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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Oral Communication Abstract - S5d

ANALYSIS OF THE ROLE OF AUXIN IN THE DEVELOPMENT OF ANTHERS AND PISTIL

POMPONI M.*, MARSILIO S.**, ALTAMURA M.M.*, CECCHETTI V.*, TORNIELLI G.B.***, COSTANTINO P.*, CARDARELLI M.**

*) Università La Sapienza Roma

**) CNR Roma

***) Università degli Studi Verona

auxin, rolB, anther dehiscence, meiosis, pistil development

Auxin plays a crucial but as yet not fully comprehended role in floral organ development.To study the effect of auxin in the process of anther development and dehiscence, we utilised a strategy based on the localised expression of the Agrobacterium rhizogenes rolB oncogene that induces a cell-autonomous state of auxin hypersensitivity. Tobacco plants were transformed with two different transcriptional fusions of the rolB coding region with the promoter of the Arabidopsis gene DMC1, specifically active during meiosis, and, respectively, with the promoter of the Petunia gene FBP7 involved in ovule development.

DMC1::rolB plants are male sterile due to 1) a delay in anther dehiscence probably preventing successful pollination and 2) alterations in meiosis causing a reduced number of pollen grains.

Delayed anther dehiscence is also observed in FBP7::rolB plants. However, these plants are not male-sterile as delayed pollen release takes place when the stigma is still receptive due to a corresponding delay in pistil development.. Furthermore, in these plants no alterations were observed in pollen grain number and morphology.

These data suggest that auxin might play a role in the meiotic process and in anther dehiscence, as well as in pistil development.