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

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 5.49

Identification of an activation-tagged arabidopsis MUTANT Defective in embryo sac development

G. CREMONA*, F. CONSIGLIO***, A. ERRICO*, R.A. BRESSAN**, C. CONICELLA***

*) DISSPA Dept. Soil, Plant and Environmental Sciences, University of Naples "Federico II", Via Università 100, 80055 Portici, Italy

**) Dept. Horticulture & Landscape Architecture, Purdue University, West Lafayette, Indiana (USA)

***) CNR-IGV, Institute of Plant Genetics, Research Division Portici, Via Università 133, 80055 Portici, Italy

Arabidopsis, activation tagging, mutant, sexual reproduction

Meiosis is a particulary significant cellular event in plant sexual reproduction because it separates the sporophytic and gametophytic generations. Plants carrying meiotic defects often show low gamete viability and low fertility, and in some cases complete sterility. Meiosis is a complex multistep process and the complexity of events suggests that many genes are involved and are tightly regulated to ensure each meiotic step. Many meiotic genes have been reported in various eukaryotic organisms, but relatively little knowledge is available on the molecular details of meiosis in flowering plants. Recently, Arabidopsis thaliana (Ath) has become a model to study meiosis in plants. The availability of a great number of T-DNA and transposon mutated lines represents a powerful tool to isolate meiotic mutants and to identify the corresponding tagged genes.

More than 300.000 activation tagging T-DNA mutant lines of Ath were generated at Purdue University (USA). A secondary screening of this collection identified several putative meiotic mutants showing reduced fertility. One line (b16) was confirmed as containing the mutation for more than one generation. The low fertility phenotype of this mutant co-segregates with the insertion marker. The genetic lesion responsible for this phenotype was identified by TAIL-PCR of the DNA flanking the insertion site. Genetic analysis of the mutant gene is being tested by crossing the mutant line to wild type to determine the inheritance control. A preliminary self-cross segregation analysis of b16 evidenced that the mutation is sporophytically expressed, monogenic and dominant. Histologycal and cytological analysis are being performed on silique and floral buds, and first evidences show that a low number of seeds occurs in the silique depending on development arrest of megaspore mother cell before embryo sac formation.

Further molecular and functional analisys will be performed to assess the rule of the mutated gene in the meiotic pathway.