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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.51

IDENTIFICATION OF BIOMARKERS ASSOCIATED WITH STRAWBERRY FRUIT QUALITY

LADDOMADA B.*, LEO L.*, PIRANDOLA P.*, GERARDI C.*, LEONE A.*, SAVINI G.**, NERI D.**, ZACHEO G.*

*) ISPA, CNR, Via Prov.le Lecce Monteroni, 73100 Lecce, Italy

**) Dip. Bioenergetica, Univ. Ancona, Via Brecce Bianche I, 60100 Ancona, Italy

strawberry, ripening, cDNA-AFLP fingerprinting, proteoma

The biochemical events that occur during the ripening of strawberry result in important changes affecting fruit quality. These include the accumulation of red anthocyanin pigments, an increase in the content of sucrose and exose, and the production of volatile flavour compounds. As a result, many changes in gene expression occur during the fruit development.

Despite the long history of genetic selections of strawberry cultivars, there are still missing information on the molecular, cellular and biochemical events that control fruit formation and quality. So far, only a few genes have been isolated and studied, and the ripening process of strawberries still remains poorly understood.

The objective of the present research was the detection of molecular determinants associated with fruit ripening events with major respect for flavour formation in cv. Paros (Fragaria x ananassa Duch.). Fruit fingerprinting by cDNA-AFLP was employed in three ripening stages of fruits (green, pink and red) in order to identify markers associated with specific aroma components and other main quality traits. Inverse PCR of polymorphic AFLP markers associated to fruit quality is in progress in order to clone and convert these AFLPs in PCR based markers (SCAR).

Different approaches for assaying fruit flavour during the ripening process were employed and the key aroma compounds variation among green, pink and red fruit of cv. Paros were detected.

Moreover, to better understand the biochemical basis of ripening processes in strawberry, the protein expression in cv. Paros was evaluated by proteoma analysis. The 2DE map matching revealed an increased protein expression in ripe compared to unripe fruits. In particular, proteins with a molecular masse of about 35 kDA were found to be expressed in unripe fruits. On the contrary, an increase of 45 kDA proteins in ripe strawberries was observed.

Lipoxygenases (LOX) and hydroperoxidelyase (HPL) enzymatic activities in green, pink and red receptacles were also assayed. A study to explore a relationship between the LOX activity and green odour is in progress.

The obtained results may provide powerful tools for improving strawberries quality by the means of breeding programs.