Caliciopsis moriondi N. Luchi, D. Migliorini & A. Santini, 2020

Migliorini, Duccio, Luchi, Nicola, Pepori, Alessia Lucia, Pecori, Francesco, Aglietti, Chiara, Maccioni, Fabio, Munck, Isabel, Wyka, Stephen, Broders, Kirk, Wingfield, Michael J. & Santini, Alberto, 2020, Caliciopsis moriondi, a new species for a fungus long confused with the pine pathogen C. pinea, MycoKeys 73, pp. 87-108 : 87

Caliciopsis moriondi N. Luchi, D. Migliorini & A. Santini sp. nov. Figures 1 , 2

Types.

Italy, Florence, Lastra a Signa, Carcheri, 43°71.58'N, 11°07.36'E, 110 m a.s.l., isolated from branches of Pinus radiata , 10 Oct. 2014, leg. N. Luchi, D. Migliorini & A. Santini, CBS 146717 (holotype); (IT1). ex-holotype sequences MN156540 (ITS), MK913586 (EF1-α), MN150120 (Bt1); duplicate deposited at Fungal Collection of the Institute for Sustainable Plant Protection-National Research Council (IT1; isotype). ITALY, Florence, Fucecchio, 43°47'17"N, 10°46'37"E, isolated from diseased Pinus radiata , 5 Dec. 2014, leg. N. Luchi, deposited at Fungal Collection of the Institute for Sustainable Plant Protection-National Research Council (IT22, paratype). ITALY, Florence, Lastra a Signa, Carcheri, 43°71.58'N, 11°07.36'E, isolated from diseased Pinus radiata , 10 Oct. 2014, leg. N. Luchi, deposited at Fungal Collection of the Institute for Sustainable Plant Protection-National Research Council (IT4, paratype). ITALY, Florence, Antella 43°44.00'N, 11°19.52'E, isolated from diseased Pinus nigra , 24 Nov. 2014, leg. D. Migliorini, deposited at Fungal Collection of the Institute for Sustainable Plant Protection-National Research Council (IT17, paratype). SPAIN, San Sebastián de Garabandal, 43°12.04'N, 4°25.25'W, isolated from diseased Pinus radiata , 25 May 2011, leg. P. Capretti, deposited at Fungal Collection of the Institute for Sustainable Plant Protection-National Research Council (SP1, paratype).

Description.

Stromata developing beneath the surface of host periderm as small, more or less circular structures, giving little external evidence of their presence at early stages. Continued growth causing the bark to break and the minute cushion-shaped stromata, developing a lobed appearance and increasing in diameter and thickness, in black short-stalked columnar ascomata. Ascomata mostly frequent protruding at the margin of cankers, single or double, rarely triple, stalks not branched, (0.45) 0.84 ± 0.02 (1.2) mm high and (51) 79 ± 2 (135) µm width. Ascigerous swelling, terminal, (106) 281 ± 8 (406) µm high and (81) 142 ± 5 (268) µm diameter, forming a brownish pulverulent mass of extruded ascospores. Asci bitunicate, clavate, 8-spored, slightly curved, pedicellate, (26) 37 ± 6 (53) µm long; pedicel 1-3 µm diameter; sporiferous part (12) 13 ± 0.4 (14.2) µm long and (5.3) 6.3 ± 0.4 (7.4) µm wide. Ascospores yellow-green colour, sub-globose to ellipsoidal and often aggregated in small masses, (3) 4.4 ± 0.07 (6.2) µm long and (1.8) 2.5 ± 0.04 (3.5) µm wide, brown when mature. Spermogonia sub-globose, papillate, sessile, aggregated below ascomatal tubes. Conidia unicellular, hyaline, smooth, slightly fusiform.

Culture characteristics.

Cultures incubated on 2% PDA, showed optimal temperature for growth at 20 °C, with slow-growth rate (1.4 mm/day). Colonies white appressed to the agar, circular to irregular, becoming fawn-colored with age, areas towards margin floccose; mycelium velutinous with funicolose areas or strongly funicolose in the inner and older parts of the mycelium. Reverse colony brownish, with brown diffusion zone in old cultures; branching septate hyphae, with frequent anastomoses and tips with dendroid branching.

Inoculation tests.

All isolates from Italy and residing in Clade II inoculated on seedlings gave rise to symptoms and lesions of variable length after six months. These were all significantly different to those of the controls (F = 119.21, p <0.000; F = 60.84, p <0.000, respectively). Inoculated plants did not show a crown dieback, but all had profuse resin production at the inoculation points. Caliciopsis moriondi fruiting bodies were clearly visible on P. halepensis , while no fructifications were seen in any of the other inoculated Pinus species.

The lengths of lesions caused by the inoculated isolates were significantly longer on P. halepensis (28.6 ± 9.04 mm) and P. pinaster (30.1 ± 7.13 mm) than on P. pinea (16.4 ± 3.16 mm) (F = 297.43, p <0.000). Caliciopsis moriondi was successfully re-isolated from all the seedlings inoculated with the pathogen, while no Caliciopsis species were re-isolated from mock-inoculated seedlings.

Hosts and distribution.

Pathogen of pine trees P. nigra , P. radiata and P. resinosa , causing cankers and resin production in Europe (France, Italy, Spain) and North America (New Hampshire, USA).

Etymology.

The name moriondi honours Prof. Francesco Moriondo (1926-2014). Francesco Moriondo was the founder of forest pathology as a discipline distinct from plant pathology in Italy. In this respect, he preferred a more ecological view of the topic as opposed to the typical mechanistic approach. During his career, he encouraged many young students to consider the reasons for the appearance of symptoms on trees, rather than considering only the causative agents. He also emphasised the importance of minor pathogens in the ecosystem, of which Caliciopsis moriondi (then C. pinea ) was one.

Notes.

Caliciopsis moriondi is commonly associated with a canker disease on Pinus spp. It differs subtly from C. pinea , based on morphological traits, including shorter ascomata, protruding and isolated from the stroma, rarely in groups of two-three, but never in more numerous groups, such as is common for C. pinea (Table 2 ).

Figures

Figure 1. Caliciopsis moriondi structures A cankers on a Pinus radiata trunk B-D ascomata growing from a canker B image of C. pinea ascigerous columns from an archive of 1970 (provided by Prof. Paolo Capretti) E-G asci H ascospores I ascigerous, terminal portion L four weeks colony grown at 20 ° C on MEA. Scale bars: 2.5 µm (F-H), 5 µm (I).

Figure 2. Morphological differences between Caliciopsis moriondi and C. pinea A-C Caliciopsis moriondi: A four-week-old colonies grown at 20 ° C on MEA B, C ascomata growing from a canker of Pinus radiata D-F Caliciopsis pinea: D four-week-old colonies grown at 20 ° C on MEA E, F ascomata growing from a canker of P. radiata.