Study of 'Redhaven' peach and its white-fleshed mutant suggests a key role of CCD4 carotenoid dioxygenase in carotenoid and norisoprenoid volatile metabolism.
BACKGROUND
Carotenoids are plant metabolites which are not only essential in photosynthesis but also important quality factors in determining the pigmentation and aroma of flowers and fruits. To investigate the regulation of carotenoid metabolism, as related to norisoprenoids and other volatile compounds in peach (Prunus persica L. Batsch.), and the role of carotenoid dioxygenases in determining differences in flesh color phenotype and volatile composition, the expression patterns of relevant carotenoid genes and metabolites were studied during fruit development along with volatile compound content. Two contrasted cultivars, the yellow-fleshed 'Redhaven' (RH) and its white-fleshed mutant 'Redhaven Bianca' (RHB) were examined.


RESULTS
The two genotypes displayed marked differences in the accumulation of carotenoid pigments in mesocarp tissues. Lower carotenoid levels and higher levels of norisoprenoid volatiles were observed in RHB, which might be explained by differential activity of carotenoid cleavage dioxygenase (CCD) enzymes. In fact, the ccd4 transcript levels were dramatically higher at late ripening stages in RHB with respect to RH. The two genotypes also showed differences in the expression patterns of several carotenoid and isoprenoid transcripts, compatible with a feed-back regulation of these transcripts. Abamine SG - an inhibitor of CCD enzymes - decreased the levels of both isoprenoid and non-isoprenoid volatiles in RHB fruits, indicating a complex regulation of volatile production.


CONCLUSIONS
Differential expression of ccd4 is likely to be the major determinant in the accumulation of carotenoids and carotenoid-derived volatiles in peach fruit flesh. More in general, dioxygenases appear to be key factors controlling volatile composition in peach fruit, since abamine SG-treated 'Redhaven Bianca' fruits had strongly reduced levels of norisoprenoids and other volatile classes. Comparative functional studies of peach carotenoid cleavage enzymes are required to fully elucidate their role in peach fruit pigmentation and aroma.
Consiglio per la Ricerca in Agricoltura, Unità di Ricerca per la Frutticoltura-Forlì (CRA-FRF), via la Canapona 1 bis, 47100 Forlì, Italy.
Federica
F
Brandi
Einat
E
Bar
Fabienne
F
Mourgues
Györgyi
G
Horváth
Erika
E
Turcsi
Giovanni
G
Giuliano
Alessandro
A
Liverani
Stefano
S
Tartarini
Efraim
E
Lewinsohn
Carlo
C
Rosati
D016000:Cluster Analysis; D049308:Dioxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005638:Fruit / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D053858:Metabolic Networks and Pathways; D009154:Mutation / Q000235:genetics*; D045792:Norisoprenoids / Q000378:metabolism*; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D025341:Principal Component Analysis; D027861:Prunus / Q000201:enzymology* / Q000235:genetics; D019655:Quantitative Trait, Heritable; D055549:Volatile Organic Compounds / Q000378:metabolism*; D014835:Volatilization
D004791:Enzyme Inhibitors; D045792:Norisoprenoids; D010940:Plant Proteins; D055549:Volatile Organic Compounds; D049308:Dioxygenases
Plant J. 2006 Mar;45(6):982-93
16507088
J Exp Bot. 2005 Jul;56(417):1877-86
15911563
Plant Cell. 2003 Jan;15(1):47-62
12509521
J Agric Food Chem. 2003 May 7;51(10):3083-91
12720396
Bioorg Med Chem. 2006 Aug 15;14(16):5555-61
16682205
J Agric Food Chem. 2010 May 26;58(10):6157-65
20415420
Plant Physiol. 2010 Oct;154(2):899-912
20671108
Plant Physiol. 2006 Nov;142(3):1193-201
16980560
BMC Mol Biol. 2010 Sep 21;11:74
20858237
J Biol Chem. 2008 Sep 5;283(36):24816-25
18611853
Genome. 2002 Jun;45(3):520-9
12033621
Plant J. 2009 Nov;60(3):424-35
19594711
J Plant Physiol. 2009 Aug 15;166(12):1241-1252
19307046
Plant J. 2008 Oct;56(2):228-238
18643974
Curr Opin Plant Biol. 2006 Jun;9(3):315-21
16616608
Plant J. 2003 Jul;35(1):44-56
12834401
Genomics. 2010 Oct;96(4):239-50
20633636
Plant Physiol. 2004 Jul;135(3):1574-82
15247398
J Agric Food Chem. 2002 Aug 14;50(17):4976-82
12166993
BMC Genomics. 2009 Sep 10;10:423
19744325
Plant J. 2004 Dec;40(6):882-92
15584954
J Sci Food Agric. 2010 May;90(7):1146-54
20393995
BMC Bioinformatics. 2008 Mar 26;9 Suppl 2:S9
18387211
J Agric Food Chem. 2003 Oct 8;51(21):6280-6
14518956
Plant Physiol. 2010 Oct;154(2):656-64
20688977
Nat Genet. 2010 Apr;42(4):322-7
20305664
Trends Plant Sci. 2010 May;15(5):266-74
20303820
Trends Plant Sci. 2003 Apr;8(4):145-9
12711223
BMC Plant Biol. 2009 May 15;9:59
19445673
J Exp Bot. 2005 Oct;56(420):2721-31
16131507
Plant Cell. 1993 Apr;5(4):379-87
8485401
BMC Plant Biol. 2007 Mar 02;7:11
17335571
Trends Plant Sci. 2010 Jan;15(1):48-56
19853493
J Exp Bot. 2010 Mar;61(3):709-19
19933319
J Biol Chem. 2008 Apr 25;283(17):11364-73
18285342
Science. 2006 Feb 10;311(5762):808-11
16469917
J Exp Bot. 2009;60(11):3011-22
19436048
Phytochemistry. 2006 Aug;67(15):1579-89
16563447
Plant Physiol. 2004 Nov;136(3):3504-14
15516502
J Agric Food Chem. 2005 Apr 20;53(8):3142-8
15826071