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 - 5.22

STUDY OF DIFFERENTIALLY EXPRESSED GENES IN APPLE

Toller C., Zini E., Baldi P., Komjanc M.

Istituto Agrario di San Michele all’Adige- via E. Mach n°1-38010 San Michele all’Adige (TN)

apple, PCR-select, differentially expressed genes

For years the Agricultural Institute of San Michele all’Adige carried out the study of the plant - pathogen interaction in apple and recently has started a project called “Advanced Biology Applied to Grape, Apple and Salmons” financed by the Caritro foundation.

In the project the apple research is developed on three principal lines: MAS (marker assisted selection) for scab and oidium resistance; identification of molecular markers related to Va scab resistance gene and isolation and cloning of resistance genes analogous and differentially expressed sequences related to fungal infection resistance and salicylic acid treatment.

Our contribution is focused on the isolation and characterisation of differentially expressed genes and sequences associated to signal transduction pathways involved in apple defence mechanisms.

In this study the PCR-Select technique is used (kit “PCR-Select cDNA Subtraction” by Clontech); method already used by E.Wang et al. (Nature Biotechnology 2001) for the identification and isolation of rare and differentially expressed genes.

Literature data say that such method is more efficient and effective in identifying rare genes than the differential display and cDNA AFLP.

The current study is turned to the molecular analysis in order to identify defence and signal transduction genes during salicylic acid treatment and SAR (systemical applied resistance) response.

At present 347 clones have been isolated and 121 of these sequenced.

The results revealed 8 most frequent sequences; the two most representative genes were a proline synthetase and a beta-1,3-glucanase (with a frequency respectively of 21.5 % and 17.3 % on the total of the sequenced clones).

It’s interesting to note also the presence of a sequence coding for a hypothetical protein highly homologue (89% of identity) to the 9 multispanning membrane protein family.

All these genes are known to be induced by salicylic acid treatment and/or fungal infection, but have never been studied in apple.

Our next step will be to confirm, by Northen analysis, the real expression of these genes in the leaf tissue.