Fast,simple,efficient Agrobacterium rhizogenes-mediated transformation system to non-heading Chinese cabbage with transgenic roots

Non-heading Chinese cabbage, a variety of Brassica campestris, is an important vegetable crop in the Yangtze River Basin of China. However,the immaturity of its stable transformation system and its low transformation efficiency limit gene function research on non-heading Chinese cabbage. Agrobacterium rhizogenes-mediated(ARM) transgenic technology is a rapid and effective transformation method that has not yet been established for non-heading Chinese cabbage plants. Here, we optimized conventional ARM approaches(one-step and two-step transformation methods) suitable for living non-heading Chinese cabbage plants in nonsterile environments. Transgenic roots in composite non-heading Chinese cabbage plants were identified using phenotypic detection, fluorescence observation, and PCR analysis. The transformation efficiency of a two-step method on four five-day-old non-heading Chinese cabbage seedlings(Suzhouqing, Huangmeigui, Wuyueman, and Sijiu Caixin) was 43.33%-51.09%, whereas using the stout hypocotyl resulted in a transformation efficiency of 54.88% for the 30-day-old Sijiu Caixin.The one-step method outperformed the two-step method;the transformation efficiency of different varieties was above 60%, and both methods can be used to obtain transgenic roots for functional studies within one month. Finally, optimized ARM transformation methods can easily,quickly, and effectively produce composite non-heading Chinese cabbage plants with transgenic roots, providing a reliable foundation for gene function research and non-heading Chinese cabbage genetic improvement breeding.

Effect of Partial Replacement of Nitrate by Amino Acid and Urea on Nitrate Content of Non-heading Chinese Cabbage and Lettuce in Hydroponic Condition

In this paper, the authors studied the effect of different mixtures of glycine (Gly), isoleucine (Iso), proline (Pro), and urea solutions used as a partial (20%) replacment of nitrate in the nitrate content and quality of non-heading Chinese cabbage and lettuce in hydroponice. Five treatments were done 12 d before harvest. Compared to the control group, Gly had the best effect in reducing the nitrate content of both vegetable leaves and petioles; the mixture of Gly, Iso and Pro ranked second and urea the least. Treatments with amino acid could also increase soluble sugar and protein contents and enhance total-N in leaves significantly. In contrast, amino acid enhanced NRA in non-heading Chinese cabbage, while they decreased it slightly in lettuce. The results showed that amino acids and urea could reduce the nitrate content of both vegetables, but they had almost the same effect on non-heading Chinese cabbage. Moreover, amino acids were more effective than urea in lettuce. As a result, it was concluded that partial replacement of nitrate with amino acids not only reduced the nitrate content but also improved the quality of vegetables.

Molecular Cloning,Expression Analysis and Localization of Exo70A1 Related to Self Incompatibility in Non-Heading Chinese Cabbage(Brassica campestris ssp.chinensis)

The exocyst is a conserved protein complex,and required for vesicles tethering,fusion and polarized exocytosis.Exo70A1,the exocyst subunit,is essential for assembly of the exocyst complex.To better understand potential roles of Exo70A1 in non-heading Chinese cabbage（Brassica campestris ssp.chinensis）,we obtained the full-length cDNA of Exo70A1 gene,which consisted of 1 917 bp and encoded a protein of 638 amino acids.BlastX showed BcExo70A1 shared 94.9% identity with Brassica oleracea var.acephala（AEI26267.1）,and clustered into a same group with other homologues in B.oleracea var.acephala and Brassica napus.Subcellular localization analysis showed BcExo70A1 was localized to punctate structures in cytosol of onion epithelial cells.Results showed that BcExo70A1 was widely presented in stamens,young stems,petals,unpollinated pistils,roots and leaves of self compatible and incompatible plants.The transcripts of BcExo70A1 in non- heading Chinese cabbage declined during initial 1.5 h after incompatible pollination,while an opposite trend was presented after compatible pollination.Our study reveals that BcExo70A1 could play essential roles in plant growth and development,and is related to the rejection of self pollen in non-heading Chinese cabbage.

