Molybdenum in the Biosphere
Molybdenum in plants
Cucumber molybdenum and iron
Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants
Molybdenum (Mo) and iron (Fe) are essential micronutrients required for crucial enzyme activities in plant metabolism. Here we investigated the existence of a mutual control of Mo and Fe homeostasis in cucumber (Cucumis sativus).
Plants were grown under single or combined Mo and Fe starvation. Physiological parameters were measured, the ionomes of tissues and the ionomes and proteomes of root mitochondria were profiled, and the activities of molybdo-enzymes and the synthesis of molybdenum cofactor (Moco) were evaluated.
Fe and Mo were found to affect each other's total uptake and distribution within tissues and at the mitochondrial level, with Fe nutritional status dominating over Mo homeostasis and affecting Mo availability for molybdo-enzymes in the form of Moco.
Fe starvation triggered Moco biosynthesis and affected the molybdo-enzymes, with its main impact on nitrate reductase and xanthine dehydrogenase, both being involved in nitrogen assimilation and mobilization, and on the mitochondrial amidoxime reducing component.
These results, together with the identification of > 100 proteins differentially expressed in root mitochondria, highlight the central role of mitochondria in the coordination of Fe and Mo homeostasis and allow us to propose the first model of the molecular interactions connecting Mo and Fe homeostasis.
Vigani, G., Di Silvestre, D., Agresta, A. M., Donnini, S., Mauri, P., Gehl, C., Bittner, F., and Murgia, I.,Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants, The New phytologist, 2017, 213, 1222-1241
Effects of tungsten on uptake, transport and subcellular distribution of molybdenum in oilseed rape at two different molybdenum levels
Due to the similarities of molybdenum (Mo) with tungsten (W) in the physical structure and chemical properties, studies involving the two elements have mainly examined their competitive relationships. The objectives of this study were to assess the effects of equimolar W on Mo accumulation, transport and subcellular distribution in oilseed rape at two Mo levels with four treatments: Mo1 (1mumol/L Mo, Low Mo), Mo1+W1 (1mumol/L Mo+1mumol/LW, Low Mo with Low W), Mo200 (200mumol/L Mo, High Mo) and Mo200+W200 (200mumol/L Mo+200mumol/L Mo, High Mo with high W). The fresh weight and root growth were inhibited by equimolar W at both low and high Mo levels. The Mo concentration and accumulation in root was increased by equimolar W at the low Mo level, but that in the root and shoot was decreased at the high Mo level. Additionally, equimolar W increased the Mo concentrations of xylem and phloem sap at low Mo level, but decreased that of xylem and increased that of phloem sap at the high Mo level. Furthermore, equimolar W decreased the expression of BnMOT1 in roots and leaves at the low Mo level, and only decreased its expression in leaves at the high Mo level. The expression of BnMOT2 was also decreased in root for equimolar W compared with the low Mo level, but increased compared with high Mo level. Moreover, equimolar W increased the proportion of Mo in cell wall fraction in root and that of soluble fraction in leaves when compared with the low Mo level. The results suggest that cell wall and soluble fractions might be responsible for the adaptation of oilseed rape to W stress.
Qin, S., Sun, X., Hu, C., Tan, Q., Zhao, X., and Xu, S.,Effects of tungsten on uptake, transport and subcellular distribution of molybdenum in oilseed rape at two different molybdenum levels, Plant science : an international journal of experimental plant biology, 2017, 256, 87-93.
Molybdenum Stress Modulates Enzymes Responsive to Oxidative Stress and Affects Seeds Viability and Vigor in Chickpea
The importance of molybdenum (Mo) for plant growth is disproportionate with respect to the absolute amounts required by most plants. Chickpea (Cicer arietinum L.) cv. K-75 plants were raised in refined sand in glasshouse at graded levels from 0.002 to 1 mu M for 100days. Mo deficiency symptoms appeared as interveinal chlorosis of middle and old leaves. Compared with the control (0.2 mu M Mo), dry matter, yield and seed protein decreased at low and excess Mo. The concentration of Mo in leaves and seed as well as the activity of nitrate reductase (NR) increased with an increase in Mo supply. The activities of antioxidative enzymes stimulate at both low and excess Mo supply. Low and excess Mo decreased the lipid peroxidation status in chickpea leaves, suggesting its antiperoxidative nature. The values of deficiency, threshold of deficiency and threshold of toxicity of Mo were, respectively, 0.38, 1.2 and 15 mu g g(-1) in leaves of chickpea.
Gopal, R., and Shukla, A. K.,Molybdenum Stress Modulates Enzymes Responsive to Oxidative Stress and Affects Seeds Viability and Vigor in Chickpea, Communications in Soil Science and Plant Analysis, 2017, 48, 43-50.
