PpAG1, a homolog of AGAMOUS, expressed in developing peach flowers and fruit

2006 ◽  
Vol 84 (5) ◽  
pp. 767-776 ◽  
Author(s):  
Teresa Martin ◽  
Ming Hu ◽  
Hélène Labbé ◽  
Sylvia McHugh ◽  
Antonet Svircev ◽  
...  

MADS-box transcription factors are known to play a central role in floral organ identity and floral meristem determinacy in many gymnosperms and angiosperms. Studies of this nature are limited in fruit tree species despite the economic importance of this group. A peach ( Prunus persica (L.) Batsch) gene, PpAG1, was isolated and shown to be homologous to the Arabidopsis thaliana (L.) Heynh. MADS-box gene AGAMOUS (AG). It is a single gene in peach and codes for a type II or MIKC-type MADS-box protein. The features of the deduced protein sequence indicate that it is similar to other AG homologs from woody plant species. The spatial and developmental patterns of expression parallel those of AG and homologs from other angiosperms with similar floral structures but with some minor differences. In the floral meristem, where AG is responsible for conversion of the vegetative meristem into the floral meristem, the differentiation of the whorls that generate the carpels and stamens coincides with the tissue-specific expression of PpAG1. It continues to be expressed in the ovules, developing fruit and seeds that subsequently develop from the carpels. Constitutive overexpression of PpAG1 in Arabidopsis, using the 35S promoter, caused the homeotic conversion of sepals to carpelloid tissues and altered petal development. This is consistent with C-function genes according to the ABC model of flower development. The data support the conclusion that PpAG1 is the peach homolog of Arabidopsis AG.

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1767
Author(s):  
Annemarie Heiduk ◽  
Dewi Pramanik ◽  
Marlies Spaans ◽  
Loes Gast ◽  
Nemi Dorst ◽  
...  

Deceptive Ceropegia pitfall flowers are an outstanding example of synorganized morphological complexity. Floral organs functionally synergise to trap fly-pollinators inside the fused corolla. Successful pollination requires precise positioning of flies headfirst into cavities at the gynostegium. These cavities are formed by the corona, a specialized organ of corolline and/or staminal origin. The interplay of floral organs to achieve pollination is well studied but their evolutionary origin is still unclear. We aimed to obtain more insight in the homology of the corona and therefore investigated floral anatomy, ontogeny, vascularization, and differential MADS-box gene expression in Ceropegia sandersonii using X-ray microtomography, Light and Scanning Electronic Microscopy, and RT-PCR. During 10 defined developmental phases, the corona appears in phase 7 at the base of the stamens and was not found to be vascularized. A floral reference transcriptome was generated and 14 MADS-box gene homologs, representing all major MADS-box gene classes, were identified. B- and C-class gene expression was found in mature coronas. Our results indicate staminal origin of the corona, and we propose a first ABCDE-model for floral organ identity in Ceropegia to lay the foundation for a better understanding of the molecular background of pitfall flower evolution in Apocynaceae.


2017 ◽  
Vol 8 ◽  
Author(s):  
Yingjun Chi ◽  
Tingting Wang ◽  
Guangli Xu ◽  
Hui Yang ◽  
Xuanrui Zeng ◽  
...  

2009 ◽  
Vol 21 (10) ◽  
pp. 3008-3025 ◽  
Author(s):  
Shinnosuke Ohmori ◽  
Mayumi Kimizu ◽  
Maiko Sugita ◽  
Akio Miyao ◽  
Hirohiko Hirochika ◽  
...  

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 765-783 ◽  
Author(s):  
Elena M Kramer ◽  
Robert L Dorit ◽  
Vivian F Irish

Abstract The specification of floral organ identity in the higher dicots depends on the function of a limited set of homeotic genes, many of them members of the MADS-box gene family. Two such genes, APETALA3 (AP3) and PISTILLATA (PI), are required for petal and stamen identity in Arabidopsis; their orthologs in Antirrhinum exhibit similar functions. To understand how changes in these genes may have influenced the morphological evolution of petals and stamens, we have cloned twenty-six homologs of the AP3 and PI genes from two higher eudicot and eleven lower eudicot and magnolid dicot species. The sequences of these genes reveal the presence of characteristic PI- and AP3-specific motifs. While the PI-specific motif is found in all of the PI genes characterized to date, the lower eudicot and magnolid dicot AP3 homologs contain distinctly different motifs from those seen in the higher eudicots. An analysis of all the available AP3 and PI sequences uncovers multiple duplication events within each of the two gene lineages. A major duplication event in the AP3 lineage coincides with the base of the higher eudicot radiation and may reflect the evolution of a petal-specific AP3 function in the higher eudicot lineage.


