Cytospora Ehrenb., Sylv. mycol. berol.: 28 (1818)

Cytospora was introduced by Ehrenberg (1818) as the type genus of the family Cytosporaceae in Diaporthales (Wehmeyer 1975; Barr 1978; Eriksson 2001; Castlebury et al. 2002). The genus is an important pathogenic fungus, causing canker and dieback on branches of a wide range of hosts with a wide distribution (Adams et al. 2005, 2006; Hyde et al. 2017, 2018; Norphanphoun et al. 2017, 2018).

Classification Sordariomycetes, Diaporthomycetidae, Diaporthales, Valsaceae

Type speciesCytospora chrysosperma (Pers.) Fr. 1823

Distribution – Worldwide

Disease symptoms – Canker and dieback disease on branches

Hosts – Species of Abies, Acer, Berberis, Betula, Ceratonia, Cornus, Cotinus, Crataegus, Elaeagnus, Eriobotrya, Eucalyptus, Juniperus, Lumnitzera, Malus, Picea, Pinus, Platanus, Platycladus, Populus, Prunus, Pyrus, Quercus, Rosa, Salix, Sequoia, Sibiraea, Sorbaronia, Sorbus, Spiraea, Styphnolobium, Syringa, Syzygium, Tibouchina, Ulmus, Vitis and Xylocarpus (Norphanphoun et al. 2018).


Morphological based identification and diversity

Cytospora is characterized by multi-loculate conidiomata with ostiolar necks and unicellular, elongate-allantoid to subcylindrical, hyaline conidia (Fan et al. 2015a, b; Norphanphoun et al. 2017, 2018; Fig. 7). The genus which was reported as causing canker diseases in many woody plants was established in 1818 and studied in detail by taxonomists (Fries 1823; Saccardo 1884). Valsa Fr. was reported as the sexual stage of this genus and therefore, Valsa was treated as a synonym of Cytospora (1818) based on the International Code of Nomenclature for Algae, Fungi, and Plants (ICN, McNeill et al. 2012), with Cytospora being the oldest and most widely used name (Adams et al. 2005; Fotouhifar et al. 2010; Fan et al. 2014; Rossman et al. 2015). Previously, the conventional identification of species in Cytospora was based on their host association, often with vague morphological descriptions. Mycologists began to elucidate the relationships between Cytospora species and their hosts, with morphological observations combined with phylogenetic analyses using internal transcribed spacer (ITS) regions as an effective fungal DNA barcode (Adams et al. 2005, 2006; Fotouhifar et al. 2010; Schoch et al. 2012). The establishment of multi-gene analyses using ITS, LSU, ACT, RPB2, TUB2 has proved comprehensive for the species level (Fan et al. 2015a, b, 2020; Liu et al. 2015; Yang et al. 2015; Hyde et al. 2016; Li et al. 2016; Norphanphoun 2017, 2018; Phookamsak et al. 2019).

Fig. Cytospora ampulliformis a stromatal habit in wood. b fruiting bodies on the substrate. c surface of fruiting bodies. d cross-section of the stroma showing conidiomata. e peridium. f ostiolar neck. g–i Conidiogenous cells with attached conidia. j Mature conidia. k, l Colonies on MEA (k-from above, l-from below). Scale bars: a = 2 mm, b = 1 mm, c= 500 µm, d, f = 200 µm, e = 50 µm, g, h = 10 µm, i, j = 5 µm.


Molecular based identification and diversity

        Comprehensive multigene phylogenetic analyses for this genus were performed by Fan et al. (2015a, b, 2020) and Norphanphoun et al. (2017, 2018).

This study reconstructs the phylogeny of Cytospora based on analyses of a combined ITS, LSU, ACT and RPB2 sequence data (Table 3, Fig 8). The phylogenetic tree is updated with recently introduced Cytospora species and corresponds to previous studies (Norphanphoun et al. 2018).

Recommended genetic markers (genus level) – LSU, ITS

Recommended genetic markers (species level) – ITS, ACT and RPB2

The accepted number of species: There are 630 species in Index Fungorum (2019) with an estimated 110 species in Kirk et al. (2008), 85 species have molecular data.

References: Fan et al. 2015a, b, Lawrence et al. 2017, Senanayake et al. 2017, 2018 (morphology), Norphanphoun et al. 2017, 2018 (morphology, phylogeny).


