Pestalotiopsis

Pestalotiopsis Steyaert, Bull. Jard. bot. État Brux. 19: 300 (1949)

Pestalotiopsis is an appendage-bearing, 5-celled conidia (asexual coelomycetes) in the family Sporocadaceae (Maharachchikumbura et al. 2014a, b; Jayawardena et al. 2016). The genus was introduced by Steyaert (1949). Pestalotiopsis species are widely distributed throughout tropical and temperate regions (Guba 1961; Maharachchikumbura et al. 2012, 2014a). Pestalotiopsis species have been isolated from dead leaves, bark, twigs, soil, polluted stream water, wood, paper, fabrics, and wool (Guba 1961; Maharachchikumbura et al. 2012, 2014a). Some species have been associated with human and animal infections, and others (e.g. P. guepinii and P. microspora) have also been isolated from extreme environments (Maharachchikumbura et al. 2014b).

ClassificationSordariomycetes, Xylariomycetidae, Amphisphaeriales, Sporocadaceae

Type speciesPestalotiopsis guepinii (Desm.) Steyaert [as ‘guepini’], Bull. Jard. bot. État Brux. 19(3): 312 (1949)

Distribution – Worldwide

Disease symptoms – Species of Pestalotiopsis cause a variety of diseases in plants including canker lesions, shoot dieback, leaf spots, needle blight, tip blight, grey blight, scabby canker, severe chlorosis, fruit rots and various post-harvest diseases (Maharachchikumbura et al. 2013a, b, 2014a, b). These pathogens reduce production and cause economic loss in apple, blueberry, coconut, chestnut, ginger, grapevine, guava, hazelnut, lychee, mango, orchid, peach, rambutan, tea and wax apple due to diseases (Maharachchikumbura et al. 2013a, b, 2014a, b). Grapevine trunk diseases are the most destructive diseases of grapevines that impact the economic production and longevity of vineyards and even leading to partial or total death of individual plants. Therefore, the initial identification of the causal agent is essential for early control of these diseases (Jayawardene et al. 2015; Maharachchikumbura et al. 2017). Pestalotoid fungi have been reported as pathogens on a variety of grapevine cultivars, causing diseases including grapevine dieback, fruit rot, postharvest disease and severe defoliation and they infect all plant parts including leaves, canes, wood, berries and flowers (Jayawardene et al. 2015; Maharachchikumbura et al. 2017). Pestalotiopsis menezesiana (Bres. & Torr.) Bissett. and P. uvicola (Spegazzini) Bissett, are the most common species recorded from grapevine around the world and especially P. biciliata are associated with trunk grapevine disease (Jayawardene et al. 2015; Maharachchikumbura et al. 2017).

Hosts– Broad range of hosts including members of Altingiaceae, Arecaceae, Bromeliaceae, Euphorbiaceae, Myrtaceae, Poaceae, Proteaceae, Rosaceae, Rutaceae, Theaceae and Vitaceae.

 

Morphological based identification and diversity

There are around 250 species, most of which were named according to their host associations (Maharachchikumbura et al. 2014a, b). However, Pestalotiopsis species are not hosted specific and are found on a wide range of plants and substrates (Jeewon et al. 2003; Lee et al. 2006; Maharachchikumbura et al. 2014a, b). They exhibit considerable diversity in phenotype, and group together based on similarities in conidial morphology (Jeewon et al. 2003; Maharachchikumbura et al. 2012, 2013a, b, 2014a, b). Considering morphology, conidial length, width, median cell length, the colour of median cells and length of the apical appendages appear to be stable characters within Pestalotiopsis (Jeewon et al. 2003; Maharachchikumbura et al. 2014b).

Pestalotiopsis guepinii was considered to be the type species of the genus described from stems and leaves of Camellia japonica collected in France, and is characterised by 5-celled conidia with three concolourous median cells, hyaline terminal cells and simple or unbranched appendages arising from the apex of the apical cell (Steyaert 1949; Maharachchikumbura et al. 2014b). Nag Raj (1985) regarded P. maculans as the type species of Pestalotiopsis with P. guepinii as a synonym. Jeewon et al. (2003) also accepted P. maculans clusters with species having concolourous median cells based on phylogenetic analysis of ITS sequence data and that P. karstenii might be a synonym of P. maculans (Maharachchikumbura et al. 2014b).

