萝卜和白菜属间杂种硫甙基因表达与组分特征分析

Gene Expression and Component Changes of Glucosinolates in A Intergeneric Hybrid Between Chinese Cabbage and Radish

硫甙是十字花科蔬菜中重要的次生代谢物质。在不同的十字花科作物中,硫甙的种类及其降解产物不同,从而产生了各自的特殊风味与生物功能。萝卜的主要硫甙4-甲基亚磺酰基-3-丁烯基硫甙(RAE)及其降解产物具有强力的抗癌活性;而白菜的主要硫甙2-羟基-3-丁烯基硫甙(PRO)的降解产物噁唑烷硫酮,被认为有致甲状腺肿大的副作用。本研究采用高效液相色谱分析法,分析了萝卜(‘36-2’)、白菜(‘Chiifu’)以及属间杂种(DH)中硫甙组分及其含量,共鉴定出13种硫甙。萝卜中的主要硫甙是4-甲硫基-3-丁烯基硫甙(RSA)和RAE;白菜中的主要硫甙为PRO、3-丁烯基硫甙(NAP)和吲哚-3-甲基硫甙(GBC);远缘杂交种的主要硫甙则有RAE、4-戊烯基硫甙(GBN)、NAP和PRO。通过与‘36-2’的比较转录组分析,发现DH中硫甙通路基因有14个下调表达和23个上调表达,其中萝卜特有基因RsIQD1.1和RsMYB34.2下调表达,而RsMYB34.1上调表达。值得注意的是萝卜中的RsFMOGS-OX2.1在DH中显著上调表达。通过与‘Chiifu’的比较分析,发现DH中硫甙通路基因有24个下调表达和15个上调表达,其中白菜特有基因BrIPMI-SSU3.1、BrIPMDH3.1和BrMAM3.1显著上调表达。这些基因在不同物种中的表达特点与其硫甙组分的变化有关。这在一定程度上证实远缘杂交可能通过改变后代的遗传组成和基因表达而改变其硫甙组成及含量,为以属间杂种作为桥梁种质实现物种间基因交流,创制高品质十字花科新种质奠定了理论基础和技术支撑。

Glucosinolates are important secondary metabolites in cruciferous vegetables.In various cruciferous crops,glucosinolates and their degradation products may be different,thus rendering their respective special flavors and biological functions.A main glucosinolates in radish,glucoraphenin(RAE)and its degradation product have powerful anticancer activity,whereas oxazolidinone,a degradation product of progoitrin(PRO),a main glucosinolate in Chinese cabbage,is considered to have the side effect of causing goiters.In this study,high performance liquid chromatography(HPLC)was used to analyze the main components and contents of glucosinolates in radish(‘36-2’),Chinese cabbage(‘Chiifu’)and raphanobrassica,a synthetic intergeneric distant hybrid(DH).A total of 13 glucosinolates were identified.The main glucosinolates in radish were glucoraphasatin(RSA)and RAE.The main glucosinolates in Chinese cabbage were PRO,gluconapin(NAP)and glucobrassicin(GBC).The main glucosinolates in the synthetic intergeneric hybrid species were RAE,glucobrassicanapin(GBN),NAP,PRO and GBC.Through the transcriptome analysis comparing DH with‘36-2’,it was found that there were 14 down-regulated expression and 23 up-regulated expression genes for glucosinolates pathway in DH,among which the radish-specific RsIQD1.1 and RsMYB34.2 were down-regulated,while RsMYB34.1 was up-regulated.Notably,the RsFMOGS-OX2.1 of radish was significantly up-regulated in DH.Through comparative analysis with‘Chiifu’,it was found that 24 glucosinolates pathway genes in DH were down-regulated and 15 were up-regulated,among which the Chinese-cabbage-specific BrIPMI-SSU3.1,BrIPMDH3.1 and BrMAM3.1 were significantly up-regulated.The expression characteristics of these genes in DH appeared to be related to the change of the composition of glucosinolates.This proved to some extent that distant hybridization may change the component and content of glucosinolates by changing the genetic composition and gene expression of the offspring,which lays a theoretical foundation and technical support for realization of gene exchanges among species by using distant hybrids as a bridge germplasm and creation of new germplasms of high quality in cruciferous crops.