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Summary The formation of developmental boundaries is a common feature of multicellular plants and animals, and impacts the initiation, structure and function of all organs. Maize leaves comprise a proximal sheath that encloses the stem, and a distal photosynthetic blade that projects away from the plant axis. An epidermally derived ligule and a joint‐like auricle develop at the blade/sheath boundary of maize leaves. Mutations disturbing the ligule/auricle region disrupt leaf patterning and impact plant architecture, yet it is unclear how this developmental boundary is established.Targeted microdissection followed by transcriptomic analyses of young leaf primordia were utilized to construct a co‐expression network associated with development of the blade/sheath boundary.Evidence is presented for proximodistal gradients of gene expression that establish a prepatterned transcriptomic boundary in young leaf primordia, before the morphological initiation of the blade/sheath boundary in older leaves.This work presents a conceptual model for spatiotemporal patterning of proximodistal leaf domains, and provides a rich resource of candidate gene interactions for future investigations of the mechanisms of blade/sheath boundary formation in maize.
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Genetic analyses of embryo homology and ontogeny in the model grass Zea mays subsp. mays
Summary The homology of the single cotyledon of grasses and the ontogeny of the scutellum and coleoptile as the initial, highly modified structures of the grass embryo are investigated using leaf developmental genetics and targeted transcript analyses in the model grassZea mayssubsp.mays.Transcripts of leaf developmental genes are identified in both the initiating scutellum and the coleoptile, while mutations disrupting mediolateral leaf development also disrupt scutellum and coleoptile morphology, suggesting that these grass‐specific organs are modified leaves.Higher‐order mutations inWUSCHEL‐LIKE HOMEOBOX3(WOX3) genes, involved in mediolateral patterning of plant lateral organs, inform a model for the fusion of coleoptilar margins during maize embryo development.Genetic, RNA‐targeting, and morphological evidence supports models for cotyledon evolution where the scutellum and coleoptile, respectively, comprise the distal and proximal domains of the highly modified, single grass cotyledon.
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- Award ID(s):
- 2016021
- PAR ID:
- 10572735
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 243
- Issue:
- 4
- ISSN:
- 0028-646X
- Format(s):
- Medium: X Size: p. 1610-1619
- Size(s):
- p. 1610-1619
- Sponsoring Org:
- National Science Foundation
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