Abstracts
Abstract
The invasive fungal pathogens Ophiostoma ulmi and O. novo-ulmi have caused two successive pandemics of Dutch elm disease since the beginning of the 20th century. In nature, the highly aggressive O. novo-ulmi may hybridize with the less aggressive O. ulmi. Growth rate and molecular analyses were conducted on an unusual, moderately aggressive O. novo-ulmi isolate, AST27, carrying an introgressed pathogenicity gene, Pat1-m; on highly aggressive O. novo-ulmi isolate H327; on O. ulmi isolates Q412T and W9; and on progeny from laboratory crosses between H327 and AST27. Genetic analysis indicated that the Pat1 and Mat1 (mating type) loci were in different linkage groups corresponding to O. novo-ulmi H327 chromosomes 1 and 2, respectively. Most of the molecular differences between the nuclear genomes of H327 and AST27 occurred in the vicinity of Pat1 and Mat1. In addition, two putative quanti-tative trait loci, Mgr1 and Mgr2, which influence mycelial growth rate at 21°C and 28°C, the optima for O. novo-ulmi and O. ulmi, were linked to Mat1 and Pat1, respectively.
Keywords:
- Ophiostoma ulmi,
- Ophiostoma novo-ulmi,
- Dutch elm disease,
- introgression
Résumé
Les champignons pathogènes envahissants Ophiostoma ulmi et O. novo-ulmi ont causé deux pandémies successives de maladie hollandaise de l’orme depuis le début du 20e siècle. On a mesuré la croissance et procédé à des analyses moléculaires chez l’isolat O. novo-ulmi AST27, modérément agressif et chez lequel le gène de pathogénie Pat1-m est introgressé; chez l’isolat O. novo-ulmi H327; chez les isolats O. ulmi Q412T et W9; ainsi que chez les descendants de croisements dirigés entre les isolats H327 et AST27. Les analyses génétiques indiquent que les loci Pat1 et Mat1 (type sexuel) sont situés sur des groupes de liaison différents qui correspondent respectivement aux chromosomes 1 et 2. Les différences moléculaires entre les génomes nucléaires des souches H327 et AST27 se retrouvent majoritairement dans le voisinage de Pat1 et de Mat1. De plus, deux loci présumés de caractères quantitatifs, Mgr1 et Mgr2, qui influencent la croissance mycélienne à 21 °C et à 28 °C (températures optimales pour O. novo-ulmi et O. ulmi) sont liés respectivement à Mat1 et à Pat1.
Mots-clés :
- Ophiostoma ulmi,
- Ophiostoma novo-ulmi,
- maladie hollandaise de l’orme,
- introgression
Appendices
REFERENCES
- Bates, M.R., K.W. Buck, and C.M. Brasier. 1993. Molecular relationships between Ophiostoma ulmi and the NAN and EAN races of O. novo-ulmi determined by restriction fragment length polymorphisms of nuclear DNA. Mycol. Res. 97 : 449-455.
- Bernier, L. 1993. Conventional and molecular genetic approaches to the study of pathogenicity in Ophiostoma ulmi sensu lato. Pages 293-307 in M. Sticklen and J. Sherald (eds.), Dutch Elm Disease Research: Cellular and Molecular Approaches. Springer-Verlag, New York, NY, USA.
- Bernier, L., and M. Hubbes. 1990a. Mutations in Ophiostoma ulmi induced by N-methyl-N'-nitro-N-nitrosoguanidine. Can. J. Bot. 68 : 225-231.
- Bernier, L, and M. Hubbes. 1990b. Meiotic analysis of induced mutations in Ophiostoma ulmi. Can. J. Bot. 68 : 232-235.
- Bouvet, G.F., V. Jacobi, K.V. Plourde, and L. Bernier. 2008. Stress-induced mobility of OPHIO1 and OPHIO2, DNA transposons of the Dutch elm disease fungi. Fungal Genet. Biol. 45 : 565-578.
- Brasier, C.M. 1981. Laboratory investigation of Ceratocystis ulmi. Pages 76-79 in R.J. Stipes and R.J. Campana (eds.), Compendium of Elm Diseases. American Phytopathological Society Press. St. Paul, MN, USA.
