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Lasionectria saulensis (Bionectriaceae, Hypocreales), a new
species from French Guiana
Christian LECHAT (†)
Jacques FOURNIER
Delphine CHADULI
Anne FAVEL
Ascomycete.org, 14 (3) : 85–88
Mise en ligne le 11/07/2022
10.25664/ART-0350
Abstract: Lasionectria saulensis sp. nov. is described and illustrated based on a collection on dead leaves of
Astrocaryum sp. (Arecaceae) in French Guiana. This species is placed in Lasionectria based on its acremo-
nium-like asexual morph, ascomata not changing colour in 3% KOH or lactic acid, and phylogenetic com-
parison of ITS and LSU sequences with known species of Lasionectria. Lasionectria saulensis is primarily
characterised by non-stromatic, pale orange, subglobose, hairy ascomata with a conical apex, and striate
ascospores. Based on comparison of morphological characteristics and molecular data with known Lasio-
nectria species, L. saulensis is proposed as a new species.
Keywords: Astrocaryum, ribosomal DNA, taxonomy.
Résumé : Lasionectria saulensis sp. nov. est décrite et illustrée d’après une récolte effectuée sur feuille morte
d’Astrocaryum sp. (Arecaceae) en Guyane française. Cette espèce est placée dans le genre Lasionectria d’après
sa forme asexuée de type Acremonium, les ascomes ne changeant pas de couleur dans KOH à 3% ou dans
l’acide lactique et la comparaison phylogénétique des séquences ITS et LSU avec les espèces connues de
Lasionectria. Lasionectria saulensis se caractérise principalement par des ascomes dépourvus de stroma,
orange pâle, subglobuleux, poilus, avec l’apex convexe et des ascospores striées. En se fondant sur la com-
paraison des caractères morphologiques et des données moléculaires avec les espèces connues, L. saulensis
est proposée comme une espèce nouvelle.
Mots-clés : ADN ribosomal, Astrocaryum, taxinomie.
Introduction
In the continuity of the inventorial survey of fungi in French
Guiana (LECHAT et al., 2022), an hypocrealean fungus was collected
on a dead palm leaf of Astrocaryum sp. This fungus was morpholog-
ically characterised, cultured and phylogenetically analysed. ITS and
LSU sequences were obtained from dry ascomata and compared
with those of 24 species having an acremonium-like asexual morph,
confirming its placement in Lasionectria (Sacc.) Cooke. Based on
these results Lasionectria saulensis Lechat & J. Fourn. is proposed as
a new species.
Materials and methods
Dry specimens were rehydrated and examined using the method
described by ROSSMAN et al. (1999). Microscopic observations and
measurements were made in water, and the ascospore ornamenta-
tion was observed in unheated lactic cotton blue. The holotype is
deposited in LIP herbarium (University of Lille, France). Cultures of
living specimens were made on PDA (Potato Dextrose Agar) with
5 mg/l of streptomycin in Petri dishes 5 cm diam. incubated at 25°C.
DNA extraction, amplification, and sequencing were performed by
ALVALAB (Oviedo, Spain): total DNA was extracted from dry speci-
mens blending a portion of them using a micropestle in 600 µl CTAB
buffer (CTAB 2%, NaCl 1.4 M, EDTA pH 8.0 20 mM, Tris-HCl pH 8.0
100 mM). The resulting mixture was incubated for 15 min at 65ºC. A
similar volume of chloroform:isoamylalcohol (24:1) was added and
carefully mixed with the samples until their emulsion. It was then
centrifuged for 10 min at 13.000 g, and the DNA in the supernatant
was precipitated with a volume of isopropanol. After a new centrifu-
gation of 15 min at the same speed, the pellet was washed in 70%
cold ethanol, centrifuged again for 2 min and dried. It was finally re-
suspended in 200 µl ddH2O. PCR amplification was performed with
the primers ITS1F and ITS4 (WHITE et al., 1990; GARDES & BRUNS, 1993)
for ITS, while LR0R and LR5 (VILGALYS & HESTER, 1990) were used to
amplify the 28S nLSU region. PCR reactions were performed under
a program consisting of a hot start at 95ºC for 5 min, followed by 35
cycles at 94ºC, 54ºC and 72ºC (45, 30 and 45 s respectively) and a
final 72ºC step for 10 min. PCR products were checked in 1% agarose
gels, and positive reactions were sequenced with primer ITS4. Chro-
matograms were checked searching for putative reading errors, and
these were corrected. Phylogenetic analyses were performed online
at www.phylogeny.lirmm.fr (DEREEPER et al., 2008). Maximum likeli-
hood phylogenetic analyses were performed with PhyML 3.0 aLRT
(ZWICKL, 2006), using the GTR + I + Γ model of evolution. Branch sup-
port was assessed using the non-parametric version of the approx-
imate likelihood-ratio test, implemented in PhyML SH-aLRT
(ANISIMOVA & GASCUEL, 2006).
