Saccharata

Denman & Crous, CBS Biodiversity Ser. (Utrecht) 2: 104. 2004.

• Classification: Dothideomycetes, Incertae sedis, Botryosphaeriales, Saccharataceae.
• Type species: Saccharata proteae (Wakef.) Denman & Crous. Holotype and ex-type culture: PREM 32915, STE-U 1694 
• DNA barcode (genus): LSU. 
• DNA barcodes (species): ITS, rpb2, tef1, tub2.

Ascomata epiphyllous, separate, becoming aggregated, unilocular, immersed, substomatal, with a central, flattened ostiole, surrounded by a continuous, clypeus-like apical thickening of the wall, obovoid, slightly depressed; ascomata wall consisting of 8–11 layers of brown pseudoparenchymatous textura angularis. Pseudoparaphyses hyaline, septate, branched, frequently attached to the top and base of the pseudothecial cavity. Asci clavate to cylindrical, stipitate, bitunicate, fissitunicate; apical chamber visible as a notch-like indentation at the apex. Ascospores uni- to biseriate, hyaline, guttulate, smooth, ellipsoidal, clavate to fusiform, frequently widest in the upper third of the ascospore, tapering to obtuse ends. Conidiomata pycnidial, black, opening by a single, central ostiole, infrequently embedded in stromatic tissue with thickened, darkened upper layer; conidiomatal wall consisting of 2–3 layers of brown textura angularis. Conidiophores hyaline, smooth, subcylindrical, branched, or reduced to conidiogenous cells, lining the inner layer of the cavity, 1–3-septate. Paraphyses intermingled among conidiophores, hyaline, smooth, subcylindrical, unbranched or branched above, with obtuse ends, 0–3-septate, extending above conidiophores or slightly above the conidia. Conidiogenous cells hyaline, smooth, phialidic, proliferating via periclinal thickening or percurrent proliferation, with or without collarettes. Conidia hyaline, smooth, thin-walled, aseptate, granular, fusiform to narrowly ellipsoid or fusoid-ellipsoid, apex subobtuse, base subtruncate or truncate with minute marginal frill, widest in the middle of the conidium. Synasexual morph formed in separate conidiomata, or in same conidiomata with asexual morph. Synasexual conidia pigmented, thick-walled, finely verruculose, ellipsoid or oval, aseptate. Spermatogonia similar to conidiomata in anatomy. Spermatogenous cells ampulliform to lageniform or subcylindrical, hyaline smooth, phialidic. Spermatia developing in conidiomata or spermatogonia, hyaline, smooth, granular, subcylindrical or dumbbell-shaped, with rounded ends (adapted from Crous et al. 2004 and Slippers et al. 2013).

Culture characteristics:

Colonies on PDA, OA and MEA spreading, with moderate aerial mycelium, usually erumpent, less frequent flat, margins irregular; surface and reverse show different shades of grey.

Optimal media and cultivation conditions:

On OA or PNA at 25 °C under continuous near-ultraviolet light to promote sporulation.

Distribution:

Commonly found in South Africa, but also Australia, North America (incl. Hawaii) and Europe.

Hosts:

Members of Proteaceae, especially in species of Banksia, Hakea, Isopogon, Lambertia, Leucospermum, Petrophile and Protea. Also found on Daviesia (Fabaceae), Encephalartos (Zamiaceae), and Eucalyptus (Myrtaceae) (see Crous et al. 2016).

Disease symptoms:

Leaf tip die-back and leaf spots.

