Neofusicoccum

Neofusicoccum Crous, Slippers & A.J.L. Phillips, Stud. Mycol. 55: 247 (2006)

 

Background

When Crous et al. (2006) split Botryosphaeria into ten distinct genera they introduced Neofusicoccum for species morphologically similar to, but phylogenetically distinct from Botryosphaeria sensu lato. Despite the similar morphology, Crous et al. (2006) considered that the Dichomera-like syn-asexual morph seen in some Neofusicoccum species distinguishes it from Botryosphaeria. However, the Dichomera-like syn-asexual morph has not been found in all species of Neofusicoccum and it is not produced consistently by all isolates of those species that are known to possess this state. Phillips et al. (2013) suggested that paraphyses, which have never been reported in conidiomata of Neofusicoccum but are known in some species of Botryosphaeria, might be a suitable character to separate the two genera. However, the similarity of paraphyses to developing conidiogenous cells makes this feature difficult to apply. Furthermore, paraphyses have not been reported in all Botryosphaeria species.

Classification Dothideomycetes, incertae sedis, Botryosphaeriales, Botryosphaeriaceae

Type speciesNeofusicoccum parvum (Pennycook & Samuels) Crous, Slippers & A.J.L. Phillips, in Crous et al., Stud. Mycol. 55: 248 (2006)

Distribution – Worldwide

Disease Symptoms – Dieback, Canker, Fruit rot

Hosts – Plurivorous on woody hosts

Morphological based identification and diversity

Currently, 43 species are known in Neofusicoccum. Cultures and DNA sequence data are available for all the known species. Although Yang et al. (2017) and Li et al. (2018) included isolates of N. terminaliae in their phylogenetic analyses, no record of this species name could be found in MycoBank or Index Fungorum, but sequences are available in GenBank and a CBS culture collection number was quoted by Li et al. (2018). Since sequence data and culture are available we provisionally include N. terminaliae as a species in Neofusicoccum. Morphologically the species are differentiated based on conidial dimensions, colouration and septation in aged conidia and pigment production in culture. Phillips et al. (2013) attempted to construct a key for identification of 22 species, but in reality plasticity of characters and overlapping of conidial dimensions rendered this attempt unreliably. Considering that a further 21 species have been introduced in Neofusicoccum since then the only reliable way to identify species is with DNA sequence data.

Species cannot be identified reliably on the basis of morphological characters alone due to plasticity and overlapping of conidial dimensions.

Molecular based identification and diversity

Species in Neofusicoccum can be distinguished with a combination of ITS and partial TEF1- α sequences. In this way, Phillips et al. (2013) distinguished 22 species while Dissanayake et al. (2016) distinguished 29 species. However, resolution of species within some complexes is not always clearly defined and for that reason, Hyde et al. (2014) recommended the use of ITS, TEF1- α and TUB2 sequence data to separate the 22 species they included in Neofusicoccum. More recently, Marin-Felix et al. (2017) used a combination of ITS, TEF1- α, TUB2 and RPB2 sequence data to resolve 34 species. Yang et al. (2017) used the same combination of loci to differentiate 31 named species and a further nine lineages that they declined to name. Li et al. (2018) also used a combination of ITS, TEF1- α, TUB2 and RPB2 sequence data when they introduced a further two species collected from China. Considering the recent trends we use the same combination of ITS, TEF1- α, TUB2 and RPB2 sequence data to separate 43 species in Neofusicoccum (Fig).

While most of the species are clearly accommodated within Neofusicoccum, N. pennatisporum and N. buxi are phylogenetically divergent and morphologically atypical of the genus. The extremely long conidia of N. pennatisporum (40–50 µm long) that can be up to 5-septate and ascospores with apical protrusions (Taylor et al. 2009) are unlike any other known species in Neofusicoccum. Conidia of N. buxi (Yang et al. 2017) are atypically shaped (sub-cylindrical) and unusually large (30–38×7–8 µm) for a species in Neofusioccum. Together with the divergent phylogeny, these are sufficient reasons to question the inclusion of these two species in Neofusicoccum.

Recommended genetic markers (genus level) – SSU, LSU

Recommended genetic markers (species level) – ITS, TEF1- α, TUB2, RPB2

Even though it is possible to distinguish all species with a combination of ITS and TEF1- α, some species complexes are resolved more clearly with the addition of TUB2 and RPB2 sequence data.

Accepted number of species: There are 41 valid species epithets in Index Fungorum (August 2018) and 41 in MycoBank (August 2018) under this genus. However, some names have since been validated and we currently accept 43 species names in Neofusicoccum.

References: Phillips et al. 2013 (morphology, phylogeny, hosts), Dissanayake et al. 2016 (phylogeny, hosts, species numbers).

