Limits...
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.

Show MeSH
Expression pattern of MtAGa, MtAGb and MtSHP genes during early floral development.In situ localization of MtAGa (A-E), MtAGb (F-J) and MtSHP (K-N) transcripts in M. truncatula wild-type flower buds. Developmental stages were defined according to [74]. MtAGa transcripts are localized in the whole floral meristem at stages 2 (A) and 4 (B). At stage 5 (C) MtAGa mRNA is detected in stamen and carpel primordia. At stage 7 (D-E) expression locates in stamens, carpel and the developing ovules. MtAGb transcripts are localized in the center of the floral meristem at stage 2 (F). At stage 4 (G) expression locates in the carpel primordia and the half of the common primordia that will give rise to the stamens. At stage 5 (H) MtAGb mRNA is detected in stamen and carpel primordia. At stage 7 (I-J) MtAGb mRNA is detected in stamens, carpel and developing ovules. MtSHP transcripts are not detected at stages 2 (K) and 5 (L). At stage 6 MtSHP transcripts are localized in the inner cells of the developing carpel (M). At stage 7 (N) expression can be detected in the developing ovules. F: floral meristem; S: sepal; C: carpel; CP: common primordia; St: stamen; P: petal; Fi: filament; A: anther; Ov: ovule.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4126672&req=5

pone-0103770-g003: Expression pattern of MtAGa, MtAGb and MtSHP genes during early floral development.In situ localization of MtAGa (A-E), MtAGb (F-J) and MtSHP (K-N) transcripts in M. truncatula wild-type flower buds. Developmental stages were defined according to [74]. MtAGa transcripts are localized in the whole floral meristem at stages 2 (A) and 4 (B). At stage 5 (C) MtAGa mRNA is detected in stamen and carpel primordia. At stage 7 (D-E) expression locates in stamens, carpel and the developing ovules. MtAGb transcripts are localized in the center of the floral meristem at stage 2 (F). At stage 4 (G) expression locates in the carpel primordia and the half of the common primordia that will give rise to the stamens. At stage 5 (H) MtAGb mRNA is detected in stamen and carpel primordia. At stage 7 (I-J) MtAGb mRNA is detected in stamens, carpel and developing ovules. MtSHP transcripts are not detected at stages 2 (K) and 5 (L). At stage 6 MtSHP transcripts are localized in the inner cells of the developing carpel (M). At stage 7 (N) expression can be detected in the developing ovules. F: floral meristem; S: sepal; C: carpel; CP: common primordia; St: stamen; P: petal; Fi: filament; A: anther; Ov: ovule.

Mentions: The expression patterns of MtAGa, MtAGb and MtSHP were analysed by Northern blot in different plant tissues and the three genes are exclusively expressed in floral and young fruit tissues (Figure 2). We performed detailed in situ hybridization experiments to show the distribution of MtAGa, MtAGb and MtSHP mRNAs during floral development (Figure 3). Both MtAGa and MtAGb transcripts began to accumulate at stage 2 of flower development. At this stage, MtAGb accumulates in the centre of the floral primordia while MtAGa signal was detected throughout the floral meristem (Figure 3F and 3A). At stage 4, MtAGb transcript was located in the region of the common primordia that will give rise to the stamens and also in the central part of the floral apex where the carpel is developing (Figure 3G). However, MtAGa expression is still observed on the whole floral meristem, including petal and sepal primordia (Figure 3B). From stage 5, expression of both paralogs was distributed uniformly in whorls 3 and 4 (Figure 3C-E and 3H-J), although hybridization signal for MtAGb was stronger on the abaxial region of the carpel. In later stages, expression of both transcripts was observed in the developing ovules, in the distal region of the carpel and on the filament of the anthers (Figure 3E and 3J). In contrast, MtSHP mRNA began to accumulate late on flower development and can be detected at stage 6 in the inner cells of the developing carpel (Figure 3M). Since late stage 7, MtSHP expression is exclusively detected in the ovules (Figure 3N).


