15.3.2019 Endophytic bacterial communities in arcto-alpine plant shape the plant and help it cope with stress
Similar to humans, plants are associated with diverse communities of micro-organisms (bacteria, fungi, viruses). These microbes colonize all plant surfaces and internal tissues, and are collectively known as the plant microbiome. Plant microbiomes are crucial for many essential functions in the plants, including growth promotion and protection against environmental stresses and diseases.
In her doctoral dissertation Cindy Jittrapan Given has studied plant microbiome of the arcto-alpine pioneer plant species, Oxyria digyna (mountain sorrel, hapro). The study showed that the microbial treatment of the plant leaves or roots reshapes the endophytic bacterial communities of plant, impacts plant phenotype and can also improve the plant's resistance to heat tress. This can play a role in future plant production, where microbes can partially replace fertilizers and herbicides and pesticides.
Plant microbiomes have been understudied for a long time, and although in the past decade, the research interest in plant-associated microbes has increased rapidly, we still know relatively little about many central aspects of these communities: for example, how do these communities form and what are their central functions in the plants? With the focus on the endophytic bacteria (bacteria inhabiting the internal tissues of the plants), the goal of this thesis was to study the assembly rules and functional diversity of the bacterial communities in different tissues (leaves and roots) of Oxyria digyna.
To study endophyte community assembly bait plants were inoculated via either leaves or roots with bacterial consortia specific for leaves or roots of O. digyna.
The taxonomic structures of endophytic bacterial communities in the O. digyna leaves were shown to differ from those in the roots, showing strong tissue-specificity. This could be explained by adaptation of bacteria to different conditions in the above- ground and below-ground tissues, but also by the divergent colonization capacity of these endophytes. Bacterial endophytes were shown to be able to modify plant morphology in a tissue specific manner. Significantly, several endophytes were shown to protect the study plants from severe heat stress. The mechanisms underlying this stress mitigation, however, require future studies.
The findings in this thesis could be useful in developing sustainable, microbe assisted plant production methods, especially for cold climate plants. Additionally, climate change is predicted to have a significant impact on the composition and functioning of the ecosystems, especially in the Arctic and it is thus important to understand the plant-microbe interactions in these ecosystems.
This study was part of research project "Diversity and functioning of endophytic bacterial communities in arctic ecosystems", funded by Finnish Academy
The dissertation is published in the series JYU Dissertations, number 62, 62 p., Jyväskylä 2019, ISSN: 2489-9003, ISBN: 978-951-39-7690-3.
Link to publication:
More information:
M.Sc Cindy Jittrapan Given, cindy.j.given@jyu.fi, +358 469333880
Communications Officer Tanja Heikkinen, tanja.s.heikkinen, puh. +358 5818351