Using a Suppression Subtractive Library-Based Approach to Identify Non-Heading Chinese Cabbage Genes Up-Regulated in Early Response to Elicitor PB90

Monitoring expression at the transcriptional level is the first essential step for the functional analysis of plant genes. Genes-encoding proteins directly involved in early response to elicitor constitute only a small fraction of all the genes affected by elicitor. Transcriptional responses to various elicitors have been extensively studied in different plants including Nicotiana and Arabidopsis thaliana; however, corresponding data aren＇t available for non-heading Chinese cabbage. To address this problem, we describe a suppression subtractive library-based approach to isolate the plant＇s ESTs up-regulated in the early induction/execution of the HR induced by elicitor PB90 from Phytophthora boehmeriae. According to their putative identification in BLAST searches against the three genome databases, 70 up-regulated genes were classified into 9 parts： some aspect of primary ＇metabolism＇ or ＇energy＇ production; ＇protein synthesis＇ or ＇protein fate＇; cellular communication/signal transduction mechanism; cell fates including Beclin, SPT1, and SPT2; HLA-B and AGO1 which participate in transcription; cellular transport and hypothetical proteins or proteins for which a function has yet to be determined. Seven selected genes such as Beclin, thioredoxin, HLA-B, MAP3K, SPT1, SPT2, and AGO1 were up-regulated induced by PB90, suggesting that the genes may play an important role in PB90-triggered HR.

Isolation and characterization of an ERF-B3 gene associated with flower abnormalities in non-heading Chinese cabbage

BrcERF-B3 gene, a member of ethylene-responsive factor family, was screened from a mutant plant in non-heading Chinese cabbage（Brassica rapa ssp. chinensis） by cDNA-AFLP technology. We got full length cDNA of two BrcERF-B3 genes by homology-based cloning from two materials and found that their nucleotide sequences were the same by sequencing. The BrcERF-B3 protein, belonging to the B3 subgroup of the ERF subfamily, shared a close relationship with B. rapa. RT-PCR result showed that BrcERF-B3 expressed only in mutant stamen rather than maintainer stamen. qRT-PCR results indicated that BrcERF-B3 expressed highly during reproductive growth development and in the early of mutant buds, suggesting BrcERF-B3 might be involved in the formation of abnormal flower in mutant. What＇s more, the expression of BrcERF-B3 was more significant to ABA, Me JA and cold stresses in mutant than in maintainer and was down-regulated in NaCl treatment in two lines, implying BrcERF-B3 might be different roles in biotic and abiotic stresses.

The Variety Screening of Green-stem Non-heading Chinese Cabbage and Dark-green-leaf Non-heading Chinese Cabbage Tolerant to Heat

[Objectives] Introducing and screening leaf vegetable varieties tolerant to heat and humidity has great significance to ensure balanced supply of vegetables in summer and autumn in Hainan Province. [Methods] On the basis of the introduction of green-stem non-heading Chinese cabbage and dark-green-leaf non-heading Chinese cabbage varieties, the varieties tolerant to heat and humidity were identified by the investigation of agronomic traits and evaluation of heat injury index. [Results] The data analysis results showed that four green-stem non-heading Chinese cabbage varieties including Huaguan Qingcaigeng F_1, Zhongguan Qinggeng, Hanshen No. 1 Qinggengcai F_1 and Huaxiawang Piaocai have the characteristics of strong tolerance to heat and high yield, and four dark-green-leaf non-heading Chinese cabbage varieties including Baimeigui, Heijingang, Xiaxue Naibaicai and Siji Baicai have the characteristics of strong tolerance to heat and high yield. [Conclusions] These eight leaf vegetable varieties are suitable for popularization in summer and autumn in Hainan Province.

Zinc chemical forms and organic acid exudation in non-heading Chinese cabbages under zinc stress

As an essential element, zinc also is a heavy metal. Non-heading Chinese cabbage showed obvious tolerance to Zn stress in former research. To further understand the mechanisms involved in Zn adaptability and detoxification, two genotypes Suzhouqing and Aijiaohuang were selected to investigate the chemical forms of Zn and root exudation. Zinc stress obvious strained the plant growth, and Aijiaohuang was more injured than Suhouqing under Zn stress. Under normal Zn levels, the chemical forms of Zn were diverse in three organs between genotypes. Results showed extractions of 2% HAc, 80% ethanol and 1 M NaCl were separately dominant in roots, petioles and leaves. However, under Zn stress (13 mg·L–1 and 52 mg·L–1) most of the Zn was extracted by 1M NaCl, and the subdominant amount of Zn was extracted by 80% ethanol. In the control only four types of organic acid could be detected. While under Zn stress, oxalic acid, tartaric acid, malic acid, lactic acid, acetic acid, citric acid and amber acid were all detected, so it could be speculated Zn detoxification with organic ligands or integrated with pectates and proteins in cells might be responsible for the adaptation of Zn stress in Chinese cabbage.

