Diversity of Cryphonectria parasitica in western Spain and identification of hypovirus‐infected isolates

Abstract

Summary Isolates of the chestnut blight fungus Cryphonectria parasitica were obtained from 44 localities in four provinces in Western Spain and characterized for vegetative compatibility (vc) types, mating types and the presence of Cryphonectria hypovirus 1 (CHV1). Among the 1232 isolates recovered from chestnut blight cankers, 11 vc types were identified: five known vc types included in EU1 to EU74 (EU1, EU11, EU12, EU28 and EU66) and six unknown vc types (CL4, CL5 CL6, CL8, CL9 and CL10). The number of vc types found per province varied between two and seven. The vc type EU11 was present in all provinces and accounted for 48.9% of all isolates. EU1 was detected in three provinces and accounted for 39.1% of the isolates. The vc types EU12, EU66, CL5 and CL6 were present in one or two provinces and comprised between 2.4% and 3% of the isolates. The other vc types were represented by only one or very few isolates. The mating type MAT‐1 was largely dominant in the provinces Leon and Avila, while both mating types MAT‐1 and MAT‐2 were found in Salamanca and Zamora. Fourteen hypovirus‐infected C. parasitica isolates were found, nine were in vc type EU1 and five in EU11, and they were detected only in the province León. All isolates analysed contained the French hypovirus subtype CHV1‐F1.

Cryphonectria parasitica isolates of the same vegetative compatibility type display different rates of transfer of CHV1 hypovirus

“…The Italian subtype (subtype I) is the most widespread (Italy, Switzerland, France, Hungary, Croatia, Bosnia and Herzegovina, Macedonia, Turkey, Greece and Spain) (Allemann et al 1999;Sotirovski et al 2006;Krstin et al 2008;Robin et al 2010;Krstin et al 2011;Akilli et al 2013;Castaño et al 2015). Other subtypes of CHV1 are found in Germany (subtype D), France (Subtypes F1 and F2) and Spain (Subtypes F1 and E) (Allemann et al 1999;Gobbin et al 2003;Zamora et al 2012). Horizontal transmission of the virus is also influenced by the transmission ability of the CHV1 virus (Deng et al 2009).…”

“…In Castilla y León, hypovirulent strains were detected in 2005 (Montenegro et al 2008) and in 2006(Zamora et al 2012). These strains appeared in a few chestnut stands in the province of León and correspond to the most extended vc types in the whole region (EU1 and EU11 infected by CHV-1 subtype F1) (Zamora et al 2012). In the autonomous region of Castilla y León, virulent C. parasitica strains are also found in chestnut stands in León, Zamora, Salamanca and Ávila and some of these belong to vc types other than EU1 and EU11.…”

Short communication: Effect of mycoviruses on growth, spore germination and pathogenicity of the fungus Fusarium circinatum

“…In fact, some mycoviruses can be used as biocontrol agents by promoting hypovirulence in their host, with the bestknown case in forest pathology being the chestnut blight caused by Cryphonectria parasitica (Carey et al, 2005;Zamora et al, 2012). Mycovirus infections can lead to induction of a cryptic state (asymptomatic), reduction of mycelial growth, change in the colour of the colony or even alteration of the specific structure formation (Rodríguez-García et al, 2014).…”

Chancro Resinoso Del Pino (Fusarium Circinatum) Historia, Evolución, Dispersión Y Estrategias De Manejo

“…Cuando CHV-1 infecta Cryphonectria parasitica que causa debilidad, lo que reduce el crecimiento del micelio y la esporulación (Zamora, González Casas, Dueñas, San Martin, & Diez, 2017;Zamora, Martín, Rigling, & Diez, 2012). Hongos infectados sólo son capaces de formar superficial (curación) cancros en los tallos, y por lo tanto los árboles pueden sobrevivir a la enfermedad.…”