18S rDNA for species of Leptolegnia and other Peronosporomycetes: justification for the subclass taxa Saprolegniomycetidae and Peronosporomycetidae and division of the Saprolegniaceae sensu lato into the Leptolegniaceae and Saprolegniaceae

Dick, M.W.; Vick, Mary C.; Gibbings, J. George; Hedderson, Terry A.; Lastra, Cláudia C. López

doi:10.1017/s0953756299008643

Cited by 74 publications

(40 citation statements)

References 20 publications

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“…Also, zoospores retained the transcript in P. infestans but lacked it in S. parasitica, although it reappeared after zoospore encystment in the latter. Such discrepancies may be attributed to differences in the biology of the spore cycles in the two species, which are widely separated within the oomycete group based on rRNA-based taxonomies (9). Alternatively, it cannot be assumed that the two Puf proteins are homologues, since they have little similarity outside of the Pum-HD.…”

Section: Discussionmentioning

confidence: 99%

A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans Is a Member of the Puf Family of Translational Regulators

Cvitanich

Judelson

2003

Eukaryot Cell

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A gene from Phytophthora infestans that was previously identified as being induced during the development of sexual spores was also found to be active during asexual sporulation. The gene, M90, was expressed as a 3.1-kb primary transcript containing two introns and was predicted to encode a member of the Puf family of translational regulators. The protein showed up to 51% amino acid identity to other Puf proteins within its 353-amino-acid RNA-binding domain. Little similarity extended beyond this region, as noted for other members of the family. Expression of M90 was measured by using RNA blots and transformants of P. infestans expressing a fusion between the M90 promoter and the ␤-glucuronidase (GUS) gene. A 1.3-kb promoter fragment conferred the normal M90 pattern of expression to the GUS reporter in transformants. In matings, expression was first detected in male and female gametangial initials and persisted in mature oospores. Expression was also observed in hyphal tips just prior to asexual sporulation, in sporangiophores, in mature sporangia, and in zoospores. The signal quickly disappeared once spores made the transition to hyphae after germination. Nutrient limitation did not induce the gene. Potential roles for a translational regulator during both sexual development and asexual sporulation are discussed.Mating, sexual sporulation, and asexual sporulation are central to the life histories of many lower eukaryotes. Mating is important because this increases genetic fitness and diversity and because sexual spores are often thick walled and thus more durable than vegetative structures. Also, both sexual and asexual spores are the main agents of dispersal for many species. Detailed molecular analyses of these pathways have been executed only for selected groups, particularly the cellular slime molds, true fungi such as ascomycetes and basidiomycetes, and green algae (2,5,10,13,31). Very limited information is available for most other lower eukaryotes, including oomycetes.Most oomycetes, which include important parasites of plants and animals, undergo both sexual and asexual sporulation. Despite their generally filamentous, fungus-like pattern of growth, oomycetes are diploid and share a close taxonomic relationship with chrysophytes, diatoms, and brown algae rather than with true fungi (3). One of the best-known oomycetes is Phytophthora infestans, which caused the Irish potato famine in the 1840s. The late blight diseases caused by P. infestans continue to have devastating effects on agricultural production and threaten food security (12).The physiology of sporulation in oomycetes is well described, but little is known at a molecular level. In heterothallic Phytophthora, sexual development occurs in response to hormonal interactions between A1 and A2 mating types (4,16,19). Male and female gametangia termed antheridia and oogonia form, and then oogonia penetrate antheridia and develop into oospores. Meiosis occurs in both gametangia, after which haploid antheridial and oogonial nuclei fuse to form a zygote...

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Section: Discussionmentioning

confidence: 99%

A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans Is a Member of the Puf Family of Translational Regulators

Cvitanich

Judelson

2003

Eukaryot Cell

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“…We retain the name Oomycetes because of its wider currency in the mycological and plant pathological communities. Oomycetes are an ancient group, but their evolutionary history is mostly inferred from molecular phylogenetic studies of living species [3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Bhattacharya et al [17] suggested a mean age for the split between Oomycetes and Bacillariophyta of 936 Ma (range: 1150 -770 Ma).…”

Section: Introductionmentioning

confidence: 99%

Evidence of parasitic Oomycetes (Peronosporomycetes) infecting the stem cortex of the Carboniferous seed fernLyginopteris oldhamia

Strullu‐Derrien

Kenrick

Rioult³

et al. 2010

Proc. R. Soc. B.

