Clubroot resistance in canola and brassica vegetable cultivars in Ontario, Canada

Clubroot, caused by the obligate pathogen <i>Plasmodiophora brassicae</i> Woronin, has been present on brassica vegetables in Ontario for decades, but was only recently identified on canola (<i>Brassica napus</i> L.). Once <i>P. brassicae</i> is present in a field, eradication is difficult, but resistant cultivars can provide effective management. Pathotype 6 has been the predominant pathotype on vegetable crops for decades, but pathotype 2 is predominant in canola fields in Ontario. Field trials were used to assess the reaction of selected canola and vegetable Brassica cultivars to pathotype 2, and controlled environment studies were conducted to evaluate the reaction of canola the same cultivars to pathotypes 2 and 6. Four canola cultivars with putative clubroot resistance were compared to two cultivars that were expected to be susceptible and three susceptible control cultivars. Several brassica vegetables were assessed: cabbage, cauliflower, broccoli, napa cabbage, rutabaga, and Shanghai pak choi (a susceptible control). The canola cultivars marketed as resistant were highly resistant in both the field and growth room trials. The canola cultivars not marketed as resistant were susceptible to pathotype 2, as expected. All of the canola cultivars were resistant to pathotype 6. The vegetable cultivars marketed as resistant or tolerant were resistant to pathotype 6 and most were resistant to pathotype 2. A putative resistant cultivar of cabbage and one of broccoli were resistant to pathotype 6 but susceptible to pathotype 2. Clubroot consistently reduced fresh shoot weight in susceptible cultivars of canola and brassica vegetables relative to resistant cultivars.

Advances in Breeding in Vegetable Brassica rapa Crops

Brassica rapa includes oil and vegetable crops having a variety of forms, such as oilseeds, leafy vegetables and turnips. Leafy types, which are called turnip greens and turnip tops, are popular crops in NW Spain, and they represent an important part of the diet. However, their cultivation is limited in southern areas or in the Mediterranean basin, probably due to a lack of adaptation. Still, they could occupy a prominent place in the Mediterranean diet, which is based on a high consumption of fruits and vegetables. In this review, we summarize the studies on the agronomical and nutritional value of these crops when grown under Mediterranean climate conditions. Data reported here might be useful for a deeper understanding of these crops for both nutritional quality and bioaccessibility, and for selecting varieties adapted to the two abovementioned Mediterranean conditions, as well as for organic farming systems, thus contributing to the diversification of traditional Brassica vegetable production systems.

A Comparative Study on the Active Constituents, Antioxidant Capacity and Anti-Cancer Activity of Cruciferous Vegetable Residues

This study is pointed out to estimate the effectiveness of two solvents in the extraction and evaluating the active ingredients and their antioxidant activity as well as anti-cancer efficiency. Therefore, residues from four different Brassica vegetables viz. broccoli, Brussels sprout, cauliflower, and red cherry radish were extracted using two procedures methods: methanolic and water crude extracts. Methanol extracts showed the highest content of total phenolic (TP), total flavonoids (TF), and total tannins (TT) for broccoli and Brussels sprouts residues. Methanolic extract of broccoli and Brussels sprouts residues showed the highest DPPH· scavenging activity (IC50 = 15.39 and 18.64 µg/ml). The methanol and water extracts of Brussels sprout residues showed the highest chelating activity (IC50 = 11.77 and 5.94 µg/ml) and exhibited the highest reducing power (EC50 =14.38 and 20.18 µg/ml) with broccoli respectively. The HPLC analysis of phenolic compounds confirmed that the methanol extract of all the residues examined possessed high amounts of catchine, rutin, cumaric, benzoic, and luteolin. The methanol extract at 100 µg/ml of Brussels sprouts residues displayed a rise cytotoxic effect on HePG2 (80.40%), MCF7 (75.49%) and HCT116 (22.74%) followed by broccoli and red cherry radish, respectively. This result confirmed that Brussels sprouts residue contain effective chemical compounds that can inhibit the proliferation of cancer cells. Therefore, these results proposed that those Brassica vegetable residues might be beneficial as a potent antioxidant and anticancer agents and strongly recommended as fixing in constituent's food applications and pharmaceutical industries.

Tumorous Stem Development of Brassica Juncea: A Complex Regulatory Network of Stem Formation and Identification of Key Genes in Glucosinolate Biosynthesis

Stem mustard is a stem variety of mustard, an important Brassica vegetable. The formation and development of the tumorous stem, which is the key organ for the direct yield and quality, is a complex biological process involving morphogenesis, material accumulation and gene regulation. In this study, we demonstrated through anatomical studies that stem swelling is mainly dependent on the increase in the number of cells and the volume of parenchyma cells in the cortex and pith. To further understand transcript and metabolic changes during stem swelling, we obtained 27,901 differentially expressed genes, of which 671 were specifically detected using transcriptome sequencing technology in all four stages of stem swelling. Functional annotation identified enrichment for genes involved in photosynthesis, energy metabolism, cell growth, sulfur metabolism and glucosinolate biosynthesis. Glucosinolates are a group of nitrogen- and sulfur-containing secondary metabolites, which largely exist in the Cruciferous vegetables. HPLC analysis of the contents and components of glucosinolates in four different stem development stages revealed eight glucosinolates, namely, three aliphatic glucosinolates (sinigrin, glucoalyssin and gluconapin), four indole glucosinolates (4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin and neoglucobrassicin) and one aromatic glucosinolate (gluconasturtiin). All these types of glucosinolates showed a significant downward trend during the stem swelling period. The content of aliphatic glucosinolates was the highest, with sinigrin being the main component. In addition, qPCR was used to validate the expression of nine genes involved in glucosinolate biosynthesis. Most of these genes were down-regulated during stem swelling in qPCR, which is consistent with transcriptome data. These data provide a basic resource for further molecular and genetic research on Brassica juncea.