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A PLENA-like gene of peach is involved in carpel formation and subsequent transformation into a fleshy fruit.

Tadiello A, Pavanello A, Zanin D, Caporali E, Colombo L, Rotino GL, Trainotti L, Casadoro G - J. Exp. Bot. (2009)

Bottom Line: Here a detailed analysis of a gene that belongs to the PLENA subfamily of MADS-box genes is shown.Interestingly, the transgenic berries constitutively expressing the PpPLENA gene show an accelerated ripening, as judged by the expression of genes that are important for tomato fruit ripening.It is suggested that PpPLENA might interfere with the endogenous activity of TAGL1, thereby activating the fruit ripening pathway earlier compared with wild-type tomato plants.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Biologia, Università di Padova, 35131 Padova, Italy.

ABSTRACT
MADS-box genes have been shown to play a role in the formation of fruits, both in Arabidopsis and in tomato. In peach, two C-class MADS-box genes have been isolated. Both of them are expressed during flower and mesocarp development. Here a detailed analysis of a gene that belongs to the PLENA subfamily of MADS-box genes is shown. The expression of this PLENA-like gene (PpPLENA) increases during fruit ripening, and its ectopic expression in tomato plants causes the transformation of sepals into carpel-like structures that become fleshy and ripen like real fruits. Interestingly, the transgenic berries constitutively expressing the PpPLENA gene show an accelerated ripening, as judged by the expression of genes that are important for tomato fruit ripening. It is suggested that PpPLENA might interfere with the endogenous activity of TAGL1, thereby activating the fruit ripening pathway earlier compared with wild-type tomato plants.

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Tomato plants constitutively expressing the peach PpPLE (794) cDNA. (A) An ESEM (environmental scanning electron microscopy) picture of a transgenic flower bud with sepals completely fused up to the blossom end of the calyx from which only the style/stigma emerges. (B) Partial removal of the fused calyx permits the partially deformed anthers to be seen. (C) An inflorescence of a transgenic line with a mild phenotype. As in A, the calyx is fused, although not as far as the top, thus allowing the petal tips to become visible at anthesis. For comparison, a wild-type flower is shown in D. Transgenic fruits at various stages of development are shown in E, where a white arrow indicates the fleshy sepals undergoing ripening. A wild-type ripe fruit with leafy sepals still attached is shown in F.
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fig4: Tomato plants constitutively expressing the peach PpPLE (794) cDNA. (A) An ESEM (environmental scanning electron microscopy) picture of a transgenic flower bud with sepals completely fused up to the blossom end of the calyx from which only the style/stigma emerges. (B) Partial removal of the fused calyx permits the partially deformed anthers to be seen. (C) An inflorescence of a transgenic line with a mild phenotype. As in A, the calyx is fused, although not as far as the top, thus allowing the petal tips to become visible at anthesis. For comparison, a wild-type flower is shown in D. Transgenic fruits at various stages of development are shown in E, where a white arrow indicates the fleshy sepals undergoing ripening. A wild-type ripe fruit with leafy sepals still attached is shown in F.

Mentions: Transformation of tomato yielded 13 different transgenic plants containing the PpPLE coding region under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Interestingly, a mutated phenotype could only be observed at the level of flowers. Three lines produced flowers and fruits that were similar to those of the wild type (Fig. 4D, F). Only one such line produced seeds that yielded kanamycin-resistant plants similar to the wild type. Eight primary transformants produced flowers with a mild mutated phenotype that consisted mostly of a calyx where the various sepals tended to be joined together to various degrees throughout their subsequent development (Fig. 4C). The fused calyx was, however, partly opened at the blossom end, thus allowing a limited anthesis to be visible (Fig. 4C). Four of the above mild lines produced seeds that, in two cases, yielded plants with a stronger phenotype. The remaining transgenic clones showed a particularly severe phenotype, with flower buds that did not open at anthesis because the sepals formed a tube-like structure that allowed only the style/stigma to become visible (Fig. 4A). The reproductive organs were present in all transformants, although in the case of the most severe phenotype the stamens looked partially deformed (Fig. 4B), probably due to mechanical constraints. Later during development, the fused calyx was partially opened by the outgrowth of the ovary-derived fruit which ripened normally (Fig. 4E) like that of the wild-type plants (Fig. 4F), although seeds were never produced and plants had to be propagated vegetatively. Contrary to what occurred in wild-type plants where the sepals maintained a leaf-like structure throughout the entire life of the fruit (Fig. 4F), in transgenic plants with a strong phenotype the sepals developed a fleshy structure and became reddish (Fig. 4E, white arrow), thus behaving like ectopic fruits.


A PLENA-like gene of peach is involved in carpel formation and subsequent transformation into a fleshy fruit.

