Comparative Analysis of Floral Scent Formation between ‘Jinhui’ and Onc. ‘Sharry Baby’ of Oncidium hybridum

doi:10.13560/j.cnki.biotech.bull.1985.2025-0833

Abstract

Abstract:

Objective A new strain ‘Jinhui’ was bred from tissue culture seedlings of Oncidium Gower Ramsey, which was tall and upright, but had no aroma. The aim of this study is to explore the non-aroma limiting factors of ‘Jinhui’ by analyzing molecular mechanism of floral scent formation involved in unscented ‘Jinhui’ and strong scented Onc. ‘Sharry Baby’, aiming to release aroma of ‘Jinhui’ by molecular technology. Method HS-SPME/GC-MS was used to determine components and contents of floral volatiles from two varieties of Oncidium hybridum. Key genes of floral scent formation were screened by transcriptome sequencing and qRT-PCR using different flower developmental stages of ‘Jinhui’ and Onc. ‘Sharry Baby’ as materials. Result GC-MS results showed that total floral volatile contents of blooming period in Onc. ‘Sharry Baby’ were 6.1 times higher than that of ‘Jinhui’. The main floral volatiles in Onc. ‘Sharry Baby’ was monoterpenes, while it was sesquiterpenes in ‘Jinhui’. The results of transcriptome sequencing showed that 55 277 unigenes were obtained, and about 81.64% unigenes were annotated by public database. In MEP pathway, the upstream pathway of monoterpenes, most of the genes, such as CMK, HDR, HDS and GPPS, were expressed higher in Onc. ‘Sharry Baby’ than that in ‘Jinhui’, thus that GPP, precursor of monoterpenes, was accumulated in the Onc. ‘Sharry Baby’. In MVA pathway, the upstream pathway of sesquiterpene, about half of genes were highly expressed in Onc. ‘Sharry Baby’, and half of them were highly expressed in ‘Jinhui’. Three terpene synthase genes (TPS) with significant differential expression were screened from transcriptome data. Among them, OhTPS1 and OhTPS2 belonged to the TPS-b family and were mainly composed of mono-TPSs genes. The expressions of OhTPS1 and OhTPS2 in Onc. ‘Sharry Baby’ were significantly higher than that in ‘Jinhui’ and increased gradually with flower development in Onc. ‘Sharry Baby’, indicating that these two genes played a key role in monoterpene biosynthesis of Onc. ‘Sharry Baby’. OhTPS3 belonged to TPS-a family and were mainly composed of sesqui-TPSs genes. The expression of OhTPS3 in ‘Jinhui’ was significantly higher than that in Onc. ‘Sharry Baby’ and increased gradually with flower development in ‘Jinhui’, indicating that this gene played a key role in sesquiterpenoid biosynthesis of ‘Jinhui’. Conclusion The main reason for low total amount of volatile compounds in ‘Jinhui’ flowers is that most of key genes in MEP pathway are low expression, which limits the accumulation of GPP, and low expression of monoterpene synthase genes also hinder the formation of monoterpene volatiles.

Key words: Oncidium hybridum, floral scent, transcriptome, terpenoids

FAN Rong-hui, LUO Yuan-hua, CHEN Yi-quan, FANG Neng-yan, CHEN Yan, ZHONG Huai-qin, YE Xiu-xian. Comparative Analysis of Floral Scent Formation between ‘Jinhui’ and Onc. ‘Sharry Baby’ of Oncidium hybridum[J]. Biotechnology Bulletin, 2026, 42(1): 105-113.