Most Pesalotiopsis species lack sexual morphs. The sexual morph of Pestalotiopsis was treated as Pestalosphaeria Barr, with the type species Pestalosphaeria concentrica collected from grey-brown spots on living leaves of Rhododendron maximum in North Carolina, USA (Maharachchikumbura et al. 2014b). Pestalosphaeria concentrica is characterised by immersed, subglobose ascomata and unitunicate, cylindrical asci with a J+ apical ring; ascospores uniseriate in the ascus, ellipsoid, pale dull brown and 2-septate (Maharachchikumbura et al. 2014b).

Pestalotiopsis species have the ability to switch life-modes as endophytes, pathogens and saprobes (Hu et al. 2007; Maharachchikumbura et al. 2012). Therefore, many endophytic and plant pathogenic Pestalotiopsis species persist as saprobes and have been isolated from dead leaves, bark and twigs (Maharachchikumbura et al. 2012, 2013a, b, 2014b).

Pestalotiopsis species that were isolated as endophyte are important in the production of novel compounds with medicinal, agricultural and industrial applications (Maharachchikumbura et al. 2014b; Xu et al. 2010, 2014). Pestalotiopsis species are a rich source for bioprospecting compared to other fungal genera, and more than 100 compounds have been isolated from Pestalotiopsis (Maharachchikumbura et al. 2014b; Xu et al. 2010, 2014).

 

Molecular based identification and diversity

Maharachchikumbura et al. (2012) tested with 10 gene regions to resolve species boundaries in Pestalotiopsis (actin, calmodulin, glutamine synthase, glyceraldehyde-3-phosphate dehydrogenase, ITS, LSU, 18S nrDNA, RNA polymerase II, tef1 and TUB2). Maharachchikumbura et al. (2014b) used phylogenetic analysis of combined ITS, TUB2 and tef1 genes to successfully resolve Pestalotiopsis species.

 

Recommended genetic markers (genus level) – LSU (as outlined in Maharachchikumbura et al. 2012)

Recommended genetic markers (species level) – ITS, TUB2 and tef1 (as outlined in Maharachchikumbura et al. 2012)

Accepted number of species: There are 360 epithets in Index Fungorum in this genus, however, 75 species with DNA sequence data are accepted.

References: Maharachchukumbura 2013, 2014b, 2016b (morphology, phylogeny)

 

