Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: November 6, 2002
Publication Date: N/A
Technical Abstract: Wild soybeans (Glycine soja) offer tremendous genetic resources for cultivated soybeans. The pod-shatter trait is critical for successful reseeding of G. soja in the wild. Modern soybean (Glycine max) cultivars have been selected for pod-shatter resistance. Coordinately- regulated expression of three genes (FUL, SHP1, and SHP2) results in the formation of dehiscence zones in the mature fruits of Arabidopsis thaliana. It is still not clear if the SHP and FUL genes identified in legumes share equivalent functions with their counterparts in A. thaliana. To understand the molecular events associated with legume pod development and ultimately pod shatter, we are characterizing soybean and Lotus japonicus homologues of A. thaliana genes that control silique development and shatter. Soybean homologues of the FUL and SHP genes that control pod shatter in A. thaliana were identified in the GenBank and TIGR sequence databases. We designed primers, amplified, and cloned the soybean FUL cDNA (GmFUL) from RNA isolated from immature pods. Similarly, database sequences encoding soybean homologues of the SHP gene were identified. The full length soybean TC sequence was derived from nine ESTs expressed in flowers and seed coats. Expression of the soybean SHP gene in these tissues is consistent with characterized expression patterns of the Arabidopsis SHP1 and SHP2 genes3. RT-PCR results indicate that both GmFUL and GmSHP are expressed in immature pods. A soybean cDNA encoding a FUL homologue (GmFUL) was cloned and characterized for expression in pods. L. japonicus contains two SHP genes, LjSHP1, and LjSHP2. In addition, transgenic Arabidopsis plants constitutively overexpressing a GmFUL construct were produced and evaluated for developmental alterations. Overexpression of GmFUL caused alterations in silique development, but did not phenocopy overexpression of AtFUL. The soybean FUL gene is a candidate for an early gene that affects soybean pod development, although based on expression in Arabidopsis, its function appears to be distinct from the Arabidopsis version.