Functions of AGL2-like MADS-box genes in maize

Functions of AGL2-like MADS-box genes in maize


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- Date/Time : Wed., 10 July 2002


     16:00-17:00 

- Speaker : Dr. Guenter Theissen


        - University of Jena

- Place : Life Science Bldg. #104

- For inquires : Professor Gynheung An Dept. of Life Science


    생명과학과 안진흥 교수 (☎279-2176)

Abstract -


Members of the clade of AGL2-like MADS-box genes are probably present in all flowering plants. In contrast to the well known ABC genes (floral homeotic genes), their function remained elusive for quite some time. We have worked on the characterization of AGL2-like MADS-box genes in the monocot maize (Zea mays ssp. mays). Previous expression studies revealed exciting and very defined patterns only in certain types of spikelet or floret primordia. This suggested functions of these genes in providing positional information or meristem determinacy during maize inflorescence development. Our functional analyses, employing transgenic technology, have focused on two genes, ZMM6 und ZMM8. Transgenic plants expressing these genes in sense or antisense orientation driven by the CaMV 35S promoter showed inflorescence phenotypes suggesting loss of spikelet or floret meristem determinacy. Surprisingly, reduction of ZMM6 or ZMM8 mRNA could not be demonstrated in the transgenic plants, suggesting a novel mechanism of posttranslational gene silencing. The roles of ZMM6 and ZMM8 in maize inflorescence development suggested by the observed loss-of-function phenotypes will be discussed in the light of recent findings for other AGL2-like genes; these include the SEPALLATA genes from Arabidopsis, and the OsMADS1 (LEAFY HULL STERILE1) gene from rice (Oryza sativa). Remarkably, several lines of evidence suggest that OsMADS1 is an ortholog of ZMM8 (and ZMM14), thus facilitating a rigorous comparison of AGL2-like gene functions in two different monocot species.