[Identification of a fungal isolate causing adzuki bean rust in Heilongjiang].

OBJECTIVE

The aim of the study is to identify the pathogen causing adzuki bean (Phaseolus angularis) rust in Daqing, Heilongjiang province.

METHODS

Adzuki bean rust leaves were collected from Daqing, Heilongjiang province, China. A pure culture of rust isolate ZXL01 was obtained by single pustule isolation. Its taxonomic status was determined by observing the number of germ pores of urediniospores, germ pore location and the wall thickness of teliopores, and sequencing ribosomal DNA internal transcribed spacer (rDNA-ITS).

RESULTS

Morphological studies showed that most of the urediospores of ZXL01 had two germ pores that were far from spores' equator area. The wall thickness of teliopores ranged from 2.9 to 3. 3 microm. The rDNA-ITS sequence of ZXL01 was clustered in one clade with 2 reference isolates of Uromyces vignae (GenBank accession numbers AB115718 and AB115731) at 99% bootstrap levels in the phylogenetic tree. A 500 bp amplified product was obtained by the specific primers UV-ITSF/R, which was specific for U. Vignae.

CONCLUSION

The morphological features and ITS analysis indicated that the rust fungus ZXL01 occurred on leaves of adzuki bean in Daqing was U. Vignae, and the accession number of GenBank was KM461700.