Background Chilling stress severely compromises tobacco production by reducing leaf biomass accumulation and deteriorating leaf quality. Lipoxygenase (LOX) plays a key role in the oxidative metabolism of linoleic and linolenic acids, which serves as the initial step for jasmonic acid (JA) biosynthesis. However, its specific function in mediating cold-induced JA accumulation and cold tolerance in Nicotiana tabacum remains elusive. Results Our results found that cold stress significantly induces NtLOX2 expression in N. tabacum. Transgenic tobacco plants overexpressing NtLOX2 (OE#NtLOX2-1 and OE#NtLOX2-2) exhibited improved cold tolerance, which was associated with increased activities of antioxidant enzymes and improved reactive oxygen species (ROS) scavenging capacity. RNA-seq analysis revealed that NtLOX2-overexpressing lines displayed upregulation of key cold-responsive genes, including COR, ERF, LRR-RLK, GST, POD, DREB, and NCED. Furthermore, genes involved in JA biosynthesis, such as ADH and OPR1, were also upregulated, concomitant with elevated levels of both JA and MeJA as confirmed by metabolic profiling. Conclusions Our results demonstrate that NtLOX2 enhances cold tolerance by stimulating JA biosynthesis and activating a downstream transcriptional network of cold-responsive and antioxidant genes. These findings posit NtLOX2 as a promising genetic target for improving cold tolerance in crops.

Lipoxygenase (LOX) catalyzes the oxidation of linoleic acids and linolenic acids, yet their specific functions in carotenoid metabolism and regulation of methyl jasmonate (MeJA) biosynthesis in Nicotiana tabacum remain poorly understood. Expression characterization revealed LOX2 grouped in 13-LOX subfamily as the dominant isoform in N. tabacum, exhibiting strong induction upon MeJA treatment. Virus-induced gene silencing of LOX2 in N. benthamiana increased carotenoid contents, including β-carotene, lutein, violaxanthin, and neoxanthin, along with elevated levels of chlorophyll a and chlorophyll b. Conversely, LOX2-overexpression transgenic lines (OE#LOX2-1 and OE#LOX2-2) exhibited reduced carotenoid content, and enhanced emission of volatiles compounds. Furthermore, these transgenic lines showed elevated 2-Hexenal and MeJA levels compared to wild-type plants, accompanied by upregulated expression of key biosynthetic genes. Our results indicates that LOX2 not only co-oxidizes carotenoids but also critically modulates MeJA biosynthesis, establishing a functional connection between carotenoid degradation and MeJA signaling. Targeted manipulation of LOX2 could serve as a promising strategy for enhancing stress resilience and flavor quality in tobacco.

Carotenoid cleavage dioxygenase 4 (CCD4) controls the rate-limiting step of β-ionone biosynthesis, making it a valuable target for healthcare and pharmaceutical applications. Nicotiana tabacum, a carotenoid-richd crop species, is a promising source for β-ionone production. This study aimed to modify CCD4 activity to increase β-ionone yield in tobacco. We identified two isoforms of CCD4 in N. tabacum, NtCCD4a and NtCCD4b, with NtCCD4a exhibiting significantly higher expression levels than NtCCD4b. Using solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC–MS), we demonstrated that NtCCD4a effectively catalyzes the cleavage of β-carotene to produce β-ionone. To improve its enzymatic activity, we applied structure-based rational design to reconstruct the active pocket of NtCCD4a, followed by high-throughput screening of mutant variants. Three single base mutants, F181G, F184L, and F337M, in NtCCD4a showed enhanced β-ionone production compared to the wild-type, with F337M yielding the highest amount. No synergistic effects were observed among the three mutants. Transgenic tobacco plants expressing the F181G, F184L, and F337M mutations had accelerated β-carotene cleavage and increased β-ionone production relative to the wild-type NtCCD4a. Our results establish a framework for the design of CCD4 in major crop species through genome editing technology.

