Sammanfattning

Shoot branching is a primary contributor to plant architecture, evolving independently in flowering plant sporophytes and moss gametophytes. Mechanistic understanding of branching is largely limited to flowering plants such as Arabidopsis, which have a recent evolutionary origin. We show that in gametophytic shoots of Physcomitrella, lateral branches arise by re-specification of epidermal cells into branch initials. A simple model co-ordinating the activity of leafy shoot (gametophore) tips can account for branching patterns, and three known and ancient hormonal regulators of sporophytic branching interact to generate the branching pattern-auxin, cytokinin and strigolactone. The mode of auxin transport required in branch patterning is a key divergence point from known sporophytic branching pathways. Although PIN-mediated basipetal auxin transport regulates branching patterns in flowering plants, this is not so in Physcomitrella, where bi-directional transport is required to generate realistic branching patterns. Experiments with callose synthesis inhibitors suggest plasmodesmal connectivity as a potential mechanism for transport.

Publicerad i

eLife
2015, Volym: 4, artikelnummer: e06808
Utgivare: ELIFE SCIENCES PUBLICATIONS LTD

SLU författare

• Ljung, Karin

  • Institutionen för skoglig genetik och växtfysiologi, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Botanik


Publikationens identifierare

DOI: https://doi.org/10.7554/eLife.06808

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/76280