Archivio Journal of Plant Pathology

Abstract:

In September 2009, in commercial greenhouse production of phalaenopsis orchid (Phalaenopsis lueddemanniana) in the Lodz region (Poland), atypical leaf spot symptoms were observed on about 15% of the plants. On 7-month-old leaves large, brown, sunken spots surrounded by yellow, water-soaked tissue, were observed. Gram-negative bacteria causing hypersensitivity reaction on tobacco, but not possessing pectolytic properties, were isolated from the brown spots. Sequence analysis of the 16S rDNA gene fragment, selected phenotypic characteristics and a pathogenicity tests on healthy phalaenopsis plants led to the conclusion that Acidovorax cattleyae is the causal agent of orchid brown spot in Poland. Analysis of genetic diversity of tested isolates by PCR-MP technique revealed only small differences between the studied isolates.