Carotenoid cleavage dioxygenase 4 (CCD4) controls the rate-limiting step of u03B2-ionone biosynthesis, making it a valuable target for healthcare and pharmaceutical applications. Nicotiana tabacum, a carotenoid-richd crop species, is a promising source for u03B2-ionone production. This study aimed to modify CCD4 activity to increase u03B2-ionone yield in tobacco. We identified two isoforms of CCD4 in N. tabacum, NtCCD4a and NtCCD4b, with NtCCD4a exhibiting significantly higher expression levels than NtCCD4b. Using solid-phase microextraction gas chromatography-mass spectrometry (SPME-GCu2013MS), we demonstrated that NtCCD4a effectively catalyzes the cleavage of u03B2-carotene to produce u03B2-ionone. To improve its enzymatic activity, we applied structure-based rational design to reconstruct the active pocket of NtCCD4a, followed by high-throughput screening of mutant variants. Three single base mutants, F181G, F184L, and F337M, in NtCCD4a showed enhanced u03B2-ionone production compared to the wild-type, with F337M yielding the highest amount. No synergistic effects were observed among the three mutants. Transgenic tobacco plants expressing the F181G, F184L, and F337M mutations had accelerated u03B2-carotene cleavage and increased u03B2-ionone production relative to the wild-type NtCCD4a. Our results establish a framework for the design of CCD4 in major crop species through genome editing technology.

BACKGROUND:Albinism in plants causes slow growth, dwarfing and even death. Most albinism is mainly focused on leaf albinism. Studies of seed albinism are still lacking and scarcely studied in higher plants with asexual reproduction. RESULTS:In this study, two seed albinism mutations (AM1 and AM2) in lotus were unable to survive in normal condition, exhibiting a decline in carotenoid and chlorophyll contents compared with wild type (WT). Metabolome analyses illustrated a total of 51 differentially changed metabolites (DCMs) in embryo of AM1 (AM1-E), AM2 (AM2-E) and WT (WT-E), along with 94 DCMs in cotyledon of AM1 (AM1-C), AM2 (AM2-C) and WT (WT-C). Forty-four DCMs were associated with metabolic pathways including flavonoid, lipid, photosynthesis and starch metabolism. Additionally, transcriptome analysis was performed to screen a total of 2060 differentially expressed genes (DEGs) in WT-E, AM1-E and AM2-E, as well as 104 DEGs in WT-C, AM1-C and AM2-C. These DEGs were highly enriched in metabolic pathways of flavonoid biosynthesis, lipid biosynthesis, chlorophyll biosynthesis, carotenoid biosynthesis and the tricarboxylic acid cycle. CONCLUSIONS:A total of 21 key genes encoding transcription factors, 100 DEGs and 44 DCMs were selected to construct correlation networks. The results suggested that combined effects of basic helix-loop-helix, myeloblastosis viral oncogene homologs, basic leucine zipper and APETALA2/ethylene-responsive factor regulated the DEGs involved in carotenoid synthesis, flavonoid biosynthesis, photosynthesis and fatty acid synthesis, which further resulted in the etiolation of N. nucifera. © 2025 Society of Chemical Industry.

As the global cash crops, the formation of distinct aroma profiles in Nicotiana tabacum have garnered significant research interest. Lipids as precursors of aroma compounds in plants, play an essential role in defining the unique aroma characteristics of tobacco. In this study, lipidomics analysis was performed to identify a total of 471 lipid components in leaves of strong fragrance tobacco (SF) and mild fragrance tobacco (MF). Comparative analysis of SF and MF revealed 70 differentially changed lipid compounds, with 26 up-regulated and 44 down-regulated lipids. The up-regulated lipids were predominantly glycoglycerolipids (GL) and glycerophospholipids (GP), while the down-regulated lipids were enriched in sphingolipids (SP) and fatty acyls (FA). Gas chromatography-mass spectrometry (GC-MS) revealed that SF exhibited relatively higher levels of cis-3-hexenal and cis-3-hexenol compared to MF. Transcriptomics analysis identified a total of 905 differential expression genes (DEGs), with 370 up-regulated and 535 down-regulated DEGs. Notably, a robust correlation was observed between the expression of the key gene lipoxygenase 5 (LOX5) and content of phosphatidylcholine (PC) (15:0_18:3), a precursors of linolenic acid. Additionally, a positive correlation was detected between LOX5 expression and the degradation products of linolenic acid, including cis-3-hexenal and cis-3-hexenol. Transient over-expression of LOX5 in tobacco leaves resulted in an enhanced accumulation of these linolenic acid degradation products. Our findings elucidate the mechanism underlying the formation of diverse aroma profiles in tobacco, and provide a theoretical basis for breeding high-quality tobacco crop.

