Table II. Enrichment of genes involved in essential oil biosynthesis in ECs compared with PCs of grapefruit peel at two different stages of development (28 mm ED and 41 mm ED), expressed as fold change.

Annotation	Citrus Affy Chip Identifier	EC versus PC Enrichment
		28 mm	41 mm
Terpenoid biosynthesis
MVA pathway
Acetyl-CoA thiolase	Cit.1287.1.S1_s_at	6.941	4.117
3-Hydroxy-3-methylglutaryl-CoA synthase	Cit.29397.1.S1_s_at	12.272	11.972
	Cit.1280.1.S1_s_at	6.551	5.119
	Cit.29249.1.S1_at	4.446	5.080
3-Hydroxy-3-methylglutaryl-CoA reductase	Cit.17889.1.S1_s_at	14.403	8.488
	Cit.23097.1.S1_s_at	10.603	6.856
MVA kinase	Cit.2723.1.S1_s_at	5.617	3.106
Phosphomevalonate kinase	Cit.37962.1.S1_at	2.891	4.609
Diphosphomevalonate decarboxylase	Cit.20947.1.S1_s_at	3.849	2.764
MEP pathway
1-Deoxy-d-xylulose 5-phosphate synthase	Cit.10053.1.S1_at	49.532	12.021
	Cit.10054.1.S1_s_at	12.292	4.887
	Cit.10056.1.S1_at	11.740	8.216
1-Deoxy-d-xylulose-5-phosphate reductoisomerase	Cit.23507.1.S1_at	12.309	11.740
	Cit.4968.1.S1_s_at	5.384	3.434
	Cit.26985.1.S1_at	3.538	2.404
2-C-Methyl-d-erythritol 4-phosphate cytidylyltransferase	Cit.14478.1.S1_at	5.452	4.375
4-(Cytidine 5′-diphospho)-2-C-methyl-d-erythritol kinase	Cit.29567.1.S1_s_at	6.659	10.413
	Cit.3446.1.S1_s_at	7.803	5.097
2-C-Methyl-d-erythritol 2,4-cyclodiphosphate synthase	Cit.1430.1.S1_s_at	5.645	4.046
4-Hydroxy-3-methylbut-2-en-1-yl diphosphate synthase	Cit.985.1.S1_at	8.931	4.878
4-Hydroxy-3-methylbut-2-en-1-yl diphosphate reductase	Cit.17714.1.S1_at	29.980	8.382
	Cit.9279.1.S1_at	4.626	3.123
	Cit.9280.1.S1_s_at	4.483	2.612
Prenyltransferases and terpene synthases
Isopentenyl diphosphate isomerase (putative)	Cit.9842.1.S1_s_at	3.430	2.800
	Cit.27203.1.S1_s_at	2.875	2.350
	Cit.9841.1.S1_s_at	2.679	2.232
Farnesyl diphosphate synthase (putative)	Cit.1688.1.S1_s_at	2.806	1.963
	Cit.35197.1.S1_at	2.333	2.917
Geranylgeranyl pyrophosphate synthase (putative)	Cit.20724.1.S1_at	25.436	7.288
	Cit.14050.1.S1_at	9.553	3.298
	Cit.16303.1.S1_at	3.544	3.159
(+)-Limonene synthase (monoterpene synthase)	Cit.9964.1.S1_s_at	9.540	3.194
	Cit.23560.1.S1_at	9.116	4.338
β-Pinene synthase (monoterpene synthase)	Cit.2694.1.S1_at	29.767	17.103
(E)-β-Ocimene synthase (monoterpene synthase)	Cit.31295.1.S1_at	3.119	1.821
Monoterpene synthase (putative)	Cit.31559.1.S1_at	2.158	1.416
β-Farnesene synthase	Cit.2936.1.S1_at	53.196	15.623
Sesquiterpene synthase (putative)	Cit.17284.1.S1_at	49.647	14.095
	Cit.30774.1.S1_at	41.631	21.153
	Cit.29748.1.S1_s_at	27.134	17.274
Coumarin and flavonoid biosynthesis
Malonyl-CoA biosynthesis
ATP citrate lyase subunit B	Cit.11635.1.S1_at	3.384	2.668
	Cit.30906.1.S1_s_at	2.948	3.718
	Cit.14414.1.S1_at	2.796	3.078
Acetyl-CoA carboxylase (biotin carboxylase subunit)	Cit.26354.1.S1_s_at	2.771	2.853
	Cit.26354.1.S1_s_at	2.771	2.853
General phenylpropanoid pathway
Phe ammonia lyase	Cit.9590.1.S1_s_at	4.452	5.469
	Cit.2241.1.S1_s_at	2.810	2.654
4-Coumarate CoA ligase	Cit.25648.1.S1_s_at	3.473	4.061
Coumarin and furanocoumarin pathway
CYP82C (hydroxylates psoralens)	Cit.5945.1.S1_at	56.028	14.715
	Cit.29478.1.S1_s_at	26.793	7.596
	Cit.2373.1.S1_s_at	17.277	4.347
Flavonoid pathway
Chalcone synthase	Cit.1966.1.S1_s_at	14.402	1.299
	Cit.10216.1.S1_at	3.008	2.146
Chalcone isomerase	Cit.5577.1.S1_at	2.145	1.632
	Cit.29773.1.S1_s_at	2.045	2.161
Flavanone 3-hydroxylase	Cit.2890.1.S1_s_at	15.901	7.209
	Cit.2889.1.S1_at	14.602	6.341
	Cit.2890.1.S1_at	8.796	5.203
Flavone synthase (CYP93D)	Cit.29489.1.S1_at	26.434	13.133
	Cit.2475.1.S1_at	21.786	13.355
	Cit.29489.1.S1_s_at	13.944	10.741
Flavonoid 3′-monooxygenase	Cit.11243.1.S1_at	12.247	3.884
	Cit.30703.1.S1_at	31.822	26.116
	Cit.4610.1.S1_s_at	49.621	12.614
	Cit.4610.1.S1_at	46.816	10.041
TT1 (glabra transcription factor)	Cit.2963.1.S1_s_at	2.375	1.433