Abstract:Glucosinolates and their degradation products are important secondary metabolite of cruciferous vegetables with the anti-cancer function. The Methylthioalkylmalate synthases encoded by various MAM genes are involved in glucosinolate side-chain elongation. MAM1 catalyzes the aliphatic glucosinolate synthesis with short-chain, while MAM3 catalyzes that with long-chain. In this study, the glucosinolate content and the expression of MAM genes were analyzed in Chinese cabbage and cabbage inbred lines during seedling and rosette stages, in order to associate MAM gene expression with the accumulation of beneficial glucosinolates. The results showed that the average glucosinolate content in cabbage was higher than that of Chinese cabbage from seedling to rosette stage. The content of 5C and 4C aliphatic glucosinolates (GBN and NAP) were predominant in Chinese cabbage, whereas the main glucosinolates in cabbage were 3C and 4C aliphatic glucosinolates (IBE, SIN and GRA). The anti-cancer components SIN and GRA were significantly higher in cabbage than those of Chinese cabbage. The genome annotations of Chinese cabbage and cabbage revealed seven MAM paralogous genes respectively. By analyzing the expression levels of MAMs, a significant difference in the relative expression level of MAM1 and MAM3 between Chinese cabbage and cabbage was detected. The expression level of BraMAM1.1 and BraMAM1.2 in Chinese cabbage was significantly lower than that of BoMAM1.1 and BoMAM1.2 in cabbage, while the expression level of BraMAM3.2 and BraMAM3.3 was significantly higher than that of BoMAM3.1. Moreover, the content of 3C aliphatic glucosinolates in cabbage was positively correlated with the expression of BoMAM1.1, and the content of 5C aliphatic glucosinolates in Chinese cabbage was positively correlated with the expression of BraMAM3.2. Collectively we speculated that the low expression of BraMAM1.1 and the high expression of BraMAM3.2 may respond to the low accumulation of 3C aliphatic glucosinolates (SIN) and the high accumulation of 5C aliphatic glucosinolates (GBN) in Chinese cabbage.

Abstract:Glucosinolates (GSLs) are a type of important secondary metabolites in cruciferous plants. GSLs and their degradation products are known with important roles in plant flavor, insect resistance and anti-cancer. Sulforaphane, the degradation product of glucoraphanin (GRA), is one of the most important anti-cancer substances. The BrAOP2 gene is a key factor that modulates the GRA content. To analyze if the GSLs content between the Chinese Cabbage-Cabbage Translocation Line A-4 was different with that of their parent Chinese Cabbage 85-1, 84 selfing progenies plants of A-4 and 85-1 were subjected to measure by High Performance Liquid Chromatography the GSLs content in rosette leaves and heading leaves at rosette, early heading and harvest head stage. The genomic and transcriptional diversity of the BrAOP2 gene were analyzed. The results showed that the average contents of total GSLs, aliphatic GSLs, PRO, GBN, GRA, NAP and GBC of A-4 selfing progenies plants were always higher than those of 85-1 in heading leaves and rosette leaves at all stages. Especially, the highest value on contents were observed in heading leaves at early heading stages. Except the content of NEO, the contents of total GSLs and other GSLs components in heading leaves were higher than those in rosette leaves. The lower expression and SNP/Indels of the BrAOP2 gene in A-4 selfing progenies plants if compared to 85-1 were observed. With these results, it is speculated that the increase on GRA content in A-4 selfing progenies plants associates with the expression of BrAOP2. Collectively, these results provided insights for further analyzing the GRA content in 85-1 and Chinese cabbage-cabbage translocation lines.

Abstract:The male sterile lines of diploid Chinese cabbage have been widely investigated for theoreticalstudies and practical uses. In tetraploid Chinese cabbage， improvement of fertility and seed setting rate in selfbred lines was favorable， while study of the male sterile lines remained un-investigated. In this study， a sterilesource（ CMS hou36gao） with new Brassica rapa L. cytoplasmic male sterile（ CMS） gene was selected fromthe diploid Chinese cabbage， and subjected for chromosome doubling using colchicine treatment. By multipleconsecutive cycles with tetraploid inbred lines D571 and D574， in conjugation with cytogenetically identifyingthe number of chromosomes， two tetraploid lines CMS-D571 and CMS-D574 that showed cytoplasmic malesterile were produced. Both lines showed sterility rate up to 100% with high seed setting rate and geneticstability. This study raised an example by using the cytoplasmic male sterility in tetraploid Chinese cabbagebreeding， and established an experimental pipeline to generate the cytoplasmic tetraploid male sterile lines.Collectively， this work laid a foundation for innovation and practical use of male sterile lines in tetraploid Chinesecabbage.

Abstract: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.

