Chrysomyxaledi, a new rust fungus sporulating in cone scales ofPicea abiesin Finland

Abstract

Seasonal fruiting and sporulation of cone rusts were investigated in Norway spruce cones during the growing season of 2007, a year after an excellent cone crop and a severe outbreak of rust. Current-year and 1-year-old cones were collected bimonthly to monthly from case-stands in southern and northern Finland and checked for rust fruitbodies. A previously unreported species of rust formed spermogonia and aecia, and sporulated on the cone scales of Norway spruce in two study areas. Morphologically, the rust was distinct from other spruce cone rusts and, based on ultrastructure of aecia and aeciospores, most closely resembled Chrysomyxa ledi. Molecular analysis of the aeciospores confirmed that the rust belonged to the C. ledi/C. rhododendri complex. The rust fruited frequently but only colonized a few scales per cone and presumably had a minor effect on cone development and seed crop.

Germination capacity ofThekopsora areolataaeciospores and the effect of cone rusts on seeds ofPicea abies

“…This suggests that the effect of C. ledi on seed development is minimal or nonexistent. This is to be expected because the rust fruits and sporulates on individual cone scales rather than colonizing the entire cone (Kaitera et al 2010;Kaitera 2013). Based on these results, we conclude that the quality of the Norway spruce seed crop could be improved if older infected cones were also removed during the cone harvest.…”

“…Most cones were collected between late September and early October, and subsequently stored at − 20°C. Rust identification was based on the standard characters of aecial and aeciospore morphology (Gäumann 1959;Kaitera et al 2009Kaitera et al , 2010. Soon after collection, ca.…”

“…& Schw.) de Bary, and C. woroninii Tranz (McBeath 1984;Kaitera et al 2009Kaitera et al , 2010. Thekopsora and Chrysomyxa are heteroecious rusts widely distributed in the northern hemisphere (Savile 1950;Gäumann 1959;Ziller 1974).…”

Two new Chrysomyxa rust species on the endemic plant, Picea asperata in western China, and expanded description of C. succinea

“…Detailed descriptions of the morphology of the two species are given in the taxonomy section. Morphology of the two rust fungi was compared with descriptions of other known Chrysomyxa species in taxonomic references (Pethybridge 1918, Takahashi & Saho 1985, Crane 2001, 2003, 2005b, Tillman-Sutela et al 2004, Kaitera et al 2010, Feau et al 2011. The two rust fungi differed from other Chrysomyxa species in aeciospore surface ornamentation and aecial peridium.…”

“…Gross morphology of the aecia and aecial perdium may be useful taxonomical characters for several species, but the morphology of teliospores and basidiospores are fairly consistent within a species. Taxonomic studies and DNA barcoding of Chrysomyxa species have been conducted in Europe, Japan and North America (Pethybridge 1918, Takahashi & Saho 1985, Crane 2001, 2003, 2005a, 2005b, Tillman-Sutela et al 2004, Kaitera et al 2010, Feau et al 2011, but morphological taxonomy at the species level is confusing due to overlapping features. Therefore, comprehensive taxonomic studies including molecular data are required.…”