Brassica Rapa Cv Research Articles

First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Australia.

In 1978 and 1979, Pseudomonas syringae pv. maculicola strains DAR 33362, DAR 33363, and DAR 33406 were isolated from diseased Brassica hirta, B. nigra, and B. napus var. napus, respectively, in Wagga Wagga and Armatree, NSW, Australia (2). Peters et al. (2) demonstrated that these strains were similar to P. syringae pv. maculicola ICMP 4326 (CFBP 1637), which was recently transferred to Pseudomonas cannabina pv. alisalensis (1). We evaluated these Australian strains to determine if they might also be P. cannabina pv. alisalensis. Amplification of DNA using the BOXA1R primer and PCR resulted in identical DNA fragment banding patterns for Australian strains DAR 33362 and DAR 33363 and P. cannabina pv. alisalensis ICMP 4326 and CFBP 6875. The third Australian strain, DAR 33406, was 90% similar to P. cannabina pv. alisalensis; in contrast, it was only 77% similar to P. syringae pv. maculicola. All strains of P. cannabina pv. alisalensis, including the pathotype strain (CFBP 6866) and all three Australian strains, were lysed by bacteriophage PBS1, which is specific for P. cannabina pv. alisalensis strains (1). To complete Koch's postulates, pathogenicity was evaluated on B. hirta, B. nigra, and B. napus var. napus. In two independent experiments, two plants of each species were inoculated with each Australian strain or a phosphate buffer control treatment. In separate experiments, pathogenicity was evaluated on the differential hosts radish (Raphanus sativus cv. Comet) and broccoli raab (Brassica rapa cv. Sorrento), and plants inoculated with the pathotypes of P. cannabina pv. alisalensis and P. syringae pv. maculicola served as additional control treatments. Inoculum was prepared by growing the bacteria on nutrient agar for 48 h (27°C), suspending the bacteria in 0.01 M phosphate buffer (pH 7.0), and adjusting each suspension to 0.6 OD at 600 nm (approximately 108 CFU/ml). Treatments were applied by spraying until runoff. DAR 33362, DAR 33363, and DAR 33406 caused typical bacterial blight symptoms on B. hirta, B. nigra, and B. napus var. napus. Infected leaves became yellow, followed by the development of small (<2 mm in diameter), angular, water-soaked, and eventually, shot-holed spots. Bacteria isolated from symptomatic tissue following surface disinfestation of tissue with sodium hypochlorite (0.525%) had identical characteristics (rep-PCR DNA fragment banding patterns and phage sensitivity) to the strains used to inoculate the plants. Additionally, DAR 33362, DAR 33363, and DAR 33406, as well as P. cannabina pv. alisalensis, caused symptoms on radish and broccoli raab while P. syringae pv. maculicola and the buffer control did not. These data support the transfer of the Australian crucifer strains, originally identified as P. syringae pv. maculicola, to P. cannabina pv. alisalensis. To our knowledge, this is the first report of a bacterial disease of crucifers caused by P. cannabina pv. alisalensis in Australia. Differentiation of these pathogens will inform crop rotation strategies for disease management.

Identification and expression analysis of chitinase genes related to biotic stress resistance in Brassica

Brassica is a very important vegetable group because of its contribution to human nutrition and consequent economic benefits. However, biotic stress is a major concern for these crops and molecular biology techniques offer the most efficient of approaches to address this concern. Chitinase is an important biotic stress resistance-related gene. We identified three genes designated as Brassica chitinase like protein (BrCLP1), BrCLP2 and BrCLP3 from a full-length cDNA library of Brassica rapa cv. Osome. Sequence analysis of these genes confirmed that BrCLP1 was a class IV chitinase, and BrCLP2 and BrCLP3 were class VII chitinases. Also, these genes showed a high degree of homology with other biotic stress resistance-related plant chitinases. In expression analysis, organ-specific expression of all three genes was high except BrCLP1 in all the organs tested and BrCLP2 showed the highest expression compared to the other genes in flower buds. All these genes also showed expression during all developmental growth stages of Chinese cabbage. In addition, BrCLP1 was up-regulated with certain time of infection by Pectobacterium carotovorum subsp. carotovorum in Chinese cabbage plants during microarray expression analysis. On the other hand, expression of BrCLP2 and BrCLP3 were increased after 6h post inoculation (hpi) but decreased from 12hpi. All these data suggest that these three chitinase genes may be involved in plant resistance against biotic stresses.

