Seiridium (Sporocadaceae): an important genus of plant pathogenic fungi

Abstract

The genus Seiridium includes multiple plant pathogenic fungi well-known as causal organisms of cankers on Cupressaceae. Taxonomically, the status of several species has been a topic of debate, as the phylogeny of the genus remains unresolved and authentic ex-type cultures are mostly absent. In the present study, a large collection of Seiridium cultures and specimens from the CBS and IMI collections was investigated morphologically and phylogenetically to resolve the taxonomy of the genus. These investigations included the type material of the most important Cupressaceae pathogens, Seiridium cardinale, S. cupressi and S. unicorne. We constructed a phylogeny of Seiridium based on four loci, namely the ITS rDNA region, and partial translation elongation factor 1-alpha (TEF), β-tubulin (TUB) and RNA polymerase II core subunit (RPB2). Based on these results we were able to confirm that S. unicorne and S. cupressi represent different species. In addition, five new Seiridium species were described, S. cupressi was lectotypified and epitypes were selected for S. cupressi and S. eucalypti.

Sporocadaceae, a family of coelomycetous fungi with appendage-bearing conidia

“…M. Ascus, ascospores and conidia of Seiridium (CBS 140403, Jaklitsch et al. 2016; CBS 343.97, from Bonthond et al. 2018).…”

“…1998) and T1/Bt2b for tub2 (Glass and Donaldson, 1995, O'Donnell and Cigelnik, 1997). The PCR mixtures for ITS, LSU, tef-1α and tub2 were prepared as in Bonthond et al. (2018).…”

“…At least 30 measurements were taken for each structure, and the mean value, standard deviation and minimum–maximum values were given, with the extreme measurements in parentheses. Length of the conidia was measured from the base of the basal cell to the base of the apical appendage, and conidial width was measured at the widest point of the conidium (Bonthond et al. 2018).…”

Fungal Planet description sheets: 1042–1111

“…Notes — Seimatosporium and allied genera have recently been revised ( Bonthond et al 2018 , Liu et al 2019 ), with 23 genera being accepted in Sporocadaceae . Nothoseiridium podocarpi is allied to Seiridium (5-septate, appendaged conidia) and Nonappendiculata (3-septate, non-appendaged conidia), but is distinct in having 4-septate, fusoid conidia with unbranched, excentric apical and basal appendages.…”

Fungi infecting woody plants: emerging frontiers

“…known as cypress canker ( Graniti 1998 , Barnes et al 2001 ). Based on a morphological and phylogenetic study, Bonthond et al (2018) have re-evaluated the taxonomy of Seiridium . Both S. cardinale and S. unicorne are redescribed, with a reference strain designated for each.…”