Thesis (MScAgric )--Stellenbosch University, 2004. / ENGLISH ABSTRACT: In an attempt to combat some of the pathogens that are associated with trunk diseases and
disorders of grapevines, research in this thesis focused on the taxonomy and pathological aspects
of Coniellai/Pilidiella, Botryosphaeria and Phomopsis spp.
Previously, conidial pigmentation was used to separate Pilidiella from Coniella.
Recently, however, the two genera have been regarded as synonymous, with the older name,
Coniella, having priority. The most important species in the Coniellai/Pilidiella complex of
grapevines is C. diplodiella (Speg.) Petr. & Syd., the causal organism of white rot of grapevines.
Previous studies found it difficult to distinguish between C. diplodiella and C. fragariae
(Oudem.) B. Sutton, which is known to occur in soil and caused leaf diseases of Fragaria and
Eucalyptus. Both these species have previously been reported from South Africa. None of the
reports on C. diplodiella could be scientifically substantiated; therefore it is still a quarantine
organism. However, this status has been questioned. Based on sequence analyses of the internal
transcribed spacer region (ITS 1, ITS 2), 5.8S gene, large subunit (LSU) and elongation factor 1-
α gene (EF l- α) from the type species of Pilidiella and Coniella, Coniella was separated from
Pilidiella, with the majority of taxa residing in Pilidiella. Pilidiella is characterised by species
with hyaline to pale brown conidia (avg. length: width >1.5), with Coniella having dark brown
conidia (avg. length: width ≤1.5). Pilidiella diplodiella, previously C. diplodiella, causal
organism of white rot of grapevines, was shown to be an older name for C. petrakii. This fungus
is present in South Africa and is therefore no longer of quarantine importance. Based on
analyses of the histone (H3) gene sequences of isolates in the P. diplodiella species complex, P.
diplodiella was separated from a newly described species, P. diplodiopsis. A new species, P.
eucalyptorum, is proposed for isolates formerly treated as C. fragariae, associated with leaf
spots of Eucalyptus spp. This species clustered basal to Pilidiella, and may represent yet a third
genus within this complex. Pilidiella destruens was newly described as anamorph of
Schizoparme destruens, which is associated with twig dieback of Eucalyptus spp. in Hawaii.
The genus Botryosphaeria Ces. & De Not. are known to be cosmopolitan, with broad host
ranges and geographical distributions. Several saprotrophic species have been reported from
grapevines, while others are severe pathogens of this host. These species include B. dothidea
(Moug.: Fr.) Ces. & De Not., B. parva Pennycook & Samuels, B. obtusa (Schwein.) Shoemaker,
B. stevensii Shoemaker, B. lutea A.J.L. Phillips and B. ribis Grossenb. & Duggar. Species
reported from South Africa as grapevine pathogens are B. obtusa, B. dothidea, B. ribis and B.
vitis (Schulzer) Sacco. In the present study, morphological, DNA sequence data (ITS 1, 5.8S, ITS
2 and EFI-α) and pathological data were used to distinguish 11 Botryosphaeria spp. associated
with grapevines from South Africa and other parts of the world. Botryosphaeria australis, B.
lutea, B. obtusa, B. parva, B. rhodina and a Diplodia sp. were confirmed from grapevines in
South Africa, while Diplodia porosum, Fusicoccum viticlavatum and F. vitifusiforme were
described as new species. Although isolates of B. dothidea and B. stevensii were confirmed from
grapevines in Portugal, neither of these species, nor B. ribis, were isolated in this study. All
grapevine isolates from Portugal, formerly presumed to be B. rib is, are identified as B. parva
based on EF1-α sequence data. Artificial inoculations on grapevine shoots showed that B.
australis, B. parva, B. ribis and B. stevensii are more virulent than the other species studied. The
Diplodia sp. collected from grapevine canes was identified as morphologically similar, but
phylogenetically distinct from D. sarmentorum, while D. sarmentorum was confirmed as
anamorph of Otthia spiraeae, the type species of the genus Otthia (Botryosphaeriaceae). A
culture identified as O. spiraeae clustered within Botryosphaeria, and is thus regarded as a
probable synonym. These findings confirm earlier suggestions that the generic concept of
Botryosphaeria should be expanded to include genera with septate ascospores and Diplodia
anamorphs.