Fine mapping and cloning of the sterility gene Bra2Ms in nonheading Chinese cabbage(Brassica rapa ssp.chinensis)

The application of a male-sterile line is an ideal approach for hybrid seed production in non-heading Chinese cabbage(Brassica rapa ssp.chinensis).However,the molecular mechanisms underlying male sterility in B.rapa are still largely unclear.We previously obtained the natural male sterile line WS24-3 of non-heading Chinese cabbage and located the male sterile locus,Bra2Ms,on the A2 chromosome.Cytological observations revealed that the male sterility of WS24-3 resulted from disruption of the meiosis process during pollen formation.Fine mapping of Bra2Ms delimited the locus within a physical distance of about 129 kb on the A2 chromosome of B.rapa.The Bra039753 gene encodes a plant homeodomain(PHD)-finger protein and is considered a potential candidate gene for Bra2Ms.Bra039753 was significantly downregulated in sterile line WS24-3 compared to the fertile line at the meiotic anther stage.Sequence analysis of Bra039753 identified a 369 bp fragment insertion in the first exon in male sterile plants,which led to an amino acid insertion in the Bra039753 protein.In addition,the 369 bp fragment insertion was found to cosegregate with the male sterility trait.This study identified a novel locus related to male sterility in non-heading Chinese cabbage,and the molecular marker obtained in this study will be beneficial for the marker-assisted selection of excellent sterile lines in non-heading Chinese cabbage and other Brassica crops.

Synergistic effects of carbon cycle metabolism and photosynthesis in Chinese cabbage under salt stress

Chinese cabbage(Brassica rapa ssp. pekinensis) has a long cultivation history and is one of the vegetable crops with the largest cultivation area in China. However, salt stress severely damages photosynthesis and hormone metabolism, nutritional balances, and results in ion toxicity in plants. To better understand the mechanisms of salt-induced growth inhibition in Chinese cabbage, RNA-seq and physiological index determination were conducted to explore the impacts of salt stress on carbon cycle metabolism and photosynthesis in Chinese cabbage. Here, we found that the number of thylakoids and grana lamellae and the content of starch granules and chlorophyll in the leaves of Chinese cabbage under salt stress showed a time-dependent response, first increasing and then decreasing. Chinese cabbage increased the transcript levels of genes related to the photosynthetic apparatus and carbon metabolism under salt stress, probably in an attempt to alleviate damage to the photosynthetic system and enhance CO_(2) fixation and energy metabolism. The transcription of genes related to starch and sucrose synthesis and degradation were also enhanced;this might have been an attempt to maintain intracellular osmotic pressure by increasing soluble sugar concentrations. Soluble sugars could also be used as potential reactive oxygen species(ROS) scavengers, in concert with peroxidase(POD)enzymes, to eliminate ROS that accumulate during metabolic processes. Our study characterizes the synergistic response network of carbon metabolism and photosynthesis under salt stress.

Physiological and transcriptome analyses of Chinese cabbage in response to drought stress

Chinese cabbage is an important leafy vegetable crop with high water demand and susceptibility to drought stress.To explore the molecular mechanisms underlying the response to drought,we performed a transcriptome analysis of drought-tolerant and-sensitive Chinese cabbage genotypes under drought stress,and uncovered core drought-responsive genes and key signaling pathways.A co-expression network was constructed by a weighted gene coexpression network analysis(WGCNA)and candidate hub genes involved in drought tolerance were identified.Furthermore,abscisic acid(ABA)biosynthesis and signaling pathways and their drought responses in Chinese cabbage leaves were systemically explored.We also found that drought treatment increased the antioxidant enzyme activities and glucosinolate contents significantly.These results substantially enhance our understanding of the molecular mechanisms underlying drought responses in Chinese cabbage.

