Pathogen Profile #1

In My Time of Dying - Phytophthora cinnamomi

Author

Alyssa Martino
May 01, 2024 • Reading Time: 6 minutes

Hello and welcome to the first weekly Robigalia newsletter!

I’m bringing this first newsletter to you from Albany in the South West region of Western Australia.

Overlooking Lake Seppings and King George Sound in Albany, Western Australia

The region is a biodiversity hotspot, home to over 6000 plant species in the area. Perhaps some of the most distinctive species in the area is Jarrah (Eucalyptus marginata). Often found in mixed stand with Marri (Corymbia calophylla), these giants can grow up to 40 meters tall and are typified by their rough bark with cream flowers.

One of the most devastating diseases in this region is Phytophthora dieback caused by the soil-borne oomycete Phytophthora cinnamomi. Considered one of the 100 worst invasive alien species globally, P. cinnamomi was first described in 1922 as the causative agent of stripe canker on cinnamon trees in Sumatra. By the mid-20th century, P. cinnamomi was identified as a major threat to various plant species worldwide, including significant agricultural crops and native vegetation in Australia, Europe, and the Americas. The pathogen is a significant concern in agricultural sectors, affecting crops such as avocados, chestnuts, and macadamias. In Europe and the Americas, P. cinnamomi has been associated with the decline of oak and chestnut populations, among other species.

In the South West Biodiversity Hotspot of Western Australia, over 40% of native plant species are considered to be susceptible to the pathogen which attacks the root system of susceptible plants, impacting the plants ability to take up water and soil nutrients. The impact has been amplified by the recent drought in Western Australia, with Phytophthora potentially increasing drought stress through further limiting water uptake by the roots.

If you’re interested in reading more about P. cinnamomi, below are a few of the papers I’ve recently come across. You can find summaries from these and future articles in my database.

Phytophthora cinnamomi articles:

  • The study explores the individual and combined effects of drought stress and infection by the soil-borne pathogen Phytophthora cinnamomi on young Eucalyptus obliqua trees. This research provides valuable insights into the resilience of E. obliqua to concurrent stresses, which is crucial for forest management and conservation strategies under changing climate conditions.

  • The study aimed to investigate the effects of a drier climate on the population dynamics of the invasive pathogen Phytophthora cinnamomi in Mediterranean forests with varying soil properties and species compositions. This study suggest that while the aridification of the Mediterranean climate might reduce average pathogen abundance, it may not prevent high abundance peaks following extreme rainfall events, highlighting the complex interplay between climate change and pathogen dynamics in forest ecosystems.

  • The study aimed to identify and confirm the pathogenicity of Phytophthora species, specifically P. cinnamomi and P. alticola, affecting Eucalyptus globulus in Portugal, and to understand the distribution and impact of these pathogens. The study highlights the need for integrated disease management strategies to protect Eucalyptus plantations from Phytophthora infections, which pose a significant threat to the forestry economy in Portugal due to the high economic value of these trees for the paper and pulp industry.

Another article of interest:

  • Review of the the plant immune system by Jones, Staskawicz, and Dangl … no further introduction needed 😅

If you found this newsletter valuable, please pass it on to anyone else who you think may enjoy these weekly updates. I would love your feedback to help shape the newsletter in the future. Please reach out to me directly with any feedback or suggestions.

Until next week,

Alyssa

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