Open field trial of genetically modified parthenocarpic tomato: seedlessness and fruit quality

BACKGROUND: Parthenocarpic tomato lines transgenic for the DefH9-RI-iaaM gene have been cultivated under open field conditions to address some aspects of the equivalence of genetically modified (GM) fruit in comparison to controls (non-GM). RESULTS: Under open field cultivation conditions, two tomato lines (UC 82) transgenic for the DefH9-RI-iaaM gene produced parthenocarpic fruits. DefH9-RI-iaaM fruits were either seedless or contained very few seeds. GM fruit quality, with the exception of a higher β-carotene level, did not show any difference, neither technological (colour, firmness, dry matter, °Brix, pH) nor chemical (titratable acidity, organic acids, lycopene, tomatine, total polyphenols and antioxidant capacity – TEAC), when compared to that of fruits from control line. Highly significant differences in quality traits exist between the tomato F1 commercial hybrid Allflesh and the three UC 82 genotypes tested, regardless of whether or not they are GM. Total yield per plant did not differ between GM and parental line UC 82. Fruit number was increased in GM lines, and GM fruit weight was decreased. CONCLUSION: The use in the diet of fruits from a new line or variety introduces much greater changes than the consumption of GM fruits in comparison to its genetic background. Parthenocarpic fruits, produced under open field conditions, contained 10-fold less seeds than control fruits. Thus parthenocarpy caused by DefH9-RI-iaaM gene represents also a tool for mitigating GM seeds dispersal in the environment

The set of germplasm used for genotypic and phenotypic characterization.

<p>Those shown in <i>italics</i> refer to entries retaining a level of heterozygosity >10%, and those shown <u>underlined</u> produced off-types with respect to plant and/or fruit type. Retained entries are shown in <b>bold</b>.</p

Fruits of accessions belonging to the three main morphological groups.

<p>Group 1∶1a = AM 269-Talindo; 1b = AM 026-Dr2; Group 2∶2a = AM 168-Angio 5; 2b = AM 031-FantE63D; 2c = AM 160-Dourga; Group 3∶3a = AM 037-Violetta di Toscana; 3b = AM 291∶17CAAS; 3c = AM 210-67/3.</p

PCA based on geographical origin (blue: “Occidental”; yellow: “Oriental”).

<p>a) The full germplasm set, and entries within b) morphological group 1, c) morphological group 2, d) morphological group 3.</p

PCA based on geographical origin showing the clustering of the “Oriental” entries with their country of origin.

<p>The accessions from Myanmar and Thailand were classified as Indochinese region.</p

Correlation coefficients between each trait and the leading three PC’s, along with the associated eigenvalues and proportions of the overall variance explained.

<p>Correlation coefficients between each trait and the leading three PC’s, along with the associated eigenvalues and proportions of the overall variance explained.</p

HCPC analysis, based on the leading six PC’s (eigenvalues >1).

<p>a) Scree plot showing the proportion of variance explained by each PC. b) PCA based on the leading two PC’s. Entries belonging to each morphological group marked by a different color (red: group 1, blue: group 2, green: group 3).</p

STRUCTURE output at <i>K</i> = 2.

<p>Each entry is represented by a horizontal line representing subgroup 1 (yellow) and subgroup 2 (blue). a) Entries ordered according to their subgroup membership. b) Entries ordered according to their geographical origin: WE: “Occidental”, EA: “Oriental”.</p

The distribution of trait-by-trait performance across the 191entries phenotyped (the ones not showing residual heterozygosity as well as phenotypic variation), and the statistical significance of the three morphology-based groups identified.

*<p>P<0.05</p>**<p>P<0.01</p>***<p>P<0.001</p