biostudies-literatureUnknown120(48)Su CDue 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 branching 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 (<i>Betula pendula</i>). Using a candidate gene approach, we identified a bushy <i>kanttarelli</i> variant with a loss-of-function mutation in the <i>BpMAX1</i> gene required for strigolactone (SL) biosynthesis. While <i>kanttarelli</i> 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 phenotyProceedings of the National Academy of Sciences of the United States of Americae2308587120https://www.ebi.ac.uk/biostudies/studies/S-EPMC10691325biostudies-literatureTree architecture: A strigolactone-deficient mutant reveals a connection between branching order and auxin gradient along the tree stem.PMC10691325Helariutta YPencik AVenegas MPSu CFernie ARNieminen KImmanen JSafronov OHimanen KAlonso-Serra JTopcu MKShi XWard SRaumonen PMahonen APHagqvist RLeyser OLjung KXie XKokosza ANovak OSalojarvi JZhang YEswaran GMuranen SPalubicki WfalseTree architecture: A strigolactone-deficient mutant reveals a connection between branching order and auxin gradient along the tree stem.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 branching 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 (<i>Betula pendula</i>). Using a candidate gene approach, we identified a bushy <i>kanttarelli</i> variant with a loss-of-function mutation in the <i>BpMAX1</i> gene required for strigolactone (SL) biosynthesis. While <i>kanttarelli</i> 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 phenoty2023-01-01T00:00:00Z2023 Nov2025-05-18T10:37:45.586Z2025-05-18T10:37:45.586ZS-EPMC106913253799194510.1073/pnas.2308587120