The genus Phomopsis (Sacc.) Bubak contains many species that are plant pathogenic or
saprotrophic. Ten species are known from grapevines. However, only two have been confirmed
as being pathogenic, namely P. viticola (Sacc.) Sacc., causal organism of Phomopsis cane and
leaf spot and P. vitimegaspora Kuo & Leu (teleomorph Diaporthe kyushuensis Kajitani &
Kanem.), causal organism of swelling arm disease of grapevines. P. amygdali (Delacr.) 1.1.
Tuset & M.T. Portilla, a known pathogen from Prunus sp., was shown to be a possible pathogen
of grapevines in a previous study. D. perjuncta Niessl. causes bleaching of dormant canes only
and is therefore of little importance as a grapevine pathogen. Recently a number of Phomopsis
isolates were obtained from grapevines in the Western Cape province of South Africa. Isolations
were made from Phomopsis-like symptoms, pruning wounds and asymptomatic nursery plants.
These isolates showed great variation in morphology and cultural characteristics. Earlier
taxonomic treatments of Phomopsis, based species identification on host specificity, cultural
characteristics and morphology. Recent studies have indicated that these characteristics can no
longer be used to distinguish species of Phomopsis due to wide host ranges and morphological
plasticity of some species. The use of anamorph/teleomorph relationships in species
identification is also untenable, since Diaporthe teleomorphs have only been described for
approximately 20% of the known Phomopsis species. In this study morphological data, DNA
sequences (ITS-I, 5.8S, ITS-2) and pathogenicity data were combined to distinguish Phomopsis
spp. from grapevines. Fifteen species of Phomopsis were delineated by phylogenetic analysis of
ITS sequence data. Diaporthe helianthi, a sunflower pathogen, was reported from grapevines for
the first time, with a further six, unknown species also distinguished. Three different clades
contained isolates previously identified as D. perjuncta. Based on type studies, it appeared that
the name D. viticola was available for collections from Portugal and Germany, a new species, D.
australafricana, was proposed for South African and Australian isolates, formerly treated as D.
perjuncta or D. viticola. An epitype specimen and culture were designated for D. perjuncta.
This species was distinguished from D. viticola and D. australafricana based on morphology and
DNA phylogeny. Artificial inoculations of green grapevine shoots indicated that, of the species
tested, P. amygdali, a known pathogen of peaches in the USA, and P. viticola were the most
virulent. / AFRIKAANSE OPSOMMING: In 'n poging om sommige patogene geassosieer met stamsiektes en syndrome, te beveg,
het die navorsing in die tesis gefokus op die taksonomie en patologiese aspekte van
ConiellaiPilidiella, Botryosphaeria en Phomopsis spp
Voorheen is konidium pigmentasie gebruik om Pilidiella (hialien tot ligbruin konidia) van
Coniella (donkerbruin konidia) te skei. Onlangs is hierdie twee genera egter as sinoniem beskou
met die ouer naam, Coniella, wat voorkeur gekry het. Die belangrikste spesies in die
ConiellaiPilidiella kompleks van wingerd is C. diplodiella (Speg.) Petr. & Syd., die
veroorsakende organisme van witvrot van wingerd. Vorige studies het dit moeilik gevind om te
onderskei tussen C. diplodiella en C. fragariae (Oudem.) B. Sutton, wat bekend is dat dit in
grond voorkom en ook blaarsiektes van Fragaria en Eucalyptus veroorsaak. Beide hierdie
spesies is tevore in Suid-Afrika aangemeld. Geen van die aanmeldings van C. diplodiella is
egter wetenskaplik bewys nie en daarom is dit steeds 'n kwarantyn organisme. Hierdie
kwarantyn status is egter bevraagteken. Op grond van DNS volgordes van die interne
getranskribeerde spasieerder area ("ITS 1", "ITS2"), die 5.8S rRNS geen, die groot ribosomale
subeenheid ("LSU") en die verlengingsfaktor 1-α geen ("EF-lα") van die tipe spesies van
Pilidiella en Coniella, is Coniella van Pilidiella geskei, met die meerderheid van die taxa wat
binne Pilidiella resorteer. Pilidiella word gekarakteriseer deur spesies met hialien tot ligbruin
konidia (gem. lengte: breedte > 1.5), in teenstelling met die donkerbruin konidia van Coniella
(gem. lengte: breedte ≤ 1.5). Daar is verder bewys dat Pilidiella diplodiella, voorheen C.