Table. Neofusicoccum. Details of the isolates used in the phylogenetic analyses. Ex-type (ex-epitype) strains are in bold and marked with an * and voucher strains are in bold

Species Isolate ITS TEF1- α tub-2 RPB2
N. algeriense CBS 137504* KJ657702 KJ657715 KX505915 N/A
N. andinum CBS 117453* AY693976 AY693977 KX464923 KX464002
N. arbuti CBS 116131* AY819720 KF531792 KF531793 KX464003
N. austral CMW 6837* AY339262 AY339270 AY339254 EU339573
N. batangarum CBS 124924* FJ900607 FJ900653 FJ900634 FJ900615
N. braziliense CMM 1285 JX513628 JX513608 KC794030 N/A
N. buxi CBS 116.75* KX464165 KX464678 N/A KX464010
N. cordaticola CBS 123634* EU821898 EU821868 EU821838 EU821928
N. corticosae CBS 120081* DQ923533 KX464682 KX464958 KX464013
N. cryptoaustrale CMW 23785* FJ752742 FJ752713 FJ752756 KX464014
N. eucalypticola CBS 115679* AY615141 AY615133 AY615125 N/A
N. eucalyptorum CBS 115791* AF283686 AY236891 AY236920 N/A
N. grevilleae CBS 129518* JF951137 N/A N/A N/A
N. hellenicum CERC 1947* KP217053 KP217061 KP217069 N/A
N. hongkongensis CERC 2973* KX278052 KX278157 KX278261 KX278283
N. ilicii CGMCC 3.18311* KY350150 KY817756 KY350156 N/A
N. italicum MFLUCC 15-0900* KY856755 KY856754 N/A N/A
N. kwambonambiense CBS 123639* EU821900 EU821870 EU821840 EU821930
N. lumnitzerae CMW 41469* KP860881 KP860724 KP860801 KU587925
N. luteum CBS 562.92 KX464170 KX464690 KX464968 KX464020
N. macroclavatum CBS 118223* DQ093196 DQ093217 DQ093206 KX464022
N. mangiferae CBS 118531* AY615185 DQ093221 AY615173 KX464023
N. mangroviorum CMW 41365* KP860859 KP860702 KP860779 KU587905
N. mediterraneum CBS 121718* GU251176 GU251308 N/A KX464024
N. microconidium CERC 3497* KX278053 KX278158 KX278262 MF410203
N. nonquaesitum CBS 126655* GU251163 GU251295 GU251823 KX464025
N. occulatum CBS 128008* EU301030 EU339509 EU339472 EU339558
N. parvum CBS 138823* AY236943 AY236888 AY236917 EU821963
N. pennatisporum MUCC 510* EF591925 EF591976 EF591959 N/A
N. pistaciae CBS 595.76* KX464163 KX464676 KX464953 KX464008
N. pistaciarum CBS 113083* KX464186 KX464712 KX464998 KX464027
N. pistaciicola CBS 113089* KX464199 KX464727 KX465014 KX464033
N. protearum CBS 114176* AF452539 KX464720 KX465006 KX464029
N. pruni CBS 121112* EF445349 EF445391 KX465016 KX464034
N. ribis CBS 115475* AY236935 AY236877 AY236906 EU339554
N. sinense CGMCC 3.18315* KY350148 KY817755 KY350154 N/A
N. sinoeucalypti CERC 2005* KX278061 KX278166 KX278270 KX278290
N. stellenboschiana CBS 110864* AY343407 AY343348 KX465047 KX464042
N. terminaliae CBS 125264 GQ471802 GQ471780 KX465053 KX464046
N. umdonicola CBS 123645* EU821904 EU821874 EU821844 EU821934
N. ursorum CMW 24480* FJ752746 FJ752709 KX465056 KX464047
N. viticlavatum CBS 112878* AY343381 AY343342 KX465058 KX464048
N. vitifusiforme CBS 110887* AY343383 AY343343 KX465061 KX464049
Botryosphaeria dothidea CBS 100564 KX464085 KX464555 KX464781 KX463951

 

Fig. First of 1000 most parsimonious trees resulting from analysis of combined ITS, TEF1-α, tub2 and RPB2 sequence data. Forty-three strains were included in the analyses, which comprise 1829 characters including gaps. The tree was rooted with Botryosphaeria dothidea. (CBS 100564). The topology of the MP tree was similar to that of the ML and BI trees. The maximum parsimony dataset consisted of 1829 characters of which 1335 were constant, 241 variable characters were parsimony uninformative. Analysis of the remaining 253 parsimony-informative characters resulted in 1000 equally most parsimonious trees with a length of 873 steps and CI = 0.674, RI = 0.762, HI = 0.326. The best scoring RAxML tree had a final likelihood value of -7311.594985. The matrix had 583 distinct alignment patterns, with 14.54% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.214778, C = 0.295225, G = 0.272849, T = 0.217148; substitution rates AC = 1.184543, AG = 5.593626, AT = 1.053227, CG = 1.490317, CT = 11.314839, GT = 1.000000; gamma distribution shape parameter α = 0.472397. Bootstrap values for MP followed by ML are given at the nodes Thickened lines represent Bayesian posterior probability scores >0.95. Ex-type and ex-epitype isolates are in bold

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