ABSTRACT. Variegated plants are highly valuable in the floriculturalmarket, yet the genetic mechanism underlying this attractive phenomenon has not been completely elucidated. In this study, we identified and measured different compounds in pink and white flower petals of peach (Prunus persica) by high-performance liquid chromatography and liquid chromatography/mass spectrometry analyses. No cyanidin-based or pelargonidin-based compounds were detected in white petals, but high levels of these compounds were found in pink petals. Additionally, we sequenced and analyzed the expression of six key structural genes in the anthocyanin biosynthesis pathway (CHI, CHS, DFR, F3'H, ANS, and UFGT) in both white and pink petals. Quantitative real-time polymerase chain reaction revealed all six genes to be expressed at greatly reduced levels in white flower petals, relative to pink. No allelic variations were found in the transcribed sequences. However, alignment of transcribed and genomic sequences of the ANS gene detected alternative splicing, resulting in transcripts (2015) of 1.071 and 942 bp. Only the longer transcript was observed in white flower petals. Since ANS is the key intermediate enzyme catalyzing the colorless leucopelargonidin and leucocyanidin to substrates required for completion of anthocyanin biosynthesis, the ANS gene is implicated in flower color variegation and should be explored in future studies. This article, together with a previous transcriptome study, elucidates the mechanism underlying peach flower color variegation in terms of the key structural genes involved in anthocyanin biosynthesis.

ABSTRACT. APETALA2 plays critical roles in establishing meristem and organ identity during plant floral development. In this study, we obtained a CeAP2-like gene by using the mRNA differential display technique to analyze the wild type and a multitepal mutant of the orchid Cymbidium ensifolium. The fulllength cDNA encoding the CeAP2-like transcription factor shows significant similarity to the cDNA of AP2 from Erycina pusilla and contains nucleotides complementary to miR172. Using a transient gene expression system of Arabidopsis protoplasts, we found that the accumulation of CeAP2-like protein and transcripts was negatively regulated by miR172, indicating this gene as a putative target of miR172. Northern blotting revealed that CeAP2-like is dominantly F.X. Yang et al. 12050©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (4): 12049-12061 (2015) expressed in the sepals and petals of the wild-type flower, and shows low expression in the gynostemium. In contrast, the accumulation of CeAP2-like transcripts decreased significantly, especially in the central part of the mutant flower, corresponding to its abnormal petals and the absence of the gynostemium. Furthermore, we found an antagonistic expression pattern between CeAP2-like and AGAMOUS in the wild type, representing A-and C-class genes that specify floral organ fate. However, this antagonistic distribution was modified in the multitepal mutant, and both genes showed lower expression than that in the wild type. This result suggested that the balance between CeAP2-like and AGAMOUS activity was important for the regulation of floral patterning in C. ensifolium. This study represents the first report on a class A gene and its regulatory role for floral development in the orchid C. ensifolium.