Search

It is well described that viral infections stimulate the emission of plant volatiles able to recruit viral vectors thereby promoting virus spread. In contrast, much less is known on the effects that emitted volatiles may have on the metabolism of healthy neighboring plants, which are potential targets for new infections through vector transmission. Watermelon mosaic virus (WMV) (genus Potyvirus, family Potyviridae) is an aphid-transmitted virus endemic in cucurbit crops worldwide. We have compared gene expression profiles of WMV-infected melon plants with those of healthy or healthy-but-cohabited-with-infected plants. Pathogenesis-related (PR) and small heat shock protein encoding genes were deregulated in cohabited plants, and PR deregulation depended on the distance to the infected plant. The signaling was short distance in the experimental conditions used, and cohabiting had a moderate effect on the plant susceptibility to WMV. Static headspace experiments showed that benzaldehyde and g-butyrolactone were significantly over-emitted by WMV-infected plants. Altogether, our data suggest that perception of a volatile signal encoded by WMV-infected tissues triggers a response to prepare healthy tissues or/and healthy neighboring plants for the incoming infections.

[EN] Jasmonic acid (JA) regulates a wide spectrum of plant biological processes, from plant development to stress defense responses. The role of JA in plant response to salt stress is scarcely known, and even less known is the specific response in root, the main plant organ responsible for ionic uptake and transport to the shoot. Here we report the characterization of the first tomato (Solanum lycopersicum)mutant, named res (restored cell structure by salinity), that accumulates JA in roots prior to exposure to stress. The res tomato mutant presented remarkable growth inhibition and displayed important morphological alterations and cellular disorganization in roots and leaves under control conditions, while these alterations disappeared when the res mutant plants were grown under salt stress. Reciprocal grafting between res and wild type (WT) (tomato cv. Moneymaker) indicated that the main organ responsible for the development of alterations was the root. The JA-signaling pathway is activated in res roots prior to stress, with transcripts levels being even higher in control condition than in salinity. Future studies on this mutant will provide significant advances in the knowledge of JA role in root in salt-stress tolerance response, as well as in the energy trade-off between plant growth and response to stress. Guardar / Salir Siguiente >

[BACKGROUND] Variations in the contents of phytochemicals with biological activity in broccoli could originate as a result of genetic and environmental factors. An understanding of the effects of growth conditions on the bioactive compounds in broccoli is essential for improving its quality and nutritive value. Using salinity (40 mmol L-1 NaCl), and foliar sprayed compounds (methionine, tryptophan and chitosan) as different stress conditions, broccoli developed in soilless culture in the greenhouse was analysed for biologically active phytochemicals (glucosinolates, caffeoyl-quinic, ferulic and sinapic derivatives and vitamin C)., [RESULTS] The application of elicitors during head formation could be beneficial for the enrichment in phytochemicals in broccoli. Management practices for increasing a given phytochemical (e.g., glucoraphanin or glucobrassicin) may be related to a decreased level of natural antioxidants (hydroxycinnamic acids). Growing broccoli hydroponically in the greenhouse in winter (Mediterranean climate) needs the supporting treatment of abiotic stress during development (i.e., NaCl, elicitors)., [CONCLUSION] The use of hydroponic growth conditions for broccoli and the application of stress factors (elicitors) at head induction and during development may serve the purpose of enhancing its nutritional quality to deliver a health-promoting food. Copyright © 2008 Society of Chemical Industry

Broccoli (Brassica oleracea L. var. Itálica) plants are known to be moderately tolerant to salinity, although scarce information exists about the mechanisms of their tolerance. Therefore, in this work, we have explored more thoroughly the response of these plants to salinity, focusing the studies on the leaf cellular water transport mediated by aquaporins, sulphur assimilation in relation to the osmotic adjustment and glucosinolates accumulation under salt-stress conditions (40 and 80 mM NaCl). At 1 day and 15 days, the osmotic water permeability coefficient (Pf) was determined in protoplasts of broccoli leaves together with the leaf cell hydraulic conductivity (Lpc). Decreases in Pf and Lpc were observed with salinity and the reductions were stronger earlier in the treatments than with long-term salt treatments. The water channel-blocking effect of HgCl2 showed the involvement of the aquaporins in the process of adaptation to salinity. In order to determine the involvement of sulphur assimilation in the osmotic adjustment under salt stress, we determined the content of glucosinolates, total sulphur (S) and sulphate (SO42−) ions. Although there were no significant differences in the S content between the salt treatments, 15 days after 80 mM NaCl addition, a decrease in SO42− and an increase in glucosinolates were observed, indicating the involvement of these compounds in the water-relations response of broccoli to salt stress.