Differential morphological and physiological responses of two oilseed Brassica species to a new herbicide ZJ0273 used in rapeseed fields

Weeds are considered as a major threat to the production of oilseed Brassica crops. The use of herbicides that are safe for crops and effective in controlling weeds is crucial for the agronomists and farmers. Propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate (ZJ0273), a derivative of 2-pyrimidinyloxy- N-aryl benzoate, is a new herbicide used in the rapeseed field. To evaluate the tolerance of Brassica species against this new herbicide, two cultivars of rapeseed Brassica napus cv. ZS 758 and Brassica rapa cv. Xiaoyoucai were tested by a foliar spray of ZJ0273 at the rate of 100, 500 and 1000 mg/L and a currently used ALS (acetolactate synthase)-inhibiting herbicide bispyribac-sodium (BS) at the rate of 100 mg/L. The results showed that both the cultivars of Brassica were less affected by ZJ0273 as compared to BS. Increasing level of ZJ0273 herbicide from 100 to 1000 mg/L increased the stress for the plants of both the cultivars as indicated by enhanced accumulation of malondialdehyde content. The activities of ALS and antioxidant enzymes (superoxide dismutase and peroxidase), soluble protein and sugar contents, photosynthetic system (SPAD value, photosynthetic rate and chlorophyll fluorescence) as well as the agronomic characters also declined consistently with each successive increase in ZJ0273 concentration. In general, the plants treated with 100 mg/L ZJ0273 recovered from the herbicide stress after 28 days. B. napus showed more tolerance than B. rapa to the new herbicide. Nevertheless, BS application at 100 mg/L did not allow the plants of both the cultivars to recover from the herbicidal stress.

Mapping of a novel locus regulating anthocyanin pigmentation in Brassica rapa

We crossed a doubled haploid line of the turnip Brassica rapa cv. ‘Iyo-hikabu’, which is pigmented with anthocyanin, with a Chinese cabbage inbred line, ‘Y54’, which lacks anthocyanin pigmentation. The presence and absence of anthocyanin pigmentation was segregated 79: 27 in the F2 population, suggesting monogenic control. A bulked segregant analysis was conducted with random amplified polymorphic DNA (RAPD) markers. A total of 480 primers were used to screen a pair of bulked DNA samples of the F2 plants. We found five RAPD markers closely linked to the pigmentation locus. A partial linkage map around the pigmentation locus was constructed with four RAPD markers, two simple sequence repeat (SSR) markers, and one cleaved amplified polymorphic sequence (CAPS) marker. A 0.84-kb fragment amplified by a random primer, OPU10, was cloned, sequenced, and then converted into a CAPS marker (OPU10C). This CAPS marker was mapped at a distance of 4 cM from the pigmentation locus in the partial linkage map and was also mapped in linkage group R07 of the previously reported reference map of B. rapa. This locus is independent of the previously reported anthocyanin-regulating anl locus mapped in R09. We named the locus Anp. The locus will be useful in plant breeding and genome characterization in B. rapa.

