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 - 4.50

MSAP (Methylation-Sensitive Amplification Polymorphism) detection of DNA methylation during germination of pepper (Capsicum annuum L.) seeDS

Portis E., Acquadro A., Quagliotti L., Lanteri S.

Di.Va.P.R.A., Genetica Agraria, Università di Torino

DNA methylation, isoschizomers, AFLP, germination, pepper

DNA methylation in plants is related to a number of epigenetic (i.e. heritable, but potentially reversible) phenomena. Heavy methylation of cytosine residues plays an important role in gene expression, and significant differences in cytosine methylation levels have been observed among various tissue types, which can be explained as one of the regulatory mechanisms during development and differentiation. Here we report on the analysis of cytosine methylation during pepper seed germination using an adaptation of the AFLP technique called MSAP (methylation-sensitive amplified polymorphism). This technique is based on using the isoschizomers HpaII and MspI, that differ in their sensitivity to methylation of their recognition sequences. Notable changes in MSAP profiles of genomic DNA obtained from embryo tissues of dry seeds and germinating seeds were detected. The changes were mainly: (I) fragments not detected in dry seeds were present after digestion with both EcoRI-MspI and EcoRI/HpaII at a certain stage during germination; (II) fragments present after both digestions in dry seeds were no longer detected upon germination.

Our results can be mainly attributed to demethylation events, which appear to be necessary for transcriptional activation during germination and show that MSAP technique may provide a very useful tool for comparative assessment of the levels of DNA methylation during seed germination. Moreover, the possibility to clone differentially methylated DNA fragments, may provide an avenue for direct identification of sequences (genes) that play an important role during seed germination.