Characterisation of Pythium and Phytophthora Species Associated with Grapevine Decline

Project Number
US PP MB 1 2002

Project title
Characterisation of Pythium and Phytophthora Species Associated with Grapevine Decline

Project leader
McLeod, A

Institution
University of Stellenbosch

Project description
Grapevine decline and replant diseases are causing great economical losses in the grapevine industry. Currently, we know that several trunk disease pathogens are involved in grapevine decline and replant diseases. Several of these trunk pathogens are endophytic pathogens that cause damage when grapevines are under stress. It is therefore important to identify biotic components that are inducing stress on grapevines, resulting in poor growth as well as increased damage by trunk disease pathogens.

Several studies have shown that replant and decline diseases of grapevine as well as many deciduous fruit trees, are caused by a complex of root pathogenic organisms. These root pathogens not only decreases water and nutrient uptake of the plant, resulting in poor growth, but also induces stress that could enhance trunk diseases. In South Africa, Pythium spp. are often isolated from diseased grapevine roots, where they are thought to play an important role in decline of young vines and replant diseases by destroying a substantial amount of root mass. However, other than studies in the late 1970’s, little is known about the Pythium and Phytophthora spp. and the extent of damage they cause on grapevines at present. The aim of this project will be to first collect various Pythium and Phytophthora isolates from grapevines showing decline and replant symptoms in vineyards and nurseries representing different climatic regions. Pythium spp. will also be collected from healthy grapevines that are not on replant soil in order to compare the Pythium population on healthy vines vs. vines showing decline. Pythium and Phytophthora isolates will be identified to species level based mainly on sequence data, but also morphological data. Lastly, the pathogenicity and virulence of the different Pythium spp. will be tested on selected rootstock cultivars in greenhouse trials. Altogether, this research is required for future development of sound control strategies of grapevine decline and replant diseases in South Africa.

Presentation(s)
Spies, C F J, Mazzola, M and McLeod, A. 2006. Characterisation of Pythium species associated with grapevine decline. Paper presented at the 44th Congress of the Southern African Society for Plant Pathology. 22-25 January 2006, South Africa.

Spies, C F J, Mazzola, M and McLeod, A. 2006. Pythium and Phytophthora species associated with grapevine decline. Paper presented at the 4th Australian Soilborne Diseases Symposium. 3-6 September 2006, Queenstown, New Zealand.

Spies, C F J, Mazzola, M and McLeod, A. 2006. Characterisation of Pythium and Phytophthora species associated with grapevine decline. Paper presented at the 29th National Congress of the South African Society for Enology and Viticulture. 14-17 November 2006, Somerset West, South Africa.

Spies, C F J, Mazzola, M and McLeod, A. 2007. Characterisation of Pythium and Phytophthora species associated with grapevine decline. Paper presented at the 45th Congress of the Southern African Society for Plant Pathology. 22-24 January 2007, Johannesburg, South Africa.

Spies, C F J, Mazzola, M and McLeod, A. 2007. Clarifying the species status of Pythium and Phytophthora on grapevine in South Africa. Presentation to the American Phytopathological Meeting. 28 July – 2 August 2007, San Diego, United States.

Spies, C F J, Mazzola, M and McLeod, A. 2008. Characterization and detection of Pythium and Phytophthora species on grapevine in South Africa. Paper presented at the 9th International Congress of Plant Pathology. 24-29 August 2008, Torino, Italy.

Spies, C F J, Mazzola, M, Mostert, L, Meitz, J C and McLeod, A. 2009. Genetic variation within the Pythium irregular species complex from grapevine in South Africa. Paper presented at the 46th Congress of the Southern African Society for Plant Pathology. 25-28 January 2009, Gordon’s Bay, South Africa.

Spies, C F J, Mazzola, M, Botha, W J, Koopman, T A, Meitz, J C, Paarwater, H, Mostert, L and McLeod, A. 2009. Characterisation of the Pythium vexans species complex from fruit crops in South Africa. Paper presented at the 46th Congress of the Southern African Society for Plant Pathology. 25-28 January 2009, Gordon’s Bay, South Africa.

Article
Spies, C F J, Mazzola, M, McLeod, A. 2006. Characterisation of Pythium species associated with grapevine decline, South African Journal of Science, v. 103 (p. 62)

Spies, C F J, Mazzola, M, McLeod, A. 2007. Clarifying the species status of Pythium and Phytophtphora on grapevine in South Africa, Phytopathology, v. 97 (p. S110)

Belbahri, L, McLeod, A, Paul, B, Calmin, G, Moralejo, E, Spies, C F J, Botha, W J, Clemente, A, Descals, E, Sanchez-Hernandez, E, Lefort, F. 2008. Intra specific and within isolate sequence variation in the ITS rDNA region of Pythium mercuriale sp. nov. (Pythiaceae) FEMS Microbiology Letters, Mnth Jul v. 284 (1) (p. 17-27)
http://doi.org/10.1111/j.1574-6968.2008.01168.x

Moraleja, E, Clemente, A, Descals, E, Belbahri, L, Calmin, G, Lefort, F, Spies, C F J, McLeod, A. 2008. Pythium recalcitrans sp. nov. revealed by multigene phylogenetic analysis, Mycologia, Mnth Mar v. 100 (2) (p. 310-319)
http://www.mycologia.org/content/100/2/310.full.pdf+html

Botha, W J, Mostert, L, Tewoldemedhin, Y T, McLeod, A. 2009. Morphological and molecular characterisation of Pythium species in South Africa, Mycological Research, v. 113 (933-51) (p. 62)

McLeod, A, Botha, W J, Meitz, J C, Spies, C F J, Tewoldemedhin, Y T, Mostert, L. 2009. Morphological and phylogenetic analysis of Pythium species in South Africa, Mycological Research, Mnth Sep v. 113 (9) (p. 933-951)

Spies, C F J, Mazzola, M, McLeod, A. 2011. Characterisation and detection of Pythium and Phytophthora species associated with grapevines in South Africa, European Journal of Plant Pathology, Mnth April v. 131 (p. 103)
http://dx.doi.org/10.1007/s10658-011-9791-5

Spies, C F J, Mazzola, M, Botha, W J, Van der Rijst, M, Mostert, L, McLeod, A. 2011. Oogonical biometry and phylogenetic analyses of the Pythium vexans species group from woody agricultural hosts in South Africa reveal distinct groups within this taxon, Fungal Biology, Mnth Feb v. 115 (2) (p. 157-168)

Dissertation
2009. Characterisation and detection of Pythium and Phytophthora species associated with grapevines in South Africa. PhD. University of Stellenbosch, Stellenbosch, South Africa.

Spies, C F J. 2009. Characterisation and detection of Pythium and Phytophthora species associated with grapevines in South Africa. University of Stellenbosch, Stellenbosch.

FinalReport.pdf

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