Selection for high and low thiocyanate ion content in kale (Brassica oleracea var. acephala)

In 1978 genetical variation for thiocyanate ion (SCN-) was found in a kale population being selected for improved digestible organic-matter yield. Four generations of half-sib family selection for high and low SCN^- content in young leaves resulted in subpopulations with almost a twofold difference in their means, no overlap in their distributions, no observable reduction in their genetical variation, and only small differences in other traits. The total observed divergence in SCN^-content was 82% of that expected for a random mating population in linkage equilibrium in the absence of genotype x environment interactions. Average heritability on a single plot basis was low, namely 30%, but was increased to 46% with two replicates. This maximised the predicted response to selection for a fixed number of families selected and a fixed total number of plots.
Bulks of the high and low subpopulations were assessed in a trial in 1988. Averaged over September and December harvests of young and mature leaves, SCN- contents were 104.5 and 58.5 mg/100 g DM, respectively. Of eight controls, cv. Merlin had the lowest content, 63.5, and cv. Proteor had the highest content, 89.6. Cultivar x harvest date, cultivar x leaf age and cultivar x harvest date X leaf age interactions were removed by a logarithmic transformation of the data. Stem contents were very low and variable with an overall mean of 10.9 in September and > 5 in December, and no significant differences between cultivars or populations.
The subpopulations will be valuable for research into possible effects of SCN content on the disease and pest resistance of kale and on the performance of animals fed kale.     

Suberoylanilide hydroxamic acid induced microspore embryogenesis and promoted plantlet regeneration in ornamental kale (Brassica oleracea var. acephala)

Protoplasma - Isolated Microspore Culture (IMC) is an efficient method to obtain the homozygous strain; however, it is difficult to apply in ornamental kale due to its low rate of microspore...     

Selection for resistance to clubroot (Plasmodiophora brassicae) in marrowstem kale (Brassica oleracea var. acephala L.)

Ninety-six cultivars of Brassica oleracea were screened for clubroot resistance in a seedling test using two populations of Plasmodiophora brassicae. The most resistant cultivars were kales. Sixteen resistant marrowstem kale cultivars of diverse geographical origin were used to start a selection programme for clubroot resistance. Four generations of selection, involving single plants, half-sib and full-sib families, reduced a disease index averaged over six clubroot populations from 41.2 to 12.5. This was lower than the most resistant cultivar in the original population, cv. Mixti 28.8, and as good as a German landrace of cabbage noted for its resistance, Bohmerwaldkohl 10.5. In comparison, the mean of five kale controls, cvs Bittern, Canson, Condor, Kestrel and Merlin, was 61.1 and the value for the most susceptible control, cabbage cv. Septa, was 89.3. In the final assessment, there were no clubroot population x B. oleracea genotype interactions and in the initial assessment of cultivars there were only small interactions which could be removed by an angular transformation of the data. It was concluded that a high level of non-differential resistance had been achieved and that it may prove durable. It was also concluded from a small field trial that this level of resistance would prevent serious yield losses in practice.     

Comparative analysis of glucosinolate production in hairy roots of green and red kale (Brassica oleracea var. acephala)

Abstract

Glucosinolates (GSLs) are sulfur- and nitrogen-containing secondary metabolites that function in plant defense and provide benefits to human health. In this study, using Agrobacterium rhizogenes R1000, green and red kale hairy roots were established. The expression levels of GSLs biosynthesis genes and their accumulation in both kale hairy roots were analyzed by quantitative real-time PCR and HPLC. The results showed that the expression of most indolic GSLs biosynthesis genes was higher in the hairy roots of green kale than in that of red kale. In contrast, the expression of BoCYP83A1 and BoSUR1 encoding key enzymes aromatic GSL biosynthesis was significantly higher in red kale hairy root. The HPLC analysis identified six GSLs. The levels of 4-methoxyglucobrassicin, glucobrassicin, and 4-hydroxyglucobrassicin were 6.21, 5.98, and 2 times higher, respectively, in green kale than in red kale, whereas the levels of neoglucobrassicin and gluconasturtiin were 16.2 and 3.48 times higher, respectively, in red kale than in green kale. Our study provides insights into the underlying mechanisms of GSLs biosynthesis in kale hairy roots and can be potentially used as “biological factories” for producing bioactive substances such as GSLs.     

l-Ascorbic acid sodium salt promotes microspore embryogenesis and chromosome doubling by colchicine in ornamental kale (Brassica oleracea var. acephala)