Metals Content in HERBAL SUPPLEMENTS
Obesity has become an international epidemic. To evaluate the level of metals in extracts of plants prescribed as weight loss supplements, different brands containing Camellia sinensis (L.) Kuntze, Citrus aurantium L., Cordia ecalyculata Vell, Ilex paraguariensis A. St.-Hil, Cissus quadrangularis L., Senna alexandrina Mill were purchased in local market, hot acid digested, and analyzed while metal content by inductively coupled plasma optical emission spectrometry, ICP-OES. Quality assurance and quality control tests were carried out in order to monitor and control the reliability of the analytical method. For each metal evaluated, a calibration curve was prepared with certified reference material. The recovery test was performed for each batch of samples. Analyses were performed in triplicate. Quantification of aluminum, barium, cadmium, cobalt, chromium, copper, iron, lithium, manganese, molybdenum, nickel, lead, vanadium, and zinc were determined. The metals most frequently detected were manganese (15.3-329,60 mg kg-1) aluminum (11.76-342.4 mg kg-1), and iron (11.14-73.01 mg kg-1) with higher levels in products containing C. sinensis China origin, I. paraguariensis Brazilian origin, C. quadrangularis, and C. aurantium China origin, respectively. To ensure safety consumption, an adequacy of the certification of Brazilian suppliers for herbal weight loss products is indispensable.
Barrella, M. V., Heringer, O. A., Cardoso, P. M., Pimentel, E. F., Scherer, R., Lenz, D., and Endringer, D. C.,Metals Content in Herbal Supplements, Biological trace element research, 2017, 175, 488-494.
Molybdenum and iron mutually impact their homeostasis in CUCUMBER (Cucumis sativus) plants
Molybdenum (Mo) and iron (Fe) are essential micronutrients required for crucial enzyme activities in plant metabolism. Here we investigated the existence of a mutual control of Mo and Fe homeostasis in cucumber (Cucumis sativus). Plants were grown under single or combined Mo and Fe starvation. Physiological parameters were measured, the ionomes of tissues and the ionomes and proteomes of root mitochondria were profiled, and the activities of molybdo-enzymes and the synthesis of molybdenum cofactor (Moco) were evaluated. Fe and Mo were found to affect each other's total uptake and distribution within tissues and at the mitochondrial level, with Fe nutritional status dominating over Mo homeostasis and affecting Mo availability for molybdo-enzymes in the form of Moco. Fe starvation triggered Moco biosynthesis and affected the molybdo-enzymes, with its main impact on nitrate reductase and xanthine dehydrogenase, both being involved in nitrogen assimilation and mobilization, and on the mitochondrial amidoxime reducing component. These results, together with the identification of > 100 proteins differentially expressed in root mitochondria, highlight the central role of mitochondria in the coordination of Fe and Mo homeostasis and allow us to propose the first model of the molecular interactions connecting Mo and Fe homeostasis.
Vigani, G., Di Silvestre, D., Agresta, A. M., Donnini, S., Mauri, P., Gehl, C., Bittner, F., and Murgia, I.,Molybdenum and iron mutually impact their homeostasis in cucumber (Cucumis sativus) plants, The New phytologist, 2017, 213, 1222-1241.
Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of ALFALFA
Rhizobia-legume symbiosis is the most well researched biological nitrogen fixation system. Coating legume seeds with rhizobia is now a recognized practical measure for improving the production of legume corp. However, the efficacy of some commercial rhizobia inoculants cannot be guaranteed in China due to the low rate of live rhizobia in these products. A greenhouse experiment was conducted to assess the effects of different rhizobial inoculant formulations on alfalfa productivity and nitrogen fixation. Two rhizobia strains, (ACCC17631 and ACCC17676), that are effective partners with alfalfa variety Zhongmu No. 1 were assessed with different concentrations of ammonium molybdate in seed-coat formulations with two different coating adhesives. Our study showed that the growth, nodulation, and nitrogen fixation ability of the plants inoculated with the ACCC17631 rhizobial strain were greatest when the ammonium molybdate application was0.2% of the formulation. An ammonium molybdate concentration of 0.1% was most beneficial to the growth of the plants inoculated with the ACCC17676 rhizobial strain. The sodium carboxymethyl cellulose and sodium alginate, used as coating adhesives, did not have a significant effect on alfalfa biomass and nitrogen fixation. However, the addition of skimmed milk to the adhesive improved nitrogenase activity. These results demonstrate that a new rhizobial seed-coat formulation benefitted alfalfa nodulation and yield.
Zhou, J., Deng, B., Zhang, Y., Cobb, A. B., and Zhang, Z.,Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of Alfalfa, PLoS One, 2017, 12, e0170179.