Nelumbo nucifera is widely consumed globally in both medicine and food industry. However, the aroma formation in N. nucifera remains largely unexplored. In this study, a total of 46 different changed metabolites (DCMs) were identified in petal, anther, seed, seedpod, and rhizome from N. nucifera cultivar of “Jinsenianhua”. Among these volatiles, Nonanal exhibited the higher relative odor activity value (ROAV) in anther, whereas the lower ROAV of Nonanal was detected in rhizome. Transcription analysis was performed to screen the key lipoxygenase (LOX) involved in synthesis of Nonanal in different tissues, revealing a positive correlation between NnLOX1 transcript and Nonanal accumulation. Transient over-expression of NnLOX1 in tobacco leaves increased Nonanal biosynthesis, which was potentially detected by a wide-range olfactory receptor (ORs) of OR1A2. Our findings highlight the crucial role of NnLOX1 in forming characteristic aroma in various tissues of N. nucifera.

Melatonin enhances photosynthesis efficiency in high plants. However, the underlying molecular mechanism remain largely unexplored. Our study provides novel insights into the multifaceted role of melatonin in Nicotiana tabacum, an important industrial crop. Foliar application of melatonin improved the photosynthetic capacity, promoted antioxidant enzymes activity, and enhanced tolerance to reactive oxygen species (ROS). Compared with control, melatonin-treated tobacco exhibited the increase in carotenoid contents including lutein, β-carotene, neoxanthin and violaxanthin, along with the higher levels of chlorophyll a and chlorophyll b. RNA-seq analysis indicated that melatonin robustly stimulated pathways related to carotenoid biosynthesis, biosynthesis of amino acids, photosynthesis, carbon fixation in photosynthetic organism, fatty acid biosynthesis, and glutathione metabolism. Co-expression network indicated the melatonin activated key transcription factors, including bHLH, WRKY, MYB, NAC, MADS6 and AP2/ERF. These transcription factors likely enhanced carotenoid biosynthesis and carbon fixation. Our results highlight the potential of melatonin as a novel eco-friendly agrochemical. Its application could address agricultural challenges by improving photosynthetic efficiency, thereby offering a sustainable solution for crop enhancement.

As the traditional herb with pharmacological compounds in China, the key genes related with terpenoid biosynthesis are still unveiled in Nelumbo nucifera. Geranylgeranyl pyrophosphate synthase (GGPPS) is one of the key enzymes in terpenoids biosynthesis, synthesizing the common precursor of GGPP for downstream enzymes for generating various terpenoids. In this study, four NnGGPPS genes were isolated from N. nucifera. Sequence and phylogenetic analyses indicate that NnGGPPS1 and NnGGPPS2 belong to large subunit (LSU). Whereas NnGGPPS3 and NnGGPPS4 are classified as small subunit (SSU) of SSU Ⅱ and SSU I, respectively. Among four NnGGPPSs, only NnGGPPS1 and NnGGPPS2 can produce GGPP in bacterial pigment complementation assay. Combination analysis of subcellular localization and gene co-expression analysis (GCN) illustrates that NnGGPPS1 is the main transcript related with methylerythritol phosphate (MEP) pathway, abscisic acid (ABA) biosynthesis, carotenoid and chlorophyll biosynthesis and degradation. Overexpression of NnGGPPS1 improves the growth of transgenic tobacco, and increases carotenoids and chlorophyll contents. Moreover, NnGGPPS1 transgenic tobacco exhibits improved photosynthesis efficiency and ROS scavenging ability. The up-regulated expression of the key genes in MEP pathway, carotenoid biosynthesis and chlorophyll biosynthesis, result in the increase of metabolic flux in NnGGPPS1 transgenic lines. Furthermore, the elevated MEP-derived primary metabolites of carotenoid and chlorophyll was attributed to enhancement of plant biomass of NnGGPPS1 transgenic lines. Therefore, NnGGPPS1 plays a vital role in biosynthesis of carotenoid and chlorophyll.