Isolated microspore culture (IMC) represents a potential alternative technique in the plant breeding process, as it allows the effective production of doubled haploid (DH) homozygous lines. However, the implementation of this technique is limited by a low rate of embryogenesis, high level of embryo death, and low frequency of chromosome doubling. Thus, we investigated the effects of using different concentrations of L-ascorbic acid sodium salt (VcNa), which has never been applied for kale, to enhance the embryogenesis and regeneration by IMC. Specifically, 1 to 5 μM VcNa was added to the NLN-13 medium of four kale genotypes, while control was grown on VcNa-free medium. Overall, 1–4 μM VcNa at pH 5.84 increased embryogenesis, with 4 μM VcNa being the optimum concentration (12.92-fold increase). The proportion of embryo deaths declined when using appropriate VcNa concentrations. To increase the frequency of chromosome doubling, an artificial chromosome doubling protocol was developed for kale microspore-derived haploids. This protocol involved dipping roots of haploid plantlets in colchicine solution and adding colchicine treatment to solid Murashige and Skoog (MS) medium. Optimum chromosome doubling of haploids was achieved by dipping their roots in 750 mg/L colchicine solution for 4–6 h and 1000 mg/L colchicine solution for 2 h (doubling for nearly 50% of haploids). In conclusion, this study delineated an effective tissue culture process in promoting chromosomal ploidy of microspore-derived regenerated plants, allowing more microspores to be maintained that have excellent ornamental characteristics through crossbreeding.

     

Jointly silencing BoDWARF,BoGA20ox and BoSP (SELF-PRUNING) produces a novel miniature ornamental Brassica oleracea var. acephala f. tricolor variety

The ornamental Brassica oleracea var. acephala f. tricolor is a good winter and spring foliage plant. Plant architecture is an important agronomic trait of plants, especially for ornamental plants with high ornamental and economic value. In this study, three miniature-related genes, BoDWARF, BoGA20ox and BoSP (SELF-PRUNING), were cloned and their tissue-specific expression patterns were analyzed. The results showed that the three genes were all highly expressed in young leaves and flowers, followed by the lateral roots, seeds and stems. To further achieve the purpose of miniaturization of plants, an RNAi expression vector, jointly targeting BoDWARF, BoGA20ox and BoSP, was constructed and transformed into kale plants. Smaller plant size and slower growth and development speed of flowers and roots were observed in jointly silenced kales. Brassinosteroids and gibberellin contents in leaves and flower buds of transgenic plants were significantly decreased. Furthermore, the expressions of brassinolide-, gibberellin- and flowering-related genes were down-regulated by varying degrees in silenced plants. These results suggest that BoDWARF, BoGA20ox and BoSP play important roles in plant architecture, and that brassinolide and gibberellin are important hormones controlling plant growth and architecture. This miniaturization strategy of kale provides an efficient approach for cultivation of new varieties of ornamental plants and crops.     

Pigment variation and transcriptional response of the pigment synthesis pathway in the S2309 triple-color ornamental kale (Brassica oleracea L. var. acephala) line

Ornamental kale is popular because of its colorful leaves and few studies have investigated the mechanism of color changes. In this study, an ornamental kale line (S2309) with three leaf colors was developed. Analysis of the anthocyanin, chlorophyll, and carotenoid contents and RNA-seq were performed on the three leaf color types. There was less chlorophyll in the white leaves and purple leaves than in the green leaves, and the anthocyanin content was greatest in the purple leaves. All the downregulated DEGs related to chlorophyll metabolism were detected only in the S2309_G vs. S2309_W comparison, which indicated that the decrease in chlorophyll content was caused mainly by the inhibition of chlorophyll biosynthesis during the leaf color change from green to white. Moreover, the expression of 19 DEGs involved in the anthocyanin biosynthesis pathway was upregulated. These results provide new insight into the mechanisms underlying the three-color formation.     