Abstract:Creating mutants is an effective way of germplasm innovation and useful basis of functional genomics research in Chinese Cabbage. In this study, the inbred line ‘A03’ of Chinese cabbage was selected as wild genotype for constructing one mutant library because of its self-compatibility and easy microspore culture. The influences of EMS treatments on vigor of M1 and M2 seeds and seedlings were investigated. The variations in phenotypic traits of M2 population at heading stage, harvest stage and reproductive growth stage were further investigated. The results showed that the more suitable mutant scheme of creating mutants was considered to soaking seeds with EMS 0.4% and with time 16 h. The way of continuous treatments with EMS on seeds of two generations could be used in constructing mutant library of Chinese cabbage. Within the obtained mutant population, there was wide variation in phenotypic traits of M2 individuals at heading stage, harvest stage and reproductive growth stage, with mutation frequencies of 21.65%, 22.40% and 25.65%, respectively.

Abstract:The product of marker linked to downy mildew resistance from cabbage could be amplified on Chinese cabbage-cabbage disomic alien addition line 1 (AC1d) and its parents Chinese cabbage and cabbage. And the product of marker linked to TuMV resistance from cabbage could be amplified on AC1d and cabbage, the corresponding product could not be amplified on Chinese cabbage. The values of plant length, plant width, head length, vitamin C and soluble protein contents during mature vegetative period in selfed progenies of AC1d showed a wide range of variation beyond corresponding values of parents Chinese cabbage and cabbage, which offered an opportunity to screen translocation lines that meet the breeding aims.

Abstract:Resistance to downy mildew, Turnip mosaic virus (TuMV), black rot, verticillium wilt and clubroot were evaluated by inoculation under controlled conditions at seedling stage in 203 Chinese cabbage inbred lines from 2012 to 2014. The result showed that 7 lines were highly resistant to downy mildew, 9 to TuMV, 0 to black rot, 31 to verticillium wilt and 12 to clubroot. Out of 203 inbred lines, 82 showed resistant to only one of these diseases, 62 ones showed resistant to two kinds of diseases, 28 lines showed resistance to three disease and 4 lines showed resistance to 4 diseases. The data also showed that inbred lines, 11-234, 04-622, 12-85, 13-108 and 09-894, were elite materials for disease resistance breeding. In addition, the difference of disease resistance was observed among three types of Chinese cabbage for spring, summer and autumn cultivation, which also existed among four heading types.

Abstract:Chinese cabbage is one of the most important vegetables in the world. Identifying and distinguishing between Chinese cabbage varieties is critical to management of genetic resources, new variety testing and seed quality supervision. In this study, we screened from 205 mapped SSR markers for those that amplify stably in PCR reaction and are easily scored and relatively evenly distributed on the ten linkage groups of Chinese cabbage. 30 such makers were selected for Chinese cabbage identification. The 30 selected markers were labeled with four fluorescent dyes and allele sizing were conducted using DNA analyzers based on capillary electrophoresis and fluorescent detection. Allele sizes of same groups of samples determined using three DNA analyzers of two models were compared and analyzed. And it was found that systematic errors often occur between DNA analyzers. Values of the systematic errors depended on the markers and varied between 1 and 4 bps. Alleles of the SSR loci were named according to the length of the amplified DNA fragment determined by an ABI 3730 XL analyzer. It was proved that systematic errors can be removed by using a group of reference varieties so that repeatability and reproducibility can be ensured for results from different laboratories. Molecular data of 184 Chinese cabbage varieties were collected based on the SSR marker detection system.

Abstract:A total of 207 pairs of SSR primers from 10 linkage groups of Brassica (A genome) were amplified on 9 Chinese cabbage varieties and 10 cabbage varieties. The result showed that 33 SSR markers were specific on Chinese cabbage compared with cabbage. These markers assigned on 10 different linkage groups of Chinese cabbage, in which 3 SSR markers on group A1, 4 SSR markers on group A2, 5 SSR markers on group A3, 2 SSR markers on group A4, 3 SSR markers on group A5, 4 SSR markers on group A6, 2 SSR markers on group A7, 1 SSR marker on group A8, 2 SSR markers on group A9 and 7 SSR markers on group A10. It laid a foundation to further identify cabbage-Chinese cabbage alien addition lines.

Abstract:The insect-resistant inbred line 508 of the non-heading Chinese cabbage (Brassica chinensis L.)as female parent and susceptible inbred line 114 as male parent were used to construct six generation populations of P1、P2、F1、BC1P1、BC1P2 and F2. The resistances of all the populations to diamondback moth (DBM) were evaluated in net, and the joint analysis method for six generations was used to analyze the inheritance of insect-resistance. The results showed that the insect-resistance was partly recessive in the combination of 508×114 and fitted to the D-1 genetic model which is one pair of major additive-dominant gene plus additive-dominant polygene’s. The heritability of the major genes in BC1P1, BC1P2 and F2 populations were respectively 57.21%、25.87% and 76.05%. The results will be helpful for us to effectively utilize the insect-resistant gene resources in insect-resistance breeding.