title: Functional analysis reveals the possible role of the C-terminal sequences and PI motif in the function of lily (Lilium longiflorum) PISTILLATA (PI) orthologues.
abstract: Two lily (Lilium longiflorum) PISTILLATA (PI) genes, Lily MADS Box Gene 8 and 9 (LMADS8/9), were characterized. LMADS9 lacked 29 C-terminal amino acids including the PI motif that was present in LMADS8. Both LMADS8/9 mRNAs were prevalent in the first and second whorl tepals during all stages of development and were expressed in the stamen only in young flower buds. LMADS8/9 could both form homodimers, but the ability of LMADS8 homodimers to bind to CArG1 was relatively stronger than that of LMADS9 homodimers. 35S:LMADS8 completely, and 35S:LMADS9 only partially, rescued the second whorl petal formation and partially converted the first whorl sepal into a petal-like structure in Arabidopsis pi-1 mutants. Ectopic expression of LMADS8-C (with deletion of the 29 amino acids of the C-terminal sequence) or LMADS8-PI (with only the PI motif deleted) only partially rescued petal formation in pi mutants, which was similar to what was observed in 35S:LMADS9/pi plants. In contrast, 35:LMADS9+L8C (with the addition of the 29 amino acids of the LMADS8 C-terminal sequence) or 35S:LMADS9+L8PI (with the addition of the LMADS8 PI motif) demonstrated an increased ability to rescue petal formation in pi mutants, which was similar to what was observed in 35S:LMADS8/pi plants. Furthermore, ectopic expression of LMADS8-M (with the MADS domain truncated) generated more severe dominant negative phenotypes than those seen in 35S:LMADS9-M flowers. These results revealed that the 29 amino acids including the PI motif in the C-terminal region of the lily PI orthologue are valuable for its function in regulating perianth organ formation.
authors: Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan 40227, ROC.
authors: Ming-Kun
authors: MK
authors: Chen
authors: Wen-Ping
authors: WP
authors: Hsieh
authors: Chang-Hsien
authors: CH
authors: Yang
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D027762:Lilium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009928:Organ Specificity; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D055503:Protein Multimerization; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D026161:MADS Domain Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant