Abstract Detail

Developmental and Structural Section

Demason, Darleen [1], Jaganatha Chetty, Venkateswari [2].

The crispa mutant and its effects on the three planes of leaf symmetry in pea (Pisum sativum).

The ARP genes encode MYB transcription factors that interact with Class 1 KNOX genes in a regulatory module that is highly conserved for meristem-leaf determination. Loss of function alleles of ARP genes and subsequent KNOX overexpression cause many unusual leaf phenotypes. These phenotypes have generally been described as displaying various losses of leaf bifaciality and formation of “knots” on adaxial surfaces, suggesting that ARP genes also play a role in determining adaxial identity in leaves. Crispa (cri) is the pea ARP gene and several loss of function alleles are known. Using the classic allele, cri1, we made exhaustive morphological and anatomical comparisons with normal plants. Since the stipules are known to be affected, we crossed cri1 with stipules reduced (st) to evaluate the double mutant. We created DR5::GUS cri1 plants to study auxin perception and did qRT-PCR to compare expression of a range of genes known to affect leaf development in pea. Leaves of cri1 plants have similar numbers and types of pinnae as normal, but fusion between stipules and petioles cause extreme hyponasty, shortening and narrowing of the petiole. The fusion occurs on the adaxial surface of the petiole and this surface on cri1 st plants shows extended adaxial meristematic activity even in the absence of stipule fusion. The rachis of the proximal region of the leaf is also shortened and “ectopic” stipules are produced on the adaxial surface under leaflets. “Knots” are produced on the narrow leaflets and include ridges, toothed margins and leaflet-like larger projections. Anatomically, these “knots” have adaxial cell types or are bifacial and express GUS. The cri1 mutants have reduced expression of LE, NAM/CUC3, PIN1 and TL and higher expression of UNI and Class 1 KNOX than normal. Therefore, Cri functions to enhance medio-lateral and distal-proximal, but suppresses adaxial expression in pea leaf development.

Broader Impacts:

1 - University of California, Botany And Plant Sciences, 900 University Ave., Riverside, CA, 92521, USA
2 - University of California, Riverside, Botany And Plant Sciences, 2150 Batchelor Hall, Riverside, CA, 92521, USA

Keywords:
development
leaf
leaf polarity
ARP genes.

Presentation Type: Oral Paper:Papers for Sections
Session: 26
Location: Jasperwood/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 10:15 AM
Number: 26001
Abstract ID:183
Candidate for Awards:None