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)

Expression pattern of MtAGa, MtAGb and MtSHP genes during early floral development.In situ localization of MtAGa (A-E), MtAGb (F-J) and MtSHP (K-N) transcripts in M. truncatula wild-type flower buds. Developmental stages were defined according to [74]. MtAGa transcripts are localized in the whole floral meristem at stages 2 (A) and 4 (B). At stage 5 (C) MtAGa mRNA is detected in stamen and carpel primordia. At stage 7 (D-E) expression locates in stamens, carpel and the developing ovules. MtAGb transcripts are localized in the center of the floral meristem at stage 2 (F). At stage 4 (G) expression locates in the carpel primordia and the half of the common primordia that will give rise to the stamens. At stage 5 (H) MtAGb mRNA is detected in stamen and carpel primordia. At stage 7 (I-J) MtAGb mRNA is detected in stamens, carpel and developing ovules. MtSHP transcripts are not detected at stages 2 (K) and 5 (L). At stage 6 MtSHP transcripts are localized in the inner cells of the developing carpel (M). At stage 7 (N) expression can be detected in the developing ovules. F: floral meristem; S: sepal; C: carpel; CP: common primordia; St: stamen; P: petal; Fi: filament; A: anther; Ov: ovule.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0103770-g003: Expression pattern of MtAGa, MtAGb and MtSHP genes during early floral development.In situ localization of MtAGa (A-E), MtAGb (F-J) and MtSHP (K-N) transcripts in M. truncatula wild-type flower buds. Developmental stages were defined according to [74]. MtAGa transcripts are localized in the whole floral meristem at stages 2 (A) and 4 (B). At stage 5 (C) MtAGa mRNA is detected in stamen and carpel primordia. At stage 7 (D-E) expression locates in stamens, carpel and the developing ovules. MtAGb transcripts are localized in the center of the floral meristem at stage 2 (F). At stage 4 (G) expression locates in the carpel primordia and the half of the common primordia that will give rise to the stamens. At stage 5 (H) MtAGb mRNA is detected in stamen and carpel primordia. At stage 7 (I-J) MtAGb mRNA is detected in stamens, carpel and developing ovules. MtSHP transcripts are not detected at stages 2 (K) and 5 (L). At stage 6 MtSHP transcripts are localized in the inner cells of the developing carpel (M). At stage 7 (N) expression can be detected in the developing ovules. F: floral meristem; S: sepal; C: carpel; CP: common primordia; St: stamen; P: petal; Fi: filament; A: anther; Ov: ovule.
Mentions: The expression patterns of MtAGa, MtAGb and MtSHP were analysed by Northern blot in different plant tissues and the three genes are exclusively expressed in floral and young fruit tissues (Figure 2). We performed detailed in situ hybridization experiments to show the distribution of MtAGa, MtAGb and MtSHP mRNAs during floral development (Figure 3). Both MtAGa and MtAGb transcripts began to accumulate at stage 2 of flower development. At this stage, MtAGb accumulates in the centre of the floral primordia while MtAGa signal was detected throughout the floral meristem (Figure 3F and 3A). At stage 4, MtAGb transcript was located in the region of the common primordia that will give rise to the stamens and also in the central part of the floral apex where the carpel is developing (Figure 3G). However, MtAGa expression is still observed on the whole floral meristem, including petal and sepal primordia (Figure 3B). From stage 5, expression of both paralogs was distributed uniformly in whorls 3 and 4 (Figure 3C-E and 3H-J), although hybridization signal for MtAGb was stronger on the abaxial region of the carpel. In later stages, expression of both transcripts was observed in the developing ovules, in the distal region of the carpel and on the filament of the anthers (Figure 3E and 3J). In contrast, MtSHP mRNA began to accumulate late on flower development and can be detected at stage 6 in the inner cells of the developing carpel (Figure 3M). Since late stage 7, MtSHP expression is exclusively detected in the ovules (Figure 3N).

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