diplodiella, veroorsakende organisme van witvrot van wingerd, die ouer naam van C. petrakii is.
Hierdie swam is teenwoordig in Suid-Afrika en P. diplodiella is dus nie meer van kwarantyn
belang nie. Op grond van analises van die histoon (H3) volgordes van spesies in die P.
diplodiella spesies kompleks, is P. diplodiella geskei van 'n nuut beskryfde spesie, P.
diplodiopsis. 'n Nuwe spesie, P. eucalyptorum, is ook voorgestel vir isolate voorheen beskou as
C. fragariae, geassosieer met blaarvlek van Eucalyptus spp. Hierdie spesie het basaal van
Pilidiella gegroepeer en mag moontlik nog 'n derde genus binne hierdie kompleks
verteenwoordig. Pilidiella destruens is nuut as anamorf van Schizoparme destruens beskryf, wat
geassosieer word met loot terugsterwing van Eucalyptus spp. in Hawaii.
Die genus Botryosphaeria Ces. & De Not. is bekend as kosmopolitaans met 'n wye
gasheerreeks en geografiese verspreiding. Verskeie saprofitiese spesies is aangemeld vanaf
wingerd, terwyl ander ernstige patogene van hierdie gasheer is. Laasgenoemde spesies sluit in B.
dothidea (Moug.: Fr.) Ces. & De Not., B. parva Pennycook & Samuels, B. obtusa (Schwein.)
Shoemaker, B. stevensii Shoemaker, B. lutea A.1.L. Phillips en B. ribis Grossenb. & Duggar.
Spesies aangemeld in Suid-Afrika as wingerdpatogene, is B. obtusa, B. dothidea, B. ribis en B.
vitis (Schulzer) Sacco In hierdie studie is morfologiese, DNS volgorde data ("ITSl", "ITS2",
5.8S en "EF-Iα") en plantpatologiese data gebruik om II Botryosphaeria spesies, geassosieer
met wingerde in Suid-Afrika en verskeie ander werelddele, te onderskei. Botryosphaeria
australis, B. lutea, B. obtusa, B. parva, B. rhodina en 'n Diplodia sp. is bevestig van wingerde in
Suid-Afrika, terwyl Diplodia porosum, Fusicoccum viticlavatum en F. vitifusiforme as nuwe
spesies beskryf is. AIhoewel isolate van B. dothidea en B. stevensii bevestig is van wingerde in
Portugal, is geen van hierdie spesies en ook nie B. ribis geïsoleer nie. AIle isolate vanaf wingerd
in Portugal, voorheen beskou as B. rib is, is as B. parva op grond van hul "EF-lα" volgordes
geïdentifiseer. Uit kunsmatige isolasies gemaak op wingerdlote is die gevolgtrekking gemaak
dat B. australis, B. parva, B. ribis en B. stevensii meer virulent is as die ander spesies wat
bestudeer is. Die Diplodia sp. versamel vanaf wingerdlote is geïdentifiseer as morfologies
eenders, maar filogeneties verskillend van D. sarmentorum, terwyl D. sarmentorum bevestig is
as die anamorf van Otthia spiraeae, die tipe spesie van die genus Otthia (Botryosphaeriaceae).