Nomenclature follows MycoBank (Westerdijk Fungal Biodiversity
Institute, Utrecht, The Netherlands).
Taxonomy
Lasionectria saulensis Lechat & J. Fourn., sp. nov. Fig. 3
MycoBank: MB844375
Diagnosis: Differs from the most similar species Lasionectria
vulpina by its longer and narrower ascospores, hyaline to pale yellow
hairs instead of orange hairs, and its occurrence on dead palm
leaves in French Guiana.
Holotype: FRENCH GUIANA, Saül, trail to Monts La Fumée, 3.63105°
N, -53.205912° E, alt. 248 m, on dead leaves of Astrocaryum sp. (Are-
caceae), 3 Apr. 2021, leg. C. Lechat, LIP CLLG21159, ex-holotype cul-
ture: no longer viable. GenBank sequences: ITS: ON206617 and LSU:
ON206592.
Etymology: The specific epithet “saulensis” refers to Saül, the lo-
cality where this species was collected.
Ascomata solitary or in groups of 2–3, superficial, scattered on
substrate, non-stromatic, subglobose, (160–)180–200(–220) µm high,
160–180 µm diam. (Me = 190 × 170 µm, n = 10), becoming slightly
cupulate when dry, easy to remove from substrate, not changing
colour in 3% KOH or lactic acid. Ascomatal apex convex, con-
colourous, glabrous. Ascomatal surface composed of angular, thin-
walled cells 8–14 × 6–12 µm with pale orange wall, bearing a crown
of hairs around ostiolar region. Hairs flexuous 25–45(–50) × 3–5 µm
wide, thick-walled, with wall 1.5–2 µm thick, septate, hyaline to pale
yellow, arising from cells of upper ascomatal wall. Ascomatal wall
20–25 µm thick, composed of two regions: outer region 12–15 µm
wide, of subglobose to elongated, thick-walled cells 4–7 × 2–3 µm,
with pale orange walls 1.5–2.5 µm thick; inner region 8–10 µm wide,
86 Ascomycete.org
Fig. 1 – Maximum likelihood phylogeny (-lnL = 2516.77551) of Lasionectria saulensis inferred by PhyML 3.0, model TS93 from a 650 bp
matrix of ITS sequences, rooted with Dialonectria diatrypicola Lechat, J. Fourn. & Gardiennet (Nectriaceae). Species marked with * have a
non-acremonium asexual morph.
Fig. 2 – Maximum likelihood phylogeny (-lnL = 2934.95332) of Lasionectria spp. inferred from LSU sequences, rooted with Fusicolla melo-
grammae Lechat & Aplin (Nectriaceae). Species marked with * have a non-acremonium asexual morph.
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Ascomycete.org
Fig. 3 – a-g: Lasionectria saulensis (Holotype CLLG21159); a: Dry ascomata on the substrate; b: Ascoma in water in side view; c: Section of
ascomatal wall showing hairs arising from wall cells; d: Asci and ascospores in water; e: Culture at 2 weeks; f: Conidiophores in lactic acid;
g: Conidia in lactic acid. Scale bars: a = 200 µm; b = 50 µm; c = 20 µm; d, f = 10 µm; g = 5 µm.