Despite the nutritional and economic importance of carotenoids and their products, regulation of carotenoid content in leaves remains to be fully elucidated. Recent findings indicate that carotenoid content are determined, at least in part, by the activity of carotenoid cleavage dioxygenase 1 (CCD1). This study examined whether NtCCD1 affects leaf carotenoids in the model plant Nicotiana tabacum . Three NtCCD1s, NtCCD1a, NtCCD1b, and NtCCD1c, were investigated including their phylogenetic relationships, conserved motifs, and exon-intron architecture. Of the three transcripts, NtCCD1c exhibited the highest expression level in various tissue as determined by real-time PCR. Confocal microscopy indicated that all NtCCD1s are located in the cytoplasm. The enzymatic activity of the NtCCD1c protein was also studied by co-expressing NtCCD1c in Escherichia coli engineered to accumulate β-carotene or lycopene. SPME-GC-MS indicated that NtCCD1c cleaves β-carotene and lycopene specifically at the 9–10/9′-10′ site to produce β-ionone and pseudoionone, respectively. Virus-induced gene silencing (VIGS) of NbCCD1 increased carotenoid contents including β-carotene, α-carotene, zeaxanthin, phytoene, lutein, violaxanthin, neoxanthin, and β-cryptoxanthin, along with a decline in reactive oxygen species (ROS). RNA-seq of silenced plants suppressed NbCCD1 but enhanced expression of essential genes encoding antioxidant enzymes including NtGST, NtCuZnSOD, NtAAO, and NtPOD, along with a decrease in expression of genes related to carbon fixation such as NtRCA1, NtRCA2, and NtRBCS. These observations suggest that NtCCD1 is a negative regulator of carotenoid content and plays an essential role in the regulation of ROS levels in tobacco leaves.

As one of the most imperative antioxidants in higher plants, carotenoids serve as accessory pigments to harvest light for photosynthesis and photoprotectors for plants to adapt to high light stress. Here, we report a small subunit (SSU) of geranylgeranyl diphosphate synthase (GGPPS) in Nicotiana tabacum, NtSSU II, which takes part in the regulation carotenoid biosynthesis by forming multiple enzymatic components with NtGGPPS1 and downstream phytoene synthase (NtPSY1). NtSSU II transcript is widely distributed in various tissues and stimulated by low light and high light treatments. The confocal image revealed that NtSSU II was localized in the chloroplast. Bimolecular fluorescence complementation (BiFC) indicated that NtSSU II and NtGGPPS1 formed heterodimers, which were able to interact with phytoene synthase (NtPSY1) to channel GGPP into the carotenoid production. CRISPR/Cas9-induced ntssu II mutant exhibited decreased leaf area and biomass, along with a decline in carotenoid and chlorophyll accumulation. Moreover, the genes involved in carotenoid biosynthesis were also downregulated in transgenic plants of ntssu II mutant. Taken together, the newly identified NtSSU II could form multiple enzymatic components with NtGGPPS1 and NtPSY1 to regulate carotenoid biosynthesis in N. tabacum, in addition to the co-expression of genes in carotenoids biosynthetic pathways.

As one of the most imperative antioxidants in higher plants, carotenoids serve as accessory pigments to harvest light for photosynthesis as well as photoprotectors for plants to adapt to high light stress. Phytoene synthase (PSY) is the entry enzyme and also the major rate-limiting enzyme in the carotenoid pathway. Here, we report a dehydration-responsive element-binding protein (DREB) transcription factor member in Nicotiana tabacum K326, NtDREB-1BL1, which regulates carotenoids biosynthesis by binding to the NtPSY promoter. The NtDREB-1BL1 transcript was widely distributed in leaves by Real-time PCR. Confocal image revealed that NtDREB-1BL1 was localized in the nucleus. The chromatin immunoprecipitation (ChIP) with the qPCR technique indicated that NtDREB-1BL1 could anchor the promoter region of NtPSY. Overexpression (NtDREB-1BL1 OE) and RNA interference (NtDREB-1BL1 RNAi) of NtDREB-1BL1 were performed to evaluate its biological function in N. tabacum. Both carotenoid and chlorophyll contents increased in transgenic plants of NtDREB-1BL1 OE compared with wild-type (WT) plants, with the augment of the genes involved in carotenoid biosynthesis. In contrast, the contents of carotenoid and chlorophyll significantly decreased in transgenic plants of NtDREB-1BL1 RNAi compared to WT, along with the decline in the expression of genes related to carotenoid biosynthesis. Moreover, transgenic plants of NtDREB-1BL1 OE exhibited enhanced tolerance under drought stress, with the weakened tolerance of drought stress in transgenic plants of NtDREB-1BL1 RNAi. In conclusion, our results illustrated the new role of transcription factor NtDREB-1BL1 in improving carotenoid biosynthesis through regulating NtPSY expression.

