Calonectria paragominensis E.I.Sanchez, T.P.F.Soares & M.A.Ferreira, 2022

Sanchez-Gonzalez, Enrique I., Soares, Thaissa de Paula Farias, Zarpelon, Talyta Galafassi, Zauza, Edival Angelo Valverde, Mafia, Reginaldo Goncalves & Ferreira, Maria Alves, 2022, Two new species of Calonectria (Hypocreales, Nectriaceae) causing Eucalyptus leaf blight in Brazil, MycoKeys 91, pp. 169-197 : 169

Calonectria paragominensis E.I.Sanchez, T.P.F.Soares & M.A.Ferreira sp. nov.

Fig. 3

Etymology.

The term " Calonectria paragominensis " refers to the microregion of Paragominas, Brazil, which is the place where the fungus was collected.

Diagnosis.

Calonectria paragominensis differs from the phylogenetically closely related species C. densa , C. humicola , C. spathiphylli and C. pseudospathiphylli with respect to its macroconidia dimensions.

Type.

Brazil,• Pará state, Paragominas microregion; 3°10'51"S, 47°18'49"W; From infected leaves of E. grandis × E. brassiana ; 20 Feb. 2020; M.A. Ferreira; holotype: UB24349, ex-type: CCDCA 11648 = PFC1. GenBank: act = ON009346 ; cmdA = OM974325 ; his3 = OM974334 ; rpb2 = OM974343 ; tef1 = OM974352 ; tub2 = OM974361 .

Description.

Sexual morph unknown. Macroconidiophores consisted of a stipe, a suite of penicillate arrangements of fertile branches, a stipe extension, and a terminal vesicle; stipe septate, hyaline, smooth, (112-)135-207(-281) × (2-)2.6-3.5(-4) μm; stipe extension septate, straight to flexuous, (123-)147-220(-295) μm long, (1.5-)1.9-2.4(-3) μm wide at the apical septum, terminating in a globose to sphaeropedunculate vesicle, (8-)8.5-10.5(-12) μm diam; lateral stipe extensions (90° to the axis) also present. Conidiogenous apparatus was (40-)56-88(-113) μm long, (45-)67-107(-129) μm wide; primary branches aseptate or 1-septate, (15.7-)18.4-25.9(-30.6) × (3.3-)4-6(-6.5) μm; secondary branches aseptate, (12.7-)14.3-19.6(-22.1) × (3-)3.5-5(-6) μm; tertiary branches aseptate, (9.9-)11.6-15.3(-17.9) × (2.8-)3.6-5.3(-6.4) μm; additional branches (-4), aseptate, (10.3-)11-13.2(-14) × (3-)3.2-4.4(-5) μm; each terminal branch produced 2-4 phialides; phialides doliiform to reniform, hyaline, aseptate, (8-)9.1-11.8(-14) × (2-)2.7-4.1(-6) μm, apex with minute periclinal thickening and inconspicuous collarette. Macroconidia were cylindrical, rounded at both ends, straight, (47-)56-66(-71) × (4-)4.8-5.9(-7) μm (av. = 61 × 5 μm), (1-3) septate, lacking a visible abscission scar, held in parallel cylindrical clusters by colorless slime. Megaconidia and microconidia were not observed.

Culture characteristics.

Colonies formed abundant white aerial mycelium on MEA at 25 °C after seven days, with irregular margins and moderate sporulation. The surface had white to buff outer margins, and sienna to amber in reverse with abundant chlamydospores throughout the medium, forming microsclerotia. The optimal growth temperature was 23.8 °C, with no growth at 5 °C; after seven days, colonies at 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C reached 7 mm, 23 mm, 38.3 mm, 36.1 mm, and 31.8 mm, respectively.

Substratum.

Leaves of E. grandis × E. brassiana .

Distribution.

Northeast Brazil.

Other specimens examined.

Brazil,• Pará state, Paragominas microregion; From infected leaves of E. grandis × E. brassiana ; 20 Feb. 2020; M.A. Ferreira; cultures PFC2, PFC3, PFC4, PFC5 .

Notes.

C. paragominensis is a new species in the C. spathiphylli species complex ( Liu et al., 2020). Morphologically, C. paragominensis is very similar to C. densa , since both form lateral stipe extensions, which have not been reported for the other three species in the complex. However, the macroconidia of C. paragominensis (av. 61 × 5 μm) are longer than those of C. densa (av. 54 × 6 μm), C. humicola (av. 51 × 5 μm) and C. pseudospathiphylli (av. 52 × 4 μm) but smaller than those of C. spathiphylli (av. 70 × 6 μm).

Figures

Figure 3. Calonectria paragominensis A, B macroconidiophore C lateral stipe extensions D, E conidiogenous apparatus with conidiophore branches and doliiform to reniform phialides F, G globose to sphaeropedunculate vesicles H, I one, two, and three-septate macroconidia. Scale bars: 20 μm.