Abstract Detail

The Role of Boundaries in Plant Diversification

Husbands, Aman [1], Skopelitis, Damianos [1], Timmermans, Marja [1].

Molecular mechanisms that position the adaxial-abaxial boundary and drive the production of flat leaf morphology.

Leaves are the primary photosynthetic organs of land plants and their innovation was crucial to the enormous success of this lineage. In keeping with their role as ‘biological solar panels’, the leaves of most species have a flat, thin shape which maximizes their photosynthetic efficiency. Flat leaf architecture is not the default state, however, as leaves initiate from the stem cell niche as radially symmetric bulges. Once primordia initiate, their growth is driven – essentially – in two dimensional space, flattening into long and wide, but shallow, structures. This directional growth must be tightly coordinated and precisely oriented, as even minor errors lead to dramatic defects in leaf shape. Leaves accomplish this by orienting the direction of growth along the sharp boundary between their adaxial and abaxial (or top and bottom) sides. Flat leaf morphology thus depends on a properly-patterned adaxial-abaxial axis, which must be carefully regulated to avoid fitness consequences. I will present our efforts to elucidate the molecular mechanisms that confer robustness to adaxial-abaxial patterning and permit the uniform, stable positioning of the adaxial-abaxial boundary. These mechanisms include mutually antagonistic behavior of adaxial and abaxial determinants, intercellular signaling by mobile small RNAs, and switch-like regulation of an evolutionarily-conserved family of transcription factors. Flat leaf production thus reveals some of the biological solutions that enable boundaries between cell fates to be reproducibly and uniformly positioned, even in organs as dynamic as developing leaves. These findings may also have implications beyond the plant kingdom, as organisms across the tree of life are known to similarly drive outgrowth along their developmental boundaries.

1 - Cold Spring Harbor Laboratory, 1 Bungtown Rd, Cold Spring Harbor, NY, 11724, United States

Keywords:
development
transcription factors
small RNAs
lipid-regulation.

Presentation Type: Symposium Presentation
Session: SY7, The Role of Boundaries in Plant Diversification - with Presentation of Pelton Award to Dr. Shirley Tucker
Location: Sundance 3/Omni Hotel
Date: Wednesday, June 28th, 2017
Time: 4:45 PM
Number: SY7008
Abstract ID:260
Candidate for Awards:None