2006 ◽  
Vol 6 ◽  
pp. 1923-1932 ◽  
Author(s):  
Takahiro Yamaguchi ◽  
Hiro-Yuki Hirano

MADS-box genes play critical roles in a number of developmental processes in flowering plants, such as specification of floral organ identity, control of flowering time, and regulation of fruit development. Because of their crucial functions in flower development, diversification of the MADS-box gene family has been suggested to be a major factor responsible for floral diversity during radiation of the flowering plants. Inflorescences and flowers in the grass species have unique structures that are distinct from those in eudicots. Thus, it is plausible that the diversification of the function of MADS-box genes may have been a key driving force in the morphological divergence of the flowers and inflorescences in the grasses. Indeed, recent progress in genetic studies has shown that MADS-box genes function in flower development inOryza sativa(rice), in support of the idea that functional diversification of the MADS-box genes was involved in evolution of the angiosperms. In this review, we summarize the functions of the major subfamilies of the MADS-box genes in rice and discuss their role in the development and evolution of rice flowers and inflorescences.


2021 ◽  
Vol 12 ◽  
Author(s):  
Silvia Moschin ◽  
Sebastiano Nigris ◽  
Ignacio Ezquer ◽  
Simona Masiero ◽  
Stefano Cagnin ◽  
...  

Nymphaeaceae are early diverging angiosperms with large flowers characterized by showy petals and stamens not clearly whorled but presenting a gradual morphological transition from the outer elements to the inner stamens. Such flower structure makes these plant species relevant for studying flower evolution. MADS-domain transcription factors are crucial components of the molecular network that controls flower development. We therefore isolated and characterized MADS-box genes from the water lily Nymphaea caerulea. RNA-seq experiments on floral buds have been performed to obtain the transcript sequences of floral organ identity MADS-box genes. Maximum Likelihood phylogenetic analyses confirmed their belonging to specific MADS-box gene subfamilies. Their expression was quantified by RT-qPCR in all floral organs at two stages of development. Protein interactions among these transcription factors were investigated by yeast-two-hybrid assays. We found especially interesting the involvement of two different AGAMOUS-like genes (NycAG1 and NycAG2) in the water lily floral components. They were therefore functionally characterized by complementing Arabidopsis ag and shp1 shp2 mutants. The expression analysis of MADS-box genes across flower development in N. caerulea described a complex scenario made of numerous genes in numerous floral components. Their expression profiles in some cases were in line with what was expected from the ABC model of flower development and its extensions, while in other cases presented new and interesting gene expression patterns, as for instance the involvement of NycAGL6 and NycFL. Although sharing a high level of sequence similarity, the two AGAMOUS-like genes NycAG1 and NycAG2 could have undergone subfunctionalization or neofunctionalization, as only one of them could partially restore the euAG function in Arabidopsis ag-3 mutants. The hereby illustrated N. caerulea MADS-box gene expression pattern might mirror the morphological transition from the outer to the inner floral organs, and the presence of transition organs such as the petaloid stamens. This study is intended to broaden knowledge on the role and evolution of floral organ identity genes and the genetic mechanisms causing biodiversity in angiosperm flowers.


2006 ◽  
Vol 6 ◽  
pp. 1933-1944 ◽  
Author(s):  
Wen-Chieh Tsai ◽  
Hong-Hwa Chen

Orchids are known for both their floral diversity and ecological strategies. The versatility and specialization in orchid floral morphology, structure, and physiological properties have fascinated botanists for centuries. In floral studies, MADS-box genes contributing to the now famous ABCDE model of floral organ identity control have dominated conceptual thinking. The sophisticated orchid floral organization offers an opportunity to discover new variant genes and different levels of complexity to the ABCDE model. Recently, several remarkable research studies done on orchid MADS-box genes have revealed the important roles on orchid floral development. Knowledge about MADS-box genes’' encoding ABCDE functions in orchids will give insights into the highly evolved floral morphogenetic networks of orchids.


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