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Flower development and sex specification in wild grapevine.

Ramos MJ, Coito JL, Silva HG, Cunha J, Costa MM, Rocheta M - BMC Genomics (2014)

Bottom Line: Additionally, we also found clusters of genes differentially expressed between genders and between developmental stages that suggest a role involved in sex differentiation.Also, the detection of differentially transcribed regions that extended existing gene models (intergenic regions) between sexes suggests that they may account for some of the variation between the subspecies.There is no evidence of differences of expression levels in genes from the ABCDE model that could explain the shift from hermaphroditism to dioecy.

View Article: PubMed Central - PubMed

Affiliation: Universidade de Lisboa, Instituto Superior de Agronomia, CBAA, Tapada da Ajuda, 1359-017 Lisboa, Portugal. rocheta@isa.ulisboa.pt.

ABSTRACT

Background: Wild plants of Vitis closely related to the cultivated grapevine (V. v. vinifera) are believed to have been first domesticated 10,000 years BC around the Caspian Sea. V. v. vinifera is hermaphrodite whereas V. v. sylvestris is a dioecious species. Male flowers show a reduced pistil without style or stigma and female flowers present reflexed stamens with infertile pollen. V. vinifera produce perfect flowers with all functional structures. The mechanism for flower sex determination and specification in grapevine is still unknown.

Results: To understand which genes are involved during the establishment of male, female and complete flowers, we analysed and compared the transcription profiles of four developmental stages of the three genders. We showed that sex determination is a late event during flower development and that the expression of genes from the ABCDE model is not directly correlated with the establishment of sexual dimorphism. We propose a temporal comprehensive model in which two mutations in two linked genes could be players in sex determination and indirectly establish the Vitis domestication process. Additionally, we also found clusters of genes differentially expressed between genders and between developmental stages that suggest a role involved in sex differentiation. Also, the detection of differentially transcribed regions that extended existing gene models (intergenic regions) between sexes suggests that they may account for some of the variation between the subspecies.

Conclusions: There is no evidence of differences of expression levels in genes from the ABCDE model that could explain the shift from hermaphroditism to dioecy. We propose that sex specification occurs after floral organ identity has been established and therefore, sex determination genes might be having an effect downstream of the ABCDE model genes.For the first time a full transcriptomic analysis was performed in different flower developmental stages in the same individual. Our experimental approach enabled us to create a comprehensive catalogue of transcribed genes across developmental stages and genders that will contribute for future work in sex determination in seed plants.

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Bright-field micrographs of longitudinal sections ofV. v. sylvestrisinflorescence. Flower meristems at development stage D and stage F of female flowers and at development stage D and F of male flowers. sp, sepals; fm, flower meristem; pt, petals. Scale bar = 75 μm.
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Fig2: Bright-field micrographs of longitudinal sections ofV. v. sylvestrisinflorescence. Flower meristems at development stage D and stage F of female flowers and at development stage D and F of male flowers. sp, sepals; fm, flower meristem; pt, petals. Scale bar = 75 μm.

Mentions: In order to compare the morphology of different flower developmental stages of wild and cultivated Vitis, buds of V. v. sylvestris and V. v. vinifera were collected during the month of April, when inflorescences from stages B (early) to H (just before blooming) could be observed [33] (Additional file 1). Buds from male, female and hermaphroditic plants could not be distinguished until stage H. Histological analysis of inflorescences showed that sepal organ primordia can be identified at stage D (Figure 2). In stage F, which was collected four days after stage D, petal and stamen primordia can be visualized in male inflorescences. Male inflorescences develop slightly earlier than the female (Figure 2) and this feature continues throughout development with a concomitant pollen release 3 to 4 days before the female flower becomes functional.Figure 2


Flower development and sex specification in wild grapevine.

Ramos MJ, Coito JL, Silva HG, Cunha J, Costa MM, Rocheta M - BMC Genomics (2014)

Bright-field micrographs of longitudinal sections ofV. v. sylvestrisinflorescence. Flower meristems at development stage D and stage F of female flowers and at development stage D and F of male flowers. sp, sepals; fm, flower meristem; pt, petals. Scale bar = 75 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4363350&req=5

Fig2: Bright-field micrographs of longitudinal sections ofV. v. sylvestrisinflorescence. Flower meristems at development stage D and stage F of female flowers and at development stage D and F of male flowers. sp, sepals; fm, flower meristem; pt, petals. Scale bar = 75 μm.
Mentions: In order to compare the morphology of different flower developmental stages of wild and cultivated Vitis, buds of V. v. sylvestris and V. v. vinifera were collected during the month of April, when inflorescences from stages B (early) to H (just before blooming) could be observed [33] (Additional file 1). Buds from male, female and hermaphroditic plants could not be distinguished until stage H. Histological analysis of inflorescences showed that sepal organ primordia can be identified at stage D (Figure 2). In stage F, which was collected four days after stage D, petal and stamen primordia can be visualized in male inflorescences. Male inflorescences develop slightly earlier than the female (Figure 2) and this feature continues throughout development with a concomitant pollen release 3 to 4 days before the female flower becomes functional.Figure 2

Bottom Line: Additionally, we also found clusters of genes differentially expressed between genders and between developmental stages that suggest a role involved in sex differentiation.Also, the detection of differentially transcribed regions that extended existing gene models (intergenic regions) between sexes suggests that they may account for some of the variation between the subspecies.There is no evidence of differences of expression levels in genes from the ABCDE model that could explain the shift from hermaphroditism to dioecy.

View Article: PubMed Central - PubMed

Affiliation: Universidade de Lisboa, Instituto Superior de Agronomia, CBAA, Tapada da Ajuda, 1359-017 Lisboa, Portugal. rocheta@isa.ulisboa.pt.

ABSTRACT

Background: Wild plants of Vitis closely related to the cultivated grapevine (V. v. vinifera) are believed to have been first domesticated 10,000 years BC around the Caspian Sea. V. v. vinifera is hermaphrodite whereas V. v. sylvestris is a dioecious species. Male flowers show a reduced pistil without style or stigma and female flowers present reflexed stamens with infertile pollen. V. vinifera produce perfect flowers with all functional structures. The mechanism for flower sex determination and specification in grapevine is still unknown.

Results: To understand which genes are involved during the establishment of male, female and complete flowers, we analysed and compared the transcription profiles of four developmental stages of the three genders. We showed that sex determination is a late event during flower development and that the expression of genes from the ABCDE model is not directly correlated with the establishment of sexual dimorphism. We propose a temporal comprehensive model in which two mutations in two linked genes could be players in sex determination and indirectly establish the Vitis domestication process. Additionally, we also found clusters of genes differentially expressed between genders and between developmental stages that suggest a role involved in sex differentiation. Also, the detection of differentially transcribed regions that extended existing gene models (intergenic regions) between sexes suggests that they may account for some of the variation between the subspecies.

Conclusions: There is no evidence of differences of expression levels in genes from the ABCDE model that could explain the shift from hermaphroditism to dioecy. We propose that sex specification occurs after floral organ identity has been established and therefore, sex determination genes might be having an effect downstream of the ABCDE model genes.For the first time a full transcriptomic analysis was performed in different flower developmental stages in the same individual. Our experimental approach enabled us to create a comprehensive catalogue of transcribed genes across developmental stages and genders that will contribute for future work in sex determination in seed plants.

Show MeSH
Related in: MedlinePlus