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 - 1.54

STRAWBERRY cDNA MICROARRAYS AS A TOOL FOR STUDYING FRUIT QUALITY TRAITS AND COMPARING ELITE GENOTYPES

C. ROSATI, F. MOURGUES, F. GIORNO, F. CARBONE, M.A. CARBONI, G. PERROTTA

ENEA, C. R. Trisaia, S.S. 106, km 419+500, 75026 Rotondella (MT), Italy

strawberry, microarrays, fruit quality, ripening, functional genomics

Cultivated octoploid strawberry (Fragaria x ananassa) is a fruit crop with hundreds of varieties grown over a wide range of latitudes. To assess fruit quality and correlate gene expression data with those from biochemical analyses and panel tests, we amplified 4512 clones of a cDNA library obtained from RNA extracted from ripening fruits and analyzed the 3061 expressed sequence tags (ESTs) which produced a sequence larger than 250 bp. Two successive runs of contig assembly reduced sequence complexity and grouped the ESTs into 1353 sequences (580 contigs and 773 singletons), 632 of which shared similarity with plant gene sequences. The highest number of BLAST hits were assigned to the Rosaceae family (652 out of 3061 processed ESTs, 21.3%), with 476 sequences (15.6% of total, 73% of Rosaceae) belonging to the genus Fragaria (both octoploid F. x ananassa and diploid F. vesca). The 50 largest contigs related to plant genes with known functions comprised 725 ESTs (23.7% of total), including genes associated with ripening (cell wall metabolism, sugar and acid synthesis, pigment formation, vitamin synthesis and allergenic properties), as well as with plant-pathogen interactions, abiotic stresses and housekeeping functions. Moreover, 125 consensus sequences were similar to mRNAs or putatively encoded proteins not yet characterized and 721 did not give any significant BLAST match. These 846 “unknown” sequences represent an invaluable resource for finding genes with new functions. Representative subsets of ESTs were used to produce cDNA microarrays and carry out experiments on genotypes with different fruit quality. In the frame of the Italian FISR Project “QUALIFRAPE”, our investigations will point out the genes whose expression level is most involved in fruit quality and post-harvest traits. Comparison of molecular, biochemical and panel test information are underway to correlate analytical data with overall consumer’s preference.