Phytophthora cinnamomi

Abstract

SUMMARYPhytophthora cinnamomi Rands was first isolated from cinnamon trees in Sumatra in 1922. The pathogen is believed to have originated near Papua New Guinea but now has a worldwide distribution. P. cinnamomi is heterothallic with A1 and A2 mating types; however, even in areas in which both mating types are present, it appears that genetic diversity arises asexually rather than as a result of sexual recombination. P. cinnamomi can grow saprophytically in the soil for long periods, rapidly capitalizing on the advent of favourable conditions to sporulate and produce vast numbers of asexual, biflagellate zoospores. The motile zoospores are attracted to suitable infection sites, where they attach and invade the plant. Within a few days, hyphae ramify throughout the tissues of susceptible plants, forming sporangia on the plant surface and rapidly amplifying the disease inoculum. Over the last 10 -15 years, molecular analyses have clarified details of the phylogeny of P. cinnamomi and other Oomycetes. Research on P. cinnamomi has given rise to a more comprehensive understanding of the structure and function of the motile zoospores. New methods have been developed for P. cinnamomi identification and diagnosis. Long-term studies of diseased sites, particular those in southern Australia, have produced a better understanding of the epidemiology of P. cinnamomi diseases. Research has also increased our knowledge of the mode of action and efficacy of inhibitors of P. cinnamomi diseases, especially the phosphonates. This review will present an overview of the advances these studies have made in our understanding of P. cinnamomi pathogenicity, epidemiology and control.Taxonomy: Phytophthora cinnamomi Rands; kingdom Chromista; phylum Oomycota; order Peronosporales; family Peronosporaceae; genus Phytophthora .Host range: Likely to infect in excess of 3000 species of plants including over 2500 Australian native species, and crops such as avocado, pineapple, peach, chestnut and macadamia.Disease symptoms: A root pathogen which usually causes rotting of fine and fibrous roots but which can also cause stem cankers. Often causes dieback of young shoots and is thought to do so as a result of interference with transpiration from roots to shoots.

Cloning, characterization and in vitro and in planta expression of a glucanase inhibitor protein (GIP) of Phytophthora cinnamomi

“…This pathogen can grow saprophytically in the soil and persists in soil or infected plant material as chlamydospores and, to a lesser extent, as oospores. It is known to survive for as long as 6 years in moist soil, and it is clear that moisture is a key factor in the establishment, spread and longevity of this pathogen [3].…”

Pathways to false positive diagnoses using molecular genetic detection methods; Phytophthora cinnamomi a case study

“…Phytophthora cinnamomi is widely distributed globally outside its presumed natural range and causes economic losses in both horticulture and in natural ecosystems (Hayden et al 2013). With over 4000 known hosts including horticultural species of significant economic importance such as avocado, pineapple, peach, chestnut, macadamia (Hardham 2005;Scott et al 2013), P. cinnamomi is considered one of the world's worst invasive alien species (Lowe et al 2000).…”

Potential for dissemination of Phytophthora cinnamomi by feral pigs via ingestion of infected plant material

“…They also impact on agricultural production and in Australia alone damage due to feral pigs is estimated to cost in excess of $107 million per annum (McLeod, 2004). The highly invasive plant pathogen P. cinnamomi infects over 3000 plant species worldwide including many agricultural, ornamental and forest species (Erwin and Ribeiro, 1996;Hardham, 2005). Shearer et al (2004) estimated that 2284 (40%) of the 5710 plant species in the South-West Botanical Province of Western Australia are susceptible to P. cinnamomi infection.…”

“…The non-fastidious diet of feral pigs typically incorporates a significant proportion of plant material including woody root material and underground structures (Masters, 1979;Choquenot et al, 1996;Giménez-Anaya et al, 2008), which are the primary sites for infection with P. cinnamomi in susceptible plants (Hardham, 2005;Hardy et al, 2007). Such foraging behaviour presents a means of pathogen dispersal in addition to the transport of contaminated soil.…”

“…Despite the introduction of both feral pigs and P. cinnamomi in many temperate habitats worldwide, very little is understood of the compounding potential of these two highly destructive and invasive species. Anecdotally, feral pigs have long been implicated in the spread of P. cinnamomi although relatively little data exists to support these claims.The non-fastidious diet of feral pigs typically incorporates a significant proportion of plant material including woody root material and underground structures (Masters, 1979;Choquenot et al, 1996;Giménez-Anaya et al, 2008), which are the primary sites for infection with P. cinnamomi in susceptible plants (Hardham, 2005;Hardy et al, 2007). Such foraging behaviour presents a means of pathogen dispersal in addition to the transport of contaminated soil.…”