Effect of different proportion of sulphur treatments on the contents of glucosinolate in kale (Brassica oleracea var. acephala) commonly consumed in Republic of Korea

Kale (Brassica oleracea L. Acephala Group) is the rich source of medicinal value sulphur compounds, glucosinolates (GLSs). The aim of this study was to investigate the effect of different proportion of sulphur (S) supplementation levels on the accumulation of GLSs in the leaves of the kale cultivar ('TBC'). High performance liquid chromatography (HPLC) separation method guided to identify and quantify six GSLs including three aliphatic (progoitrin, sinigrin and gluconapin) and three indolyl (glucobrassicin, 4-methoxyglucobrassicin and neoglucobrasscin) respectively. Analysis of these distinct levels of S supplementation revealed that the accumulation of individual and total GLSs was directly proportional to the S concentration. The maximum levels of total GLSs (26.8 µmol/g DW) and glucobrassicin (9.98 µmol/g DW) were found in lower and upper parts of the leaves supplemented with 1 mM and 2 mM S, respectively. Interestingly, aliphatic GSLs were noted predominant in all the parts (50.1, 59.3 and 56% of total GSLs). Among the aliphatic and indolyl GSLs, sinigrin and glucobrassicin account 35.3 and 30.88% of the total GSLs. From this study, it is concluded that supply of S enhance the GSLs accumulation in kale.     

观赏羽衣甘蓝SSR标记分型与亲缘关系研究

观赏羽衣甘蓝凭借优良的观赏特性和抗逆性已经成为重要的冷季观赏植物。国内观赏羽衣甘蓝育种起步较晚,并且缺乏对种质资源遗传背景的系统研究。本研究应用SSR标记对不同类型的观赏羽衣甘蓝材料进行标记分型和亲缘关系分析。从99对均匀分布于甘蓝基因组的SSR引物中筛选出46对多态性好的引物,对27份不同类型的观赏羽衣甘蓝材料进行标记分型,共扩增出210个多态性位点,平均PIC值为0.58。进一步利用标记分型结果进行STRUCTURE群体结构、UPGMA聚类和聚类热图分析,结果显示3种分析结果基本一致,可以将27份材料分为圆叶、羽叶和皱叶3种类型,其中圆叶和羽叶类型的亲缘关系更近,与皱叶类型的亲缘关系较远;STRUCTURE分析还可以将双亲为不同类型的杂交种材料进行区分;聚类热图分析可以将标记分型结果形象的展示出来。本研究为进一步建立观赏羽衣甘蓝分子指纹图谱,明确种质资源的遗传背景,建立观赏羽衣甘蓝分子标记辅助选择育种体系,培育具有自主知识产权的新品种奠定基础。     

Coordinated regulation of anthocyanin biosynthesis through photorespiration and temperature in peach (Prunus persica f. atropurpurea)

The usual red color of young leaves of peach (Prunus persica f. atropurpurea) is due to the accumulation of anthocyanin. Real-time PCR analysis revealed a strong correlation between the expression levels of anthocyanin biosynthetic genes and anthocyanin content in leaves at different developmental stages. The expression profiles of both anthocyanin biosynthetic genes and photorespiratory genes showed significant changes in leaves held in the dark or exposed to heat stress, compared with controls. The expression of anthocyanin biosynthetic genes dramatically decreased in peach red leaves following dark or heat treatments, resulting in a significant decrease of anthocyanin accumulation. However, the photorespiration-related genes GDCH and GOX exhibited increased expression in peach leaves after dark or heat treatment. Moreover, the expression levels of GDCH and GOX in the Arabidopsis chi/f3′h mutant that does not accumulate anthocyanins were higher than in the wild type. Overall, these results support the hypothesis that photorespiration-related genes might be involved in the regulation of anthocyanin biosynthesis. This finding provides a new insight into our understanding of the mechanism underlying the control of anthocyanin biosynthesis in plants.     

羽衣甘蓝种子主要品质性状的表现及其相关性

随机挑选148份羽衣甘蓝种质资源和高世代材料,分析了成熟种子的含油量、蛋白质、硫苷和7种主要脂肪酸成分的表现特征及其相关性。结果表明:羽衣甘蓝成熟种子平均含油量为29.48%,平均蛋白质含量为45.13%,含油量和蛋白质总量为74.61%。硫苷含量的变幅最大,变异系数为31.72%。7种主要脂肪酸成分中,油酸和芥酸的含量较高,其次为亚油酸,棕榈酸和硬脂酸的含量较低。除硫苷含量和硬脂酸含量外,其余9个性状的表现均呈单峰正态分布。相关性分析表明,大多数性状间都具有显著或极显著的相关性,这与对甘蓝型、白菜型和芥菜型3种类型油菜的研究结果相一致。在羽衣甘蓝中存在一些优异的种质资源,通过筛选可以在油菜优质育种中加以利用。