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 - 5.07

TOWARDS THE FUNCTIONAL CHARACTERISATION OF RICE GSTs

Frova C., De Toma G., Soranzo N., Sari Gorla M.

Dipartimento di Genetica e di Biologia dei Microrganismi, Università di Milano

GSTs, rice, macroarrays, cadmium, hydrogen peroxide

Glutathione S-transferases (GSTs) are a super-family of multifunctional enzymes ubiquitously distributed in bacteria, fungi, plants and animals. These proteins have evolved multiple functions in the metabolism of endogenous compounds as well as foreign toxic compounds and have important roles in cellular protection against a wide range of biotic and abiotic stresses. Recent studies in maize, soybean and Arabidopsis have shown that the family encompasses 42, 25 and 47 members respectively. With the aim of extensively characterise the Gst gene family in rice, we have previously isolated in silico 58 putative Gst genes and 3 pseudogenes, belonging to the four major plant phylogenetic classes: phi (16), tau (39), zeta (3), theta (2), plus 1 gene for a putative microsomal GST.

As a first step towards the functional characterisation of the diverse members of this super-family in rice, 29 cDNAs representing all GST classes were cloned by RT- PCR and used to study OsGST expression in response to treatment with oxidative stress (H₂O₂), heavy metals (Cadmium) and a panel of herbicides. The analysis was performed by probing specifically prepared macroarray filters with mRNA from roots of rice seedlings hydroponically grown in control conditions and in presence of the above stress factors.

The first results indicate that some tau and zeta class GSTs are transcriptionally induced by oxidative stress. The response of phi GSTs is more heterogeneous, at least one being apparently induced and one repressed by H₂O₂ treatment. Analysis of the response to cadmium is currently under way.