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Thin sections of petrified fossils made during the latter part of the nineteenth and early twentieth centuries to investigate the internal tissue systems of plants now provide an important new source of information on associated micro-organisms. We report a new heterokont eukaryote (Combresomyces williamsonii sp. nov.) based on exquisitely preserved fossil oogonia, antheridia and hyphae from the Carboniferous (Pennsylvanian: Bashkirian stage) of UK. The structure of the oogonia and antheridia and features observed within the hyphae demonstrate a relationship with Oomycetes (Peronosporomycetes). The fossil microorganism was documented in situ in petrified stem cortex and rootlets of the extinct seed fern Lyginopteris oldhamia (Pteridospermales). The main observed features point towards a pythiaceous Oomycete but links to biotrophic Albuginales or Peronosporaceae cannot be ruled out owing to the observation of a possible haustorium. Our study provides the earliest evidence for parasitism in Oomycetes.

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“…It has been proposed and widely accepted that oomycetes should still be considered fungi as they share many functional characteristics such as modes of nutrient absorption and growth habit with the true Fungi (Money 1998). Using small "f" on the word fungi is a practical solution when we want to speak about an inclusive functional group (Dick 2001). The phylum Pseudofungi is now narrowed down to a monophyletic clade containing oomycetes, hyphophytrids and Pirsonia (Cavalier-Smith and Chao 2006) and no longer includes all the straminipilous fungi (Tsui et al 2009), therefore, pseudofungi is not a useful colloquial name for mycologists.…”

Section: The Great Schismmentioning

confidence: 99%

“…This taxonomic concept whereby the unifying structures are the flagellar hairs, is broader and more appropriate for the oomycetes and their related groups. The first proposal for stramenopiles was not formally presented as a kingdom but Dick (2001) did propose that the name kingdom Straminipila be applied. Unfortunately, there has been a fairly significant amount of confusion in the correct spelling of this name.…”

Section: The Great Schismmentioning

confidence: 99%

“…The name oomycetes (Winter 1880) and its associated formal name Oomycota (Arx 1967) will be used throughout this chapter. An alternative group name, the Peronosporomycetes, was formally proposed by Dick (2001) and is here considered a synonym as in Kirk et al (2008). The name change to Peronosporomycete was proposed because of an overly strict interpretation of the International Code of Botanical Nomenclature.…”

Section: Introductionmentioning

confidence: 99%

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Fifty years of oomycetes—from consolidation to evolutionary and genomic exploration

Lévesque

2011

Fungal Diversity

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Transformative changes in biological sciences during the past 25 years have led to many significant advances in oomycete research. Before the last half century there were some hints that the oomycetes were related to some algae but it is now definitively demonstrated that they do not share an evolutionary path with kingdom Eumycota and are instead placed in a new kingdom Straminipila. Clarifying this once and for all has created many opportunities, but the rapid expansion of the research community has caused some fragmentation, probably much more so than in other groups of fungi because of a lack of a unifying forum for the members of the community working on issues such as taxonomy or phylogeny. Prior to the advent of molecular phylogenetics, mycologists working in zoosporic fungi were examining the ultrastructure of the zoospore, mainly focussing on the flagellar apparatus, and managed to generate phylogenies or define clades of zoospore producing fungi that remained for the most part valid after the advances in molecular biology. Comprehensive molecular phylogenies that have been published for some genera of the oomycetes have helped in recognising a large number of new species and in the development of a wide range of DNA-based diagnostic tools. The number of genomes available for this group is increasing rapidly, pushing further the discoveries of novel host-parasite interaction mechanisms in oomycetes. Some important plant diseases that were believed to be under control have re-emerged and many new diseases have appeared particularly in forestry and even in mammals. The research community has been able to respond rapidly and effectively to these new challenges. New ecological roles for the oomycetes were found in the suppression of plant diseases and reduction of plant invasineness in natural ecosystems. There are still many challenges ahead in the oomycete community, probably the most pressing one is to establish a robust tree of life foundation like the Assembling the Fungal Tree of Life initiative. The oomycete research community is dynamic and has put to very good use the many new technological advances.

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18S rDNA for species of Leptolegnia and other Peronosporomycetes: justification for the subclass taxa Saprolegniomycetidae and Peronosporomycetidae and division of the Saprolegniaceae sensu lato into the Leptolegniaceae and Saprolegniaceae

Cited by 74 publications

References 20 publications

A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans Is a Member of the Puf Family of Translational Regulators

A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans Is a Member of the Puf Family of Translational Regulators

Evidence of parasitic Oomycetes (Peronosporomycetes) infecting the stem cortex of the Carboniferous seed fernLyginopteris oldhamia

Fifty years of oomycetes—from consolidation to evolutionary and genomic exploration

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