The Origins of Phytophthora Species Attacking Legumes in Australia

• Published in: Advances in Botanical Research Vol. 24; pp. 431 - 456
• Main Authors: Irwin, J.A.G., Crawford, A.R., Drenth, A.
• Format: Book Chapter Journal Article
• Language: English
• Published: United Kingdom Elsevier Science & Technology 1997
• Subjects: AGRICULTURE & FARMING; asexual reproduction; Botany & plant sciences; ENERGY TECHNOLOGY & ENGINEERING; Fabaceae; genetic variation; host specificity; literature reviews; origin; phylogeny; Phytophthora; Phytophthora vignae; plant pathogenic fungi; sexual reproduction; speciation; taxonomy; Australia
• ISBN: 9780120059249; 012005924X
• ISSN: 0065-2296; 2162-5948
• DOI: 10.1016/S0065-2296(08)60081-6

This chapter discusses the origins of phytophthora species attacking legumes in Australia. Phytophthora is one of the world's most economically significant genera of plant pathogens. In Australia alone, it is estimated to cause annual production loss in excess of $200 million. This does not include damage in natural ecosystems and subsequent losses to associated industries, such as tourism. Pasture legumes have played a major role in Australian agriculture for a long time. At the beginning of this century it was found that the accidentally introduced subterranean clover would flourish in regions with a winter rainfall and a short growing season. Phytophthora species may either be homothallic or heterothallic. The sexual spores, called “oospores” arise from fusion of two morphologically different gametangia; the oogonium and the antheridium. Despite many investigations, limited information is available concerning the dormancy of oospores and stimuli, which trigger their germination. Understanding the origins of Phytophthora provides insights into speciation processes, as well as applied relevance with respect to sources of resistance, particularly if a long history of co–evolution is expected. Gene–for–gene interactions in plant pathogens are the most rigorous demonstrations of co–evolution between antagonistic species. Hence, plant pathology has the potential to significantly contribute to the understanding of co–evolution and speciation in evolutionary biology.