An Evidence to Use Cotes/a plutellae (Kurdjumov) (Hymenoptera: Braconidae) as a Field Control Agent against Diamondback Moth, Plutella xylostella L (Lepidoptera: Plutellidae)

The parasitic effectiveness of Cotesia plutellae Kurdjumov for the control of diamondback moth (DBM), Plutella xylostella L., was investigated without spraying pesticides in the greenhouse, and the damage degrees of Brassica rapa cv. Pakchoi grown in parasitoid-applied plot and control plot were evaluated. Among the 961 fourth instar DBM larvae collected in the common cabbage fields at Kwanshan region in Taiwan, 336 cocoons of C. plutellae were harvested from DBM larvae, which showed a parasitism rate of 35.0%. A total of 650 DBM adults and 600 C. plutellae adults were released according to the releasing scheme in the experiment plot. As a result, 56.7% of the DBM larvae were parasitized by C. plutellae adults 12 days before harvest, and the parasitism reached 80.8% at six days before harvest. At the harvest time, a population density of C. plutellae cocoons in the experiment plot was 2.2/plant, and that of normal DBM larvae was 0.5/plant. The density of DBM in the control plot was much higher than in the parasitoid-released plot by 7.7/plant. In the first survey, the density of DBM larvae on a Pakchoi plant was quite low, 0.3 ∼ 0.8 larvae. However, the DBM population increased dramatically after six days later, 5.7-10.1 larvae/plant. The population density of DBM larvae showed clear difference between the parasitoid-released plot and control plot. The parasitism increased to nearly two fold within a week after the release of DBM adults. As a further study, a combining use of two or more species para-sitoids could be considered to improve a parasitism against DBM in the fields.

(473) Influences of Fertilizer Source and Insecticide Application on Phenolic Compounds in Pac Choi (Brassica rapa L.)

Implications of dietary phenolic compounds for human health and disease prevention have been indicated by a body of literature. A greenhouse pot study was performed to investigate the impacts of fertilizer source and preventive insecticide application on phenolic compound levels in pac choi [Brassica rapa (L.) cv. Mei Qing]. A two-way randomized complete-block design with five replications was used in this experiment. Fertilizer source consisted of two levels: conventional fertilizer (pre-plant application of Osmocote slow-release fertilizer), and organic fertilizer (pre-plant application of vermicompost and fertigation with compost tea and fish emulsion). Insecticide application consisted of three levels: organic (pyrethrin) vs. conventional (permethrin), and a plain water control. At harvest, total phenolics and individual phenolic compounds in pac choi leaves (blades) were analyzed by Folin assay and HPLC, respectively. Head weight of pac choi was significantly higher under conventional fertilizer treatment, while it was not affected by insecticides. Total phenolic content of pac choi was significantly increased by organic fertilizer treatment. HPLC results indicated that organic fertilizer treatment resulted in significantly higher levels of individual phenolic compounds, including chlorogenic acid and ferulic acid. In contrast, preventive insecticide application showed little effect on the phenolics in pac choi. Correlation analysis excluded the influence of plant size (head weight) on phenolic content in pac choi. Differential N-forms, rates of nutrient release, and/or variable nutrient content in organic and conventional fertilizer treatments may contribute to elevated phenolic content in organically fertilized pac choi.

Host suitability of some crucifers for root-knot nematodes in southern Spain

Abstract Six crucifer species as potential cover crops, Ethiopian mustard (Brassica carinata line C-101), turnip (Brassica rapa cv. Norfolk), radish (Raphanus sativus), wild rocket (Eruca vesicaria), wild cabbage (Moricandia moricandioides) and white mustard (Sinapis alba), were tested for susceptibility to Meloidogyne arenaria race 2, M. incognita race 1 and M. javanica. Experiments were conducted under glasshouse conditions at 22-28°C for 2 months after inoculation of plants with eggs and second-stage juveniles. All crucifers were infected by Meloidogyne spp. The nematode and crucifer species significantly influenced the severity of root galling and nematode reproduction. Among the plants tested, turnip was the most suitable host for all three Meloidogyne spp. as indicated by severity of root galling and nematode reproduction. The least suitable hosts were wild rocket for M. arenaria, radish for M. incognita and white mustard for M. javanica. The reproduction fitness of M. javanica was greater than that of M. arenaria race 2 and M. incognita race 1 on all plants.

