| Brassica oleracea L., especially cabbage (Brassica oleracea L. var. capitata L.) is a worldwide vegetable crop belonging to the Brassica genera of Cruciferae, with high nutritional value and economic value. It is one of the most important vegetable crops in China.Glucosinolates(GSs) is a group of plant secondary metabolites, which widely exist in the roots, caudexes and fruits of Cruciferae. Especially, the plant family of Brassica, has a high GS content. Their degration products, such as isothiocyanates and indole products, have been widely studied as the self-defence compounds for plants and cancer-prevention agents for human beings. Therefore, to study GSs component and content in Brassica and explore the relationship between GSs and clubroot will provides theoretical support for evaluating Brassica oleracea L. germplasm resources, improving nutrition quality and disease resistance, and breeding of highly beneficial glucosinolate-containing varieties and disease-resistant varieties.In this study,4varieties of Brassica oleracea L. and60Brassica oleracea L. var. capitata L. were choosen. Evaluation to GS composition and content in their leaves was conducted by HPLC, which would be useful to exploit GS component and content in different varieties of Brassica oleracea L. and on different development stage of Brassica oleracea L. var. capitata L.. To explore the relationship between GSs and clubroot, glucosinolates composition and contents also were evaluated taking8cabbage cultivars(4cultivars were susceptible and4cultivars were tolerant)as experiment materials. The main conclusions were as follows:1. Making leaves lyophilized to dryness, using methanol as extraction agent and extracting under75℃is an efficient extraction method for glucosinolates.2.8types of GSs were detected by HPLC in4varieties of Brassica oleracea L.(Brassica oleracea L. var. capitata L., Brassica oleracea L. var. rubra DC, Brassica oleracea L. var. acephala DC. and Brassica oleracea L. var. gemmifera Zenk.), including5aliphatic glucosinolates(IBE, PRO, RAA, SIN and NAP),3indolyl GSs(4OH, GBC and4ME), and NAP was not detected in Brassica oleracea L. var. acephala DC. Among4varieties, the aliphatic GSs were the major glucosinolates except Brassica oleracea L. var. acephala DC. Brassica oleracea L. var. rubra DC. had the highest content of total GSs, then Brassica oleracea L. var. capitata L. and Brassica oleracea L. var. gemmifera Zenk., and Brassica oleracea L. var. acephala DC. had the lowest content of GSs. GBC was the major individual GS for4varieties, especially Brassica oleracea L. var. acephala DC. with the highest ratio for72.5%.3. The HPLC analysis showed the same result that8types of GSs were detected in leaves of60cabbages on both seedling stage and maturity, and also the content of total aliphatic GSs was higher than the total indolyl GSs. IBE and GBC were the main GS profiles for cabbages on different development stage. The contents of total GSs, total aliphatic GSs and total indolyl GSs on maturity were higher than seedling stage. And the content of individual GS on seedling stage varied more significantly than maturity.(1)The mean contents of total GSs, total aliphatic GSs and total indolyl GSs on maturity and seedling stage were29.986and21.237μmol·g-1(DW),19.590and13.372μmol·g-1(DW),10.396and7.869μmol·g-1(DW).(2)The result on beneficial GSs showed that the content of RAA, GBC and SIN varied significantly. For the content of RAA, the content on maturity varied from0.085to14.458μmol·g-1(DW), and varied from0.059to10.335μmol·g-1(DW) on seedling stage. For the content of GBC, it varied from2.553to22.794μmol·-1(DW) on maturity stage, and varied from1.349to31.185μmol·g-1(DW) on seedling stage. For the content of SIN, it varied from0.087to11.590μmol·g-1(DW) on maturity stage, and varied from0.091to9.994μmol·g-1(DW) on seedling stage.(3)Correlation analysis showed that the correlation of the content of total aliphatic GSs, total aliphatic GSs and the same types aliphatic GSs were highly significant, and the correlation of the content of GBC was significant on different development stage.4.The study on the relationship between glucosinolates and clubroot showed that9types GSs in the root of cabbages were detected,8types of them were the same with the leaves of cabbages, and the additional one was a kind of aromatic GS—2-phenylethyl-GS. In the roots, the contents of total aliphatic GSs> total indolyl GSs> total aromatic GSs. For the roots of cabbages, SIN and NAS were the major glucosinolate profiles.The content of each GS was increased in the susceptible and tolerant cultivars compared to the control group. The content of aromatic GS in roots of the4tolerant cultivars was significantly higher than the control group, while the content of total indolyl GSs in roots of the4susceptible cultivars was significantly higher than the control group, which directly affected the content of total GSs. |
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