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

Salsomaggiore Terme, Italy - 26/29 September, 2001

ISBN 88-900622-1-5

Poster Abstract

BIOCHEMICAL CHARACTERIZATION OF SOME ECOTYPES OF “CIPOLLA BIANCA DI POMPEI” BY ENDOSPERM SEED PROTEIN ANALYSIS THROUGH AE-HPLC

MENNELLA G., ONOFARO SANAJA’ V., D’ALESSANDRO A., MILONE M., DESIDERIO A.

Istituto Sperimentale per l’Orticoltura, Via Cavalleggeri 25, 84098 Pontecagnano, Salerno

peppemennella@libero.it

Water-, salt-, alcohol–, and alkali- soluble seed proteins extracted by 22 ecotypes of “Cipolla bianca di Pompei” (Allium cepa L.) were analysed by anionic exchange-high performance liquid chromatography (AE - HPLC), sodium dodecil sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and isoelectrofocusing (IEF). AE - HPLC elution profiles (time range 0 to 40 mins) at 280 nm of water–soluble proteins evidenced the presence of 12-15 peaks, which allowed all the ecotypes studied to be distinguished from each other. The differences detected were both qualitative (presence/absence of one or more peaks) and quantitative; the water–soluble proteins were useful in differentiating ecotypes and cultivars while the other seed proteic fractions only showed a weak polymorphism. SDS – PAGE and IEF showed a minor degree of resolution and did not allow to identify unequivocally all the ecotypes studied. The possibility of discriminating between closely related onion ecotypes during the course of breeding programmes could allow the identification of biochemical markers linked to useful agronomical traits.

As observed by chromatographic analysis, the globulin composition of onion water–soluble seed protein appears to be independent of environmental growth conditions.

Another purpouse of this research is the full characterization of the available typical onion germplasm to obtain Community recognition and denomination, such as Denomination of Protected Origin (D.O.P.), Indication of Protected Origin (I.G.P.), Specificity Attestation (A.S.).

Either a molecular and bio-agronomical characterization or an evaluation of the pungency in bulbs from ecotypes grown at the same location and at different locations are also in progress.

The biochemical method here developed results of high resolution, cost-effective and time-saving for characterization and genetic purity assesment of the ecotypes studied.