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


Species name Isolate no GenBank accession numbers
Cytospora acaciae CBS 468.69 DQ243804
C. ailanthicola CFCC 89970* MH933618 MH933653 MH933526 MH933592 MH933494 MH933565
C. abyssinica CMW 10181* AY347353
C. ampulliformis MFLUCC 16-0583* KY417726 KY417760 KY417692 KY417794
C. amygdali CBS 144233* MG971853 MG972002
C. atrocirrhata CFCC 89615 KR045618 KR045700 KF498673 KU710946 KP310858 KR045659
C. austromontana CMW 6735* AY347361
C. beilinensis CFCC 50493* MH933619 MH933654 MH933527 MH933495 MH933561
C. berberidis CFCC 89927* KR045620 KR045702 KU710990 KU710948 KU710913 KR045661
C. berkeleyi StanfordT3* AY347350
C. brevispora CBS 116811* AF192315
C. bungeanae CFCC 50495* MH933621 MH933656 MH933529 MH933593 MH933497 MH933563
C. californica CBS 144234* MG971935 MG972083 MG971645
C. carbonacea CFCC 89947 MH933622 MH933657 MH933530 MH933594 MH933498 MH933564
C. carpobroti CMW 48981* MH382812 MH411216 MH411212 MH411207
C. cedri CBS 196.50 AF192311
C. celtidicola CFCC 50497* MH933623 MH933658 MH933531 MH933595 MH933499 MH933566
C. centrivillosa MFLUCC 16-1206* MF190122 MF190068 MF377600
C. ceratosperma CBS 116.21 AY347335
C. ceratospermopsis CFCC 89626* KR045647 KR045726 KU711011 KU710978 KU710934 KR045688
C. chrysosperma CFCC 89981 MH933625 MH933660 MH933533 MH933597 MH933501 MH933568
C. cinerostroma CMW 5700* AY347377
C. cotini MFLUCC 14-1050* KX430142 KX430143 KX430144
C. curvata MFLUCC 15-0865* KY417728 KY417762 KY417694 KY417796
C. davidiana CXY 1350* KM034870
C. diatrypelloidea CMW 8549* AY347368
C. elaeagni CFCC 89632 KR045626 KR045706 KU710995 KF765708 KU710918 KR045667
C. eriobotryae IMI 136523* AY347327
C. erumpens MFLUCC 16-0580* KY417733 KY417767 KY417699 KY417801
C. eucalypti LSEQ AY347340
C. eucalypticola ATCC 96150* AY347358
C. eucalyptina CMW 5882 AY347375
C. eugeniae CMW 7029 AY347364
C. euonymicola CFCC 50499* MH933628 MH933662 MH933535 MH933598 MH933503 MH933570
C. euonymina CFCC 89993* MH933630 MH933664 MH933537 MH933600 MH933505 MH933590
C. fraxinigena MFLUCC 14-0868* MF190133 MF190078
C. friesii CBS 194.42 AY347328
C. fugax CBS 203.42 AY347323
C. germanica CXY 1322 JQ086563 JX524617
C. gigalocus CFCC 89620* KR045628 KR045708 KU710997 KU710957 KU710920 KR045669
C. granati CBS 144237* MG971799 MG971949 MG971514 MG971664
C. hippophaës CFCC 89639 KR045632 KR045712 KU711001 KU710961 KU710924 KR045673
C. japonica CBS 375.29 AF191185
C. joaquinensis CBS 144235* MG971895 MG972044 MG971605 MG971761
C. junipericola MFLU 17-0882* MF190125 MF190072 MF377580
C. juniperina CFCC 50501* MH933632 MH933666 MH933539 MH933602 MH933507
C. kantschavelii CXY 1383 KM034867
C. kunzei CBS 118556 DQ243791
C. leucosperma CFCC 89622 KR045616 KR045698 KU710988 KU710944 KU710911 KR045657
C. longiostiolata MFLUCC 16-0628* KY417734 KY417768 KY417700 KY417802
C. longispora CBS 144236* MG971905 MG972054 MG971615 MG971764
C. lumnitzericola MFLUCC 17-0508* MG975778 MH253453 MH253457 MH253461
C. mali CFCC 50028 MH933641 MH933675 MH933548 MH933606 MH933513 MH933577
C. melnikii MFLUCC 15-0851* KY417735 KY417769 KY417701 KY417803
C. mougeotii ATCC 44994 AY347329
C. multicollis CBS 105.89* DQ243803
C. myrtagena CBS 116843* AY347363
C. nitschkii CMW 10180* AY347356
C. nivea MFLUCC 15-0860 KY417737 KY417771 KY417703 KY417805
C. oleicola CBS 144248* MG971944 MG972098 MG971660 MG971752
C. palm CXY 1280* JN411939 KJ781297
C. parakantschavelii MFLUCC 15-0857* KY417738 KY417772 KY417704 KY417806
C. parapersoonii T28.1* AF191181
C. parapistaciae CBS 144506* MG971804 MG971954 MG971519 MG971669
C. paratranslucens MFLUCC 15-0506* KY417741 KY417775 KY417707 KY417809