Numerous epidemiological studies indicate that Brassica vegetables in general and broccoli in particular protect humans against cancer; they are rich sources of glucosinolates and posses a high content on flavonoids, vitamins, and mineral nutrients. The contents of total intact glucosinolates, total phenolics, vitamin C, and minerals (potassium, sodium, calcium, magnesium, iron, manganese, zinc, and copper) in the edible portions of freshly harvested broccoli (florets), which was subjected to stir-frying treatments, were evaluated. In the present work, the stir-fry cooking experiments were carried out using different edible oils from plant origin (refined olive oil, extra virgin olive oil, sunflower oil, peanut oil, soyabean oil, and safflower oil) known and used worldwide. Results showed that during stir-frying, phenolics and vitamin C were more affected than glucosinolates and minerals. Stir-fry cooking with extra virgin olive, soybean, peanut, or safflower oil did not reduce the total glucosinolate content of the cooked broccoli compared with that of the uncooked sample. The vitamin C content of broccoli stir-fried with extra virgin olive or sunflower oil was similar to that of the uncooked sample, but greater than those samples stir-fried with other oils.

Broccoli (Brassica oleracea L. var. 'Italica') is a recognized health-promoting vegetable and shows a moderate sensitivity to salinity. As very little is known about the effect of salt stress on broccoli plants, the objective was to evaluate nitrogen (N), phosphorous (P), and sulfur (S) nutrition in plants grown under saline conditions. For this objective, the contents of nitrate, phosphate, and sulfate, and total nitrogen, phosphorus, and sulfur, as well as related metabolic enzymes, were determined for plants grown with 0, 20, 40, 60, 80, or 100 mM sodium chloride (NaCl) for two weeks. Nitrate, phosphate, and sulfate concentration in leaves and roots showed a maximum at 40-60 mM NaCl. Up to these salt levels, broccoli plants showed a normal development, but over these salt levels, broccoli plants showed a decrease of nitrate reductase and an increase of the acid phosphatase. From 60 to 100 mM NaCl, the nutritional disorders indicated that the threshold of resistance was exceeded.

Cooking as a domestic processing method has a great impact on food nutrients. Most Brassica (Brassicaceae, Cruciferae) vegetables are mainly consumed after being cooked, and cooking considerably affects their health-promoting compounds (specifically, glucosinolates, phenolic compunds, minerals, and vitamin C studied here). The microwave cooking process presents controversial results in the literature due to the different conditions that are employed (time, power, and added water). Therefore, the aim of this work was to study the influence of these conditions during microwave cooking on the human bioactive compounds of broccoli. The results show a general decrease in the levels of all the studied compounds except for mineral nutrients which were stable under all cooking conditions. Vitamin C showed the greatest losses mainly because of degradation and leaching, whereas losses for phenolic compounds and glucosinolates were mainly due to leaching into water. In general, the longest microwave cooking time and the higher volume of cooking water should be avoided to minimize losses of nutrients.

Broccoli (Brassica oleracea L. var. Italica) is a recognised health-promoting vegetable, which is moderately sensitive to salinity. In this study, the primary response of broccoli plants (cv. Marathon) to salinity has been characterised. For this, leaf water relations, nutrient composition, root hydraulic conductivity (L 0) and the effect of mercury (an aquaporin blocker) on L 0 were determined for plants grown with 0, 20, 40, 60, 80 or 100 mM NaCl for 2 weeks. During the 2 weeks of treatment, the plants showed a two-phase growth response to salinity. During the first phase (1 week), growth reduction was high, probably related to water stress as no osmotic adjustment occurred and reductions of L 0, the mercury effect and Gs were observed. After 2 weeks, the growth reduction could have resulted from internal injury caused by Na+ or Cl−, since osmotic adjustment was achieved and water relations plus the mercury effect were re-established to a high degree, indicating high aquaporin functionality. The fact that aquaporin functionality fits well with the overall water relations response is very relevant, since the two-phase adaptation to salinity may imply two types of aquaporin regulation.

People's diet offers a greater and more diverse group of plant bioactives than do drugs, and they often do not realise that many drugs are derived from the compounds originally discovered in plant foods. Numerous epidemiological studies indicate that Brassica vegetables in general, and broccoli in particular, protect humans against cancer since they are rich sources of glucosinolates as well as possessing a high content of flavonoids, vitamins and mineral nutrients. One unusual phytotherapic role of broccoli is for skin diseases—the juice of the leaves is used to treat warts. However, the main use of broccoli stems from its health-promoting properties. Some criteria have been proposed to evaluate the possibilities of developing new “functional foods” to reduce the risk of specific cancers; largely in broccoli, which is associated with cancer protection. Processing conditions, transport, domestic cooking, etc., affect the health-promoting properties of broccoli and these have been widely studied. This review makes an in-depth study of the chemical and biological characterization of the phytochemicals of broccoli and the effects on the bioactive composition of broccoli.