- Brasier, C.M. 1986a. A comparison of pathogenicity and cultural characteristics in the EAN and NAN aggressive sub-groups of Ophiostoma ulmi. Trans. Brit. Mycol. Soc. 87 : 1-13.
- Brasier, C.M. 1986b. The population biology of Dutch elm disease: its principal feature and some implications for other host-pathogen systems. Adv. Plant Pathol. 5 : 55-118.
- Brasier, C.M. 1987. Some genetical aspects of necrotrophy with special reference to Ophiostoma-ulmi. Pages 297-310 in P.R. Day and G.J. Jellis (eds.), Genetics and Plant Pathogenesis. Blackwell Scientific Publications, Oxford, UK.
- Brasier, C.M. 1990. China and the origins of Dutch elm disease: an appraisal. Plant Pathol. 39 : 5-16.
- Brasier, C.M. 1991.Ophiostoma novo-ulmi sp. nov., causative agent of current Dutch elm disease pandemics. Mycopathologia 115 : 151-161.
- Brasier, C.M. 1995. Episodic selection as a force in fungal evolution with special reference to clonal speciation and hybrid introgression. Can. J. Bot. 73 : S1213-1221.
- Brasier, C.M., and F. Afsharpour. 1979. The aggressive and non-aggressive strains of Ceratocystis ulmi in Iran. Eur. J. For. Pathol. 9 : 113-122.
- Brasier, C.M., K.W. Buck, M. Paoletti, L. Crawford, and S.A. Kirk. 2004. Molecular analysis of evolutionary changes in populations of Ophiostoma novo-ulmi. Invest Agrar: Sist Recur For 13 : 93-103.
- Brasier, C.M., S.A. Kirk, N.D. Pipe, and K.W. Buck. 1998. Rare interspecific hybrids in natural populations of the Dutch elm disease pathogens Ophiostoma ulmi and O. novo-ulmi. Mycol. Res. 102 : 45-57.
- Brasier, C.M., S.A Kirk, and S. Tegli. 1995. Naturally occurring non cerato-ulmin producing mutants of Ophiostoma novo-ulmi are pathogenic but lack aerial mycelium. Mycol. Res. 99 : 436-440.
- Brasier, C.M., J. Lea, and M.K. Rawlings. 1981. The aggressive and non-aggressive strains of Ceratocystis ulmi have different temperature optima for growth. Trans. Brit. Mycol. Soc. 76 : 213-218.
- Brasier, C.M., and M.D. Mehrotra. 1995.Ophiostoma himal-ulmi sp. nov., a new species of Dutch elm disease fungus endemic to the Himalayas. Mycol. Res. 99 : 205-215.
- Brasier, C.M., and J.F. Webber. 1987. Positive correlations between in vitro growth rate and pathogenesis in Ophiostoma ulmi. Plant Pathol. 36 : 462-466.
- Comeau, A.M., J. Dufour, G.F. Bouvet, M. Nigg, V. Jacobi, B. Henrissat, J. Laroche, R.C. Levesque, and L. Bernier. 2015. Functional annotation of the Ophiostoma novo-ulmi genome: insights into the phytopathogenicity of the fungal agent of Dutch elm disease. Genome Biol. Evol. 7 : 410-430.
- Dewar, K., and L. Bernier. 1995. Inheritance patterns of nonhomologous chromosomes in Ophiostoma ulmi sensu lato. Curr. Genet. 27 : 541-549.
- Dewar, K., J. Bousquet, J. Dufour, and L. Bernier. 1997. A meiotically reproducible chromosome length polymorphism in the ascomycete fungus Ophiostoma ulmi (sensu lato). Mol. Gen. Genet. 255 : 38-44.
- Dusabenyagasani, M., J. Dufour, and L. Bernier. 2000. Approaches for genomic mapping of the Dutch elm disease pathogens. Phytopathology 90 : S21 (Abstract).
