in symptomatic and asymptomatic trees from guava orchards. Erwinia psidii strain IBSBF 1576 was inoculated (107CFU mL(-1)) into young guava shoots and plant tissue was analysed at 0, 5, 10, and 15 days after inoculation. Symptoms were observed after 5 days and all inoculated shoots were PCR positive at all times, by both BIO-PCR and conventional PCR. Under natural infection conditions, 40 samples were tested by BIO-PCR from each of three guava orchards, 20 showing symptoms and 20 asymptomatic. PCR was positive for 58 out of 60 symptomatic samples (96.7%) and for 6.7% of asymptomatic samples, showing that the method can be used to detect the pathogen at early stages of infection. This PCR method may be used as a diagnostic tool to assess bacterial survival, dissemination and disease outbreaks.

• 出版日期2016-9