Defect in an immune regulator gene BrSRFR1 leads to premature leaf senescence in Chinese cabbage

Leaf senescence is the final stage of leaf development, where the nutrients and energy of senescent leaves are redistributed to developing tissues or organs for plant growth, reproduction, and defense. Outer leaves are photosynthetic organs that usually senesce at the late heading stage in Chinese cabbage, and premature leaf senescence often reduces leafy head yield and quality. In this study, 11 premature leaf senescence mutants were screened from an ethyl methanesulfonate-mutagenized population of the double haploid line ‘FT' in Chinese cabbage. At the early heading stage, the mutants exhibited edge yellowing within its outer leaves, and at the mature stage, its leafy head weight decreased significantly. Genetic analysis revealed that the mutated trait of all 11 mutants corresponds to single gene recessive inheritance. Semi-diallel cross tests showed that 5 of the 11 were allelic mutants. MutMap and Kompetitive Allele Specific PCR genotyping revealed that BraA01g001400.3C was the candidate gene, which is orthologous of Arabidopsis SUPPRESSOR OF rps4-RLD 1, encoding an immune regulator, so we named it as BrSRFR1. All the BrSRFR1 in the five allelic mutants exhibited single nucleotide polymorphisms at different positions on their exons and led to premature translation termination, which confirmed that defect in BrSRFR1 led to premature leaf senescence. These results verify the role of Br SRFR1 on leaf senescence and provide a new insight into the mechanisms of leaf senescence in Chinese cabbage, which reveals a novel function of SRFR1 in plant development.

The construction of a genetic linkage map of non-heading Chinese cabbage (Brassica campestris ssp.chinensis Makino)

Non-heading Chinese cabbage （Brassica carnpestris ssp. chinensis Makino） is one of the most important vegetables in eastern China. A genetic linkage map was constructed using 127 doubled haploid （DH） lines, and the DH population was derived from a commercial hybrid ＂Hanxiao＂ （lines SW-13 x L-118）. Out of the 614 polyrnorphic markers, 43.49% were not assigned to any of the linkage groups （LGs）. Chi-square tests showed that 42.67% markers were distorted from expected Mendelian segregation ratios, and the direction of distorted segregation was mainly toward the paternal parent L-118. After sequentially removing the markers that had an interval distance smaller than 1 cM from the upper marker, the overall quality of the linkage map was increased. Two hundred and sixty-eight molecular markers were mapped into 10 LGs, which were anchored to the corresponding chromosome of the B. rapa reference map based on com- mon simple sequence repeat （SSR） markers. The map covers 973.38 cM of the genome and the average interval distance between markers was 3.63 cM. The number of markers on each LG ranged from 18 （R08） to 64 （R07）, with an average interval distance within a single LG from 1.70 cM （R07） to 6.71 cM （R06）. Among these mapped markers, 169 were sequence-related amplified polymorphism （SRAP） molecular markers, 50 were SSR markers and 49 were random amplification polymorphic DNA （RAPD） markers. With further saturation to the LG9 the current map offers a genetic tool for loci analysis for important agronomic traits.

Isolation and Characterization of a Novel Chitosan-Binding Protein from Non-Heading Chinese Cabbage Leaves

Abstract: To know the mechanism of ammonia assimilation in non-heading Chinese cabbage (Brassica campestrish L. ssp. chinensis (L.) Makino) leaves regulated by chitosan (CTS), a CTS-binding protein was isolated from non-heading Chinese cabbage leaves using the chitosan affinity chromatography approach and this CTS-binding protein was partially characterized. The profile of the 53.1 kDa purified protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis was compared with the native molecular weight of 106.5 kDa, which indicated that the purified protein was a dimer with identical subunits. After isoelectric focusing, a band was obtained at pH 8.25. The agglutination test and periodic acid-Schiff staining further revealed that the protein was a glycoprotein with lectin activity. Moreover, the purified protein contained 17.4% (w/w) neutral carbohydrate and 82.56% (w/w) protein. The comparison of this protein and the 67 kDa CTS-binding protein isolated previously from Rubus culture tissue exhibited some differences in characterization. According to results of peptide mass fingerprinting analysis, the protein purified in the present study does not show any similarity with any protein in the protein data bank. Thus, it was deduced that the protein purified in the present study is a novel CTS-binding protein.

