The Structure And Function Characterization Of Two Chimonanthus Praecox (L.) Link MADS-box Genes

Wintersweet(Chimonanthus praecox Link) is an important species originating from China,where it is cultivated with a long history owing to its important characteristics,such as blooming in deep winter, having strong fragrance and stress resistance et al..However,the genie expression situations of wintersweet are not yet reported.MADS-box transcription factors are named after the initials of the four originally identified members: The yeast MINICHROMOSOME MAINTENANCE 1((?)CM1) protein,the Arabidopsis AGAMOUS ((?)G),the Antirrhinum DEFICIENS((?)EF) proteins and the human serum response factor(SRF). MADS-box genes are the key genes involved in growth and development regulation in plants.Most of them play important roles in reproductive development.They involve in the control of vegetative growth, ovule development,seed coat development,root development,embryogenesis or symbiotic induction.CpAGL6 is 948 bp in length with a 726 nucleotides ORF that encodes a putative protein of 241 amino acids protein that showed 85%identity to Persea americana Pe.am.AGL6.2,73%identity to Oryza sativa OsMADS6.CpAGL6 are composed of the N-terminal M(M.ADS) domain,followed by theâ… (intervening),K(keratin like),and C(carboxyl-terminal) domains.The phylogenetic tree analysis revealed that CpAGL6 is belonged to the AP1/AGL9 family AGL6 clade.The spatial expression patten of the CpAGL6 gene in the different tissues of vegetative plant parts and inflorescence,different stages of wintersweet flower development were determined by RT-PCR.We found CpAGL6 is preferentially expressed in medium tepals,and in timecourse experiments,CpAGL6 expression changed in series.Ectopic expression of CpAGL6 led to retarded growth and earlier flowering in Arabidopsis,and changed stamen number and morphology in 35S:CpAGL6 transgenic Arabidopsis.RT-PCR analyses indicated that flowering time alteration in 35S::CpAGL6 transgenic Arabidopsis plants were correlated with the up-regulation of LFY,FT,API,SOC1 and CO 1 transcripts by CpAGL6,flowering time lessening in transgenic plants were also closely related to the down-regulation of the repressors FLC and CO2 of Arabidopsis flowering.And we found that SEP and AG were activated by CpAGL6.CpAP3 is 901 bp in length with a 645 nucleotides ORF that encodes a putative protein of 214 amino acids protein that showed 91%identity to Calycanthus floridus AP3-1.CpAP3 are composed of the N-terminal M(MADS) domain,followed by theâ… (intervening),K(keratin like),and C(carboxyl-terminal) domains.The phylogenetic tree analysis revealed that CpAP3 is belonged to the AP3/PI family paleoAP3 lineage.The spatial expression patten of the CpAP3 gene in the different tissues of vegetative plant parts and inflorescence,different stages of wintersweet flower development were determined by RT-PCR.We found CpAP3 is preferentially expressed in flower organ,and in timecourse experiments,CpAGL6 expression changed in series,max appeared in flower-bud period.Ectopic expression of CpAP3 changed nothing in Arabidopsis.There were still no petals in 35s:CpAP3 ap3,but the days to flower was as same as the WT Arabidopsis.