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APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat

The spikelet is the basic unit of the grass inflorescence. In tetraploid (Triticum turgidum) and hexaploid wheat (Triticum aestivum), the spikelet is a short indeterminate branch with two proximal sterile bracts (glumes) followed by a variable number of florets, each including a bract (lemma) with a...

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Autores principales: Debernardi, Juan Manuel, Greenwood, Julian R., Jean Finnegan, E., Jernstedt, Judy, Dubcovsky, Jorge
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6972666/
https://www.ncbi.nlm.nih.gov/pubmed/31494998
http://dx.doi.org/10.1111/tpj.14528
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author Debernardi, Juan Manuel
Greenwood, Julian R.
Jean Finnegan, E.
Jernstedt, Judy
Dubcovsky, Jorge
author_facet Debernardi, Juan Manuel
Greenwood, Julian R.
Jean Finnegan, E.
Jernstedt, Judy
Dubcovsky, Jorge
author_sort Debernardi, Juan Manuel
collection PubMed
description The spikelet is the basic unit of the grass inflorescence. In tetraploid (Triticum turgidum) and hexaploid wheat (Triticum aestivum), the spikelet is a short indeterminate branch with two proximal sterile bracts (glumes) followed by a variable number of florets, each including a bract (lemma) with an axillary flower. Varying levels of miR172 and/or its target gene Q (AP2L5) result in gradual transitions of glumes to lemmas, and vice versa. Here, we show that AP2L5 and its related paralog AP2L2 play critical and redundant roles in the specification of axillary floral meristems and lemma identity. AP2L2, also targeted by miR172, displayed similar expression profiles to AP2L5 during spikelet development. Loss‐of‐function mutants in both homeologs of AP2L2 (henceforth ap2l2) developed normal spikelets, but ap2l2 ap2l5 double mutants generated spikelets with multiple empty bracts before transitioning to florets. The coordinated nature of these changes suggest an early role of these genes in floret development. Moreover, the flowers of ap2l2 ap2l5 mutants showed organ defects in paleas and lodicules, including the homeotic conversion of lodicules into carpels. Mutations in the miR172 target site of AP2L2 were associated with reduced plant height, more compact spikes, promotion of lemma‐like characters in glumes and smaller lodicules. Taken together, our results show that the balance in the expression of miR172 and AP2‐like genes is crucial for the correct development of spikelets and florets, and that this balance has been altered during the process of wheat and barley (Hordeum vulgare) domestication. The manipulation of this regulatory module provides an opportunity to modify spikelet architecture and improve grain yield.
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spelling pubmed-69726662020-01-27 APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat Debernardi, Juan Manuel Greenwood, Julian R. Jean Finnegan, E. Jernstedt, Judy Dubcovsky, Jorge Plant J Original Articles The spikelet is the basic unit of the grass inflorescence. In tetraploid (Triticum turgidum) and hexaploid wheat (Triticum aestivum), the spikelet is a short indeterminate branch with two proximal sterile bracts (glumes) followed by a variable number of florets, each including a bract (lemma) with an axillary flower. Varying levels of miR172 and/or its target gene Q (AP2L5) result in gradual transitions of glumes to lemmas, and vice versa. Here, we show that AP2L5 and its related paralog AP2L2 play critical and redundant roles in the specification of axillary floral meristems and lemma identity. AP2L2, also targeted by miR172, displayed similar expression profiles to AP2L5 during spikelet development. Loss‐of‐function mutants in both homeologs of AP2L2 (henceforth ap2l2) developed normal spikelets, but ap2l2 ap2l5 double mutants generated spikelets with multiple empty bracts before transitioning to florets. The coordinated nature of these changes suggest an early role of these genes in floret development. Moreover, the flowers of ap2l2 ap2l5 mutants showed organ defects in paleas and lodicules, including the homeotic conversion of lodicules into carpels. Mutations in the miR172 target site of AP2L2 were associated with reduced plant height, more compact spikes, promotion of lemma‐like characters in glumes and smaller lodicules. Taken together, our results show that the balance in the expression of miR172 and AP2‐like genes is crucial for the correct development of spikelets and florets, and that this balance has been altered during the process of wheat and barley (Hordeum vulgare) domestication. The manipulation of this regulatory module provides an opportunity to modify spikelet architecture and improve grain yield. John Wiley and Sons Inc. 2019-10-15 2020-01 /pmc/articles/PMC6972666/ /pubmed/31494998 http://dx.doi.org/10.1111/tpj.14528 Text en © 2019 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Original Articles
Debernardi, Juan Manuel
Greenwood, Julian R.
Jean Finnegan, E.
Jernstedt, Judy
Dubcovsky, Jorge
APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title_full APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title_fullStr APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title_full_unstemmed APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title_short APETALA 2‐like genes AP2L2 and Q specify lemma identity and axillary floral meristem development in wheat
title_sort apetala 2‐like genes ap2l2 and q specify lemma identity and axillary floral meristem development in wheat
topic Original Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6972666/
https://www.ncbi.nlm.nih.gov/pubmed/31494998
http://dx.doi.org/10.1111/tpj.14528
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