该研究从生理生化及分子水平分析粉藕鄂莲5号、脆藕鄂莲3号和中间型鲜切莲藕鄂莲4号褐变的机制,从中选取最适合鲜切加工的莲藕品种.结果表明,鲜切低温贮藏48 h后,3个莲藕品种中,鄂莲4号表观变化较明显.鄂莲3号的褐变度、呼吸强度、还原性糖、丙二醛含量低于鄂莲4号和5号,然而其超氧阴离子自由基、维生素C的含量较高.此外,通过抗氧化系统酶活性分析发现鄂莲3号的多酚氧化酶酶活性较低,过氧化物酶和超氧化物歧化物酶活性明显高于鄂莲4号和5号.荧光定量PCR结果显示,鲜切低温贮藏48 h后,鄂莲3号多酚氧化酶编码基因表达量较低,而锰超氧阴离子和过氧化物酶编码基因的表达量高于鄂莲4号和5号.综上所述,鄂莲3号最适宜做鲜切加工.

Abstract Lotus (Nelumbo Adans.), a relict plant, is testimony to long-term sustained ecological success, but the underlying genetic changes related to its survival strategy remain unclear. Here, we assembled the high-quality lotus genome, investigated genome variation of lotus mutation accumulation (MA) lines and reconstructed the demographic history of wild Asian lotus. We identified and validated 43 base substitutions fixed in MA lines, implying a spontaneous mutation rate of 1.4 × 10−9 bases/generation in lotus shoot stem cells. The past history of the lotus revealed that the ancestors of the lotus in eastern and southern Asia could be traced back to ~20 million years ago and twice experienced significant bottlenecks and population splits. We further identified selected genes among three lotus groups in different habitats, suggesting that 453 differed genes between the tropical and temperate group and 410 differed genes between two subgroups from Northeastern China and the Yangtze River–Yellow River Basin might play important roles in natural selection in the lotus’s adaptation and resilience. Our findings not only improve understanding of the evolutionary history of the lotus and the genetic basis of its survival advantages, but also provide valuable data for addressing various questions in evolution and protection for relict plants.

As the largest group of structurally diverse metabolites, terpenoids are versatile natural compounds that act as metabolism mediators, plant volatiles, and ecological communicators. However, few terpenoid compounds have been identified in plant parts of sacred lotus (Nelumbo nucifera Gaertn.). To elucidate the molecular genetic basis of the terpene biosynthetic pathway, terpenes from different parts of the plant, including seeds (S), young leaves (YL), mature leaves (ML), white flowers (WF), yellow flowers (YF), and red flowers (RF), were identified by LC-MS/MS and the relative contents of the same terpenes in different parts were compared. The results indicate that all plant parts primarily consist of triterpenes, with only minor quantities of sesquiterpenes and diterpenes, and there were differences in the terpene content detected in different plant parts. To illustrate the biosynthesis of various terpenoids, RNA sequencing was performed to profile the transcriptomes of various plant parts, which generated a total of 126.95 GB clean data and assembled into 29,630 unigenes. Among these unigenes, 105 candidate unigenes are involved in the mevalonate (MVA) pathway, methyl-erythritol phosphate (MEP) pathway, terpenoid backbone biosynthesis pathway, and terpenoid synthases pathway. Moreover, the co-expression network between terpene synthase (TPS) and WRKY transcription factors provides new information for the terpene biosynthesis pathway.

目的 克隆地黄多药及有毒化合物外排(multidrug and toxic compound extrusion,MATE)转运蛋白基因RgMATE6,并进行亚细胞定位与时空表达分析,为深入研究其在地黄转运次生代谢产物中的分子功能奠定基础.方法 利用地黄转录组数据库候选基因序列,利用实时荧光PCR (RT-PCR)克隆RgMATE6基因;利用生物信息学软件对其编码蛋白的结构、理化性质、同源性和进化树进行分析;通过与绿色荧光蛋白(GFP)融合表达进行亚细胞定位;利用实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)的方法测定该基因的时空表达模式.结果 克隆获得1892bp的RgMATE6基因序列,RgMATE6基因编码524个氨基酸、具有2个典型的MatE结构域和12个跨膜结构;RgMATE6蛋白与越橘的VcMATE6蛋白亲缘关系最近;RgMATE6-GFP载体瞬时表达的结果发现RgMATE6蛋白定位在液泡膜上;qRT-PCR分析发现RgMATE6基因在地黄不同时期的根中表达最高,尤其是块根膨大前期.结论 RgMATE6蛋白定位在液泡膜上,在地黄块根膨大期的根中表达较高,初步表明RgMATE6可能参与地黄体内次生代谢产物向液泡转运的过程.