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

Species Isolate/Voucher No ITS TUB2 tef1
Pestalotiopsis adusta ICMP 6088* JX399006 JX399037 JX399070
P. aggestorum LC6301* KX895015 KX895348 KX895234
P. anacardiacearum IFRDCC 2397* NR120255.1 KC247155 KC247156
P. arceuthobii CBS 434.65* NR147561 KM199427 KM199516
P. arengae CBS 331.92* NR147560 KM199426 KM199515
P. australasiae CBS 114126* NR147546 KM199409 KM199499
P. australis CBS 114193* KM199332 KM199383 KM199475
P. biciliata CBS 124463* KM199308 KM199399 KM199505
P. brachiata LC2988* KX894933 KX895265 KX895150
P. brassicae CBS170.26* NR147562  – KM199558
P. camelliae MFLUCC 12-0277* NR120188 JX399041 JX399074
P. chamaeropis CBS 186.71* KM199326 KM199391 KM199473
P. clavata MFLUCC 12-0268* JX398990 JX399025 JX399056
P. colombiensis CBS 118553* NR147551  KM199421 KM199488
P. digitalis ICMP 5434* KP781879 KP781883  –
P. dilucida LC3232* KX894961 KX895293 KX895178
P. diploclisiae CBS 115587* NR147552 KM199419 KM199486
P. diversiseta MFLUCC 12-0287* NR120187 JX399040 JX399073
P. dracontomelon MFUCC 10-0149* KP781877  – KP781880
P. ericacearum IFRDCC 2439* KC537807 KC537821 KC537814
P. formosana NTUCC 17-009* MH809381 MH809385 MH809389
P. furcata MFLUCC 12-0054* JQ683724 JQ683708 JQ683740
P. gaultheria IFRD 411-014* KC537805 KC537819 KC537812
P. gibbosa NOF3175* LC311589 LC311590 LC311591
P. grevilleae CBS 114127* NR147548 KM199407  KM199504
P. hawaiiensis CBS 114491* NR147559 KM199428 KM199514
P. hollandica CBS 265.33* KM199328 KM199388 KM199481
P. humus CBS 336.97* KM199317 KM199420 KM199484
P. inflexa MFLUCC 12-0270* JX399008 JX399039 JX399072
P. intermedia MFLUCC 12-0259* JX398993 JX399028 JX399059
P. italiana MFLUCC 12-0657* KP781878 KP781882 KP781881
P. jester CBS 109350* KM199380 KM199468 KM199554
P. jiangxiensis LC4399* KX895009 KX895341 KX895227
P. jinchanghensis LC6636* KX895028 KX895361 KX895247
P. kenyana CBS 442.67* KM199302 KM199395 KM199502
P. knightiae CBS 114138* KM199310 KM199408 KM199497
P. licualacola HGUP 4057* KC492509 KC481683 KC481684
P. linearis MFLUCC 12-0271* JX398992 JX399027 JX399058
P. longiappendiculata LC3013* KX894939 KX895271 KX895156
P. lushanensis LC4344* KX895005 KX895337 KX895223
P. macadamiae BRIP 63738b* KX186588 KX186680 KX186621
P. malayana CBS 102220* NR147550 KM199411 KM199482
P. monochaeta CBS 144.97* KM199327 KM199386 KM199479
P. montellica MFLUCC 12-0279* JX399012 JX399043 JX399076
P. neolitseae NTUCC 17-011* MH809383 MH809387 MH809391
P. novae-hollandiae CBS 130973* NR147557 KM199425 KM199511
P. olivaceae PSHI2002* AY687883 DQ333580
P. oryzae CBS 353.69* KM199299 KM199398 KM199496
P. pallidotheae MAFF 240993* NR111022 LC311584 LC311585
P. papuana CBS 887.96* KM199318 KM199415 KM199492
P. parva CBS 265.37* KM199312 KM199404 KM199508
P. photinicola GZCC 16-0028* KY092404 KY047663 KY047662
P. portugalica CBS 393.48* KM199335 KM199422 KM199510
P. rhizophorae MFLUCC 17-0416* MK764283 MK764349 MK764327
P. rhododendri IFRDCC 2399* NR120265 KC537818 KC537811
P. rhodomyrtus HGUP 4230* KF412648 KF412642 KF412645
P. rosea MFLUCC 12-0258* JX399005 JX399036 JX399069
P. scoparia CBS 176.25* KM199330 KM199393 KM199478
P. shorea MFLUCC 12-0314* KJ503811 KJ503814 KJ503817
P. spathulata CBS 356.86* NR147558 KM199423 KM199513
P. telopeae CBS 114161* NR147545 KM199403 KM199500
P. thailandica MFLUCC 17-1616* MK764285 MK764351 MK764329
P. trachicarpicola IFRDCC 2440* NR120109 JQ845945 JQ845946
P. unicolor MFLUCC 12-0276* JX398999 JX399030  –
P. verruculosa MFLUCC 12-0274* NR120185  – JX399061
P. yanglingensis LC4553* KX895012 KX895345 KX895231
P. yunnanensis HMAS 96359* AY373375  –

Fig. Phylogram generated from RAxML analysis based on combined ITS, TUB2 and tef1 sequences of all the accepted species of Pestalotiopsis. Related sequences were obtained from GenBank. Seventy-nine taxa are included in the analyses, which comprise 1581 characters including gaps. The tree was rooted in Neopestalotiopsis cubana (CBS 600.96) and N. saprophytica (MFLUCC 12-0282). Tree topology of the ML analysis was similar to the BYPP and MP. The best scoring RAxML tree with a final likelihood value of -12269.881063 is presented. The matrix had 763 distinct alignment patterns, with 15.79% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.234129, C = 0.293516, G = 0.211518, T = 0.260837; substitution rates AC = 1.189917, AG = 3.402399, AT = 1.153875, CG = 1.001451, CT = 4.301074, GT = 1.000000; gamma distribution shape parameter α = 0.283001. The maximum parsimonious dataset consisted of 948 constant, 450 parsimony-informative and 183 parsimony-uninformative characters. The parsimony analysis of the data matrix resulted in the maximum of ten equally most parsimonious trees with a length of 1962 steps (CI = 0.498, RI = 0.697, RC = 0.347, HI = 0.502) in the first tree. RAxML and maximum parsimony bootstrap support value ≥50% and BYPP ≥0.90 values are shown near the nodes. The scale bar indicates 10 changes per site. The ex-type strains are in bold.

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