Fast tracking alien gene discovery by molecular markers in a late flowering Chinese cabbage-cabbage translocation line‘AT7–4'

Flowering time is an important agronomic trait of Chinese cabbage with late flowering being a primary breeding objective.In our previous work,we obtained Chinese cabbage-cabbage translocation lines that contained several beneficial cabbage genes.Cabbage-specific molecular markers show that these genes were coming from chromosome C01 of cabbage.In this study,we investigated the inheritance of flowering time in a couple of translocation lines and analyzed the transmission rate of molecular markers in the offspring.Consequently,we obtained the late flowering Chinese cabbage-cabbage translocation line‘AT7–4’in which the flowering time was later than that of‘85–1’by about 7 days under 4-week vernalization.Based on previous studies of the genomes of Chinese cabbage and cabbage,we located the cabbage-specific molecular markers that were closely linked at the top of the chromosome A01 in the F2mapping population generated by self-crossing F1s derived from a cross between the translocation line‘AT7–4’and Chinese cabbage‘14–36’.Five flowering-related genes in the alien fragment were found by functional annotation and their molecular markers were developed.This study lays the foundation for the future improvement of Chinese cabbage varieties using A-C translocation lines.

Blue light induces leaf color change by modulating carotenoid metabolites in orange-head Chinese cabbage(Brassica rapa L.ssp. pekinensis)

Carotenoids are involved in the formation of plant leaf color as well as photosystem photoprotection. This study showed that blue light significantly induced up-regulation of the total carotenoid content in the inner leaves of orange-head Chinese cabbage(OHCC). Furthermore, the transcriptomic analysis revealed that blue light treatment induced upregulation of genes in photosynthesis(BrHY5-2, BrCOP1 and BrDET1) and the methylerythritol 4-phosphate pathways(BrGGPS, BrDXS and BrHDR) upstream of the carotenoid metabolic pathway. Carotenoid metabolomic analysis revealed that the accumulation of several orange and red carotenoids(lycopene, zeaxanthin, β-carotene, lutein, and β-cryptoxanthin) after blue light treatment contributed to the deepening of the leaf coloration, suggesting that short-term blue light treatment could be used to boost nutritional quality. The light signal gene BrHY5-2 participated in the blue light-induced transcriptional regulation of carotenoid biosynthesis in OHCC. Overexpression of BrHY5-2 in Arabidopsis significantly increased the total carotenoid content and the sensitivity to blue light. The above findings revealed new insights about blue-light-induced carotenoid synthesis and accumulation in OHCC lines. They suggested a new engineering approach to increase the nutritional value of vegetables.

Comprehensive analysis of the full-length transcripts and alternative splicing involved in clubroot resistance in Chinese cabbage

Chinese cabbage is an economically important Brassica vegetable worldwide, and clubroot, which is caused by the soilborne protist plant pathogen Plasmodiophora brassicae is regarded as a destructive disease to Brassica crops. Previous studies on the gene transcripts related to Chinese cabbage resistance to clubroot mainly employed RNA-seq technology,although it cannot provide accurate transcript assembly and structural information. In this study, PacBio RS II SMRT sequencing was used to generate full-length transcriptomes of mixed roots at 0, 2, 5, 8, 13, and 22 days after P. brassicae infection in the clubroot-resistant line DH40R. Overall, 39 376 high-quality isoforms and 26 270 open reading frames(ORFs) were identified from the SMRT sequencing data. Additionally, 426 annotated long noncoding RNAs(lncRNAs),56 transcription factor(TF) families, 1 883 genes with poly(A) sites and 1 691 alternative splicing(AS) events were identified. Furthermore, 1 201 of the genes had at least one AS event in DH40R. A comparison with RNA-seq data revealed six differentially expressed AS genes(one for disease resistance and five for defensive response) that are potentially involved in P. brassicae resistance. The results of this study provide valuable resources for basic research on clubroot resistance in Chinese cabbage.