Figures/Tables 7

References 34

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基因 Gene	正向引物 Forward primer sequence （5′-3′）	反向引物 Reverse primer sequence （5′-3′）
OhTPS1	ATGATGACTACATACAATCGCTAC	TCAAGTCCAAGTTGGCATAG
OhTPS2	ACCTCGTCTACATCATCAGC	CCTTCAATTTATTCCTTTCG
OhTPS3	TTATTGATGCGCTACAACG	CAATCCACGTACATTTCCA
Actin	AATGTGCCTGCTATGTATGTTGCT	GGGCATATCCTTCGTAGATTG

基因 Gene	正向引物 Forward primer sequence （5′-3′）	反向引物 Reverse primer sequence （5′-3′）
OhTPS1	ATGATGACTACATACAATCGCTAC	TCAAGTCCAAGTTGGCATAG
OhTPS2	ACCTCGTCTACATCATCAGC	CCTTCAATTTATTCCTTTCG
OhTPS3	TTATTGATGCGCTACAACG	CAATCCACGTACATTTCCA
Actin	AATGTGCCTGCTATGTATGTTGCT	GGGCATATCCTTCGTAGATTG

序号No.	保留时间Retention time （min）	挥发化合物 Volatile component	分子式 Molecular formula
				金辉 Jinhui			香水文心Onc. Sharry baby
				花蕾前期Early bud period	花蕾中期Mid bud period	盛花期Blooming period	花蕾前期Early bud period	花蕾中期Mid bud period	盛花期Blooming period
1	1.931	丙酮 2-Propanone	C₃H₆O	0.11±0.02	0.17±0.02	0.01±0.01	-	-	-
2	2.833	3-戊酮 3-Pentanone	C₅H₁₀O	0.27±0.05	0.29±0.03	0.11±0.03	-	-	-
3	2.921	叶醇 Leaf alconol	C₆H₁₂O	-	-	-	0.32±0.07	0.62±0.07	0.65±0.07
4	3.933	正己醛 Hexanal	C₆H₁₂O	0.35±0.04	0.23±0.03	0.05±0.02	0.64± 0.33	0.74±0.38	-
5	4.427	正己醇 Hexyl alconol	C₆H₁₄O	-	-	-	0.33±0.05	0.58±0.05	1.08±0.07
6	5.233	丙烯醛 2-Propenal	C₇H₆O₂	-	-	-	0.56±0.43	0.43±0.23	-
7	5.876	α-派烯 α-Pinene	C₁₀H₁₆	-	-	-	-	1.56±0.54	6.47±0.45
8	6.746	1-戊烯-3-醇 Ethyl vinyl carbinol	C₇H₉ClO	0.15±0.03	0.30±0.03	0.05±0.02	-	-	-
9	7.500	香桧烯（+）-Sabinene	C₁₀H₁₆	-	-	-	-	0.12±0.01	0.55±0.09
10	7.672	β-派烯 β-Pinene	C₁₀H₁₆	-	-	-	-	0.20±0.02	0.44±0.12