Safety Assessment of Recombinant Green Fluorescent Protein Orally Administered to Weaned Rats

Several proposed biotechnological applications of green fluorescent protein (GFP) are likely to result in its introduction into the food supply of domestic animals and humans. We fed pure GFP and diets containing transgenic canola expressing GFP to young male rats for 26 d to evaluate the potential toxicity and allergenicity of GFP. Animals (n = 8 per group) were fed either AIN-93G (control), control diet plus 1.0 mg of purified GFP daily, modified control diet with 200 g/kg canola (Brassica rapa cv Westar), or control diet with 200 g/kg transgenic canola containing one of two levels of GFP. Ingestion of GFP did not affect growth, food intake, relative weight of intestine or other organs, or activities of hepatic enzymes in serum. Comparison of the amino acid sequence of GFP to known food allergens revealed that the greatest number of consecutive amino acid matches between GFP and any food allergen was four, suggesting the absence of common allergen epitopes. Moreover, GFP was rapidly degraded during simulated gastric digestion. These data indicate that GFP is a low allergenicity risk and provide preliminary indications that GFP is not likely to represent a health risk.

Dehydration and dehiscence in siliques of Brassica napus and Brassica rapa

Silique dehiscence (shattering) in Brassica species has a pronounced effect on agricultural yields. Shattering is highly variable and difficult to quantify, and consequently there have been few studies that explore interspecies variation in shattering in relation to silique development. In this paper, a rapid and simple method has been developed for quantifying silique dehiscence. The variable-speed pod splitter is a mechanical device that provides a measure of the impact force required to trigger shattering of individual siliques. We have used the variable-speed pod splitter to show that siliques of Brassica rapa cv. Parkland were significantly more resistant to shattering than those of Brassica napus cv. Quantum. Siliques of both species became prone to shattering following a short period of rapid dehydration during which their water content fell from approx. 70% to approx. 10% (based on weight). Magnetic resonance imaging of individual siliques of varying ages revealed that water loss occurred from the inside the pericarp in B. napus cv. Quantum and from the outside of the pericarp in B. rapa cv. Parkland. We suggest a mechanism for how this difference in the pattern of water loss contributed to the difference in susceptibility to shatter between the two cultivars.Key words: shattering, magnetic resonance imaging, canola, valve.

The last step of the ethylene biosynthesis pathway in turnip tops (Brassica rapa) seeds: Alterations related to development and germination and its inhibition during desiccation.

The involvement of ethylene in zygotic embryogenesis is a little known aspect of the growth and development in higher plants. In the present work, we study the alterations of the last step of the ethylene biosynthesis pathway during the formation period of turnip tops (Brassica rapa cv. Rapa) seeds and its repercussions in the germination process and post-germinative growth. For this, we chose 11 different phases of silique development, the first being the recently fertilized pistil and the last being the silique just prior to its dehiscence (ca. 2 months post-anthesis). In the 11 phases, ethylene production was detected in both whole silique (with or without seeds) and in the seeds enclosed by the silique wall. The levels of ACC, ACO and ethylene production proved high in seeds belonging to: (1) the pod in the very early phases, when the seeds were growing but without photosynthetic competence; (2) the silique at maximum growth, in which the seeds will initiate desiccation and loss of photosynthetic activity. During the phases prior to dehiscence, there was a marked inhibition in the last step of the ethylene biosynthesis pathway. In viable dry seeds, no ACO activity was detected and the ACC levels were 4-fold lower than at the onset of the silique senescence. Germination brings about a net synthesis of ACC with respect of the stores dry seed. This fact, together with other results presented in this work, point towards, as in other seeds, a dependence of ethylene synthesis for radicle emergence. The possible role played by the silique wall in the control of ethylene biosynthesis during zygotic embryogenesis, as well as the participation of ethylene as a hormonal signal in the triggering of seed desiccation in Brassica rapa cv. Rapa, are discussed in depth.