- Et-Touil, A., C.M. Brasier, and L. Bernier. 1999. Localization of a pathogenicity gene in Ophiostoma novo-ulmi and evidence that it may be introgressed from O. ulmi. Molec. Plant-Microbe Interac. 12 : 6-15.
- Et-Touil, A., D. Rioux, F.M. Mathieu, and L. Bernier. 2005. External symptoms and histopathological changes following inoculation of elms putatively resistant to Dutch elm disease with genetically close strains of Ophiostoma. Can. J. Bot. 83 : 656-667.
- Forgetta, V., G. Leveque, J. Dias, D. Grove, R. Lyons Jr., S. Genik, C. Wright, S. Singh, N. Peterson, M. Zianni, J. Kieleczawa, W. Hintz, V. Jacobi, L. Bernier, R. Levesque, and K. Dewar. 2013. Sequencing of the Dutch elm disease fungus genome using the Roche/454 GS-FLX Titanium system in a comparison of multiple genomics core facilities. J. Biomol. Tech. 24 : 39-49.
- Khoshraftar, S., S. Hung, S. Khan, Y. Gong, V. Tyagi, J. Parkinson, M. Sain, A.M. Moses, and D. Christendat. 2013. Sequencing and annotation of the Ophiostoma ulmi genome. BMC Genomics 14 : 162.
- Lander, E.S, P. Green, J. Abrahamson, A. Barlow, M.J. Daly, S.E. Lincoln, and L. Newburg. 1987. MAPMAKER: an interactive computer package for constructing primary genetic linkage maps of experimental and natural populations. Genomics 1 : 174-181.
- Michelmore, R.W., I. Paran, and R.V. Kessell. 1991. Identification of markers linked to disease resistance genes by bulked segregant analysis: a rapid method to detect markers in specific genomic regions using segregating populations. Proc. Natl. Acad. Sci. USA 88 : 9828-9832.
- Orita, M., Y. Suzuki, T. Sekiya, and K. Hayashi. 1989. Rapid and sensitive detection of point mutations and DNA polymorphisms using the polymerase chain reaction. Genomics 5 : 874-879.
- Paoletti, M., K.W. Buck, and C.M. Brasier. 2006. Selective acquisition of novel mating type and vegetative incompatibility genes via interspecies gene transfer in the globally invading eukaryote Ophiostoma novo-ulmi. Mol. Ecol. 15 : 249-262.
- Pipe, N.D., C.M. Brasier, and K.W. Buck. 2000. Two natural cerato-ulmin deficient mutants of Ophiostoma novo-ulmi: one has an introgressed O. ulmicu gene; the other has an O. novo-ulmicu gene with a mutation in an intron splice consensus sequence. Mol. Plant Pathol. 1 : 379-382.
- Pipe, N.D., K.W. Buck, and C.M. Brasier. 1995. Molecular relationships between Ophiostoma ulmi and the NAN and EAN races of O. novo-ulmi determined by RAPD markers. Mycol. Res. 99 : 653-658.
- Scala, F., F. Bertelli, L. Coppola, G. Del Sorbo, S. Tegli, and A. Scala. 1997. Comparative determination of cerato-ulmin on cell surface and in mycelial extracts of pathogenic and non-pathogenic Ophiostoma species. Mycol. Res. 101 : 829-834.
- Takai, S. 1980. Relationship of the production of the toxin, cerato-ulmin, to synnemata formation, pathogenicity, mycelial habit, and growth of Ceratocystis ulmi isolates. Can. J. Bot. 58 : 658-662.
- Takai, S., and W.C. Richards. 1978. Cerato-ulmin, a wilting toxin of Ceratocystis ulmi: isolation and some properties of cerato-ulmin from the culture of C. ulmi. Phytopathol. Z. 91 : 129-146.
- Temple, B, P.A. Horgen, L. Bernier, and W.E. Hintz. 1997. Cerato-ulmin, a hydrophobin secreted by the causal agents of Dutch elm disease, is a parasitic fitness factor. Fungal Genet. Biol. 22 : 39-53.
- Zolan, M., and P. Pukkila. 1986. Inheritance of DNA methylation in Coprinus cinereus. Mol. Cell. Biol. 6 : 195-200.