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 - 3.42

Identification of activation-tagged mutants with “few seeds” phenotype in arabidopsis

CREMONA G.*, CAMMARERI M.*, ERRICO A.*, BRESSAN R.A.**, CONICELLA C.***

*) 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-IMOF, Research Institute for Vegetable and Ornamental Plant Breeding, Via Università 133, 80055 Portici, Italy

activation tagging, arabidopsis, mutant, sexual reproduction

The present work is framed in a research project concerning the isolation of female sporogenesis genes in Arabidopsis as sexual plant model. Since many genes involved in the reproduction process may not be identified by knockout mutant phenotypes due to lethality or functional redundancy, the activation tagging strategy was pursued by a T-DNA vector, pSKI015, containing multimerized transcriptional enhancers from CaMV35S. This vector allowed the isolation of over 30 dominant mutants with various phenotypes in Arabidopsis (Weigel et al., Plant Physiol 2000). Thousands of insertion lines have been generated by in planta transformation with Agrobacterium at Purdue University (USA). A preliminary screening identified tens of pools including T-DNA insertion lines that can be putative reproduction mutants with reduced silique fertility. The subsequent screening was performed on the basis of the phenotype “few seeds” in 1200 plants coming from 60 T2 independent insertion lines: five putative mutants were isolated. Two mutants confirmed the phenotype for two generations and cosegregation with T-DNA which was monitored by the marker gene bar conferring resistance to the herbicide glufosinate and by PCR with specific primers to known sequences of the gene. An amplified fragment of 413 bp was detected in all mutants. The segregation analysis evidenced in self-crosses that the two mutations were both dominant, but one was gametophytic and the other sporophytic. Following genetic analysis, two T-DNA inserts possibly occurred in the gametophytic mutant which exhibited also a reduction in pollen stainability. TAIL-PCR and cytological characterization will be performed in these mutants.