The Effect of MSW Compost on Metal Uptake and Yield Of Wheat, Barley and Canola in Less Productive Farming Soils of Alberta

Experiments were started in May 1998 at two sites to measure various crop responses to a mixed municipal solid waste-biosolids cocompost (named Nutri Plus) and examine the fate of certain metals associated with Nutri Plus compost. There were six treatments: Check, 50, 100, and 200 T compost/ha, NPKS (75 kg nitrogen (N) /ha, 20 kg phosphorus (P)/ha, 45 kg potassium (K) and 18 kg sulphur (S)/ha), PK (20 kg P, 45 kg K/ha), and three crops: canola (Brassica rapa cv. ‘Hysyn 110’), wheat (Triticum aestivum L. cv. ‘Roblin’) and barley (Hordeum vulgare L. cv. ‘Lacombe’). Each treatment was replicated four times and was in a complete randomized block design. In the compost treatments, 20 kg P and 45 kg K were applied due to low concentration of these two nutrients in the compost. Soil and plant samples were analyzed for nutrient content such as N, P and K. In addition, plant samples and soil samples after the compost application were also analyzed for elemental content of As, B, Cr, Co, Cu, Zn Se, Mo, Cd, Hg and Pb. The research results show that the compost slightly increased heavy metal concentrations in the soil but did not cause any phytoxicity to crops. Yield from 100 and 200 T/ha application was higher with the compost than with NPKS treatment. However, the yield of the 50 T/ha application was similar to that of NPKS treatment. Comparing the two sites, the compost apparently was more beneficial at Site 1 than at Site 2 in the year of application. This is likely due to the lower indigenous soil fertility and poor soil physical properties at Site 1. The N content in cereal grains was similar among the compost treatments but lower than the Check and NPKS treatments due to the diluting effect of higher yield. The oil content in canola seed was similar among all treatments. The results suggest that Nutri Plus compost applications generated positive yield responses in all three crops. Crop yield increased as the application rate increased. Heavy metal loading was not an immediate problem with the compost application, although it will limit total compost application over time to the same soil

RESPONSIVENESS OF DELIA SPP. (DIPTERA: ANTHOMYIIDAE) TO COLORED STICKY TRAPS IN FLOWERING AND ROSETTE STAGE CANOLA

AbstractThe responses of adult cabbage maggot [Delia radicum (L.)], turnip maggot [D. floralis (Fallén)], radish maggot [D. planipalpis (Stein)], and seedcorn maggot [D. platura (Meigen)] to sticky traps painted blue, yellow, green, non-UV-reflecting white, or UV-reflecting white, were determined in a field of canola (Brassica rapa cv. Tobin) at the rosette and flowering stages. Traps colored white, blue, or yellow generally caught higher numbers of D. radicum, D. floralis, and D. planipalpis than did traps colored green or UV-reflecting white. Depending on the crop developmental stage and its background color, response to color sometimes differed both within and between the sexes. This was most pronounced for D. floralis, for which blue and white traps were preferred by males at the rosette stage but not die flowering stage, and for which white, but not blue, traps were preferred by females at the rosette siage. White and blue, but not yellow, were the colors preferred by male and female D. platura in our study, with UV-reflecting white also being preferred by males during the flowering stage. It was observed dial catches on white and yellow traps were often significantly different and [hat white versus yellow preferences could be reversed within or between males and females of certain species during the rosette or flowering stages. The data suggest dial the concurrent use of white and yellow sticky traps should be considered when conducting relative abundance surveys of Delia spp. in canola fields.

Enhancement of shoot regeneration from cotyledon explants of Brassica rapa ssp oleifera through pretreatment with auxin and cytokinin and use of ethylene inhibitors

The presence of benzyladenine or naphthaleneacetic acid in seed germination medium markedly enhanced subsequent shoot regeneration from the base of the excised cotyledon explants of Brassica rapa cv. Horizon. Cotyledon explants from younger seedlings (3 or 4-day old) produced more shoots than those from older seedlings. Addition of the ethylene inhibitor aminoethoxyvinylglycine (1.0 μM) to the regeneration medium improved shoot regeneration three fold.

