Geographical distribution and phenotypic and molecular characterization of Neonectria fuckeliana, associated with upper-stem cankers of Pinus radiate in Chile

Abstract

Neonectria fuckeliana is a fungus that lives in the northern hemisphere as a saprophyte or weakly pathogenic on native conifers. However, in New Zealand and Chile it is a pathogen in commercial plantations of Pinus radiata causing upper-stem cankers and malformations. The aims of this study were to determine the geographical distribution of N.fuckeliana in Chile and to characterize, phenotypically and molecularly, N. fuckeliana isolated from four geographical locations (Carahue, Toltén, Pucón and Paillaco). The geographical distribution was determined through field surveys, based on the symptoms and signs associated with the presence of the pathogen. Phenotypic characterization included the color of colonies, growth rates and size of conidia. Molecularly, the internal transcribed spacer (ITS) region of the rDNA was amplified using primers ITS5, ITS4 and NS1, NS2 and sequenced. According to the results, N.fuckeliana is distributed along > 450 km in the coast from Biobío Region (5860100N - 627358E 18H) to Los Lagos Region (5423863N - 636153E 18G) in Chile. Phenotypically, three colors of colonies were identified: red, yellow and pale yellow; red being the predominant (> 70 %) in all locations. In addition, it was determined that isolates recovered in Region of La Araucanía had higher growth and conidia sizes than those of Los Ríos Region. Molecular characterization confirmed the identification of N. fuckeliana, with 99 % identity with sequences of N.fuckeliana from Europe and New Zealand deposited in Genbank (KJ022020 and HQ840404) without genetic differences among Chilean isolates obtained in this study.