Locations of a smut fungus, Urocystis tranzscheliana in host plant, Primula sieboldii

Abstract

Primula sieboldii (Primulaceae) is a common plant grown in woodlands of Japan and listed as an endangered species. A smut fungus, Urocystis tranzscheliana has been reported to cause systemic infection of this plant and destroys its seed production because this fungus produces sori in its ovaries. However, locations and behavior of the fungus in the plant have not been clarified. Specific primers for PCR detections of this fungus were designed and its locations in different tissues of the plant were examined. The fungus was detected from rhizomes, scapes and flowers in infected plants, but not detected from roots, rachises and leaves. The fungus was also detected in rhizomes of ramets originated from infected plants. Fungal DNA was not amplified in any tissues of non-infected plants. These results suggest that the fungus survives in rhizomes in infected plants and moves to flower organs through new flower buds and scapes along with plant growth. The fungus also transmits to new ramets through asexual buds.