paper natureIn 26/06/2014, the journal Nature Communications published a research developed in the Plant Molecular Genetics Laboratory of the Botany Department (IB/USP), headed by Profa Dra Magdalena Rossi, with collaboration of Prof. Fernando Carrari’s group of the Biotecnology Institute (Argentina National Agropecuary Technology Institute).

Tomatoes have high nutritional value and are consumed worldwide, making them important components of human diet. Among its nutraceutical compounds, vitamins and antioxidants molecules are of utmost importance. In this context, the group identifies the importance of the VTE3 gene, which encodes for a vitamin E biosynthetic pathway enzyme, for the vitamin E content in tomato fruits.

In the gene promoter region (the part that promotes its transcription) there is a SINE type retrotransposon (a mobile genetic element) that can be methylated, i.e. it can be epigenetically modified (a change in the DNA that does not change the base sequence). When this occurs, the gene transcription is reduced, therefore, less enzyme is translated and, consequently, the vitamin E content in the fruit is lowered. On the other hand, when the SINE is demethylated, the gene expression is raised and higher vitamin E levels are found. The two gene versions, or epialleles, are found naturally in tomato and the conversion of one to another depends on the environment conditions.

For the first time, epigenetic regulation of an agronomical trait was demonstrated, moreover, these results exemplifies how the regulation of gene expression can affect the plant phenotypic plasticity allowing its adaptation to the environment.

The paper can be accessed in this link.

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On 2014 March 22th, the argentine newspaper "Página/12" in the section "Futuro" (future) published an interview aboute the tomato lines silenced for the SPA (sugar partition-affecting) protein. These lines were a result of the post-doctoral research of Luisa Fernanda Bermúdez under the guidance of professor Maria Magdalena Rossi, with colaboration of INTA (Instituto Nacional de Tecnologia Agropecuaria - Argentina) members. The research was published in "The Plant Journal" with highlights in the 2014 march edition (Volume 77; Issue 5)

The interview to the newspapers includes many topics as researches tbat lead to the SPA protein identification; patents and transgeny, and can be read in this link.

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Every fruit accumulates sugars and other nutrients during its development. In order to do so, the developing fruit receives carbon from leaves in the form of sugars, especially sucrose, which is a product of photosynthesis and exported to sink organs (roots, flowers and fruits). One of the points that affect the plant yield is the traffic between source and sink tissues regulation. Researchers of Bioscience Institute, headed by Professor Magdalena Rossi of the Botany Department (USP), using tomato as a model system identified a protein that acts within the chloroplast, organelle responsible for photosynthesis, which regulates the sugar transport from leaf to fruit. By developing a transgenic tomato line with a reduction in this protein synthesis, the researchers demonstrated a higher sugar transport from leaf for fruits, therefore named SPA (Sugar Partition-Affecting). This effect, demonstrated by a diversity of biochemical parameters, resulted in plants with bigger and more tomatoes. This could be a good approach to increase the yield of agronomically important plants to improve the harvests. “The functional characterization of SPA open doors for the establishment of new strategies in order to increase food production, one of the great challenges for scientists working with the biology of agronomically important plants. The next steps include large scale tests to evaluate the plant performance and assess the SPA function in other species”, comments the project leader.

The research is alredy published online in the Plant Journal, and you can access by this link the manuscript version full text.