Ilyonectria P. Chaverri & Salgado, in Chaverri et al., Stud. Mycol. 68:69 (2011)

Species of Ilyonectria (Nectriaceae, Hypocreales) are important soil-borne pathogens of various woody and herbaceous plant hosts. Ilyonectria species are cosmopolitan and are found on a wide range of hosts (Chaverri et al. 2011). They are mostly associated with root diseases and stem cankers (Seifert et al. 2003; Halleen et al. 2004, 2006; Chaverri et al. 2011; Cabral et al. 2012a,b,c; Vitale et al. 2012; Lombard et al. 2013; Aiello et al. 2014). There are 23 species of Ilyonectria, all associated with disease symptoms of their original plant hosts (Chaverri et al. 2011; Cabral et al. 2012a,c; Lombard et al. 2013, 2014; Aiello et al. 2014). Ilyonectria is a well-known genus causing black foot rot of grapevines in various countries (Halleen et al. 2003, 2004, 2006; Chaverri et al. 2011; Cabral et al. 2012a, b, c; Lombard et al. 2014).

Classification Sordariomycetes, Hypocreomycetidae, Hypocreales, Nectriaceae

Type speciesIlonectria radicicola (Gerlach & L. Nilsson) P. Chaverri & Salgado, in Chaverri et al., Stud. Mycol. 68:71 (2011)

Distribution – Worldwide

Disease symptoms – Black foot disease, black root rot

      Characteristic symptoms of black foot disease include a reduction in root biomass and root hairs with sunken and necrotic lesions (Hallen et al. 2006). Severe necrosis of the root system results in stunting, wilting, leaf chlorosis, browning and leaf drop prior to death (Parkinson et al. 2017).

Hosts – Wide host range including plant genera in Amaryllidaceae, Aracaceae, Araliaceae, Cupressaceae, Fagaceae, Liliaceae, Myrtaceae, Pinaceae, Proteaceae, Rosaceae, Strelitziaceae and Vitaceae (Farr and Rossman 2019).


Morphological based identification and diversity

The genus Ilyonectria was introduced based on I. radicicola as the type species, to accommodate Neonectria species belonging to the “N. radicicola” group (Booth 1959). This genus has asexual morphs and belonged to Booth’s Group 3 (chlamydospores and microconidia present, Booth 1966; Chaverri et al. 2011; Lombard et al. 2014). Molecular phylogenetic studies revealed that Ilyonectria, as originally conceived, was paraphyletic (Cabral et al. 2012a, c; Lombard et al. 2013, 2014). There are 31 species epithets of Ilyonectria listed in Index Fungorum (2019). Conidial size, culture characters, and molecular data enabled the separation of Ilyonectria species (Cabral et al. 2012a, c; Lombard et al. 2013, 2014).


Molecular based identification and diversity

The highest resolution between species of Ilyonectria can be achieved with histone (His3) gene region. The topologies of the phylogenetic tree (Fig. 15) is similar to previous studies done on this genus (Cabral et al. 2012a; Lombard et al. 2014).


Recommended genetic markers (genus level) – ITS, LSU, tef1, TUB2

Recommended genetic markers (species level) –tef1, TUB2, His3

The accepted number of species: 23 species

References: Booth 1959, 1966 (morphology), Cabral et al. 2012a,b,c; Lombard et al. 2013, 2014 (morphology, phylogeny).


Table Details of the Ilyonectria 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/Voucher no ITS tef1 tub2 His3
Campylocarpon fasciculare CBS 112613 AY677301 JF735691 AY677221 JF735502
Ilyonectria capensis CBS 132815* JX231151 JX231119 JX231103 JX231135
I. coprosmae CBS 119606* JF735260 JF735694 JF735373 JF735505
I. crassa CBS 139.30* JF735275 JF735723 JF735393 JF735534
I. cyclaminicola CBS 302.93* JF735304 JF735770 JF735432 JF735581
I. destructans CBS 264.65* AY677273 JF735695 AY677256 JF735506
I. europaea CBS 129078* JF735294 JF735756 JF735421 JF735567
I. gamsii CBS 940.97 AM419065 JF735766 AM419089 JF735577
I. leucospermi CBS 132809* JX231161 JX231129 JX231113 JX231145
I. liliigena CBS 189.49* JF735297 JF735762 JF735425 JF735573
I. liriodendri CBS 110.81* DQ178163 JF735696 DQ178170 JF735507
I. lusitanica CBS 129080 JF735296 JF735759 JF735423 JF735570
I. macroconidialis CBS 112615 AY677290 JF735836 AY677233 JF735647
I. mors-panacis CBS 306.35* JF735288 JF735746 JF735414 JF735557
I. palmarum CBS 135754* HF937431 HF922614 HF922608 HF922620
I. panacis CBS 129079* AY295316 JF735761 JF735424 JF735572
I. protearum CBS 132811* JX231157 JX231125 JX231109 JX231141
I. pseudodestructans CBS 129081 AJ875330 JF735752 AM419091 JF735563
I. robusta CBS 308.35* JF735264 JF735707 JF735377 JF735518
I. rufa CBS 156.47 AY677272 JF735730 AY677252 JF735541
I. strelitziae CBS 142253 * KY304649 KY304727 KY304755 KY304621
I. venezuelensis CBS 102032 * AM419059 JF735760 AY677255 JF735571
I. vredenhoekensis CBS 132807* JX231155 JX231123 JX231107 JX231139


Fig. Phylogenetic tree generated by maximum likelihood analysis of combined ITS, TEF, TUB, and His3 sequence data of Ilyonectria species. Twenty-three strains are included in the analyses, which comprise 2242 characters including gaps. The tree is rooted in Campylocarpon fasciculare. The tree topology of the ML analysis was similar to the one generated from BI (Figure not shown). The best scoring RAxML tree with a final likelihood value of -9669.617830 is presented. The matrix had 507 distinct alignment patterns, with 5.11% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.219321, C = 0.325516, G = 0.222910, T = 0.230587; substitution rates AC = 0.215721, AG = 0.328038, AT = 0.225653, CG = 0.615208, CT = 5.798530, GT = 1.000000; gamma distribution shape parameter α = 0.518017. Maximum likelihood bootstrap support values ≥60% and Bayesian posterior probabilities ≥95 (BYPP) are indicated above or near the nodes. Ex-type strains are in bold.

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