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Two euAGAMOUS genes control C-function in Medicago truncatula.

Serwatowska J, Roque E, Gómez-Mena C, Constantin GD, Wen J, Mysore KS, Lund OS, Johansen E, Beltrán JP, Cañas LA - PLoS ONE (2014)

Bottom Line: This species is therefore a good experimental system to study the effects of gene duplication within the AG subfamily.Our results show that the M. truncatula euAG- and PLENA-like genes are an example of subfunctionalization as a result of a change in expression pattern.In contrast, MtSHP expression appears late during floral development suggesting it does not contribute significantly to the C-function.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV). Ciudad Politécnica de la Innovación, Valencia, Spain.

ABSTRACT
C-function MADS-box transcription factors belong to the AGAMOUS (AG) lineage and specify both stamen and carpel identity and floral meristem determinacy. In core eudicots, the AG lineage is further divided into two branches, the euAG and PLE lineages. Functional analyses across flowering plants strongly support the idea that duplicated AG lineage genes have different degrees of subfunctionalization of the C-function. The legume Medicago truncatula contains three C-lineage genes in its genome: two euAG genes (MtAGa and MtAGb) and one PLENA-like gene (MtSHP). This species is therefore a good experimental system to study the effects of gene duplication within the AG subfamily. We have studied the respective functions of each euAG genes in M. truncatula employing expression analyses and reverse genetic approaches. Our results show that the M. truncatula euAG- and PLENA-like genes are an example of subfunctionalization as a result of a change in expression pattern. MtAGa and MtAGb are the only genes showing a full C-function activity, concomitant with their ancestral expression profile, early in the floral meristem, and in the third and fourth floral whorls during floral development. In contrast, MtSHP expression appears late during floral development suggesting it does not contribute significantly to the C-function. Furthermore, the redundant MtAGa and MtAGb paralogs have been retained which provides the overall dosage required to specify the C-function in M. truncatula.

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Two euAGAMOUS genes in Medicago truncatula.(A) Gene structure of MtAGa and MtAGb. Coding sequences are represented as boxes and introns as dotted lines. Black triangles localize the position of the Tnt1 insertions present in the mutant lines mtaga (NF13380) and mtagb (NF4908) used in this study. (B) Neighbor-Joining Tree of euAG and PLENA homologs from a selection of diverse species. The numbers next to the nodes refer to bootstrap values from 10000 pseudo-replicates. (C) Distribution of putative LFY binding sites in the first intron of MtAGa, MtAGb and MtSHP genes as identified with the use of a position-specific scoring matrix using a cutoff value of −20.
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pone-0103770-g001: Two euAGAMOUS genes in Medicago truncatula.(A) Gene structure of MtAGa and MtAGb. Coding sequences are represented as boxes and introns as dotted lines. Black triangles localize the position of the Tnt1 insertions present in the mutant lines mtaga (NF13380) and mtagb (NF4908) used in this study. (B) Neighbor-Joining Tree of euAG and PLENA homologs from a selection of diverse species. The numbers next to the nodes refer to bootstrap values from 10000 pseudo-replicates. (C) Distribution of putative LFY binding sites in the first intron of MtAGa, MtAGb and MtSHP genes as identified with the use of a position-specific scoring matrix using a cutoff value of −20.

Mentions: The M. truncatula population used for the screening of mutants was described in detail [33], [34], [35], [36] (http://bioinfo4.noble.org/mutant/). The mtagb allele was identified by PCR screening of a segregating population of approximately 10,000 independent lines, using primers annealing to the MtAGb sequence (AGb-F, Table S2) in combination with primers annealing to the LTR borders of the Tnt1 retroelement (Tnt1-F; Table S2 and Figure S3). We identified a line (NF4908) with an insertion of the retroelement located in the first intron at 277 bp of the starting codon (Figure 1A). The R1 plants were genotyped by PCR using the Tnt1-F primer in combination with the gene-specific primers MtAGb-F and MtAGb-Rgenomic (Table S2 and Figure S3B). Approximately 70% of the plants showed a mutant phenotype and co-segregated with the Tnt1 insertion.


