0012-4966/03/0708- $25.00 © 2003 MAIK “Nauka / Interperiodica” 0368 Doklady Biological Sciences, Vol. 391, 2003, pp. 368–370. Translated from Doklady Akademii Nauk, Vol. 391, No. 5, 2003, pp. 715–717. Original Russian Text Copyright © 2003 by Shchennikova, Shulga, Angenent, Skryabin. Flowering is a conserved process in higher plants and is controlled by a network of hierarchically inter- acting genes [1]. The study of this process in the model plants Arabidopsis thaliana, Petunia hybrida, and Anti- rrhinum majus gave rise to the development of the ABCDE model [2–4]. In this model, A-activity deter- mines sepal and petal identity; B-activity determines petal and stamen identity; C-activity, the identity of the stamen and carpel; D-activity, the identity of the ovule; and E-activity is involved in the petal, stamen, and car- pel identity determination. Each activity is determined by a group of genes, most of which encode the MADS- box transcription factors [5]. It was suggested that the MADS-box proteins formed quaternary complexes that regulated the transcription of target genes [4, 6]. In A. thaliana, the petal identity is determined by the com- plex AP1/SEP3/PI/AP3 (which corresponds to A/E/B/B activities); the stamen identity is determined by AG/SEP3/PI/AP3 (C/E/B/B); and the carpel iden- tity, by SEP3/SEP3/AG/AG complex (E/E/C/C). During the evolution of plants, floral organs have evolved from leaves. The ancestors of MADS-box genes have evolved into floral homeotic genes, which determine the identity of the perianth and reproductive flower organs [7], which makes MADS-box genes attractive for plant development evolution studies. Compositae are believed to be the most evolutionary advanced family of flowering plants. A specific feature of Compositae plants is the capitulum, which is usually composed of florets of different types at different devel- opmental stages. The capitulum looks and functions like a single large flower. Study of the Compositae inflorescence provides a deeper insight into the ABCDE model and evolution of seed plants. Recent molecular studies of flower development in Gerbera hybrida, a member of the Compositae family, shed more light on the genetic control of Compositae capit- ulum morphogenesis [8–10]. The goal of this work was to investigate inflorescence development in the chry- santhemum Dendrathema grandiflora cv. Parliament, which is one of the most widespread ornamental plants in the world. The identification and characterization of key regu- latory genes constitute the main approach to analysis of various developmental mechanisms. Messenger RNA isolated from the chrysanthemum inflorescence tissue at the early stage of development was used for the cre- ation of a cDNA library [11]. Hybridization of cDNA library with a specific probe (the MADS-box of gene HAM75, Helianthus annuus, MADS, isolated by O.A. Shulga) resulted in the identification of eight full- length cDNA copies of CDM genes (Chrysanthemum, D. grandiflora, MADS) (table). The cDNA library was also assayed using the yeast two-hybrid GAL4 system [4, 15]. Analysis of the cDNA library in this system with CDM86 as a bait resulted in the isolation of two full-length cDNA copies of MADS-box genes CDM19 and CDM115. Two- GENERAL BIOLOGY Genetic Regulation of Inflorescence Development in Chrysanthemum A. V. Shchennikova*, O. A. Shulga*, G. C. Angenent**, and K. G. Skryabin* Presented by Academician S.V. Shestakov February 14, 2003 Received February 27, 2003 *Center for Bioengineering, Russian Academy of Sciences, pr. 60-letiya Oktyabrya 7/1, Moscow, 117312 Russia **Plant Research International, Born-Zuid, Gebouw 122, Bornsesteeg 65, Wageningen, 6708 PD The Netherlands Characteristics of the cDNAs of CDM genes CDM cDNA Encoded protein size (number of amino acid residues) GenBank accession number Homologous genes from A. thaliana CDM8 237 AY173056 AGL8 CDM41 243 AY173055 AGL8/AP1 CDM111 246 AY173054 AP1 CDM44 249 AY173057 AGL9(SEP3) CDM77 246 AY173058 AGL2/AGL4 CDM36 216 AY173065 AGL20 CDM86 196 AY173061 PI CDM19 231 AY173064 AP3 CDM115 229 AY173060 AP3 CDM104 250 AY173062 AGL6 CDM37 265 AY173059 AG