Tadiello A, Pavanello A, Zanin D, Caporali E, Colombo L, Rotino GL, Trainotti L, Casadoro G - J. Exp. Bot. (2009)

Tomato plants constitutively expressing the peach PpPLE (794) cDNA. (A) An ESEM (environmental scanning electron microscopy) picture of a transgenic flower bud with sepals completely fused up to the blossom end of the calyx from which only the style/stigma emerges. (B) Partial removal of the fused calyx permits the partially deformed anthers to be seen. (C) An inflorescence of a transgenic line with a mild phenotype. As in A, the calyx is fused, although not as far as the top, thus allowing the petal tips to become visible at anthesis. For comparison, a wild-type flower is shown in D. Transgenic fruits at various stages of development are shown in E, where a white arrow indicates the fleshy sepals undergoing ripening. A wild-type ripe fruit with leafy sepals still attached is shown in F.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2651465&req=5

fig4: Tomato plants constitutively expressing the peach PpPLE (794) cDNA. (A) An ESEM (environmental scanning electron microscopy) picture of a transgenic flower bud with sepals completely fused up to the blossom end of the calyx from which only the style/stigma emerges. (B) Partial removal of the fused calyx permits the partially deformed anthers to be seen. (C) An inflorescence of a transgenic line with a mild phenotype. As in A, the calyx is fused, although not as far as the top, thus allowing the petal tips to become visible at anthesis. For comparison, a wild-type flower is shown in D. Transgenic fruits at various stages of development are shown in E, where a white arrow indicates the fleshy sepals undergoing ripening. A wild-type ripe fruit with leafy sepals still attached is shown in F.
Mentions: Transformation of tomato yielded 13 different transgenic plants containing the PpPLE coding region under the control of the cauliflower mosaic virus (CaMV) 35S promoter. Interestingly, a mutated phenotype could only be observed at the level of flowers. Three lines produced flowers and fruits that were similar to those of the wild type (Fig. 4D, F). Only one such line produced seeds that yielded kanamycin-resistant plants similar to the wild type. Eight primary transformants produced flowers with a mild mutated phenotype that consisted mostly of a calyx where the various sepals tended to be joined together to various degrees throughout their subsequent development (Fig. 4C). The fused calyx was, however, partly opened at the blossom end, thus allowing a limited anthesis to be visible (Fig. 4C). Four of the above mild lines produced seeds that, in two cases, yielded plants with a stronger phenotype. The remaining transgenic clones showed a particularly severe phenotype, with flower buds that did not open at anthesis because the sepals formed a tube-like structure that allowed only the style/stigma to become visible (Fig. 4A). The reproductive organs were present in all transformants, although in the case of the most severe phenotype the stamens looked partially deformed (Fig. 4B), probably due to mechanical constraints. Later during development, the fused calyx was partially opened by the outgrowth of the ovary-derived fruit which ripened normally (Fig. 4E) like that of the wild-type plants (Fig. 4F), although seeds were never produced and plants had to be propagated vegetatively. Contrary to what occurred in wild-type plants where the sepals maintained a leaf-like structure throughout the entire life of the fruit (Fig. 4F), in transgenic plants with a strong phenotype the sepals developed a fleshy structure and became reddish (Fig. 4E, white arrow), thus behaving like ectopic fruits.

Bottom Line: Here a detailed analysis of a gene that belongs to the PLENA subfamily of MADS-box genes is shown.Interestingly, the transgenic berries constitutively expressing the PpPLENA gene show an accelerated ripening, as judged by the expression of genes that are important for tomato fruit ripening.It is suggested that PpPLENA might interfere with the endogenous activity of TAGL1, thereby activating the fruit ripening pathway earlier compared with wild-type tomato plants.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Biologia, Università di Padova, 35131 Padova, Italy.

ABSTRACT
MADS-box genes have been shown to play a role in the formation of fruits, both in Arabidopsis and in tomato. In peach, two C-class MADS-box genes have been isolated. Both of them are expressed during flower and mesocarp development. Here a detailed analysis of a gene that belongs to the PLENA subfamily of MADS-box genes is shown. The expression of this PLENA-like gene (PpPLENA) increases during fruit ripening, and its ectopic expression in tomato plants causes the transformation of sepals into carpel-like structures that become fleshy and ripen like real fruits. Interestingly, the transgenic berries constitutively expressing the PpPLENA gene show an accelerated ripening, as judged by the expression of genes that are important for tomato fruit ripening. It is suggested that PpPLENA might interfere with the endogenous activity of TAGL1, thereby activating the fruit ripening pathway earlier compared with wild-type tomato plants.

Show MeSH
Related in: MedlinePlus