Ljung, Karin
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
Research article2013Peer reviewedOpen access
Su, Chang; Kokosza, Andrzej; Xie, Xiaonan; Pencik, Ales; Zhang, Youjun; Raumonen, Pasi; Shi, Xueping; Muranen, Sampo; Topcu, Melis Kucukoglu; Immanen, Juha; Hagqvist, Risto; Safronov, Omid; Alonso-Serra, Juan; Eswaran, Gugan; Venegas, Mirko Pavicic; Ljung, Karin; Ward, Sally; Mahonen, Ari Pekka; Himanen, Kristiina; Salojarvi, Jarkko;
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Due to their long lifespan, trees and bushes develop higher order of branches in a perennial manner. In contrast to a tall tree, with a clearly defined main stem and branch-ing order, a bush is shorter and has a less apparent main stem and branching pattern. To address the developmental basis of these two forms, we studied several naturally occurring architectural variants in silver birch (Betula pendula). Using a candidate gene approach, we identified a bushy kanttarelli variant with a loss - of- functionmutation in the BpMAX1 gene required for strigolactone (SL) biosynthesis. While kanttarelli is shorter than the wild type (WT), it has the same number of primary branches, whereas the number of secondary branches is increased, contributing to its bush -like phenotype. To confirm that the identified mutation was responsible for the phenotype, we phen-ocopied kanttarelli in transgenic BpMAX1::RNAi birch lines. SL profiling confirmed that both kanttarelli and the transgenic lines produced very limited amounts of SL. Interestingly, the auxin (IAA) distribution along the main stem differed between WT and BpMAX1::RNAi. In the WT, the auxin concentration formed a gradient, being higher in the uppermost internodes and decreasing toward the basal part of the stem, whereas in the transgenic line, this gradient was not observed. Through modeling, we showed that the different IAA distribution patterns may result from the difference in the number of higher -order branches and plant height. Future studies will determine whether the IAA gradient itself regulates aspects of plant architecture.
tree architecture; branching modeling; strigolactones; auxin distribution; Betulapendula
Proceedings of the National Academy of Sciences of the United States of America
2013, Volume: 120, number: 48, article number: e2308587120
SDG7 Ensure access to affordable, reliable, sustainable and modern energy for all
SDG13 Take urgent action to combat climate change and its impacts
Developmental Biology
Botany
DOI: https://doi.org/10.1073/pnas.2308587120
https://res.slu.se/id/publ/128345