'n Kultuur wat as 0. spiraeae geïdentifiseer is, het binne Botryosphaeria gegroepeer, en word
dus as 'n moontlike sinoniem beskou. Hierdie bevindinge bevestig vroeëre voorstelle dat die
generiese konsep van Botryosphaeria uitgebrei behoort te word om genera met gesepteerde
askospore en Diplodia anamorwe in te sluit.
Die genus Phomopsis (Sacc.) Bubak bevat verskeie spesies wat as of plantpatogenies, of
saprofities, beskryf is. Tien spesies is bekend op wingerd. Slegs twee is as patogenies bevestig,
naamlik P. viticola (Sacc.) Sacc., veroorsakende organisme van loot-en-blaarvlek ("streepvlek")
en P. vitimegaspora Kuo & Leu (teleomorf Diaporthe kyushuensis Kajitani & Kanem.),
veroorsakende organisme van geswelde arm van wingerd. In 'n vroeëre studie is bevind dat P.
amygdali (Delacr.) 1.1. Tuset & M.T. Portilla, 'n bekende patogeen van Prunus sp., moontlik ook
'n patogeen van wingerd mag wees. D. perjuncta Niessl. veroorsaak egter net verbleiking van
dormante lote en is dus van min belang as 'n wingerd patogeen. Gedurende die afgelope twee
jaar is verskeie Phomopsis isolate van wingerde in die Wes-Kaap provinsie van Suid-Afrika
verkry. Isolasies is gemaak van Phomopsis-agtige simptome, snoeiwonde en asimptomatiese
kwekeryplante. Die isolate verkry uit hierdie materiaal het groot variasie ten opsigte van
morfologie en kultuureienskappe getoon. Vroeëre taksonomiese verhandelings van Phomopsis
het spesies-identifikasie op gasheerspesifisiteit, kultuureienskappe en morfologie gebasseer.
Onlangse studies het egter getoon dat, weens wye gasheerreekse en morfologiese plastisiteit van
somnuge spesies, hierdie eienskappe me meer gebruik kan word om Phomopsis spesies te
identifiseer nie. Die gebruik van anamorflteleomorf verwantskappe in die identifikasie van
Phomopsis spesies ook onbruikbaar omdat Diaporthe teleomorwe vir slegs ongeveer 20% van
die bekende Phomopsis spesies beskryf is. Die huidige studie het dus morfologiese data, DNS
volgordes ("ITS 1", 5.8S, "ITS2") en patogenisiteitsdata gekombineer ten einde Phomopsis spp.
vanaf wingerd te identifiseer. Vyftien Phomopsis spesies is deur die filogenetiese analise van die
interne getranskribeerde spasieerder area ("ITS") volgordes geskei. Diaporthe helianthi, 'n
bekende patogeen van sonneblomme, is vir die eerste maal op wingerd aangeteken, terwyl 'n
verdere ses, tans onbekende spesies van Phomopsis ook geidentifiseer is. Drie verskillende
groepe het isolate bevat wat voorheen as D. perjuncta geidentifiseer is. Gebasseer op studies van
tipes, het dit voorgekom dat die naam D. viticola beskikbaar is vir isolate uit Portugal en
Duitsland. 'n Nuwe spesie, D. australafricana, is voorgestel vir Suid-Afrikaanse en Australiese
isolate wat voorheen behandel is as D. perjuncta of D. viticola. 'n Epitipe monster en kultuur is
vir D. perjuncta benoem. Hierdie spesie is van D. viticola en D. australafricana onderskei op
grond van morfologie en DNS filogenie. Kunsmatige inokulasies van groen wingerdlote het
getoon dat P. amygdali, bekende perske patogeen, en P. viticola die mees virulent was.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/49879 |
| Date | 04 1900 |
| Creators | Van Niekerk, Jan Marthinus |
| Contributors | Crous, P. W., Fourie, P. H., Stellenbosch University. Faculty of AgriSciences. Dept. of Plant Pathology . |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
| Format | 142 p. : ill. |
| Rights | Stellenbosch University |
Page generated in 0.0043 seconds