Submitted to: Annual International Plant & Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2004
Publication Date: 1/14/2005
Citation: Ackerrman, C.M., Yu, Q., Moore, P.H., Paull, R.E., Steiger, D.L., Ming, R., Cloning and characterization of a superman ortholog in polygamous papaya. Annual International Plant & Animal Genome XIII Conference. Abstracts P507, pg 197. 2005. Interpretive Summary: Abstract Only
Technical Abstract: In monoecious plants, the floral regulatory gene SUPERMAN (SUP) is reported to be an upstream negative regulator of the B function organ-identity genes, acting to establish a boundary in the forth whorl between stamens and carpels. The role of SUP in dioecious plants is not known. Papaya has year round production of male, female, and hermaphrodite flowers and may be an ideal model for testing the function of SUP in all three types of flowers on both monoecious and dioecious plants. We used the Arabidopsis thaliana SUP (AtSUP) gene to screen a papaya BAC library. Positive BAC clones were grouped into one of four categories based on the size of the fragment showing homology to AtSUP. The four fragment sizes were 1.2K, 2.5K, 3.5K and 4.0K. The positive sub-clones were sequenced through primer walking. Sequence analysis showed that the papaya SUP ortholog, PSUP, encodes a 3.5K protein showing 43% identity and 52% similarity with that encoded by AtSUP. Preliminary results from in situ hybridization showed that PSUP is expressed in all three sex forms of three papaya genotypes: Kapoho, SunUp and Drew. Very young flower buds of all sexes showed strong expression along the periphery of the flower primordium while expression in the older flower buds is weaker and concentrated in the anthers. In the case of the male flower buds, expression in the stamens is stronger in young buds, but decreases with increasing age of the bud.