Notes:

Saccharata is the only genus located in the family Saccharataceae, which was recently introduced by Slippers et al. (2013). This genus was described by Crous et al. (2004) in order to accommodate “Botryosphaeria” proteae, and subsequently several additional species were added to the genus from South Africa. All the species were found on Proteaceae expect Saccharata kirstenboschensis, which was isolated from Encephalartos princeps (Crous et al. 2008). South African Saccharata spp. that occur on Proteaceae can be distinguished from other members of Botryosphaeriales by their asexual morphology, which includes a hyaline, fusicoccum-like and a pigmented diplodia-like asexual morph (Crous et al. 2013). However, Crous et al. (2016) introduced eight species from a range of hosts (Myrtaceae and Proteaceae) in Australia, and also widened the generic concept to include the genus Neoseptorioides (3-septate, cylindrical conidia; Crous et al. 2015). In spite of the range of variation observed in the asexual morphs, morphology of the sexual morphs of Australian and South African species appear remarkably conserved.

References:

• Crous et al. 2008, 2013, 2016 (morphology and phylogeny). 
• Crous PW, Denman S, Taylor JE, et al. (2004). Cultivation and Diseases of Proteaceae: Leucadendron, Leucospermum and Protea. CBS Biodiversity Series 2. CBS-KNAW Fungal Biodiversity Centre, Utrecht, the Netherlands.
• Crous PW, Denman S, Taylor JE, et al. (2013). Cultivation and Diseases of Proteaceae: Leucadendron, Leucospermum and Protea. CBS Biodiversity Series 13. CBS-KNAW Fungal Biodiversity Centre, Utrecht, the Netherlands.
• Crous PW, Wingfield MJ, Burgess TI, et al. (2016). Fungal Planet description sheets: 469–557. Persoonia 37: 218–403.
• Crous PW, Wingfield MJ, le Roux JJ, et al. (2015e). Fungal Planet description sheets: 371–399. Persoonia 35: 264–327.
• Crous PW, Wood AR, Okada G, et al. (2008). Foliicolous microfungi occurring on Encephalartos. Persoonia 21: 135–146.
• Slippers B, Boissin E, Phillips AJ, et al. (2013). Phylogenetic lineages in the Botryosphaeriales: a systematic and evolutionary framework. Studies in Mycology 76: 31–49.

Table 19. DNA barcodes of accepted Saccharata spp.

¹CBS: Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands. ^T indicates ex-type strain.

²ITS: internal transcribed spacers and intervening 5.8S nrDNA; rpb2: partial RNA polymerase II second largest subunit gene; tef1: partial translation elongation factor 1-alpha gene; tub2: partial β-tubulin gene.

•  Crous PW, Groenewald JZ, Taylor JE (2009). Saccharata intermedia. Fungal Planet 43. Persoonia 23: 198–199.
• Crous PW, Wingfield MJ, Burgess TI, et al. (2016). Fungal Planet description sheets: 469–557. Persoonia 37: 218–403.
• Crous PW, Wingfield MJ, le Roux JJ, et al. (2015). Fungal Planet description sheets: 371–399. Persoonia 35: 264–327.
• Crous PW, Wood AR, Okada G, et al. (2008). Foliicolous microfungi occurring on Encephalartos. Persoonia 21: 135–146.
• Marincowitz S, Crous PW, Groenewald JZ, et al. (2008a). Microfungi occurring on Proteaceae in the fynbos. CBS Biodiversity Series 7. CBS-KNAW Fungal Biodiversity Centre, Utrecht, the Netherlands.
• Marincowitz S, Groenewald JZ, Wingfield MJ, et al. (2008b). Species of Botryosphaeriaceae occurring on Proteaceae. Persoonia 21: 111–118.
• Phillips AJ, Alves A, Abdollahzadeh J, et al. (2013). The Botryosphaeriaceae: genera and species known from culture. Studies in Mycology 76: 51–167.
• Schoch CL, Crous PW, Groenewald JZ, et al. (2009). A class-wide phylogenetic assessment of Dothideomycetes. Studies in Mycology 64: 1–15-S10.
• Slippers B, Boissin E, Phillips AJ, et al. (2013). Phylogenetic lineages in the Botryosphaeriales: a systematic and evolutionary framework. Studies in Mycology 76: 31–49.
• Yang T, Groenewald JZ, Cheewangkoon R, et al. (2017). Families, genera and species of Botryosphaeriales. Fungal Biology 121: 322–346.