Mycologia
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
DOI: 10.3852/mycologia.99.1.59
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Peever, T.L.
Right arrow Articles by Kaiser, W.J.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Peever, T.L.
Right arrow Articles by Kaiser, W.J.
Agricola
Right arrow Articles by Peever, T.L.
Right arrow Articles by Kaiser, W.J.
Mycologia, 99(1), 2007, pp. 59-77.
© 2007 by The Mycological Society of America

Evolutionary relationships among Ascochyta species infecting wild and cultivated hosts in the legume tribes Cicereae and Vicieae


T.L. Peever 1
M.P. Barve
L.J. Stone

     Department of Plant Pathology, Washington State University, Pullman, Washington 99164-6430

W.J. Kaiser 2

     3394 Chickory Way, Boise, Idaho 83706

Evolutionary relationships were inferred among a worldwide sample of Ascochyta fungi from wild and cultivated legume hosts based on phylogenetic analyses of DNA sequences from the ribosomal internal transcribed spacer regions (ITS), as well as portions of three protein-coding genes: glyceraldehyde-3-phosphate-dehydrogenase (G3PD), translation elongation factor 1-alpha (EF) and chitin synthase 1 (CHS). All legume-associated Ascochyta species had nearly identical ITS sequences and clustered with other Ascochyta, Phoma and Didymella species from legume and nonlegume hosts. Ascochyta pinodes (teleomorph: Mycosphaerella pinodes [Berk. & Blox.] Vestergen) clustered with Didymella species and not with well characterized Mycosphaerella species from other hosts and we propose that the name Didymella pinodes (Berk. & Blox.) Petrak (anamorph: Ascochyta pinodes L.K. Jones) be used to describe this fungus. Analysis of G3PD revealed two major clades among legume-associated Ascochyta fungi with members of both clades infecting pea ("Ascochyta complex"). Analysis of the combined CHS, EF and G3PD datasets revealed that isolates from cultivated pea (P. sativum), lentil (Lens culinaris), faba bean (Vicia faba) and chickpea (Cicer arietinum) from diverse geographic locations each had identical or similar sequences at all loci. Isolates from these hosts clustered in well supported clades specific for each host, suggesting a co-evolutionary history between pathogen and cultivated host. A. pisi, A. lentis, A. fabae and A. rabiei represent phylogenetic species infecting pea, lentil, faba bean and chickpea, respectively. Ascochyta spp. from wild relatives of pea and chickpea clustered with isolates from related cultivated hosts. Isolates sampled from big-flower vetch (Vicia grandiflora) were polyphyletic suggesting that either this host is colonized by phylogenetically distinct lineages of Ascochyta or that the hosts are polyphyletic and infected by distinct evolutionary lineages of the pathogen. Phylogenetic species identified among legume-associated Ascochyta spp. were fully concordant with previously described morphological and biological species.

Key words: Ascochyta blight, chitin synthase, DNA sequence, glyceraldehyde-3-phosphate-dehydrogenase, internal transcribed spacer, legumes, PCR, phylogeny, translation elongation factor alpha

1 Corresponding author. E-mail: tpeever{at}wsu.edu






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2007 by The Mycological Society of America.