Nutrient deficiencies in Brassica napus modify the ionomic composition of plant tissues: a focus on cross-talk between molybdenum and other nutrients
The composition of the ionome is closely linked to a plant's nutritional status. Under certain deficiencies, cross-talk induces unavoidable accumulation of some nutrients, which upsets the balance and modifies the ionomic composition of plant tissues. Rapeseed plants (Brassica napus L.) grown under controlled conditions were subject to individual nutrient deficiencies (N, K, P, Ca, S, Mg, Fe, Cu, Zn, Mn, Mo, or B) and analyzed by inductively high-resolution coupled plasma mass spectrometry to determine the impact of deprivation on the plant ionome. Eighteen situations of increased uptake under mineral nutrient deficiency were identified, some of which have already been described (K and Na, S and Mo, Fe, Zn and Cu). Additionally, as Mo uptake was strongly increased under S, Fe, Cu, Zn, Mn, or B deprivation, the mechanisms underlying the accumulation of Mo in these deficient plants were investigated. The results suggest that it could be the consequence of multiple metabolic disturbances, namely: (i) a direct disturbance of Mo metabolism leading to an up-regulation of Mo transporters such as MOT1, as found under Zn or Cu deficiency, which are nutrients required for synthesis of the Mo cofactor; and (ii) a disturbance of S metabolism leading to an up-regulation of root SO4 2- transporters, causing an indirect increase in the uptake of Mo in S, Fe, Mn, and B deficient plants.
Maillard, A., Etienne, P., Diquelou, S., Trouverie, J., Billard, V., Yvin, J. C., and Ourry, A.,Nutrient deficiencies in Brassica napus modify the ionomic composition of plant tissues: a focus on cross-talk between molybdenum and other nutrients, Journal of experimental botany, 2016.
Molybdenum FERTILIZATION effect on nodulation, yield and quality of green gram grown in the soils of southern agro-climatic zone of Tamil Nadu, India
A pot experiment was conducted under natural condition with green gram (cultivar CO 6) using twenty bulk soil samples collected from major soil series of Southern agro climatic zone of Tamil Nadu.
Application of graded levels of molybdenum (Mo) at 0, 0.025, 0.050, 0.075 and 0.1 mg kg-1 positively influenced the yield, nodulation characteristics and nutritional quality of green gram crop. The highest number of nodules, dry weight nodules per plant, nodule N concentration and chlorophyll content of leaves were registered at 0.075 mg kg-1 level.
Similarly, the seed and stover yield, uptake of N, P, K and Mo by green gram were also increased with molybdenum application up to 0.075 mg kg-1 level beyond which they declined.
However, the amount of protein in seed significantly increased with increasing levels of Mo up to 0.1 mg kg-1 level in different soils.
Hence, Mo application not only increased the yield but also enhanced the nutritional quality of green gram through effective nodulation.
Velmurugan, R., and Mahendran, P. P.,Molybdenum fertilization effect on nodulation, yield and quality of green gram grown in the soils of southern agro-climatic zone of Tamil Nadu, India, Legume Research, 2015, 38, 798-803.
[Green gram, also known as the mung bean, is a small round bean similar in shape to the field pea. People in the U.S. primarily eat green gram as a sprout, and as a bean it cooks up fast and has a sweet flavor. With its high fiber and nutrient content, it offers a number of health benefits. www.livestrong.com.]
Molybdate effect of molybdenum on nodulation, plant yield and nitrogen uptake in hairy vetch (Vicia villosa Roth)
Hairy vetch (Vicia villosa Roth) is a leguminous cover crop that is generally used as a green manure to sustain soil health in arable land. Molybdenum (Mo) acts as a cofactor for the nitrogenase (NA) and nitrate reductase (NR) enzymes, which are important for nitrogen (N) fixation, nitrate reduction and N transport in plants. In this study, we applied various doses of Mo to soil to evaluate their efficacy on nodulation, nodule characteristics and biomass production of hairy vetch. Mo application increased the number and size of nodules and NA and NR enzyme activity in hairy vetch. This increase in enzyme activity increased N assimilation and led to higher biomass yield. Plants grown in soil that received 0.5mg Mo kg-1 showed optimal physical and biochemical properties in nodules, and these properties may explain the increased N fixation in hairy vetch. Higher Mo doses (1.0 mg kg-1) led to the deterioration of nodule structure and, hence, reduced enzymatic activity in plants. The 16S rRNA gene sequencing and cluster analysis showed that the bacterial isolates found in the nodules of hairy vetch roots belonged to the Rhizobiaceae family and shared high sequence similarity with Rhizobium leguminosarum and Agrobacterium tumefaciens. Application of 0.63mg Mo kg-1 to soil was the optimum dose to maximize the biomass yield of hairy vetch.