11	8.245	β-月桂烯 β-Myrcene	C₁₀H₁₆	-	-	-	1.83±0.13	6.59±0.30	6.50±0.63
12	9.834	D-柠檬烯 D-Limonene	C₁₀H₁₆	-	-	-	-	0.62±0.12	2.74±0.22
13	9.928	1，8-桉叶素 1，8-Cineole	C₁₀H₁₆	-	-	-	-	6.27±0.63	15.34±0.79
14	10.080	苯甲醇 Benzyl alcohol	C₇H₈O	-	-	-	-	0.62±0.16	2.37±0.83
15	10.616	β-罗勒烯 β-Ocimene	C₁₀H₁₆	-	0.44±0.02	1.83±0.13	-	10.39±0.51	31.84±1.47
16	12.784	芳樟醇 Linalool	C₁₀H₁₆	-	-	-	-	2.34±0.23	10.63±0.56
17	14.912	异辛醇 Isooctanol	C₈H₁₈O	-	-	-	0.51±0.23	0.52±0.15	-
18	15.567	顺-3-壬烯醇 cis-3-Nonenol	C₉H₁₈O	-	-	-	-	-	0.30±0.05
19	15.953	γ-木糖烯 γ-Muurolene	C₁₅H₂₄	-	0.20±0.01	0.10±0.04	-	-	-
20	16.383	α-萜品烯 α-Terpineol	C₁₀H₁₈O	-		-	-	1.92±0.25	7.08±2.88
21	16.425	α-古巴烯 α-Copaene	C₁₅H₂₄	0.12±0.02	1.54±0.23	8.49±0.41	-	-	-
22	17.155	β-波旁烯 β-Bourbonene	C₁₅H₂₄	-	0.07±0.02	0.25±0.04	-	0.41±0.10	1.30±0.17
23	20.807	γ-榄香烯 γ-Elemene	C₁₅H₂₄	-	0.04±0.01	0.14±0.03	-	-	-
24	21.029	1-十六炔 1-Hexadecyne	C₁₅H₂₄	-	-	-	-	-	0.50±0.10
25	21.447	α-古芸烯 α-Gurjunene	C₁₅H₂₄	-	0.02±0.01	0.16±0.02	-	-	-
26	23.121	β-瑟林烯 β-Selinene	C₁₅H₂₄	-	-	0.12±0.03	-	-	-
27	23.220	β-橄榄烯 γ-Maaliene	C₁₅H₂₄	-	0.10±0.02	0.30±0.05	-	-	-
28	24.179	β-石竹烯 β-Caryophyllene	C₁₅H₂₄	-	0.72±0.05	2.94±0.15	-	0.10±0.06	2.03±0.08
29	25.955	γ-杜松烯 γ-Cadinene	C₁₅H₂₄	-	-	-	-	0.12±0.03	0.66±0.06
30	26.140	大根香叶烯 Germacrene D	C₁₅H₂₄	-	0.03±0.01	0.11±0.07	-	0.55± 0.04	4.58±1.61
31	26.611	惕各酸苄酯 Benzyl tiglate	C₁₂H₁₄O₂	-	-	-	-	0.31±0.06	0.89±0.30
32	26.846	α-法呢烯 α-Farnesene	C₁₅H₂₄	-	0.09±0.01	0.05±0.05	-	2.06±0.51	10.30±1.09
33	28.573	反式-橙花叔醇 Nerolidol	C₁₅H₂₄	-	-	-	-	0.37± 0.06	1.60±0.20
34	28.921	鲨烯 Squalene	C₃₀H₅₀	-	-	-	-	1.28±0.36	4.98±0.42

