Clarification on rust species potentially infecting pea (Pisum sativum L.) crop and host range of Uromyces pisi (Pers.) Wint Eleonora Barilli a, * , Ana Moral a , Josefina C. Sillero b , Diego Rubiales a a Institute for Sustainable Agriculture, CSIC, Apdo. 4084, E-14080 Córdoba, Spain b IFAPA, Centro Alameda del Obispo, Apdo. 3092, E-14080 Córdoba, Spain article info Article history: Received 4 July 2011 Received in revised form 4 January 2012 Accepted 8 January 2012 Keywords: Pea rust Uromyces pisi Host range abstract Rust is a serious disease of pea whose casual agent is not always understood. In this paper we studied reaction of pea accessions to seven rust species infecting closely related legumes, finding that indeed pea can be infected mainly by Uromyces pisi, followed by Uromyces viciae-fabae. Other rust species like Uromyces striatus, Uromyces ciceris-arietini, Uromyces anthyllidis and Uromyces vignae can also infect and reproduce on pea, although in a minor extent. All U. pisi isolates tested were very virulent on pea accessions, but isolates UpPt-03 and UpKeS-05 (from Palmar de Troya, Spain and Kafr-El-Sheik, Egypt respectively) were significantly most infective. In addition to this we studied in detail the host range of U. pisi by inoculating multiple accessions of various legumes with urediospores of seven isolates of U. pisi from different geographical origins. Both experiments were performed under controlled conditions. Based on the evidence presented here the host range of U. pisi is greater than previously recorded, including genotypes belonging to Cicer arietinum, Vicia articulada, Vicia ervilia and Vicia faba, which were not mentioned before. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Pea rust is a serious disease of worldwide distribution causing yield losses in pea (Pisum sativum L.). In years of epidemics, rust results in affected leaves drying up and detaching from the plant, so beans remain undeveloped and consequently yield losses can be more than 30% (EPPO, 2010). The pathogen develops in warm, humid weather and may cause significant damage when epidemics start early in the season and when springs are humid and temperate (Sillero et al., 2006; Emeran et al., 2008). Most reports refer to Uromyces viciae-fabae (Pers.) J. Schröt (syn. Uromyces fabae Pers de Bary) (Xue and Warkentin, 2001; Singh et al., 2004; Vijayalakshmi et al., 2005; Kushwaha et al., 2006) as the causal agent of pea rust. However, few observations on morphology or attempts for classification are provided in these reports. It was recently suggested that Uromyces pisi (Pers.) Wint. is the principal agent causing pea rust at least in temperate regions (Barilli et al., 2009a), what is in agreement with earlier observations by Gäumann (1959). Although pea seedling could be infected by U. viciae-fabae under controlled conditions, pea accessions were little infected under field conditions by isolates from Australia, the Netherlands, Spain or Syria (Barilli et al., 2009a). Little is known of pathogenicity on pea by other rusts species. U. pisi is macroscopically identical to U. viciae-fabae in the ure- dial stage (being urediospores responsible for disease development under field conditions causing a multi-cycling infection), but they can be distinguished by the morphology of telia and infection structures (Emeran et al., 2005; Sillero et al., 2006) as well as by molecular tools (Emeran et al., 2008; Barilli et al., 2011). It seems that U. pisi is less specialised than other Uromyces species (Gäumann, 1959; Emeran et al., 2008), but its host range has not yet been clarified. Knowledge about host range of a biotrophic fungus (as Uromyces) is of high agronomic and epidemiologic importance. In fact, one of the constraints showed by the species belonging to this genus is that several rust species may infect the same host plants ex. U. viciae-fabae and U. pisi on pea (Barilli et al., 2009b). In addition, it is possible that a rust fungus may infect a plant species that previously was thought to be resistant ex. Medicago spp. that was recently added to Uromyces ciceris-arietini host range (Stuteville et al., 2010). These features impede a clear pathogen characterisation and, as consequence, its control. The purpose of the research reported here were (i) to determine the host status of pea against other major legume rusts, (ii) to * Corresponding author. Tel.: þ34 957499211; fax: þ34 957499252. E-mail addresses: ebarilli@ias.csic.es, e.nora@libero.it (E. Barilli). Contents lists available at SciVerse ScienceDirect Crop Protection journal homepage: www.elsevier.com/locate/cropro 0261-2194/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.cropro.2012.01.019 Crop Protection 37 (2012) 65e70