C. pini CBS 224.52* AY347316
C. pistaciae CBS 144238* MG971802 MG971952 MG971517 MG971667
C. platanicola MFLU 17-0327* MH253451 MH253452 MH253449 MH253450
C. platycladi CFCC 50504* MH933645 MH933679 MH933552 MH933610 MH933516 MH933581
C. platycladicola CFCC 50038* KT222840 MH933682 MH933555 MH933613 MH933519 MH933584
C. plurivora CBS 144239* MG971861 MG972010 MG971572 MG971726
C. populicola CBS 144240* MG971891 MG972040 MG971601 MG971757
C. populina CFCC 89644 KF765686 KF765702 KU711007 KU710969 KU710930 KR045681
C. predappioensis MFLUCC 17-2458* MG873484 MG873480
  MFLU 17-0327 MH253451 MH253452 MH253449 MH253450
C. prunicola MFLU 17-0995* MG742350 MG742351 MG742353 MG742352
C. pruinopsis CFCC 50034* KP281259 KP310806 KP310836 KU710970 KP310849 KP310819
C. pruinosa CBS 201.42 DQ243801
C. punicae CBS 144244 MG971943 MG972091 MG971654 MG971798
C. quercicola MFLUCC 14-0867* MF190129 MF190073
C. rhizophorae MUCC302 EU301057
C. ribis CBS 187.36 DQ243810
C. rosae MFLUCC 14-0845* MF190131 MF190075
C. rostrata CFCC 89909* KR045643 KR045722 KU711009 KU710974 KU710932 KR045684
C. rusanovii MFLUCC 15-0854* KY417744 KY417778 KY417710 KY417812
C. salicacearum MFLUCC 15-0509* KY417746 KY417780 KY417712 KY417814
C. salicicola MFLUCC 14-1052* KU982636 KU982635 KU982637
C. salicina MFLUCC 15-0862* KY417750 KY417784 KY417716 KY417818
C. schulzeri CFCC 50040 KR045649 KR045728 KU711013 KU710980 KU710936 KR045690
C. sibiraeae CFCC 50045* KR045651 KR045730 KU711015 KU710982 KU710938 KR045692
C. sophorae CFCC 89598 KR045654 KR045733 KU711018 KU710985 KU710941 KR045695
C. sophoricola CFCC 89595* KR045655 KR045734 KU711019 KU710986 KU710942 KR045696
C. sophoriopsis CFCC 89600* KR045623 KP310804 KU710992 KU710951 KU710915 KP310817
C. sorbi MFLUCC 16-0631* KY417752 KY417786 KY417718 KY417820
C. sorbicola MFLUCC 16-0584* KY417755 KY417789 KY417721 KY417823
C. spiraeae CFCC 50049* MG707859 MG707643 MG708196 MG708199
C. tamaricicola CFCC 50508* MH933652 MH933687 MH933560 MH933617 MH933523 MH933588
C. tanaitica MFLUCC 14-1057* KT459411 KT459412 KT459413
C. thailandica MFLUCC 17-0262* MG975776 MH253455 MH253459 MH253463
C. tibouchinae CPC 26333* KX228284 KX228335
C. translucens CXY 1351 KM034874 KM034895
C. ulmi MFLUCC 15-0863* KY417759
C. valsoidea CMW 4309* AF192312
C. variostromatica CMW 6766* AY347366
C. vinacea CBS 141585* KX256256 KX256277 KX256235
C. viticola CBS 141586* KX256239 KX256260 KX256218
C. xylocarpi MFLUCC 17-0251* MG975775 MH253462 MH253458 MH253454

Fig Phylogenetic tree generated by maximum likelihood analysis of combined ITS, LSU, ACT and RPB2 sequence data of Cytospora species. Related sequences were obtained from GenBank. Eighty-five isolates are included in the analyses, which comprise 2756 characters including gaps. Single gene analyses were carried out and compared with each species, to compare the topology of the tree and clade stability. The tree was rooted with Diaporthe eres (AFTOL-ID 935). The tree topology of the ML analysis was similar to the MP. The best scoring RAxML tree with a final likelihood value of -8386.622374 is presented. The matrix had 388 distinct alignment patterns, with 11.83% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.245798, C = 0.237676, G = 0.273178, T = 0.243348; substitution rates AC = 1.882600, AG = 4.123164, AT = 2.015920, CG = 0.907833, CT = 12.626910, GT = 1.000000; gamma distribution shape parameter α = 1.105097. RAxML bootstrap support values ≥70% (BT) and bayesian posterior probabilities ≥0.95 (PP) are shown respectively near the nodes. Ex-type strains are in bold.

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