umu.sePublications
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Abiotic stress and plant-microbe interactions in Norway spruce
Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Norway spruce (Picea abies) is a dominant tree species in boreal forests with extensive ecological and economic value. Climate change is threatening these ecosystems, with rising temperatures impacting cold hardening and increasing drought stress in regions experiencing lower precipitation. Increasing atmospheric CO2 concentrations and nitrogen deposition can, in contrast, partially offset such negative effects by improving tree growth and carbon uptake. Similar to aboveground carbon fixation, carbon sequestration in boreal soils is important. Bacteria and fungi mineralize organic matter and, by making nutrients available for plants, are important for tree health. The ability of Norway spruce and the associated microbiota to adapt to climate change is of fundamental importance for ecosystem functioning and is the focus of this thesis.

Norway spruce seedlings were subjected to cold or drought stress and the transcriptional response compared to known mechanisms in the model plant Arabidopsis thaliana. Analyses revealed that while there was overlap in the stress responses between species, including increased osmotic and oxidative stress tolerance, the majority of differentially expressed genes were stress-responsive only in Norway spruce. Importantly, transcription factors of the abscisic acid dependent and independent pathways were not differentially expressed or were missing homolog sequences in Norway spruce, indicating that different regulatory pathways are active in Norway spruce and suggesting that stress response has evolved differently in the species. Furthermore, differential gene expression in roots differed extensively from that of needles in response to stress and highlighted the need for separate profiling in above- and belowground tissues.

In another study at the Flakaliden research site in northern Sweden, the effects of long-term nutrient addition on the microbiota associated with mature Norway spruce were tested. In agreement with earlier findings, nutrient addition improved tree growth and phylogenetic marker gene analysis on DNA of fungi and bacteria provided new insights into associated changes in plant-microbe interactions. Microbial diversity increased over time and compositional changes in nitrophilic community members indicated changes in carbon and nitrogen cycling at the plant-microbe interface, which has implications for carbon storage in boreal forest soils in the future. Follow-up RNA-based techniques largely confirmed community members from marker gene analysis.

In summary, understanding of both the Norway spruce-specific responses to abiotic stress and the ability of the associated microbiota to cope with the environmental changes are essential for future productivity, survival and distribution of Norway spruce forests. Sustainability will depend on tree vitality and a more holistic understanding of tree-microbe interactions is required to model future sustainability.

Abstract [sv]

Gran (Picea abies) är en dominant art i boreala skogar, och har stort ekologiskt och ekonomiskt värde. Klimatförändringar hotar dessa ekosystem med stigande temperaturer som orsakar torkstress i regioner med låg nederbörd. Förändringar i årstidernas längd påverkar också de processer som växter använder för att skydda sig mot frost. Ökade halter av atmosfärisk koldioxid och deposition av atmosfäriskt kväve kan å andra sidan medföra ökad tillväxt och ökat upptag av kol, vilket till viss del kan minska de negativa effekter som klimatförändringarna orsakar. Inbindning av kol, i både vegetation och mark, är en viktig mekanism. I marken är det bakterier och svampar som mineraliserar organiskt material och tillgängliggör näringsämnen för växter, och dessa mikoorganismer är därför viktiga för växters vitalitet och tillväxt. Den här avhandlingen fokuserar på hur granen, och de mikroorganismer som lever associerade med granen, anpassar sig till klimatförändringarna, vilket är nödvändigt för ett fungerande ekosystem.

Granplantor utsattes för kyla eller torka och granens transkriptom jämfördes med resultat från experiment utförda i modellväxten backtrav (Arabidopsis thaliana). Gran och backtrav uppvisade till viss del liknande stressresponser med ökad tolerans mot osmotisk och oxidativ stress men majoriteten av de gener som var differentiellt uttryckta i gran var inte differentiellt uttryckta i backtrav. Detta indikerar att stressresponserna har utvecklats annorlunda i gran jämfört med backtrav. Flera välkarakteriserade transkriptionsfaktorer som i backtrav reglerar uttrycket av gener som ingår i flera stressresponser antingen saknade motsvarigheter i gran, eller var inte differentiellt uttryckta. Detta pekar i sin tur på att de regulatoriska nätverk som var aktiva i gran skiljer sig från de som var aktiva i backtrav. I tillägg var genuttrycket i respons till stress i rötter och barr distinkt olika och tydliggör behovet av analys av vävnader båda ovan och under jord.

I en annan studie vid Flakalidens försökspark i norra Sverige undersöktes effekterna av långsiktig gödsling på de mikroorganismer som är associerade med granen. Tidigare studier har visat att tillväxten hos vuxna granar ökade vid gödsling, men studier av mikroorganimer saknas. Här analyserades fylogenetiska markörer hos DNA från svamp och bakterier insamlade från Flakaliden, vilket gav nya insikter i hur växter interagerar med mikrober. Ökad diversitet över tid och förändrad sammansättning av samhället av nitrofila arter indikerar förändringar i utbytet av kväve och kol mellan växt och mikroorganism, vilket tyder på att ökad gödsling kan påverka framtida inlagring av kol i marken i den boreala skogen. Uppföljande försök med RNA-baserade tekniker bekräftade till stor del mikrobiomets sammansättning.