88 Ascomycete.org
of elongated, flattened thin-walled cells 7–12 × 1.5–2 µm, with hya-
line walls 1–1.5 µm thick. Asci (55–)60–65(–70) × 8–9 µm (Me = 62.5
× 8.5 µm, n = 20), stipitate, clavate, apex rounded, with a refractive
thickening, containing eight biseriate ascospores or biseriate above
and uniseriate below. Ascospores (9.5–)10–12(–13) × 2.5–3 µm (Me
= 11 × 2.8 µm, n = 30), narrowly ellipsoidal to fusiform, attenuated
and rounded at ends, equally two-celled, with two drops in each
cell, slightly constricted at septum, hyaline, striate.
Culture characteristics: After two weeks on PDA at 25°C, colony
25–30 mm diam., aerial mycelium white, without colouration in
medium. Mycelium composed of septate, hyaline, smooth hyphae
2–2.5 µm diam. Conidiophores monomorphic, arising from aerial
hyphae, macronematous, flexuous, hyaline 28–50 µm long, 2.5–
3 µm diam. at base, faintly granulose, 1-septate, bearing terminal,
subulate conidiogenous cells 30–38 µm long, with a non-flared col-
larette. Conidia ellipsoidal to subcylindrical, rounded at end, without
abscission scar, aseptate, 5–8(–10) × 2–2.5 µm (Me = 6.5 × 2.2 µm,
n = 30), hyaline, smooth. Unfortunately, the culture of this specimen
is no longer viable.
Results and discussion
Within Bionectriaceae, Lasionectria is defined by hairy ascomata
not changing colour in 3% KOH or lactic acid, ascomatal wall of two
regions, hairs arising from cells of ascomatal wall, convex apex, stri-
ate ascospores and an acremonium-like asexual morph (LECHAT &
FOURNIER, 2019; ROSSMAN et al., 1999). Lasionectria saulensis fits well
this definition, and our phylogenetic analyses of ITS and LSU se-
quences (Fig. 1–2) comparing L. saulensis with known bionectria-
ceous species having an acremonium-like asexual morph,
unambiguously place the new species in Lasionectria. The conspic-
uous crown of hairs surrounding a glabrous apex may easily mislead
to the closely related genus Ijuhya Starbäck. In Ijuhya, ascomatal wall
differs in being only one-layered but, in critical cases like here, a for-
mal generic placement requires molecular support.
Morphologically, L. saulensis is similar to L. vulpina (Cooke) Ross-
man & Samuels (ROSSMAN et al., 1999) but differs from it by having
longer and narrower ascospores (9.5–)10–12(–13) × 2.5–3 µm vs.
(7–)8–11(–13) × 3–4 µm, white to pale yellow hairs vs. orange hairs,
89% similarity of ITS sequences, and its occurrence in tropical areas.
Based on morphological features combined with the results of our
phylogenetic analyses, L. saulensis is proposed as a new species.
Note: To our knowledge, Lasionectria saulensis is the first species
of Lasionectria reported from French Guiana.
Acknowledgements
Dr Amy Rossman (Oregon State University Corvallis, U.S.A.) is
warmly thanked for her advice and scientific help and for her pre-
submission review. We express our appreciation to Parc Amazonien
de Guyane (PAG) for having organised the field trips to Saül in the
context of the ABC inventorial project.
Author’s contributions
Christian Lechat was responsible for the conception of the study,
cultures, morphological studies, phylogenetic analyses, design of
figures and plates and writing a first draft. Jacques Fournier critically
reviewed the first draft and proposed an improved version and took
care of the registration at MycoBank. Delphine Chaduli and Anne
Favel managed the culture collection in which the culture was to be
deposited and took care of the registrations at GenBank. All authors
except CL read and approved the final manuscript.
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2: J. Fournier – Las Muros, 09420 Rimont, France – jfournzeroneuf@gmail.com
1: C. Lechat (†)
3: D. Chaduli – CIRM-CF, INRAE, Aix Marseille Univ, UMR1163 BBF (Biodiversité et Biotechnologie Fongiques), 13288 Marseille Cedex 09, France – delphine.chaduli@univ-amu.fr
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2 4
4: A. Favel – CIRM-CF, INRAE, Aix Marseille Univ, UMR1163 BBF (Biodiversité et Biotechnologie Fongiques), 13288 Marseille Cedex 09, France – anne.favel@univ-amu.fr
