Lamproconium (Grove) Grove, British

Norphanphoun, Chada, Hongsanan, Sinang, Doilom, Mingkwan, Bhat, Darbhe J., Wen, Ting-Chi, Senanayake, Indunil C., Bulgakov, Timur S. & Hyde, Kevin D., 2016, Lamproconiaceae fam. nov. to accommodate Lamproconium desmazieri, Phytotaxa 270 (2), pp. 89-102 : 95-98

Lamproconium (Grove) Grove, British Stem- and Leaf-Fungi (Coelomycetes) (Cambridge) 2: 321 (1937)

Melanconium sect. Lamproconium Grove, Bull. Misc. Inf., Kew : 161 (1918)

Type species:— Lamproconium desmazieri (Berk. & Broome) Grove.

Lamproconium desmazieri (Berk. & Broome) Grove [as ‘ desmazieri ’], British Stem- and Leaf-Fungi (Coelomycetes) (Cambridge) 2: 321 (1937) Figs. 2–4

Discella desmazieri Berk. & Broome, Ann. Mag. nat. Hist., Ser. 2 5: 377 (1850)

Melanconium desmazieri (Berk. & Broome) Sacc., Michelia 2(no. 7): 355 (1881)

Melanconis desmazieri Petr., Annls. mycol. 36(1): 55 (1938)

Facesoffungi number: FoF02249

Pathogen causing canker on branches or twigs of lime trees ( Tilia spp. ). Lime cankers associated with L. desmazieri , produced splitting and longitudinal breakage of the outer branches, the symptom will appear as localized, sunken, slightly discolored, dark blue to black lesions on branches discoloration and necrosis of the branches. Branch/top dieback associated with L. desmazieri in having black terminal dead shoots, apex downwards initially discoloration; becoming wilted, with brown to dark brown discoloration at the base, midrib, and finally becoming dry and dead. Sexual morph: Undetermined. Asexual morph: Conidiomata 800–1000 × 400–550 µm diam., pycnidial, solitary, partly immersed in host tissue, uniloculate, dark blue, with a raised centre. Pycnidium 50–70 μm, with multi-layered wall, thin at inner layer, hyaline, comprising wall cells of textura angularis. Paraphyses interspersed within conidiophores. Conidiophores 30–120 µm, arising from the outermost wall layer at the basal of pycnidium , filiform or cylindrical, pale bluish to hyaline, septate, branched, smooth-walled. Conidiogenous cells cylindrical to subcylindrical, annellidic, with flared periclinal thickenings in the collarette zone, colourless to olivaceous, smooth-walled. Conidia 22–28.5 × 8–10 µm (x̅ = 25.25 × 9 µm, n = 30), fusiform, ellipsoid, infrequently slightly curved, aseptate, initially hyaline, bluish to glistening dark blue at maturity, narrowly rounded at ends, smooth-walled.

Material examined:— RUSSIA. Rostov region: Krasnosulinsky district, Donskoye forestry, artificial forest, on dead branches of Tilia cordata Mill. (Tiliaceae) , 21 May 2014, T. Bulgakov ( MFLU 14 - 0780, reference specimen designated here, PDD); living culture, MFLUCC 14-1047, KUMCC. RUSSIA. Rostov region: Shakhty city, Central urban microdistrict, Central Park, parkland, on dying brunches (necrotrophic) of T. tomentosa Moench , 9 July 2015, T. Bulgakov ( MFLU 15-1940, PDD); living culture, MFLUCC 15-0870, KUMCC. RUSSIA. Rostov region: Krasnosulinsky district, Donskoye forestry, ravine forest, on dead branches of T. cordata , 18 June 2015, T. Bulgakov ( MFLU 15-2037, PDD); living culture, MFLUCC 15-0871, KUMCC. RUSSIA. Rostov region: Rostovon-Don city, territory of Southern Federal University, parkland, on dead and dying branches of T. cordata , 23 April 2015, T. Bulgakov ( MFLU 15-2111, PDD); living culture, MFLUCC 15-0872, KUMCC. RUSSIA. Rostov region: Krasnosulinsky district, Donskoye forestry, ravine forest, on dying branches of T. cordata , 18 June 2015, T. Bulgakov ( MFLU 15-2192, PDD); living culture, MFLUCC 15-0873, KUMCC.

Notes:— Lamproconium was introduced as a section of Melanconium by Grove (1918) and as a subgenus ( Index Fungorum 2016), with Melanconium desmazieri as the type species. The taxon with bright coloured spores was collected on living twigs of Tilia sp. in the UK. Grove (1937) had raised the subgenus to generic rank. In this study, we have determined our collections as having fusiform, ellipsoid, infrequently slightly curved, aseptate and glistening, dark blue conidia, with narrowly rounded ends (22–28.5 × 8–10 µm). The morphology of our collections is similar to Lamproconium desmazieri (Table 2). Therefore, we introduce our collections as belonging to the genus Lamproconium .

Petrak (1938) reported Melanconis desmazieri as the sexual morph of Melanconium desmazieri , also from Tilia sp. In the phylogenetic study of Castlebury et al. (2002), based on LSU sequence data, Melanconis desmazieri fell outside Melanconidaceae sensu stricto and grouped with Hercospora tiliae . These taxa were therefore placed in Diaporthales genera incertae sedis ( Castlebury et al. 2002, Voglmayr et al. 2012, Voglmayr & Jaklitsch 2014). Phylogenetic analyses in this study generated from maximum likelihood, maximum parsimony and Bayesian analyses using combined ITS and LSU sequence data from 67 taxa (including our new strains), indicate that L. desmazieri belongs with Hercospora tiliae as a distinct lineage of Diaporthales ( Fig. 1 ). Hence, we synonymize M. desmazieri under L. desmazieri and designate one of our collections as a reference specimen for L. desmazieri .

Figures

FIGURE 1. Maximum likelihood (ML) majority rule consensus tree of combined ITS and LSU sequence data based on MP, ML and Bayesian analyses. Values above the branches indicate maximum parsimony and maximum likelihood bootstrap ≥70%, (MPBS/MLBS). Values at the third positions, respectively, above or below the branches represent posterior probabilities (BI PP ≥ 0.95) from Bayesian inference analysis. The tree is rooted to Magnaporthe salvinii and M. grisea. Strain numbers are given following the taxon names. The new sequences resulting from this study are in blue. Synonyms are in red. Ex-type strains are in black bold.

FIGURE 2. Lamproconium desmazieri (= Melaconium desmazieri) (redrawn from Grove 1918). A. Conidia. B. Conidiophores and developing conidia.

FIGURE 3. Dieback disease caused by Lamproconium desmazieresi (MFLU 14-0780, reference specimen). A, B. Tilia cordata with conidiomata on twigs and branches. C. Immersed conidiomata on branch.

FIGURE 4. Lamproconium desmazieresi (MFLU 14-0780, reference specimen). A–C. Conidiomata on host. D. Cross section of a conidioma. E. Peridium and raised host tissue. F. Apex of conidioma. G–I. Conidiogenous cells with attached conidia (note: annellations at the tip of the conidiogenous cell). J. Immature conidium. K–M. Mature conidia. N. Germinating conidium. Scale bars:A, B = 2 mm, C = 1 mm, D = 500 µm, E = 100 µm, F = 200 µm, G, H = 30 µm, I = 20 µm, J–M = 10 µm, N = 30 µm.