Effect of Foliar Application of Amino Acid on the Quality and Enzyme Activity of Flowering Chinese Cabbage(Brassica parachinensis Bailey)

A pot experiment was conducted to study the influences of foliar application of glycine,alanine,lysine,and glutamic acid in 200 mg/kg or 500 mg/kg upon the quality and enzyme activity of flowering Chinese cabbage（Brassica parachinensis Bailey）.The results showed that all the application of these four amino acids could increase the yield of flowering Chinese cabbage,significantly raise the content of soluble sugar,and reduce the accumulation of nitrate.The applications of three other amino acids except alanine can increase the content of soluble proteins and decrease the accumulation of oxalic acid.However,the application of amino acid has insignificant influences on the SPAD number of chlorophyll,and causes the decrease of Vitamin C content.Meanwhile,the application of amino acid can improve the activity of nitrate reductase（NR） and glutamate dehydrogenase（GDH） as well.It shows that the application of amino acid is beneficial to improve ammonia metabolism,reduce the accumulation of nitrate and oxalic acid,increase the content of soluble sugar and soluble proteins,and improve the quality of flowering Chinese cabbage.

Investigation on the Sterility Changeover of Male Sterility Line CMS7311 in Heading Chinese Cabbage

Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating temperature in light-growth-incubator and outdoor natural day/night alternating temperature respectively. It showed that the sterility of CMS7311 has significant change with temperature. The constant temperature of 6 - 12 degreesC was suitable to induce the changeover of sterility (CGS) of CMS7311 ; the shortest treatment time for CGS induction at this temperature was 3 d. The significant value of sterility changeover of CMS7311 occurred at the constant temperature of 6 - 9 degreesC after treatment for 6 - 9 d. The intensity of CGS was stronger under constant temperature than under alternate temperature, but the shortest treatment time inducing CGS has no difference between them. When treated for 9 d under the day/night alternating temperature of 11/7 degreesC, its sterility could also turn to normal fertility (near to sterile grade I or zero). In normal condition, the interval from the end of temperature treatment to the beginning of CGS induction was 10 - 16 d. In the condition of natural day/night alternating temperature, the lower limit of temperature for effective CGS induction was at the daily mean temperature ( DMT) of 3. 5 - 6. 8 degreesC, and the shortest treatment time which could induce the sterility changeover was also longer than that under constant temperature, being 11d at DMT of 1.5 - 3.1 degreesC. In addition, for the apical dominance, the flower bud on the first lateral branch showed the CGS 8 - 10 d later than the flower bud on the main stem under the same temperature with the same days of treatment. The intensity of CGS of CMS7311 on the first lateral branch was also weaker than the flower bud on the main stem.

Effects of Hypergravity on Physiological and Biochemical Characteristics of Chinese Cabbage

The Chinese cabbage seed used in this study was Xinfengkang 90. The tested seeds were treated with 1 000×g, 2 000×g and 4 000×g of hypergravity for 20, 40 and 60 min respectively. The Chinese cabbage leaves were col ected at the early seedling stage for the determination of free proline content, POD activity and SOD activity. The results showed the free proline content was lowest in the seeds treated with 40-min 2 000-g gravity, while it was highest for the 60-min 4 000-g gravity treatment. Compared to the control, al the hypergravity treatments inhibited the synthesis of free proline. The POD activity was highest in the seeds treated with 20-min 1 000-g gravity, while it was lowest in the seeds treated with 60-min 2 000-g gravity. Considering the SOD activity, the 40-min 1 000-g gravity treatment was highest, and the 60-min 4 000-g gravity treatment was lowest. lt was indicated that appropriate hypergravity treatment was conducive to increasing the SOD activity.

Directional Breeding of An Oval-ecotype Male Sterile Line of Chinese Cabbage(Brassica campestris L. ssp. pekinensis)

[Objective] The study aimed to explore the method for directional breeding of a male-sterile line in oval-ecotype Chinese cabbage. [Method] Based on ＂Multiple Allele Hypothesis of Genic Male Sterile Chinese Cabbage＂, an inbred line ＇06048＇ of oval ecotype was used as the receptor, and male fertile plant of ＇AB12＇ was used as the donor line. Crossing, backcross, selfing, testcross and sibling were ap- plied to transfer the multiple alleles under the directional genetic model. [Result] Segregation ratio of every generation was consistent with theoretical value. A new male sterile line with 100% male sterility and ＇06048＇ horticultural traits was ob- tained successfully, which accomplished the transfer of male sterile multiple allele and horticultural characters of receptor line at the same time. [Conclusion] The re- search verifies that the model of directional transfer is feasible, provides a theoreti- cal basis for the directional transfer of Chinese cabbage with other horticultural traits whose genotype is msms. The model can also be applied to other Brassica crops, to generate genetic male sterile lines with specific botanical traits and high-quality economic traits.