Vår förståelse av hur granen svarar på abiotisk stress och mikrobernas förmåga att anpassa sig till miljöförändringarna är avgörande för granens framtid i ett hållbart skogsbruk. En mer holistisk syn på hur träd och mikroorganismer interagerar kommer att vara nödvändig för att åstadkomma detta.

Place, publisher, year, edition, pages
Umeå: Umeå University , 2018. , p. 58
Keywords [en]
Norway spruce, boreal forest, cold, drought, bacteria, fungi, plant-microbe interactions, climate change
National Category
Botany
Identifiers
URN: urn:nbn:se:umu:diva-152835ISBN: 978-91-7601-970-2 (print)OAI: oai:DiVA.org:umu-152835DiVA, id: diva2:1259961
Public defence
2018-12-14, KBE303 (Stora Hörsalen), KBC-huset, Umeå, 10:00 (English)
Opponent
Supervisors
Available from: 2018-11-23 Created: 2018-10-31 Last updated: 2018-11-19Bibliographically approved
List of papers
1. Norway spruce deploys canonical and delayed cold acclimation responses in a tissue-specific manner
Open this publication in new window or tab >>Norway spruce deploys canonical and delayed cold acclimation responses in a tissue-specific manner
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-152855 (URN)
Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-11-19
2. Candidate regulators and target genes of drought-stress in needles and roots of Norway spruce
Open this publication in new window or tab >>Candidate regulators and target genes of drought-stress in needles and roots of Norway spruce
(English)Manuscript (preprint) (Other academic)
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-152831 (URN)
Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-11-19
3. Microbial community response to growing season and plant nutrient optimisation in a boreal Norway spruce forest
Open this publication in new window or tab >>Microbial community response to growing season and plant nutrient optimisation in a boreal Norway spruce forest
Show others...
2018 (English)In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 125, p. 197-209Article in journal (Refereed) Published
Abstract [en]

Interactions between Norway spruce trees and bacteria and fungi in nutrient limited boreal forests can be beneficial for tree growth and fitness. Tree-level effects of anthropogenic nutrient addition have been well studied, however understanding of the long-term effects on the associated microbiota is limited. Here, we report on the sensitivity of microbial community composition to the growing season and nutrient additions. Highthroughput sequencing of the bacterial 16S rRNA gene and fungal ITS1 region was used to characterise changes in the microbial community after application of a complete mineral nutrient mixture for five and 25 years. The experiment was conducted using the Flakaliden forest research site in northern boreal Sweden and included naturally low nutrient control plots. Needle and fine root samples of Norway spruce were sampled in addition to bulk soil during one growing season to provide comprehensive insight into phyllosphere and belowground microbiota community changes. The phyllosphere microbiota was compositionally distinct from the belowground communities and phyllosphere diversity increased significantly over the growing season but was not influenced by the improved nutrient status of the trees. In both root and soil samples, alpha diversity of fungal, in particular ectomycorrhizal fungi (EMF), and bacterial communities increased after long-term nutrient optimisation, and with increasing years of treatment the composition of the fungal and bacterial communities changed toward a community with a higher relative abundance of nitrophilic EMF and bacterial species but did not cause complete loss of nitrophobic species from the ecosystem. From this, we conclude that 25 years of continuous nutrient addition to a boreal spruce stand increased phylotype richness and diversity of the microbiota in the soil, and at the root-soil interface, suggesting that long-term anthropogenic nutrient inputs can have positive effects on belowground biodiversity that may enhance ecosystem robustness. Future studies are needed to assess the impact of these changes to the microbiota on ecosystem carbon storage and nitrogen cycling in boreal forests.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Boreal forest, Ectomycorrhiza, Microbial community composition, Norway spruce, Balanced nutrient addition, Illumina MiSeq
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-151103 (URN)10.1016/j.soilbio.2018.07.005 (DOI)000444660400020 ()
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2018-11-19Bibliographically approved
4. Reproducibility and biological information of tree-associated metacommunities using RNA Sequencing and DNA amplicon profiling
Open this publication in new window or tab >>Reproducibility and biological information of tree-associated metacommunities using RNA Sequencing and DNA amplicon profiling
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Botany
Identifiers
urn:nbn:se:umu:diva-152833 (URN)
Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-11-19

Open Access in DiVA

fulltext(17461 kB)52 downloads
File information
File name FULLTEXT01.pdfFile size 17461 kBChecksum SHA-512
855e5783b90f89a32228843bb66c0cc357a5819fb8c32f717658f3f15919b53a245c935812e23ceaa4939994ecd513a4d1aef7c3be4652ac24286eff21eee813
Type fulltextMimetype application/pdf
spikblad(69 kB)7 downloads
File information
File name SPIKBLAD01.pdfFile size 69 kBChecksum SHA-512
da502bfa002fb70a0e8471ff4513f928da78b0ed65a2de5de1585c8a799b2accc790b84b940f5a42ced60a33023425bc955174a4a9816b6e22f9e73fcb4850cc
Type spikbladMimetype application/pdf

Authority records BETA

Haas, Julia Christa

Search in DiVA

By author/editor
Haas, Julia Christa
By organisation
Department of Plant Physiology
Botany

Search outside of DiVA

GoogleGoogle Scholar
Total: 52 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 305 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf