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

ANALYSIS OF CYTOSINE METHYLATION PATTERN IN RESPONSE TO WATER DEFICIT IN PEA ROOT TIPS

GHIANI A.*, LABRA M.**, CASAZZA G.**, CITTERIO S.****, SGORBATI S.****, VANNINI C.***, RUFFINI-CASTIGLIONE M.*****, BRACALE M.***

* Dipartimento di Produzione Vegetale, Università di Milano, Via Celoria 2, 20133 Milano, Italy

** Department of Biology, Università di Milano, Via Celoria 26, 20133 Milano, Italy

*** DBSF, Università dell’ Insubria, Via J.H. Dunant 3, 21100 Varese Italy

**** Dipartimento di Scienze dell’Ambiente e del Territorio Universita’ degli Studi di Milano - Bicocca, P.zza della Scienza 1, 20126 Milano Italy

***** Istituto di Mutagenesi e Differenziamento, CNR Area della Ricerca, Via Moruzzi, 56124 Pisa Italy

Pisum sativum L., MSAP, water stress, DNA methylation

The correlation between environmental stress and DNA methylation has been studied by following the methylation status of cytosine residues in the DNA of pea root tip exposed to water deficit. DNA methylation was evaluated by two complementary approaches: (I) immunolabelling, by means of a monoclonal antibody against 5-methylcytosine, to define the relative abundance of cytosine-methylated sequences in DNA and in particular in CCGG sequences; (II) MSAP (Methylation-Sensitive Amplified Polymorphism) to verify if methylation and de-methylation in response to water deficit may be related to specific DNA sequences. Immunolabelling showed that water stress induces cytosine-hypermethylation in the pea genome. Regarding the CCGG target sequence, an increase of methylation specifically in the second cytosine (about 40% of total site investigated) was revealed by immunoblot and MSAP analyses. In addition, MSAP band profile detected in three independent repetitions was highly reproducible, suggesting that, at least for the CCGG target sequence, methylation was addressed to specific DNA sequences.