A novel role for the floral homeotic gene <i>APETALA2</i> during <i>Arabidopsis</i> fruit development

Ripoll, Juan-José; Roeder, Adrienne; Ditta, Gary S.; Yanofsky, Martin F.

doi:10.1242/dev.073031

Cited by 104 publications

(114 citation statements)

References 95 publications

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“…, and SHP2 (Dinneny et al, 2005;Ripoll et al, 2011). These also include genes that are known to show changes in expression pattern in other indehiscent Brassicaceae fruits (Avino et al, 2012;Mühlhausen et al, 2013).…”

Section: Comparative Morphology Of the Dimorphic Fruitsmentioning

confidence: 99%

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

et al. 2016

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Understanding how plants cope with changing habitats is a timely and important topic in plant research. Phenotypic plasticity describes the capability of a genotype to produce different phenotypes when exposed to different environmental conditions. In contrast, the constant production of a set of distinct phenotypes by one genotype mediates bet hedging, a strategy that reduces the temporal variance in fitness at the expense of a lowered arithmetic mean fitness. Both phenomena are thought to represent important adaptation strategies to unstable environments. However, little is known about the underlying mechanisms of these phenomena, partly due to the lack of suitable model systems. We used phylogenetic and comparative analyses of fruit and seed anatomy, biomechanics, physiology, and environmental responses to study fruit and seed heteromorphism, a typical morphological basis of a bet-hedging strategy of plants, in the annual Brassicaceae species Aethionema arabicum. Our results indicate that heteromorphism evolved twice within the Aethionemeae, including once for the monophyletic annual Aethionema clade. The dimorphism of Ae. arabicum is associated with several anatomic, biomechanical, gene expression, and physiological differences between the fruit and seed morphs. However, fruit ratios and numbers change in response to different environmental conditions. Therefore, the life-history strategy of Ae. arabicum appears to be a blend of bet hedging and plasticity. Together with the available genomic resources, our results pave the way to use this species in future studies intended to unravel the molecular control of heteromorphism and plasticity.

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Section: Comparative Morphology Of the Dimorphic Fruitsmentioning

confidence: 99%

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

et al. 2016

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“…This led us to question the specificity of AP2 DNA binding in vivo, especially in relation to its biological functions. AP2 has diverse biological functions such as seed development (Jofuku et al, 2005;Ohto et al, 2009), shoot apical meristem maintenance (Würschum et al, 2006), control of floral timing (Yant et al, 2010), preventing replum overgrowth during fruit development (Ripoll et al, 2011), establishment of floral meristem identity (Schultz and Haughn, 1993;Shannon and Meeks-Wagner, 1993), floral organ specification (Bowman et al, 1989;Kunst et al, 1989) and the regulation of homeotic gene expression (Drews et al, 1991). Perhaps the lack of strong inherent DNA-binding specificities underlies the diverse biological roles of AP2.…”

Section: Dna Binding Specificities Of Ap2 Domain Proteinsmentioning

confidence: 99%

The floral homeotic protein APETALA2 recognizes and acts through an AT-rich sequence element

et al. 2012

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SUMMARYCell fate specification in development requires transcription factors for proper regulation of gene expression. In Arabidopsis, transcription factors encoded by four classes of homeotic genes, A, B, C and E, act in a combinatorial manner to control proper floral organ identity. The A-class gene APETALA2 (AP2) promotes sepal and petal identities in whorls 1 and 2 and restricts the expression of the C-class gene AGAMOUS (AG) from whorls 1 and 2. However, it is unknown how AP2 performs these functions. Unlike the other highly characterized floral homeotic proteins containing MADS domains, AP2 has two DNA-binding domains referred to as the AP2 domains and its DNA recognition sequence is still unknown. Here, we show that the second AP2 domain in AP2 binds a non-canonical AT-rich target sequence, and, using a GUS reporter system, we demonstrate that the presence of this sequence in the AG second intron is important for the restriction of AG expression in vivo. Furthermore, we show that AP2 binds the AG second intron and directly regulates AG expression through this sequence element. Computational analysis reveals that the binding site is highly conserved in the second intron of AG orthologs throughout Brassicaceae. By uncovering a biologically relevant AT-rich target sequence, this work shows that AP2 domains have wide-ranging target specificities and provides a missing link in the mechanisms that underlie flower development. It also sets the foundation for understanding the basis of the broad biological functions of AP2 in Arabidopsis, as well as the divergent biological functions of AP2 orthologs in dicotyledonous plants.

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“…Thus, the gene regulatory networks involved in the development of both dry and fleshy fruits may be similar, although the outcomes are morphologically very different. The Arabidopsis thaliana transcription factor APETALA2 (AP2) and its tomato (Solanum lycopersicum) ortholog AP2a, for example, are both involved in fruit development, but At-AP2 regulates dehiscence zone development in the dry silique (Ripoll et al, 2011), whereas Sl-AP2a influences fleshy fruit ripening via regulation of ethylene biosynthesis and signaling (Chung et al, 2010;Karlova et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

The Tomato FRUITFULL Homologs TDR4/FUL1 and MBP7/FUL2 Regulate Ethylene-Independent Aspects of Fruit Ripening

Bemer

Karlova

Ballester³

et al. 2012

Plant Cell

297

276

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Tomato (Solanum lycopersicum) contains two close homologs of the Arabidopsis thaliana MADS domain transcription factor FRUITFULL (FUL), FUL1 (previously called TDR4) and FUL2 (previously MBP7). Both proteins interact with the ripening regulator RIPENING INHIBITOR (RIN) and are expressed during fruit ripening. To elucidate their function in tomato, we characterized single and double FUL1 and FUL2 knockdown lines. Whereas the single lines only showed very mild alterations in fruit pigmentation, the double silenced lines exhibited an orange-ripe fruit phenotype due to highly reduced lycopene levels, suggesting that FUL1 and FUL2 have a redundant function in fruit ripening. More detailed analyses of the phenotype, transcriptome, and metabolome of the fruits silenced for both FUL1 and FUL2 suggest that the genes are involved in cell wall modification, the production of cuticle components and volatiles, and glutamic acid (Glu) accumulation. Glu is responsible for the characteristic umami taste of the present-day cultivated tomato fruit. In contrast with previously identified ripening regulators, FUL1 and FUL2 do not regulate ethylene biosynthesis but influence ripening in an ethylene-independent manner. Our data combined with those of others suggest that FUL1/2 and TOMATO AGAMOUS-LIKE1 regulate different subsets of the known RIN targets, probably in a protein complex with the latter.

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A novel role for the floral homeotic gene APETALA2 during Arabidopsis fruit development

Cited by 104 publications

References 95 publications

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

Developmental Control and Plasticity of Fruit and Seed Dimorphism in Aethionema arabicum

The floral homeotic protein APETALA2 recognizes and acts through an AT-rich sequence element

The Tomato FRUITFULL Homologs TDR4/FUL1 and MBP7/FUL2 Regulate Ethylene-Independent Aspects of Fruit Ripening

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