Comparison of Diplodia Tip Blight Pathogens in Spanish and North American Pine Ecosystems.

Ana Aragonés,Rosa Raposo,Nebai Mesanza,Stephen Wyka,Tania Manzanos,Margarita Elvira-Recuenco,Denise R Smith,Glen Stanosz,Eugenia Iturritxa,Michael Simmons,Mónica Berbegal,Isabel A Munck

doi:10.3390/microorganisms9122565

Abstract

Diplodia tip blight is the most ubiquitous and abundant disease in Spanish Pinus radiata plantations. The economic losses in forest stands can be very severe because of its abundance in cones and seeds together with the low genetic diversity of the host. Pinus resinosa is not genetically diverse in North America either, and Diplodia shoot blight is a common disease. Disease control may require management designs to be adapted for each region. The genetic diversity of the pathogen could be an indicator of its virulence and spreading capacity. Our objective was to understand the diversity of Diplodia spp. in Spanish plantations and to compare it with the structure of American populations to collaborate in future management guidelines. Genotypic diversity was investigated using microsatellite markers. Eight loci (SS9–SS16) were polymorphic for the 322 isolates genotyped. The results indicate that Diplodia sapinea is the most frequent Diplodia species present in plantations of the north of Spain and has high genetic diversity. The higher genetic diversity recorded in Spain in comparison to previous studies could be influenced by the intensity of the sampling and the evidence about the remarkable influence of the sample type.

Highlights

Diplodia scrobiculata detection is considered something exceptional in this region where both Diplodia species co-occurred in the same tree
Limited distribution in the USA and Mexico, where it was found to coexist with D. sapinea
Spain detected in this study was extremely stands in northern Spain

Summary

Introduction

Don. is the most widespread exotic forest species susceptible to the fungal pathogen Diplodia sapinea (Fr.) Fuckel Diplodia pinea (Desm.) Kickx., Sphaeropsis sapinea (Fr.:Fr./Dyko and Sutton)) in Spain. The first record of the introduction of P. radiata D. Don in Spain is its presence in a garden in Lekeitio (Bizkaia) in the mid-19th century [1]. It was considered an appropriate candidate for forestry in Spain based on previous acclimatization studies [2]. The first plantations of this tree species in Spain were established at the end of the 19th century in the Basque Country. A policy of reforestation of public lands [3] led to an increase in the area covered by plantations, which reached

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Conclusion