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A clarified position for Solanum lycopersicum var. cerasiforme in the evolutionary history of tomatoes (solanaceae).

Ranc N, Muños S, Santoni S, Causse M - BMC Plant Biol. (2008)

Bottom Line: Model-based analysis showed that the 144 S. lycopersicum var. cerasiforme accessions were structured into two groups: one close to the domesticated group and one resulting from the admixture of the S. lycopersicum and S. pimpinellifolium genomes.The potential use of the admixed group of S. lycopersicum var. cerasiforme for association genetics studies is also discussed.These collections are available for the scientific community and can be used as standardized panels for coordinating efforts on identifying novel interesting genes and on examining the domestication process in more detail.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UR1052, Unité de Génétique et d'Amélioration des Fruits et Légumes, Montfavet 84 143, France. Nicolas.Ranc@avignon.inra.fr

ABSTRACT

Background: The natural phenotypic variability present in the germplasm of cultivated plants can be linked to molecular polymorphisms using association genetics. However it is necessary to consider the genetic structure of the germplasm used to avoid false association. The knowledge of genetic structure of plant populations can help in inferring plant evolutionary history. In this context, we genotyped 360 wild, feral and cultivated accessions with 20 simple sequence repeat markers and investigated the extent and structure of the genetic variation. The study focused on the red fruited tomato clade involved in the domestication of tomato and confirmed the admixture status of cherry tomatoes (Solanum lycopersicum var. cerasiforme). We used a nested sample strategy to set-up core collection maximizing the genetic diversity with a minimum of individuals.

Results: Molecular diversity was considerably lower in S. lycopersicum i.e. the domesticated form. Model-based analysis showed that the 144 S. lycopersicum var. cerasiforme accessions were structured into two groups: one close to the domesticated group and one resulting from the admixture of the S. lycopersicum and S. pimpinellifolium genomes. SSR genotyping also indicates that domesticated and wild tomatoes have evolved as a species complex with intensive level of hybridization. We compiled genotypic and phenotypic data to identify sub-samples of 8, 24, 32 and 64 cherry tomato accessions that captured most of the genetic and morphological diversity present in the entire S. lycopersicum var. cerasiforme collection.

Conclusion: The extent and structure of allelic variation is discussed in relation to historical events like domestication and modern selection. The potential use of the admixed group of S. lycopersicum var. cerasiforme for association genetics studies is also discussed. Nested core collections sampled to represent tomato diversity will be useful in diversity studies. Molecular and phenotypic variability of these core collections is defined. These collections are available for the scientific community and can be used as standardized panels for coordinating efforts on identifying novel interesting genes and on examining the domestication process in more detail.

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Core collection representativeness for fruit weight, Soluble Solid Content and Titratable Acidity. Classes are those used for core collections (cc) design.
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Figure 5: Core collection representativeness for fruit weight, Soluble Solid Content and Titratable Acidity. Classes are those used for core collections (cc) design.

Mentions: For fruit weight (FW), soluble solid content (SSC) and titratable acidity (TA), the core collection of 64 accessions best represented the phenotypic variability of the global sample even though extreme phenotypes were not represented (Figure 5). The sample consisting of 32 accessions seemed to be the best compromise because of its small number of accessions and its representativeness.


A clarified position for Solanum lycopersicum var. cerasiforme in the evolutionary history of tomatoes (solanaceae).

Ranc N, Muños S, Santoni S, Causse M - BMC Plant Biol. (2008)

Core collection representativeness for fruit weight, Soluble Solid Content and Titratable Acidity. Classes are those used for core collections (cc) design.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2657798&req=5

Figure 5: Core collection representativeness for fruit weight, Soluble Solid Content and Titratable Acidity. Classes are those used for core collections (cc) design.
Mentions: For fruit weight (FW), soluble solid content (SSC) and titratable acidity (TA), the core collection of 64 accessions best represented the phenotypic variability of the global sample even though extreme phenotypes were not represented (Figure 5). The sample consisting of 32 accessions seemed to be the best compromise because of its small number of accessions and its representativeness.

Bottom Line: Model-based analysis showed that the 144 S. lycopersicum var. cerasiforme accessions were structured into two groups: one close to the domesticated group and one resulting from the admixture of the S. lycopersicum and S. pimpinellifolium genomes.The potential use of the admixed group of S. lycopersicum var. cerasiforme for association genetics studies is also discussed.These collections are available for the scientific community and can be used as standardized panels for coordinating efforts on identifying novel interesting genes and on examining the domestication process in more detail.

View Article: PubMed Central - HTML - PubMed

Affiliation: INRA, UR1052, Unité de Génétique et d'Amélioration des Fruits et Légumes, Montfavet 84 143, France. Nicolas.Ranc@avignon.inra.fr

ABSTRACT

Background: The natural phenotypic variability present in the germplasm of cultivated plants can be linked to molecular polymorphisms using association genetics. However it is necessary to consider the genetic structure of the germplasm used to avoid false association. The knowledge of genetic structure of plant populations can help in inferring plant evolutionary history. In this context, we genotyped 360 wild, feral and cultivated accessions with 20 simple sequence repeat markers and investigated the extent and structure of the genetic variation. The study focused on the red fruited tomato clade involved in the domestication of tomato and confirmed the admixture status of cherry tomatoes (Solanum lycopersicum var. cerasiforme). We used a nested sample strategy to set-up core collection maximizing the genetic diversity with a minimum of individuals.

Results: Molecular diversity was considerably lower in S. lycopersicum i.e. the domesticated form. Model-based analysis showed that the 144 S. lycopersicum var. cerasiforme accessions were structured into two groups: one close to the domesticated group and one resulting from the admixture of the S. lycopersicum and S. pimpinellifolium genomes. SSR genotyping also indicates that domesticated and wild tomatoes have evolved as a species complex with intensive level of hybridization. We compiled genotypic and phenotypic data to identify sub-samples of 8, 24, 32 and 64 cherry tomato accessions that captured most of the genetic and morphological diversity present in the entire S. lycopersicum var. cerasiforme collection.

Conclusion: The extent and structure of allelic variation is discussed in relation to historical events like domestication and modern selection. The potential use of the admixed group of S. lycopersicum var. cerasiforme for association genetics studies is also discussed. Nested core collections sampled to represent tomato diversity will be useful in diversity studies. Molecular and phenotypic variability of these core collections is defined. These collections are available for the scientific community and can be used as standardized panels for coordinating efforts on identifying novel interesting genes and on examining the domestication process in more detail.

Show MeSH
Related in: MedlinePlus