Alam, F., Kim, T. Y., Kim, S. Y., Alam, S. S., Pramanik, P., Kim, P. J., and Lee, Y. B.,Effect of molybdenum on nodulation, plant yield and nitrogen uptake in hairy vetch (Vicia villosa Roth), Soil Science and Plant Nutrition, 2015, 61, 664-675.
MOLYBDATE PLANTS SOYBEAN SEED COATING
In Japan, soybeans are generally cultivated in paddy fields which often have poor drainage. West of the Kanto region, the seeds are sown in the rainy season. Therefore, the seedling establishment is prone to damage by the rain after sowing. The generation of sulfide ions in flooded and reduced soil is thought to be one factor causing this flooding damage. Since molybdate ions suppress the generation of sulfide ions, the effect of coating soybean seeds with molybdenum compounds, on the seedling establishment under a flooded condition was examined. Soybean seeds were coated with several kinds of poorly-soluble molybdenum compounds at different concentrations. The coated seeds were sown in soil and then flooded for 3 d at 25 - 30 degrees C. Seedlings were not established from seeds not coated with molybdenum compounds. Seedling establishment was appreciably improved by coating the seeds with a molybdenum compound at the rate of 0.5 - 1 mol-Mo kg(-1) seed. Seedling establishment was especially improved by coating with molybdenum trioxide. Accordingly, coating the soybean seed with molybdenum compounds could mitigate the flooding damage occurring after sowing.
Hara, Y.,Improvement of Soybean Seedling Establishment under a Flooded Condition by Seed Coating with Molybdenum Compounds, Plant Production Science, 2015, 18, 161.
MOLYBDATE (?) PLANTS DRY BEAN MOLYBDENUM REQUIREMENTS NO LIMING
Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20mgkg(-1). In one experiment dolomitic lime was added at the rate of 2.5g per kg of soil before the application of Mo treatments and incubated 5weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20mgkg(-1). Maximum shoot dry weight was obtained with the addition of 17mgMokg(-1) in the experiment with Mo rates without lime and 9.69mgMokg(-1) in the experiment of Mo rates with lime application. Maximum seed yield was obtained with the application of 10.48mgMokg(-1) in the experiment that did not receive lime along with Mo treatments and 10.28mgMokg(-1) in the experiment that received lime along with Mo treatments. Similarly, the maximum number of pods per plant was obtained with the addition of 9.33mgMokg(-1) in the experiment that did not receive lime and 8.83mgMokg(-1) in the experiment that did receive lime. Maximum root length was obtained with the addition of 12.38Mokg(-1) in the experiment that did not receive lime and 9.75mgMokg(-1) in the experiment that received lime. Maximum root dry weight was obtained with the addition of 11.67mgMokg(-1) in the experiment that did not receive lime and 9.28mgMo in the experiment that received lime. Soil properties determined after harvest of dry bean plants were not influenced significantly with the addition of Mo in the Oxisol under investigation.
Fageria, N. K., Stone, L. F., and Santos, A. B.,Molybdenum Requirements of Dry Bean with and without Liming, Communications in Soil Science and Plant Analysis, 2015, 46, 965.
MOLYBDATE (?) PLANTS RED BASIL
Red basil (Ocimum basilicum L.) cv. Red Rubin was cultivated in model pot experiment in the soil amended by arsenic, cadmium and lead solutions in stepwise concentrations representing the soil concentration levels of former mining area in the vicinity of Pribram, Czech Republic. The element levels added to the soil reached up to 40 mg Cd, 100 mg As, and 2000 mg Pb per kg of soil. Moreover, essential macro-and microelements as well as cyanidine contents were investigated to assess their potential interactions with the risk elements. The extractable element portions in soils determined at the end of vegetation period differed according to the individual elements. Whereas the plant-available (extractable with 0.11M CH3COOH) content of Cd represented 70-100% of the added Cd, the mobile portion of Pb did not exceed 1%. The risk element content in plants reflected the increasing element contents in soil. The dominant element portions remained in plant roots indicating the limited translocation ability of risk elements to the aboveground biomass of this plant species. Although the risk element contents in amended plants significantly increased, no visible symptoms of phytotoxicity occurred. However, the effect of enhanced risk element contents on the essential element uptake was assessed. Considering inter-element relationships, elevated sulphur levels were seen in amended plants, indicating its possible role of phytochelatin synthesis in the plants. Moreover, the molybdenum contents in plant biomass dropped down with increasing risk element uptake by plants confirming As-Mo and Cd-Mo antagonism. The increasing content of cyanidine in the plant biomass confirmed possible role of anthocyanins in detoxification mechanism of risk element contaminated plants and suggested the importance of anthocyanin pigments for risk element tolerance of plants growing in contaminated areas.
Ruzickova, P., Szakova, J., Havlik, J., and Tlustos, P.,The effect of soil risk element contamination level on the element contents in Ocimum basilicum L, Archives of Environmental Protection, 2015, 41, 47.