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 - 4.06

DISSECTING GRAPE LEAF DEVELOPMENT AND SENESCENCE AT THE MOLECULAR LEVEL

C. MOSER*, M. PINDO*, C. SEGALA*, P. FONTANA*, E. BLANZIERI**, P. GATTO*, A. ZAMBONI*, M. BERTAMINI*⁺, N. NEDUCHENZIAN*⁺, R. VELASCO*

*) Istituto Agrario S. Michele a/Adige; S. Michele a/Adige-Trento (⁺Area Biologia Avanzata; Unità Operativa Viticoltura)

**) Dip. di Informatica e Telecomunicazioni Università di Trento

grape, gene expression, ESTs, arrays, leaf development

Leaf development and senescence are biological processes under tight genetic control. It has been observed that during leaf expansion photosynthetic rates typically increase and vice-versa during leaf senescence they decline. A photosynthetically efficient leaf is important during ripening of grape berries in order to achieve high sugar and secondary metabolites concentrations. High-throughput sequencing of ESTs and gene expression analysis, on a genome-wide scale, have opened new possibilities to shed light on complex biological questions like leaf senescence.

Following such an approach we have started two years ago the construction and characterization of cDNA libraries from different grape tissues and the collection of a large number of expressed sequences. The sequence information has been processed via bioinformatics tools in order to estimate redundancy and to assign a putative function to each clone on homology base. Up to now we sequenced about 8000 ESTs organized in a searchable and soon publicly accessible grapevine database. Clustering of the sequences revealed that about 70 - 85 % of them, are found only in one tissue, suggesting a marked organ specialization, at least for the highly abundant transcripts. A subset of the cDNA clones (ca. 2300 unigenes) have been spotted on high-density nylon filters and probed with RNA isolated from cv. 'Pinot noir' leaves in 5 different developmental stages. Analysis of gene expression data has been carried out by looking at genes involved in specific metabolic functions and by clustering methods. In addition, transcription profiles have been interpreted in the light of physiological measurements like pigments changes, electron transport activities and total soluble proteins content.

Preliminary results, to be validated and further characterized, identified a group of genes that are up-regulated during leaf senescence.