Characterization and T-DNA insertion sites identification of a multiple-branches mutant br in Betula platyphylla × Betula pendula.

Plant architecture, wood properties, photosynthetic characteristics, and IAA and Zeatin contents in main and lateral branches' apical buds changed in br over the study's time period. One T-DNA insertion was identified on the first exon of BpCOI1, which resulted in the reduction of BpCOI1 expression and abnormal perception to MeJA in br. These mutation phenotypes might be associated with a partial loss of BpCOI1 in birch.