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

Fig. 4

Etymology.

The term " Calonectria imperata " is in honor of the city of Imperatriz, Brazil, which was close to the place where the fungus was collected.

Diagnosis.

Calonectria imperata differs from the phylogenetically closely related species C. brassiana , C. glaebicola , C. piauiensis and C. venezuelana with respect to the number of unique alleles and stipe dimensions.

Type.

Brazil,• Maranhão state, Cidelândia municipality; 5°09'24"S, 47°46'26"W; From infected leaves of E. urophylla ; 20 Feb. 2020; M.A. Ferreira; holotype: UB24350, ex-type: CCDCA 11649 = PFC6. GenBank: act = ON009351 ; cmdA = OM974330 ; his3 = OM974339 ; rpb2 = OM974348 ; tef1 = OM974357 ; tub2 = OM974366 .

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, (135-)151-198(-227) × (2-)2.6-3.4(-4) μm; stipe extension septate, straight to flexuous, (151-)169-220(-254) μm long, (1.5-)1.9-2.7(-3) μm wide at the apical septum, terminating in an ellipsoidal to narrowly obpyriform vesicle (3-)3.1-4.6(-6) μm diam. Conidiogenous apparatus was (50-)66-100(-127) μm long, (41-)62-89(-110) μm wide; primary branches aseptate, (14.6-)19-24.8(-28.5) × (2.5-)3.2-4(-4.5) μm; secondary branches aseptate, (12.1-)13.5-18.2(-24.2) × (2.3-)2.8-3.7(-4) μm; tertiary branches aseptate, (10.1-)11-15(-18.1) × (1.9-)2.3-3.2(-4.1) μm; each terminal branch producing 2-4 phialides; phialides doliiform to reniform, hyaline, aseptate, (8-)9.1-13(-15) × (2-)2.7-3.3(-4) μm, apex with minute periclinal thickening and inconspicuous collarette. Macroconidia were cylindrical, rounded at both ends, straight, (38-)43-49(-52) × (2-)2.7-3.2(-4) μm (av. = 46 × 3 μm), (-1) septate, lacking a visible abscission scar, held in parallel cylindrical clusters by colorless slime. Megaconidia and microconidia were not observed.

Culture characteristics.

Colonies formed moderate aerial mycelium on MEA at 25 °C after seven days, with moderate sporulation. The surface had white to buff outer margins, and sepia to umber in reverse with abundant chlamydospores throughout the medium, forming microsclerotia. The optimal growth temperature was 25 °C, with no growth at 5 °C; after seven days, colonies at 10 °C, 15 °C, 20 °C, 25 °C, and 30 °C reached 10.1 mm, 25.5 mm, 29.1 mm, 44.5 mm, and 40.6 mm, respectively.

Substratum.

Leaves of E. urophylla .

Distribution.

Northeast Brazil.

Other specimens examined.

Brazil,• Maranhão state, Cidelândia municipality; 5°09'24"S, 47°46'26"W; From infected leaves of E. urophylla ; 20 Feb. 2020; M.A. Ferreira; cultures PFC7, PFC8, PFC9 . Brazil • Maranhão state, Itinga do Maranhão; 4°34'43"S, 47°29'48"W; from infected leaves of E. urophylla ; 20 Feb. 2020; M.A. Ferreira; culture PFC9 .

Notes.

C. imperata is a new species in the C. candelabrum species complex ( Liu et al., 2020). Morphologically, C. imperata is very similar to its closest relatives, from which it can be distinguished based on stipe dimensions and phylogenetic inference. Stipe of C. imperata (135-227 × 2-4 μm) is larger than those of C. piauiensis (50-110 × 4-6 μm), C. glaebicola (50-130 × 5-7 μm), and C. venezuelana (35-100 × 4-8 μm) but narrower than those of C. brassiana (55-155 × 5-8 μm). Additionally, C. imperata lacks lateral stipe extensions, which are present in C. piauiensis .

Figures

Figure 4. Calonectria imperata A-C macroconidiophore D-G ellipsoidal to narrowly obpyriform vesicles H-J conidiogenous apparatus with conidiophore branches and doliiform to reniform phialides K, L macroconidia. Scale bars: 20 μm.