Plenodomus Preuss

Linnaea 24: 145. 1851.

• Synonyms: Phoma sect. Plenodomus (Preuss) Boerema, Kesteren & Loer., Trans. Brit. Mycol. Soc. 77: 61. 1981.
• Diploplenodomus Diedicke, Ann. Mycol. 10: 140. 1912.
• Plectophomella Moesz, Magyar Bot. Lapok 21: 13. 1922.
• Apocytospora Höhn., Mitt. Bot. Lab. TH Wien 1: 43. 1924.
• Deuterophoma Petri, Boll. R. Staz. Patalog. Veget. Roma 9: 396. 1929.
• For Additional synonyms of the asexual morph and sexual morph genera listed below see Boerema et al. (1994) and Khashnobish et al. (1995), respectively.
• Classification: Dothideomycetes, Pleosporomycetidae, Pleosporales, Leptosphaeriaceae
• Type species: Plenodomus lingam (Tode: Fr.) Höhn. Representative strains: CBS 532.66 and CBS 475.81.
• DNA barcodes (genus): LSU, ITS.
• DNA barcodes (species): tub2, rpb2.

Ascomata solitary, scattered or in small groups, erumpent to superficial, subglobose, broadly or narrowly conical, small- to medium sized, dark brown to black, smooth, ostiolate; ostiole apex with a conical, well developed papilla; ascomatal wall composed of two to several layers of scleroplectenchymatous cells. Hamathecium comprising long, septate, pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate, cylindrical, rounded at the apex, with an ocular chamber, short pedicel. Ascospores cylindrical to ellipsoidal, yellowish brown, septate, not or slightly constricted at septa, guttulate and lacking a mucilaginous sheath, cell above central septum slightly wider. Conidiomata. Type 1: solitary, scattered or in small groups, erumpent to superficial, subglobose or flask shaped with a broad base, mostly black, ostiolate; ostiole with a long neck and well developed poroid papilla in the apex. Type 2: solitary, scattered or in small groups, erumpent to superficial, mostly subglobose, ostiolate; ostiole slightly papillate with a narrow pore or opening via a rupture. Conidiomatal wall composed of several layers with thick-walled cells of textura angularis, surface heavily pigmented. Conidiophores reduced to conidiogenous cells. Conidiogenous cells phialidic, hyaline, smooth, ampulliform. Conidia hyaline, aseptate, ellipsoidal to subcylindrical (adapted from Ariyawansa et al. 2015b). 

Culture characteristics:

Colonies on OA yellow/green to olivaceous grey, dull green, or translucent, aerial mycelium tenuous, margin irregular and whitish, compact, floccose.

Optimal media and cultivation conditions:

OA or PNA near-ultraviolet light (12 h light, 12 h dark) to promote sporulation at 25 °C.

Distribution:

Worldwide.

Hosts:

As pathogens of herbaceous plants in different families, most records refer to Asteraceae, and on leaves, branches, bark, wood and dead stems of various trees and shrubs of Brassicaceae, Lamiaceae, Rutaceae, Salicaceae and Vitaceae. In addition, some Plenodomus species are found as opportunistic or pathogenic fungi on Apiaceae, Bignoniaceae, Caprifoliaceae, Fabaceae, Rosaceae, Ulmaceae and Umbelliferae.

Disease symptoms:

Leaf spots, stem lesions, slow wilt, bark canker, root rot, shoot dieback.

Notes: The genus Plenodomus was first established by Preuss (1851), and recently re-introduced and placed in the family Leptosphaeriaceae by de Gruyter et al. (2013). The genus mainly consists of species that formerly belonged to Phoma section Plenodomus and the sexual morph Leptosphaeria. Plenodomus includes several well-known important plant pathogens, such as Plen. biglobosus, Plen. lindquistii, Plen. tracheiphilus, and Plen. wasabiae.

References:

• Boerema et al. 2004 (morphology and pathogenicity); de Gruyter et al. 2013, Ariyawansa et al. 2015 (morphology and phylogeny).
• Ariyawansa HA, Phukhamsakda C, Thambugala KM, et al. (2015). Revision and phylogeny of Leptosphaeriaceae. Fungal Diversity 74: 19–51.
• Boerema GH, de Gruyter J, van Kesteren HA (1994). Contributions towards a monograph of Phoma (Coelomycetes) – III. 1. Section Plenodomus: Taxa often with a Leptosphaeria teleomorph. Persoonia 15: 431–487.
• De Gruyter J, Woudenberg JHC, Aveskamp MM, et al. (2013). Redisposition of Phoma-like anamorphs in Pleosporales. Studies in Mycology 75: 1–36.
• Khashnobish A, Shearer CA, Crane JL (1995). Reexamination of species of Leptosphaeria on asteraceous hosts. Mycotaxon 54: 91–106.
• Preuss CGT (1851). Übersicht untersuchter Pilze, besonders aus der Umgegend von Hoyerswerda. Linnaea 24: 99–153.

Table 15. DNA barcodes of accepted Plenodomus spp.

¹CBS: Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands; CGMCC: Chinese General Microbiological Culture Collection Center, Beijing, China; MFLUCC: Mae Fah Luang University Culture Collection, Chiang Ria, Thailand. ^T and ^ET indicate ex-type and ex-epitype strains, respectively.

²ITS: internal transcribed spacers and intervening 5.8S nrDNA; rpb2: partial RNA polymerase II second largest subunit gene; tub2: partial β-tubulin gene.

• Ariyawansa HA, Phukhamsakda C, Thambugala KM, et al. (2015). Revision and phylogeny of Leptosphaeriaceae. Fungal Diversity 74: 19–51.
• Câmara MP, Palm ME, van Berkum P, et al. (2002). Molecular phylogeny of Leptosphaeria and Phaeosphaeria. Mycologia 94: 630–640.
• De Gruyter J, Woudenberg JHC, Aveskamp MM, et al. (2013). Redisposition of Phoma-like anamorphs in Pleosporales. Studies in Mycology 75: 1–36.
• Hu MJ, Cox KD, Schnabel G, et al. (2011). Monilinia species causing brown rot of peach in China. PloS ONE 6: 1–14.
• Marin-Felix Y, Groenewald JZ, Cai, L, et al. (2017). Genera of phytopathogenic fungi: GOPHY 1. Studies in Mycology xxxx.
• Voigt K, Cozijnsen AJ, Kroymann J (2005). Phylogenetic relationships between members of the crucifer pathogenic Leptosphaeria maculans species complex as shown by mating type (MAT1-2), actin, and beta-tubulin sequences. Molecular Phylogenetics and Evolution 37: 541–557.