Are oomycetes ambushing native bush regeneration?

Be a part of an investigation into why the germination rates of kānuka decrease drastically in the field, compared to greenhouse or laboratory set-ups. The factors that this project focuses on are soil and on its microbial communities, particularly oomycetes (e.g., Phytophthora, Pythium, Lagena).

Project Background

Prior to human colonisation, 85% of Aotearoa was covered by indigenous forests. Most of these forests have been converted into farmland, pasture, urban areas, and non-native forests. Currently, natural forests occupy only 29% of New Zealand (NZ) land area, including early successional forests growing on grasslands. In recent years, efforts have increased to reestablish native forests on sites that are too marginal for pasture or plantation forests, including for carbon sequestration. Kānuka (Kunzea ericoides, Myrtaceae) is a native tree species which has gained great interest for indigenous forest regeneration from grasslands. Kānuka have the potential to invade infertile, poorly drained sites, and can be both ecto- and arbuscular mycorrhizal, which can benefit the reestablishment of other native tree species.

Reforestation by direct seeding is less laborious than transplanting seedlings and could allow greater restoration of difficult to access sites. However, the ability to undertake widespread restoration with kānuka is severely limited by failure of direct sown seeds. Even though germination and growth in greenhouse are highly successful, kānuka germination rate in the field is extremely low. Across numerous studies, kānuka seeds sown with a wide range of experimental treatments have had no success – but no prior study has investigated the role of pathogens. Soil-borne pathogens are an important factor influencing plants life cycles, and oomycetes are highly infective, ubiquitous, and frequently kill seeds and seedlings.

Project Overview

Here a summer scholar will be offered the opportunity to be a part of an investigation into why the germination rates of kānuka decrease drastically in the field, compared to greenhouse or laboratory set-ups. The factors that this project focuses on are soil and on its microbial communities, particularly oomycetes (e.g., Phytophthora, Pythium, Lagena). Oomycetes are soil borne pathogens which have significant impacts on various plant life stages and are widely diffused in soil. Oomycetes are particularly well known to inhibit seed germination and kill forest tree seedlings. Research has also shown that oomycetes in NZ can be particularly abundant in early successional sites.  The main aim of this project is to understand if oomycetes influence kānuka growth and whether they play a role in kānuka seed germination. If oomycetes effects are significant, the summer scholar will help determine which oomycete species are particularly responsible.

Opportunities for learning

Hosted at University of Canterbury, the student will be working with soil samples from the local Horomaka area. As a summer scholar there is the opportunity to develop bioprotection research skills. Specifically, when determining the type of oomycete species that are significant, the scholar will conduct baiting experiments followed by molecular analyses, and direct sequencing from diseased and healthy roots and/or seeds. There is also the chance to set up an in vivo experiment (to test oomycete impact on kānuka germination), test oomycete suppression methods, be involved in a greenhouse experiment design and execution and to gain molecular biology skills.

Connected Research

By building on the concept of holistic environmental health; for which the natural system is considered as source of both negative and beneficial feedback loops, this research greatly contributes to Pou Titirangi (specifically Pou 1.1). By using soil from the Banks Peninsula region, the research conducted within this project helps aid the research in Pou 1.1.2. Not only does this research intertwine with Pou Titirangi, but by providing a broader understanding of oomycetes in the environment it also complements Pou Tokomanawa.

Scholarship Amount:

A total of $6000 tax free is available for each scholarship. Fortnightly payments will be made for the duration of the scholarship, with the final payment of $1000 on receipt of the approved student project report.

Application Process

Please download and complete the BA Summer scholar student application form 2023 (Word doc).  Send your completed application form, along with a CV and a Cover Letter detailing why you feel you would be suitable for this position.

Along with your CV and cover Letter, send your completed application form to Elena Johnson [email protected] before the closing date Sunday 15th October, 2023