Restricted genetic diversity can supply only a limited number of elite genes for modern plant cultivation and transgenesis. In this study, we demonstrate that rational design enables the engineering of geranylgeranyl diphosphate synthase (NtGGPPS), an enzyme of the methylerythritol phosphate pathway (MEP) in the model plant Nicotiana tabacum. As the crucial bottleneck in carotenoid biosynthesis, NtGGPPS1 interacts with phytoene synthase (NtPSY1) to channel GGPP into the production of carotenoids. Loss of this enzyme in the ntggpps1 mutant leads to decreased carotenoid accumulation. With the aim of enhancing NtGGPPS1 activity, we undertook structure-guided rational redesign of its substrate binding pocket in combination with sequence alignment. The activity of the designed NtGGPPS1 (a pentuple mutant of five sites V154A/I161L/F218Y/I209S/V233E, d-NtGGPPS1) was measured by a high-throughput colorimetric assay. d-NtGGPPS1 exhibited significantly higher conversion of IPP and each co-substrate (DMAPP ~1995.5-fold, GPP ~25.9-fold, and FPP ~16.7-fold) for GGPP synthesis compared with wild-type NtGGPPS1. Importantly, the transient and stable expression of d-NtGGPPS1 in the ntggpps1 mutant increased carotenoid levels in leaves, improved photosynthetic efficiency, and increased biomass relative to NtGGPPS1. These findings provide a firm basis for the engineering of GGPPS and will facilitate the development of quality and yield traits. Our results open the door for the structure-guided rational design of elite genes in higher plants.

Background Carotenoids play important roles in photosynthesis, hormone signaling, and secondary metabolism. Phytoene synthase (PSY) catalyzes the first step of the carotenoid biosynthetic pathway. In this study, we aimed to characterize the PSY genes in tobacco and analyze their function. Results In this study, we identified three groups of PSY genes, namely PSY1, PSY2 , and PSY3, in four Nicotiana species; phylogenetic analysis indicated that these genes shared a high similarity with those in tomato but not with those in monocots such as rice and maize. The expression levels of PSY1 and PSY2 were observed to be highest in leaves compared to other tissues, and they could be elevated by treatment with certain phytohormones and exposure to strong light. No PSY3 expression was detected under these conditions. We constructed virus-induced PSY1 and PSY2 silencing in tobacco and found that the newly emerged leaves in these plants were characterized by severe bleaching and markedly decreased carotenoid and chlorophyll content. Thylakoid membrane protein complex levels in the gene-silenced plants were also less than those in the control plants. The chlorophyll fluorescence parameters such as Fv/Fm, ΦPSII, qP, and NPQ, which reflect photosynthetic system activities, of the gene-silenced plants were also significantly decreased. We further performed RNA-Seq and metabonomics analysis between gene-silenced tobacco and control plants. RNA-Seq results showed that abiotic stress, isoprenoid compounds, and amino acid catabolic processes were upregulated, whereas the biosynthesis of cell wall components was downregulated. Metabolic analysis results were consistent with the RNA-Seq. We also found the downstream genes in carotenoid biosynthesis pathways were upregulated, and putative transcription factors that regulate carotenoid biosynthesis were identified. Conclusions Our results suggest that PSY can regulate carotenoid contents not only by controlling the first biosynthesis step but also by exerting effects on the expression of downstream genes, which would thereby affect photosynthetic activity. Meanwhile, PSY may affect other processes such as amino acid catabolism and cell wall organization. The information we report here may aid further research on PSY genes and carotenoid biosynthesis.

1-氨基环丙烷-1-羧酸氧化酶(ACOs)是乙烯合成通路的限速酶,对于研究乙烯在调控高等植物生长发育过程中的作用具有重要意义.本研究从子莲(Nelumbo nucifera)“太空莲36号”基因组中鉴定出8个NnACOs基因,即NnACO、NnACOlike、NnACO1X1、NnACO 1X2、NnACO1X3、NnACO1like、NnACO5和NnACO5like.其编码蛋白都含有Fe (Ⅱ)(His177-X-Asp179Xn-His234)和抗坏血酸(Arg244-X-Ser246)特异性的结合位点,以及ACOs酶活必需的保守性氨基酸位点(Lys297和Arg300).进一步分析了NnACOs外显子的剪切方式、系统进化关系和保守性基序,对NnACO进行同源模型.RT PCR结果表明,NnACO和NnACOlike基因主要表达于莲的花和地下茎.在莲开花和地下茎膨大过程中,NnACO和NnACOlike表达量随之升高.此外,低温胁迫也可诱导NnACO和NnACOlike的表达.该研究为未来阐明NnACOs在调控莲的生长发育和抗逆方面的作用奠定了理论基础.