Two euAGAMOUS genes control C-function in Medicago truncatula.

Serwatowska J, Roque E, Gómez-Mena C, Constantin GD, Wen J, Mysore KS, Lund OS, Johansen E, Beltrán JP, Cañas LA - PLoS ONE (2014)

Two euAGAMOUS genes in Medicago truncatula.(A) Gene structure of MtAGa and MtAGb. Coding sequences are represented as boxes and introns as dotted lines. Black triangles localize the position of the Tnt1 insertions present in the mutant lines mtaga (NF13380) and mtagb (NF4908) used in this study. (B) Neighbor-Joining Tree of euAG and PLENA homologs from a selection of diverse species. The numbers next to the nodes refer to bootstrap values from 10000 pseudo-replicates. (C) Distribution of putative LFY binding sites in the first intron of MtAGa, MtAGb and MtSHP genes as identified with the use of a position-specific scoring matrix using a cutoff value of −20.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126672&req=5

pone-0103770-g001: Two euAGAMOUS genes in Medicago truncatula.(A) Gene structure of MtAGa and MtAGb. Coding sequences are represented as boxes and introns as dotted lines. Black triangles localize the position of the Tnt1 insertions present in the mutant lines mtaga (NF13380) and mtagb (NF4908) used in this study. (B) Neighbor-Joining Tree of euAG and PLENA homologs from a selection of diverse species. The numbers next to the nodes refer to bootstrap values from 10000 pseudo-replicates. (C) Distribution of putative LFY binding sites in the first intron of MtAGa, MtAGb and MtSHP genes as identified with the use of a position-specific scoring matrix using a cutoff value of −20.
Mentions: The M. truncatula population used for the screening of mutants was described in detail [33], [34], [35], [36] (http://bioinfo4.noble.org/mutant/). The mtagb allele was identified by PCR screening of a segregating population of approximately 10,000 independent lines, using primers annealing to the MtAGb sequence (AGb-F, Table S2) in combination with primers annealing to the LTR borders of the Tnt1 retroelement (Tnt1-F; Table S2 and Figure S3). We identified a line (NF4908) with an insertion of the retroelement located in the first intron at 277 bp of the starting codon (Figure 1A). The R1 plants were genotyped by PCR using the Tnt1-F primer in combination with the gene-specific primers MtAGb-F and MtAGb-Rgenomic (Table S2 and Figure S3B). Approximately 70% of the plants showed a mutant phenotype and co-segregated with the Tnt1 insertion.

Bottom Line: This species is therefore a good experimental system to study the effects of gene duplication within the AG subfamily.Our results show that the M. truncatula euAG- and PLENA-like genes are an example of subfunctionalization as a result of a change in expression pattern.In contrast, MtSHP expression appears late during floral development suggesting it does not contribute significantly to the C-function.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV). Ciudad Politécnica de la Innovación, Valencia, Spain.

ABSTRACT
C-function MADS-box transcription factors belong to the AGAMOUS (AG) lineage and specify both stamen and carpel identity and floral meristem determinacy. In core eudicots, the AG lineage is further divided into two branches, the euAG and PLE lineages. Functional analyses across flowering plants strongly support the idea that duplicated AG lineage genes have different degrees of subfunctionalization of the C-function. The legume Medicago truncatula contains three C-lineage genes in its genome: two euAG genes (MtAGa and MtAGb) and one PLENA-like gene (MtSHP). This species is therefore a good experimental system to study the effects of gene duplication within the AG subfamily. We have studied the respective functions of each euAG genes in M. truncatula employing expression analyses and reverse genetic approaches. Our results show that the M. truncatula euAG- and PLENA-like genes are an example of subfunctionalization as a result of a change in expression pattern. MtAGa and MtAGb are the only genes showing a full C-function activity, concomitant with their ancestral expression profile, early in the floral meristem, and in the third and fourth floral whorls during floral development. In contrast, MtSHP expression appears late during floral development suggesting it does not contribute significantly to the C-function. Furthermore, the redundant MtAGa and MtAGb paralogs have been retained which provides the overall dosage required to specify the C-function in M. truncatula.

Show MeSH