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Xinwang Zhang, Ikuo Nakamura, and Masahiro Mii

., 2001 ). To our knowledge, however, PCR-RFLP analysis has not been used for determining the parents of garden petunias. Chalcone synthase is a key enzyme of the anthocyanin biosynthesis and encoded by the structural Chs gene ( Heller and Hahlbrock

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Dan D. MacLean, Dennis P. Murr, Jennifer R. DeEll, and Eugene Kupferman

The ethylene antagonist 1-methylcyclopropene (1-MCP) was investigated for its potential impact on the transcription of key flavonoid biosynthetic (PAL and CHS) and ethylene perception (ERS1) genes during the postharvest storage of pear (Pyrus × communis L.). Optimally harvested red and green `d'Anjou' fruit were treated with 1 μL·L-1 1-MCP for 24 h at 0 °C to 1 °C, and subsequently placed in cold storage (0–1 °C, 90–95% RH). Fruit were removed every 21 days for 126 days, and evaluated for firmness, TSS, and ethylene and volatile production for up to 10 days (≈21 °C). Tissue samples were collected for Northern blot analysis and determination of flavonoid and chlorogenic acid content. PAL content increased during the 1-week simulated marketing period irrespective of storage duration, which coincided with an increase in respiration and ethylene content. Although it was still detectable, total PAL content was dramatically reduced by the 1-MCP treatment. CHS was abundant immediately after harvest and after removal from storage, but declined rapidly thereafter, and was not detectable after 1 week at room temperature. The 1-MCP treatment further exacerbated this decreasing trend in CHS content. ERS1 content appears to be stable throughout storage and the simulated marketing period, with levels lower in 1-MCP-treated fruit. These results suggest that 1-MCP significantly inhibits the transcription of key flavonoid and ethylene regulatory enzymes, possibly compromising the nutraceutical content of pear fruit. The increase in PAL with the concomitant decrease of CHS after removal from storage suggests a diversion of carbon from flavonoid compounds into simple phenols, such as chlorogenic acid.

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Paola S. Cotroneo, Maria P. Russo, Manuela Ciuni, Giuseppe Reforgiato Recupero, and Angela R. Lo Piero

Genes encoding chalcone synthase (CHS), anthocyanidin synthase (ANS), and UDP-glucose-flavonoid 3-O-glucosyltransferase (UFGT), some of the enzymes of anthocyanin biosynthetic pathway, were assayed in two different experiments using quantitative real-time reverse transcriptase (RT)-PCR, in order to test their transcription levels in the flesh of blood and common orange [Citrus sinensis (L.) Osbeck] fruit, and to investigate their role in anthocyanin accumulation in the same tissue. The first experiment compared a blood orange and a common orange cultivar during seven different fruit maturation stages. This was followed by the test of 11 different genotypes at the end of the winter season. Data collected from the first experiment, over the blood orange cultivar, were statistically analyzed using the Pearson correlation coefficient. Results show that CHS, ANS, and UFGT mRNA transcripts are up- and co-regulated in the blood orange cultivar, whereas they are down-regulated in the common orange cultivar. There is evidence of correspondence between the target genes expression level and the content of the pigment assessed. The second test confirms this correlation and shows that enzyme synthesis levels and pigment accumulation, in plants grown under the same environmental conditions, are dependent on the differences occurring among the genotypes tested. These results suggest that the absence of pigment in the common orange cultivars may be caused by the lack of induction on the structural genes expression. This is the first report on the characterization of the relationships between biosynthetic genes expression and fruit flesh anthocyanin content in blood oranges.

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Dineshkumar Selvaraj, Sherif Sherif, Mohd Sabri Pak Dek, Gopinadhan Paliyath, Islam El-Sharkawy, and Jayasankar Subramanian

ABGs, designated Pd-PAL , Pd-CHS , Pd-DFR , Pd-ANS , and Pd-UFGT (GenBank accession numbers are listed in Supplemental Table 2 ) were isolated from frozen fruit skin tissues (at the commercial harvesting date) using the reverse transcription PCR

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Hongmei Ma, Margaret Pooler, and Robert Griesbach

biosynthesis genes. Six enzymes are generally involved in the anthocyanin biosynthesis pathway: chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), and UDP

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Robert J. Griesbach, Ronald M. Beck, John Hammond, and John R. Stommel

been extensively studied. There is an absence of chalcone synthase enzyme (CHS) activity in the white tissue compared with the colored tissue ( Mol et al., 1983 ). A more complete analysis of structural gene expression in the Star mutant demonstrated

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John R. Stommel and Judith M. Dumm

synthase (CHS) is the first and key regulatory enzyme of flavonoid biosynthesis. Chalcone is isomerized by chalcone isomerase to naringenin and flavanone 3-hydroxylase converts naringen into dihydrokaempferol. The dihydroflavonols are subsequently converted

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Gordon J. Lightbourn, John R. Stommel, and Robert J. Griesbach

. RNA analysis. Flavonoid gene expression [MYC, MYB, and WD transcription factors, anthocyanin synthase ( Ans ), dihydroflavonol reductase ( Dfr ), and chalcone synthase ( Chs )] was compared under inductive and noninductive environments for

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David Gopaulchan, Adrian M. Lennon, and Pathmanathan Umaharan

) cloned and characterized the expression of four genes encoding key enzymes within the anthocyanin biosynthetic pathway, CHS , F3H , DFR , and ANS and demonstrated that the CHS , F3H , and ANS genes were coordinately controlled, whereas DFR was

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John R. Stommel, Gordon J. Lightbourn, Brenda S. Winkel, and Robert J. Griesbach

synthase (CHS) is the first enzymatic step of the biosynthetic pathway. Twelve different CHS genes ( ChsA , B , C , D , E , F , G , H , I , J , K , and L ) have been identified in P . × hybrida ( Koes et al., 1989 ) and two ( c2 and whp ) in