Pseudopyricularia

Pseudopyricularia Klaubauf, M.-H. Lebrun & Crous, in Klaubaufet al., Stud. Mycol. 79: 109 (2014)

 

Background

Pseudopyricularia is a dematiaceous hyphomycete genus introduced by Klaubauf et al. (2014) based on the type species P. kyllingae Klaubauf, Lebrun & Crous. The genus name refers to its morphological similarity to Pyricularia. Pseudopyricularia species are plant pathogens mostly associated with sedges, but they can also occur on other plants. Pseudopyricularia taxa have been also recorded as saprobes, e.g. P. higginsii was found saprobic on dead leaves of Typha orientalis (Typhaceae) (Klaubauf et al. 2014).

ClassificationSordariomycetes, Diaporthomycetidae, Magnaporthales, Pyriculariaceae

Type speciesPseudopyricularia kyllingae Klaubauf, M.-H. Lebrun & Crous, in Klaubaufet al., Stud. Mycol. 79: 109 (2014)

Distribution – Iran, Israel, Japan, New Zealand and Philippines

Disease Symptoms – Leaf spot

            The symptoms start as minute scattered angular, water-soaked translucent spots on the lower surface of leaves, which enlarge and appear on the upper surface.

Hosts – Main pathogens on Cyperaceae (Klaubauf et al. 2014). Pseudopyricularia bothriochloae was found on Bothriochloa bladhii (Poaceae) causing angular leaf spots (Marin-Felix et al. 2017), and P. iraniana can infect leaves of Juncus sp. (Pordel et al. 2017).

Morphological based identification and diversity

Pseudopyricularia species are characterized by solitary conidiophores with mostly terminal conidiogenous cells that form a rachis with several protruding, flat-tipped denticles, and obclavate, brown, guttulate, septate conidia with a truncate, slightly protruding, not darkened hilum (Klaubauf et al. 2014). Ellis (1976) considered Pyricularia higginsii (presently referred to as Pseudopyricularia higginsii) as a synonym under Dactylaria. However, it was not accepted by subsequent studies (Bussaban et al. 2005; Klaubauf et al. 2014). Some Pseudopyricularia species were formerly described in Pyricularia. Several isolates previously recognized as Pyricularia higginsii were later confirmed as a species complex which represents three related species (P. cyperi, P. kyllingae, P. higginsii) belonging to Pseudopyricularia (Klaubauf et al. 2014). Pyricularia bothriochloae was also transferred to Pseudopyricularia bothriochloae (Marin-Felix et al. 2017). Species of Pseudopyricularia can be mainly differentiated from Pyricularia sensu stricto by having short, determinate, brown conidiophores with an apical rachis with flat-tipped denticles. However, because of the similarity of conidial characters, morphological species identification of Pseudopyricularia is challenging. Conidial characters cannot be used alone as a taxonomic criterion at generic level without phylogenetic analyses (Klaubauf et al. 2014).

Molecular based identification and diversity

DNA sequence data is crucial for species identification in Pseudopyricularia and morphology similar taxa. Previous studies were mainly based on morphological identification. The order Magnaporthales previously comprised the monotypic family Magnaporthaceae which contains 13 genera and more than 100 species (Zhang et al. 2011; Illana et al. 2013; Luo and Zhang 2013; Klaubauf et al. 2014). Klaubauf et al. (2014) carried out phylogenetic analyses on Pyricularia species based on combined ITS, LSU, RPB1, ACT, CAL sequence data. The result revealed two new families, namely Ophioceraceae and Pyriculariaceae, and ten new genera, including Pseudopyricularia; three species were included in Pseudopyricularia. Crous et al. (2015) described the fourth species P. hagahagae Crous & M.J. Wingf. based on LSU sequence data. Marin-Felix et al. (2017) found that P. bothriochloae was located in the Pseudopyricularia clade in a phylogenetic tree based on ITS and LSU sequence data, thus P. bothriochloae was combined under P. bothriochloae. The latest phylogenetic study on Pseudopyricularia was carried out by Pordel et al. (2017). LSU and RPB1 sequence data revealed two new Pseudopyricularia species, P. hyrcaniana A. Pordel & M. Javan-Nikkhah and Ps. iraniana A. Pordel & M. Javan-Nikkhah. The present study reconstructs the phylogeny based on analyses of ITS, LSU, RPB1, ACT and CAL sequence data for this genus, with all the species accepted to date, and it corresponds to previous studies (Pordel et al. 2017).

Recommended genetic markers (genus level) – LSU, RPB1

Recommended genetic markers (species level) – ACT, RPB1, ITS, CAL

Accepted number of species: Seven species

References: Klaubauf et al. 2014, Pordel et al. 2017 (morphology, phylogeny).

 

Table Pseudopyricularia. Details of the isolates used in the phylogenetic analyses. Ex-type (ex-epitype) strains are in bold and marked with an * and voucher strains are in bold.

Species Isolate ITS LSU RPB1 ACT CAL
Macgarvieomyces borealis CBS 461.65* KM484854 DQ341511 KM485070 KM485170 KM485239
M. juncicola CBS 610.82 KM484855 KM484970 KM485071 KM485171 KM485240
Pseudopyricularia bothriochloae CBS 136427* KF777186 KY905701 KY905700
P. cyperi CBS 133595* KM484872 KM484990 AB818013 AB274453 AB274485
P. cyperi CBS 665.79 KM484873 DQ341512 KM485093 KM485178 KM485248
P. cyperi PH0053 KM484874 KM485094 KM485179 KM485249
P. hagahagae CPC 25635* KT950851 KT950877 KT950873
P. higginsii CBS 121934 KM484875 KM484991 KM485095 KM485180 KM485250
P. hyrcaniana IRAN2758C* KP144447 KP144452 KY457270 KY457260
P. hyrcaniana UTFC-PO11 KP144448 KY457266 KY457271 KY457261
P. hyrcaniana UTFC-PO12 KM207211 KY457267 KY457272 KY457262
P. iraniana IRAN 2761C* KY457258 KY457268 KY457273 KY457264
P. iraniana UTFC-PO12 KM207210 KP144454 KY457263
P. kyllingae CBS 133597* KM484876 KM484992 KM485096 AB274451 AB274484
P. kyllingae PH0054 KM484877 KM484993 KM485097 KM485181 KM485251

Fig Phylogenetic tree generated by maximum likelihood analysis of combined ITS, LSU, RPB1, ACT and CAL sequence data of Pseudopyricularia species. Related sequences were obtained from GenBank. Fifteen strains are included in the analyses. Tree was rooted with Macgarvieomyces borealis (CBS 461.65) and M. juncicola (CBS 610.82). The best scoring RAxML tree with a final likelihood value of -10627.314729 is presented. The matrix had 771 distinct alignment patterns, with 20.13% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.244984, C = 0.283221, G = 0.271087, T = 0.200708; substitution rates AC = 1.176383, AG = 2.920484, AT = 1.126771, CG = 1.004552, CT = 6.091634, GT = 1.000000; gamma distribution shape parameter α = 1.511342. RAxML bootstrap support values ≥60% are shown respectively near the nodes. The scale bar indicates 0.02 changes. The ex-type (ex-epitype) strains are in bold.

Ruvi
ruvi.jaya@yahoo.com
No Comments

Post A Comment

Translate »