EVALUATION OF THE FUNCTION AND EXPRESSION PATTERN OF MEDICAGO TRUNCATULA AUXIN RESPONSE FACTOR B3 AFTER HETEROLOGOUS EXPRESSION IN ARABIDOPSIS THALIANA.

The phytohormone auxin plays a vital role in almost every aspect of plant growth and development. Expression of auxin-responsive genes is controlled by a family of Auxin Response Factor (ARF) transcription factor family. This study examined the function and expression pattern of a gene encoding Auxin Response Factor B3 from Medicago truncatula (MtARF-B3) after its heterologous expression in the model plant Arabidopsis thaliana. Stable transgenic plants with ARF-B3 overexpres-sion, downregulation and transcriptional reporters were constructed. Transcriptional and histochemical assays revealed a stable MtARF-B3 expression in various stages of somatic embryogenesis and during the postembryonic development of A. thaliana. Morphological analysis and morphometric measurements confirmed the important role of MtARF-B3 in general plant growth and development, root growth and seed production. [ABSTRACT FROM AUTHOR]