序号No.	保留时间Retention time （min）	挥发化合物 Volatile component	分子式 Molecular formula
				金辉 Jinhui			香水文心Onc. Sharry baby
				花蕾前期Early bud period	花蕾中期Mid bud period	盛花期Blooming period	花蕾前期Early bud period	花蕾中期Mid bud period	盛花期Blooming period
1	1.931	丙酮 2-Propanone	C₃H₆O	0.11±0.02	0.17±0.02	0.01±0.01	-	-	-
2	2.833	3-戊酮 3-Pentanone	C₅H₁₀O	0.27±0.05	0.29±0.03	0.11±0.03	-	-	-
3	2.921	叶醇 Leaf alconol	C₆H₁₂O	-	-	-	0.32±0.07	0.62±0.07	0.65±0.07
4	3.933	正己醛 Hexanal	C₆H₁₂O	0.35±0.04	0.23±0.03	0.05±0.02	0.64± 0.33	0.74±0.38	-
5	4.427	正己醇 Hexyl alconol	C₆H₁₄O	-	-	-	0.33±0.05	0.58±0.05	1.08±0.07
6	5.233	丙烯醛 2-Propenal	C₇H₆O₂	-	-	-	0.56±0.43	0.43±0.23	-
7	5.876	α-派烯 α-Pinene	C₁₀H₁₆	-	-	-	-	1.56±0.54	6.47±0.45
8	6.746	1-戊烯-3-醇 Ethyl vinyl carbinol	C₇H₉ClO	0.15±0.03	0.30±0.03	0.05±0.02	-	-	-
9	7.500	香桧烯（+）-Sabinene	C₁₀H₁₆	-	-	-	-	0.12±0.01	0.55±0.09
10	7.672	β-派烯 β-Pinene	C₁₀H₁₆	-	-	-	-	0.20±0.02	0.44±0.12
11	8.245	β-月桂烯 β-Myrcene	C₁₀H₁₆	-	-	-	1.83±0.13	6.59±0.30	6.50±0.63
12	9.834	D-柠檬烯 D-Limonene	C₁₀H₁₆	-	-	-	-	0.62±0.12	2.74±0.22
13	9.928	1，8-桉叶素 1，8-Cineole	C₁₀H₁₆	-	-	-	-	6.27±0.63	15.34±0.79
14	10.080	苯甲醇 Benzyl alcohol	C₇H₈O	-	-	-	-	0.62±0.16	2.37±0.83
15	10.616	β-罗勒烯 β-Ocimene	C₁₀H₁₆	-	0.44±0.02	1.83±0.13	-	10.39±0.51	31.84±1.47
16	12.784	芳樟醇 Linalool	C₁₀H₁₆	-	-	-	-	2.34±0.23	10.63±0.56
17	14.912	异辛醇 Isooctanol	C₈H₁₈O	-	-	-	0.51±0.23	0.52±0.15	-
18	15.567	顺-3-壬烯醇 cis-3-Nonenol	C₉H₁₈O	-	-	-	-	-	0.30±0.05
19	15.953	γ-木糖烯 γ-Muurolene	C₁₅H₂₄	-	0.20±0.01	0.10±0.04	-	-	-
20	16.383	α-萜品烯 α-Terpineol	C₁₀H₁₈O	-		-	-	1.92±0.25	7.08±2.88
21	16.425	α-古巴烯 α-Copaene	C₁₅H₂₄	0.12±0.02	1.54±0.23	8.49±0.41	-	-	-
22	17.155	β-波旁烯 β-Bourbonene	C₁₅H₂₄	-	0.07±0.02	0.25±0.04	-	0.41±0.10	1.30±0.17
23	20.807	γ-榄香烯 γ-Elemene	C₁₅H₂₄	-	0.04±0.01	0.14±0.03	-	-	-
24	21.029	1-十六炔 1-Hexadecyne	C₁₅H₂₄	-	-	-	-	-	0.50±0.10
25	21.447	α-古芸烯 α-Gurjunene	C₁₅H₂₄	-	0.02±0.01	0.16±0.02	-	-	-
26	23.121	β-瑟林烯 β-Selinene	C₁₅H₂₄	-	-	0.12±0.03	-	-	-
27	23.220	β-橄榄烯 γ-Maaliene	C₁₅H₂₄	-	0.10±0.02	0.30±0.05	-	-	-
28	24.179	β-石竹烯 β-Caryophyllene	C₁₅H₂₄	-	0.72±0.05	2.94±0.15	-	0.10±0.06	2.03±0.08
29	25.955	γ-杜松烯 γ-Cadinene	C₁₅H₂₄	-	-	-	-	0.12±0.03	0.66±0.06
30	26.140	大根香叶烯 Germacrene D	C₁₅H₂₄	-	0.03±0.01	0.11±0.07	-	0.55± 0.04	4.58±1.61
31	26.611	惕各酸苄酯 Benzyl tiglate	C₁₂H₁₄O₂	-	-	-	-	0.31±0.06	0.89±0.30
32	26.846	α-法呢烯 α-Farnesene	C₁₅H₂₄	-	0.09±0.01	0.05±0.05	-	2.06±0.51	10.30±1.09
33	28.573	反式-橙花叔醇 Nerolidol	C₁₅H₂₄	-	-	-	-	0.37± 0.06	1.60±0.20
34	28.921	鲨烯 Squalene	C₃₀H₅₀	-	-	-	-	1.28±0.36	4.98±0.42