Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 1.41

ISOLATION OF DNA FRACTIONS DIFFERENTIALLY EXPRESSED IN CITRUS DURING RIPENING PROCESS

D. SALUZZI, L. MILELLA, G. MARTELLI, I. GRECO

Dipartimento di Biologia, Difesa e Biotecnologie AgroForestali, Università degli Studi della Basilicata, Contrada Macchia Romana, 85100 Potenza

citrus, ripening process, differentially DNA fractions expression

Development, maturation and ripening of fruits has received considerable experimental attention, primarily due to the uniqueness of such processes to plant species and the importance of fruit as a significant aspect of human dietary intake and nutrition. Molecular and genetic analysis of fruit development, and especially ripening of fleshy fruits, has resulted in significant gains in knowledge over recent years especially considering metabolic pathway characterizing commercial and nutritional fruit quality (Canel et al., 1996; Moriguchi T., et al 2002).

Ripening has an impact on fibre content and composition, lipid metabolism, and the levels of vitamins and various antioxidants (Ronen et al., 1999). The ability to understand and manipulate, through breeding or biotechnology, key control points or regulatory points of specific ripening process such as carotenoid, flavonoid, vitamin, and flavour volatiles, will allow the control of nutrition and quality characteristics linked to ripening.

The present work was pointed to isolate DNA fractions differentially expressed in Citrus during ripening process.

To investigate this process fruits of four orange genotypes, were collected at two different ripening stages: green and ripe. The fruit were frozen in liquid nitrogen and stored at -80°C. Totally RNA and mRNA were isolated from different fruit tissue and cDNA was obtained in order to perform several experiments of differential display and cDNA-AFLP. Specific and random primers were also utilized in order to isolate sequences with high level of similarity with gene involved in ripening process.

Using that techniques, 150 differentially expressed fraction were isolated: 48 using cDNA-AFLP experiment and the others with random and specific primers. All fragments differentially expressed among the ripening stages and coming from the different genotypes utilized were sequenced. The sequences obtained were compared against public databases for similarity with genes yet isolated.

Twenty sequences shown high homology with genes encoding protein with known activity as epimerase, carotene desaturase and Zinc methabolism enzymes.

The results obtained by the use of specific primers inspire to improve the analyses of the ripening process with the aim of isolate key control points of specific metabolic pathway.