When the BRANCHED network bears fruit: how carpic dominance causes fruit dimorphism in Aethionema

0489220 - ÚEB 2019 RIV GB eng J - Journal Article
Lenser, T. - Tarkowská, Danuše - Novák, Ondřej - Wilhelmsson, P. - Bennett, T. - Rensing, S. A. - Strnad, Miroslav - Theissen, G.
When the BRANCHED network bears fruit: how carpic dominance causes fruit dimorphism in Aethionema.
Plant Journal. Roč. 94, č. 2 (2018), s. 352-371. ISSN 0960-7412. E-ISSN 1365-313X
R&D Projects: GA MŠMT(CZ) LO1204
Institutional support: RVO:61389030
Keywords : Aethionema arabicum * auxin * branched1 * carpic dominance * cytokinin * fruit development * fruit dimorphism * molecular evolution * phytohormones * shoot branching
OECD category: Plant sciences, botany
Impact factor: 5.726, year: 2018

Life in unpredictably changing habitats is a great challenge, especially for sessile organisms like plants. Fruit and seed heteromorphism is one way to cope with such variable environmental conditions. It denotes the production of distinct types of fruits and seeds that often mediate distinct life-history strategies in terms of dispersal, germination and seedling establishment. But although the phenomenon can be found in numerous species and apparently evolved several times independently, its developmental time course or molecular regulation remains largely unknown. Here, we studied fruit development in Aethionema arabicum, a dimorphic member of the Brassicaceae family. We characterized fruit morph differentiation by comparatively analyzing discriminating characters like fruit growth, seed abortion and dehiscence zone development. Our data demonstrate that fruit morph determination is a ‘last-minute’ decision happening in flowers after anthesis directly before the first morphotypical differences start to occur. Several growth experiments in combination with hormone and gene expression analyses further indicate that an accumulation balance of the plant hormones auxin and cytokinin in open flowers together with the transcript abundance of the Ae. arabicum ortholog of BRANCHED1, encoding a transcription factor known for its conserved function as a branching repressor, may guide fruit morph determination. Thus, we hypothesize that the plasticity of the fruit morph ratio in Ae. arabicum may have evolved through the modification of a preexisting network known to govern correlative dominance between shoot organs.
Permanent Link: http://hdl.handle.net/11104/0283673