Multi-locus phylogeny of Pleosporales: a taxonomic, ecological and evolutionary re-evaluation

Abstract

Five loci, nucSSU, nucLSU rDNA, TEF1, RPB1 and RPB2, are used for analysing 129 pleosporalean taxa representing 59 genera and 15 families in the current classification of Pleosporales. The suborder Pleosporineae is emended to include four families, viz.Didymellaceae, Leptosphaeriaceae, Phaeosphaeriaceae and Pleosporaceae. In addition, two new families are introduced, i.e. Amniculicolaceae and Lentitheciaceae. Pleomassariaceae is treated as a synonym of Melanommataceae, and new circumscriptions of Lophiostomataceaes. str., Massarinaceae and Lophiotrema are proposed. Familial positions of Entodesmium and Setomelanomma in Phaeosphaeriaceae, Neophaeosphaeria in Leptosphaeriaceae, Leptosphaerulina, Macroventuria and Platychora in Didymellaceae, Pleomassaria in Melanommataceae and Bimuria, Didymocrea, Karstenula and Paraphaeosphaeria in Montagnulaceae are clarified. Both ecological and morphological characters show varying degrees of phylogenetic significance. Pleosporales is most likely derived from a saprobic ancestor with fissitunicate asci containing conspicuous ocular chambers and apical rings. Nutritional shifts in Pleosporales likely occured from saprotrophic to hemibiotrophic or biotrophic.

Keywords: Environmental habit; evolution; molecular phylogeny; nutritional mode; taxonomy.

Fig 1.

RAxML tree with bootstrap values after 1000 pseudo repetitions on the nodes. The values below the nodes are percentages of 500 jacknife resamplings. Pleosporalean leaves highlighted in red and bold are marine or maritime taxa, in blue and bold are freshwater taxa, and others are terrestrial ones. Relevant biological or morphological characters plotted on the leaves are abbreviated as follows: Biology: Mono – monocotyledons; Dico – dicotyledons; Gy – Gymnosperm; SF – Stream foam;? – unknown; X – no information. Morphology: SZ – size, OS – ostiole, SP – shape, ST – septum, CL – colour; Ascoma size: S – small (diam < 300 μm), M–medial (300 μm < diam < 600 μm), L – large (diam > 600 μm); ostiole: P – pore-like ostiole, Sl – slite-like ostiole, Nil – no opening. Ascospore shape: Fi – filiform, Fu – fusiform, NF – narrowly fusiform, BF – broadly fusiform, Cy – cylindrical; ascospore septum: 1 – one transverse septum, 2 – two transverse septa, 3 – three transverse septa, >3 – more than three transverse septa, M– muriform, Ap – apiosporous; ascospore colour: H – hyaline, B – brown, PB – pale brown, RB – reddish brown, DB – dark brown, Y – yellow, PY – pale yellow.? – characters unknown. - – anamorph strain.

Fig 1.

RAxML tree with bootstrap values after 1000 pseudo repetitions on the nodes. The values below the nodes are percentages of 500 jacknife resamplings. Pleosporalean leaves highlighted in red and bold are marine or maritime taxa, in blue and bold are freshwater taxa, and others are terrestrial ones. Relevant biological or morphological characters plotted on the leaves are abbreviated as follows: Biology: Mono – monocotyledons; Dico – dicotyledons; Gy – Gymnosperm; SF – Stream foam;? – unknown; X – no information. Morphology: SZ – size, OS – ostiole, SP – shape, ST – septum, CL – colour; Ascoma size: S – small (diam < 300 μm), M–medial (300 μm < diam < 600 μm), L – large (diam > 600 μm); ostiole: P – pore-like ostiole, Sl – slite-like ostiole, Nil – no opening. Ascospore shape: Fi – filiform, Fu – fusiform, NF – narrowly fusiform, BF – broadly fusiform, Cy – cylindrical; ascospore septum: 1 – one transverse septum, 2 – two transverse septa, 3 – three transverse septa, >3 – more than three transverse septa, M– muriform, Ap – apiosporous; ascospore colour: H – hyaline, B – brown, PB – pale brown, RB – reddish brown, DB – dark brown, Y – yellow, PY – pale yellow.? – characters unknown. - – anamorph strain.

Fig. 2.

A. Xenolophium applanatum. Ascomata on the host surface. Note the slit-like ostiole. B. Trematosphaeria pertusa. Ascomata on the host surface. Note the pore-like ostiole. C, E, H. Murispora rubicunda. C. Ascomata on the host surface. Note the purple woody substrate. E. Clavate 8-spored asci with short pedicels in pseudoparaphyses. H. Muriform ascospore with wide mucilaginous sheath. D. I. Trematosphaeria sp. D. Fusiform mature or immature 8-spored asci with pseudoparaphyses. I. multisepate dark brown ascospore. F. Neomassariosphaeria grandispora. Ascospores with sheath. G. Aglospora profusa. Apical aparatus. Note the conspicuous apical ring. J. Amniculicola immersa. Hyaline fusiform ascospores in ascus. Scale bars; A–C = 100 μm, D–J = 20 μm.