The expression, localization, and effect of a human interferon in plants

The ORF II of Cauliflower mosaic virus (CaMV) DNA was replaced with the human IFN αD coding sequence to yield a stable CaMV strain designated Ca524 i. Inoculation of turnip ( Brassica rapa cv “Just Right”) with strain Ca524 i DNA excised from plasmid pCa524 i resulted in the production of biologically active IFN αD in infected plants. This was also true for its mutant (Ca562 i) where one of the CYS codons was deleted. IFN αD produced in planta did not hamper superinfection with a single-stranded (+) sense RNA plant virus, turnip yellow mosaic virus (TYMV). Antibody gold labeling techniques and electron microscopy of infected plants showed that IFN was localized in the CaMV inclusion bodies.

Effects of applied sulfur on glucosinolate and oil concentrations in the seeds of rape (Brassica napus L.) and turnip rape (Brassica rapa L. var. silvestris (Lam.) Briggs)

The effect of sulfur availability on glucosinolate concentration in seed meal of glasshouse grown Brassica nupus cv. Wesbrook and Brassica rapa cv. Runyip was studied. In addition, field trials were evaluated to determine the degree of variability of glucosinolate concentrations in the seed and of sulfur in the plants of rapeseed grown at a number of sites throughout New South Wales.Glucosinolate concentration in seeds grown in the glasshouse increased (P &lt; 0.01) in both cultivars with increasing sulfur application, ranging from an average of 5 8mol at 4 8g g-1 to 55 8mol at 100 8g g-1 sulfur. Bunyip containcd significantly higher concentrations (Pt0-01) than Wesbrook. Increased rates of sulfur application resulted in increased (P &lt; 0.01) seed oil concentrations (from 28.7 to 37.6%), yield (3.1-27.1 g) and 1000-grain weights (2.1-2.9 g). Field trials showed site (P &lt; 0.01) and cultivar (P&lt;0.01) variation in glucosinolate levels. However, sulfur did not appear to be an independently limiting factor in field-grown plants.

Effects of water stress on glucosinolate and oil concentrations in the seeds of rape (Brassica napus L.) and turnip rape (Brassica rapa L. var. silvestris [Lam.] Briggs)

Growing-season conditions influence the concentration of glucosinolates in the meal of rapeseed, but the reasons for this are unknown. We studied the effect of water stress on glucosinolate concentration in the seed meal of Brassica napus cv. Wesbrook and Brassica rapa cv. Bunyip. Plants were either wellwatered or given a reduced supply of water which was managed to produce a desired degree of plant water stress either throughout growth or only after flowering. Glucosinolate concentration in seeds increased (P&lt;0.01) in both cultivars from an average 18.2 �mol/g in unstressed plants to 35.0 �mol/g under the influence of water stress. There was no significant difference between the 2 stressed treatments. Water stress also decreased (P &lt; 0.0 1) seed oil concentrations (from 36.9 to 31.4%), yields (from 5.3 to 0.9 g/plant) and 1000-grain weights (from 4.1 to 3.0 g).

Detection of T-DNA transfer to plant cells by A. tumefaciens virulence mutants using agroinfection

To test whether virulence mutants of Agrobacterium tumefaciens are capable of promoting T-DNA transfer into plant cells, a tandem array of Cauliflower Mosaic Virus (CaMV) DNA was cloned between T-region border sequences on a wide host range plasmid and introduced into various virulence mutants. The resulting strains were used to infect Brassica rapa cv. Just Right. This assay, recently referred to as agroinfection, is based on the appearance of viral symptoms following transfer of T-DNA to plant cells, and is shown to be at least 100 times more sensitive in detecting T-DNA transfer than tumour formation. Mutants in the loci vir A, B and G, which were avirulent on turnip, failed to induce virus symptoms. Of the two vir D mutants tested, neither induced tumours, but one was capable of inducing virus symptoms. Mutants in vir E, C and F, which induced respectively no, small and normal tumours on turnip, all induced virus symptoms.