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Non-heading Chinese cabbage originated in China. It is a popular vegetable widely planted in the middle and lower reaches of the Yangtze River with extremely rich germplasm resources, short growth cycle, high yield and rich nutrients. In the paper, based on the six varieties of non-heading Chinese cabbage, excellent germplasm resources, the development and application of breeding technology, the research progress and existing problems of genetic breeding technology and molecular biology of non-heading Chinese cabbage were discussed. To solve these problems, we suggest continuing to collect germplasm resources at the edge of the original habitat of non-heading Chinese cabbage and create more breeding materials in terms of germplasm resources, strengthening the research on genome-based molecular design breeding technology in terms of breeding technology, and establishing an efficient system of genetic transformation and gene editing in non-heading Chinese cabbage in terms of molecular biology. It is expected to provide a theoretical basis for the creation of new varieties of non-heading Chinese cabbage and the research of molecular biology. [ABSTRACT FROM AUTHOR]

Non-heading Chinese cabbage (Brassica campestris ssp. chinensis) is an important vegetative crop in the south of China. As an antioxidant, anthocyanin is the major quality trait for vegetables with purple leaves or petioles. However, the molecular biosynthetic mechanism of anthocyanin in non-heading Chinese cabbage has not been explained exclusively. In this study, two non-heading Chinese cabbage with contrasting colors in the leaves were used as the materials for RNA-seq. A total of 906 DEGs were detected, and we found that the anthocyanin and flavonoid biosynthetic pathways are significantly enriched in the purple NHCC. The transcriptome result was verified by RT-qPCR. Though bioinformatics analysis, BcTT8 was selected as the candidate gene for the regulation of anthocyanin synthesis, and the characterization of BcTT8 was elucidated by the functional analyses. The results proved that BcTT8 is a nucleus protein and phylogenetically close to the TT8 protein from Brassica. After silencing BcTT8, the total anthocyanin content of pTY-BcTT8 plants decreased by 42.5%, and the relative expression levels of anthocyanin pathway genes BcDFR, BcLODX and BcUF3GT-1 were significantly downregulated, while the transcription level of BcFLS was significantly upregulated. Compared with the wild type, the transgenic Arabidopsis showed obvious violet in the cotyledons part, and the anthocyanin biosynthetic genes such as AtDFR and AtLODX were significantly upregulated. In conclusion, BcTT8 is critical in the anthocyanin synthesis process of non-heading Chinese cabbage. Our findings illustrated the molecular mechanism of anthocyanin biosynthesis in non-heading Chinese cabbage. [ABSTRACT FROM AUTHOR]

Key message: We developed a novel Agrobacterium-mediated anther transformation for Wucai in planta, and in this procedure, the male germ line was the predominant target. Wucai (Brassica campestris L.), a variant of non-heading Chinese cabbage, is widely cultured in China and only improved by classic breeding methods. Here, a novel and efficient in planta Agrobacterium-mediated anther transformation method is developed based on the optimization of several factors that affect anther transformation. After optimization, transformation with the manual pollination application led to increased transient GUS expression in anthers (reaching 91.59%) and the transformation efficacies in planta (0.59–1.56% for four commercial cultivars). The stable integration and inheritance of the transgenes were further examined by molecular and genetic analyses. Three T2 transgenic lines presented a segregation ratio of 3:1, which was consistent with the Mendelian feature of a single dominant gene. In addition, the GUS histochemical assay and genetic crossing analysis revealed that the male germ line was the predominant target in this transformation. This optimized transformation system could provide a useful tool for both the improvement of cultivar qualities and investigation of functional genes in Wucai. [ABSTRACT FROM AUTHOR]

Reasonable application of microbial agents can significantly improve soil environment and increase the yield and quality of vegetables. In this study, we examined the effects of different forms of microbial agents on the growth and quality of Brassica rapa L. ssp. chinensis Makino (non-heading Chinese cabbage) under the conditions of no microbial agent application, liquid and solid microbe agents application. The results showed that compared with no microbial agent, application of liquid and solid microbial agent significantly improved soil urease activity, plant nitrogen content, leaf area, SPAD value, and net photosynthetic rate, and increased vegetable production by 26.9% and 34.4% respectively. Meanwhile, the total phenol content and ascorbic acid content of non-heading Chinese cabbage were increased and nitrate content was significantly decreased by applying microbial agents. Thus, rational application of microbial agents promoted the yield and quality of non-heading Chinese cabbage. From the perspective of vegetable growth, liquid microbial agents work fast, solid microbial agents had good long-term efficacy. The cooperating application with organic and inorganic fertilizers would facilitate the excellent quality and high yield of vegetables.

Ascorbic acid (L-AsA) is an important antioxidant in plants and humans. Vegetables are one of the main sources of ascorbic acid for humans. For instance, non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) is considered as one of the most important vegetables in south China. To elucidate the mechanism by which AsA accumulates, we systematically investigated the expression profiles of D-mannose/L-galactose pathway-related genes. We also investigated the recycling-related genes and AsA contents in different tissues of three non-heading Chinese cabbage cultivars, 'Suzhouqing', 'Wutacai' and 'Erqing' containing different amounts of AsA. Our results showed that six genes [D-mannose-6-phosphate isomerase 1 (PMI1), GDP-L-galactose phosphorylase 1 (GGP1), GGP2, GGP4, GDP-mannose-3', 5'-epimerase1 (GME1), and GME2] were expressed at high level and ascorbate oxidase (AAO) was expressed at low level. This expression pattern contributes, at least partially, to higher AsA accumulation in the leaves and petioles than in the roots. Eight genes (PMI1, GME, GGP, L-galactose-1-phosphate phosphatase, L-galactose dehydrogenase, L-galactono-1, 4-lactone dehydrogenase, monodehydroascorbate reductase 1, and glutathione reductase1) were also expressed at high level; AAO and ascorbate peroxidase (APX) were expressed at low level. This expression pattern may similarly contribute to higher AsA accumulation in 'Wutacai' and 'Suzhouqing' than in 'Erqing'. Therefore, the high expression levels of PMI, GME, and GGP and the low expression level of AAO contributed to the high AsA accumulation in non-heading Chinese cabbage., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)