Universität zu Köln

Chandler, J. W. and Werr, W. (2014). Arabidopsis floral phytomer development: auxin response relative to biphasic modes of organ initiation. J. Exp. Bot., 65 (12). S. 3097 - 3111. OXFORD: OXFORD UNIV PRESS. ISSN 1460-2431

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Abstract

In the Arabidopsis inflorescence meristem (IM), auxin is considered a prepatterning signal for floral primordia, whereas a centripetal mode of positional information for floral organ identity is inherent to the ABCE model. However, spatio-temporal patterns of organ initiation in each whorl at the earliest initiation stages are largely unknown. Evidence suggests that initial flower development occurs along an abaxial/adaxial axis and conforms to phytomer theory. Use of the founder cell marker DORNROSCHEN-LIKE (DRNL) as a tool in leafy, puchi, and apetala 1 cauliflower mutant backgrounds suggests that bract founder cells are marked at the IM periphery. The DRNL transcription domain in the wild-type IM is spatially discrete from DR5 expression, suggesting that bract initiation is independent of canonical auxin response. When bracts develop in lfy and puchi mutant floral primordia the initiation of lateral sepals precedes the specification of medial sepals compared with wild type, showing an interplay between bract and abaxial sepal founder cell recruitment. In the perianthia (pan) mutant background, DRNL expression indicates that a radial outer whorl arrangement derives from splitting of sepal founder cell populations at abaxial and adaxial positions. This splitting of incipient sepal primordia is partially dependent on PRESSED FLOWER (PRS) activity and implies that sepal specification is independent of WUSCHEL and CLAVATA3 expression, as both marker genes only regain activity in stage-2 flowers, when patterning of inner floral organs switches to a centripetal mode. The transition from an initially abaxial/adaxial into a centripetal patterning programme, and its timing represent an adaptive trait that possibly contributes to variation in floral morphology, especially unidirectional organ initiation.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Chandler, J. W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Werr, W. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-434534
DOI:	10.1093/jxb/eru153
Journal or Publication Title:	J. Exp. Bot.
Volume:	65
Number:	12
Page Range:	S. 3097 - 3111
Date:	2014
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1460-2431
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SHOOT APICAL MERISTEMS; FLOWER DEVELOPMENT; TRANSCRIPTION FACTORS; MEDICAGO-TRUNCATULA; BRACT SUPPRESSION; GENE-EXPRESSION; PERIANTHIA GENE; HOMEOBOX GENE; DORNRA-SCHEN; ABC MODEL Multiple languages Plant Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/43453