Analyses of responsible genes of morphological mutants in the Japanese morning glory.

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The semi-dominant feathered (fe) mutants in the Japanese morning glory have strongly crumpled or rolled leaves, and flowers with deeply split or tube-like petals folding back at their tips. Histological analysis showed that the number of stomata in abaxial side decreased in fe mutants. These mutant Phenotypes suggest that FE is involved in establishment of organ polarity. We isolated a rare fe revertant caused by excision of a transposable element inserted in FE gene. Tpn1 family which belong to En/Spn related transposable elements is known to induce most mutations in the Japanese morning glory. FE gene was isolated using Simplified Transposon Display(STD) method which allows visualization and isolation of Tpn transposon-flanking sequences from high copy-number lines. FE gene encodes a protein in the GARP family of putative transcription factors, and has high homology with KANADI1(KAN1) gene of Arabidopsis. We suppose that FE expresses on abaxial side of lateral organs, and specify the … More abaxial identity as KAN. Gentic and molecular analyses showed that the strong fe phenotype is caused by an additional mutation occurred in fe background.The prtaloid(pt) mutants have petaloid stamens and short sepaloid carpel. This phenotype seems to be caused by the mutation of a C-function floral homeotic gene. Mutations of duplicated(dp) cause a substitution of reproductive organs to perianth organs (petals and sepals). An En/Spm-related transposable element, Tpn-botan, was inserted in the second intron of a C-funtion MADS-box gene DP and the subsequent excision event led to a deletion of a substantial part of the original Tpn element and DP genome (dp-1 allele). We assumed that pt is a week DP allele and examined the genomic structure of the second intron of DP gene in pt mutants. A full length Tpn 109 was inserted in the same place of dp-1 allele in the pt mutant. It is known that pt phenotypes become weaker during shoot growth, but Tpn 109 insertion was still obeserved in weak phenotype flower. Therefore, pt phenotype is caused by reduction of DP gene transcripts by low splicing efficiency or split cis-regulatory elements. To examine the deletion mechanism mediated by Tpn transposon, I analyzed genomic structures of other two dp alleles (dp-2, dp-3). dp-2 and dp-3 alleles have two and three rearranged Tpn 109 elements, respectively, and genomic region between two Tpn 109 elements was deleted. Less