Expression of a-Amylase in Phaseolus vulgaris and Vigna mungo Plants

Levels of starch and soluble sugar in pods of Phaseolus vulgarisand Vigna mungo plants were analyzed during the course of maturationof fruits. The results suggest that the immature pods of P.vulgaris function to some extent as temporary reservoirs ofcarbohydrates for growth of seeds. A less clear pattern of accumulationof starch was observed in pods of maturing fruits of Vigna mungo.Measurements of a-amylase activites in pods of maturing fruitsand immunoblotting with an antiserum against     

Ontogeny of Somatic Embryos of Vigna aconitifolia, Vigna mungo and Vigna radiata

Callus cultures were initiated from immature cotyledons of Vignaaconitifolia, V. mungo and V. radiata on MS medium supplementedwith NAA, picloram or 2, 4-D. On transfer to L-6 liquid mediumsupplemented with low concentrations of picloram, GA₃ and cytokinins,large number of somatic embryos differentiated from the callus.The cells destined to become somatic embryos divided to formspherical or filamentous proembryos. From the filamentous proembryo,the embryo proper developed either at single or multiple sites.Development of somatic embryos from multiple sites resultedin several embryos connected by a common suspensor at the radicleend. Continued divisions of the proembryos led to globular,heart shaped and dicotyledonary stages of somatic embryogenesis.The somatic embryos of V. mungo and V. aconitifolia differentiatedinto tiny plantlets at low frequency (1%) in liquid suspensioncultures supplemented with zeatin, picloram and GA₃. Vigna aconitifolia Jacq, Marechal, mothbean, Vigna mungo L. Hepper, urdbean, Vigna radiata L. Wilczk, mungbean, somatic embryo     

Measurement of nitrite reductase in leaf tissue of Vigna mungo

The enzyme nitrite reductase (EC 1.6.6.4) is generally assayed in terms of disappearance of nitrite from the assay medium. We describe a technique which allowed estimation of the enzyme level in leaf tissues of Vigna mungo (L). Hepper in terms of the release of the product (NH₃) of the enzyme reaction. The technique is offered as an alternative, possibly more convenient method for assay of nitrite reductase in plant tissue in vivo.     

Nitrogen Relationships of Vigna mungo in Pure Stands and in Celosia argentea Mixtures

Dynamics of the nitrogen relationships of Vigna mungo in pureand in mixed stands with Celosia argentea, a common weed ofleguminous crops in certain regions of India, were investigated.The weed significantly depressed nodulation and reduced thedry matter and nitrogen yield of the legume which was lowestat the highest density of the weed. A significant amount ofnitrogen transfer occurred from the legume in the weed mixtureswhich appeared to be taken up by the weed plants. Therefore,weed plants benefited from their association with the legumeby accumulating more dry matter and nitrogen in the legume mixtures.The possible competitive or biochemical interference of theweed with nitrogen relationships of the legume in mixtures isdiscussed. Vigna mungo, Celosia argentea, pure stands, mixed stands, total nitrogen, interference     

Biochemical Changes in Nodules of Vigna mungo (L.) During Vegetative and Reproductive Stages of Plant Growth in the Field

Nitrogenase activity in root nodules of Vigna mungo L. attaineda peak at the flowering stage and declined thereafter. Levelsof soluble proteins, particularly leghaemoglobin, and ratesof protein and RNA synthesis declined with nitrogenase. Activitiesof protease and RNase increased with the ageing or nodules.Carbohydrate utilization, sugar levels and ATP were maximumat the early pod stage and gradually declined with age. Theseinterrelated changes point to a loss of nitrogenase activityas the first indicator of nodule senescence that is linked withflowering. Later, losses of proteins, total sugar and ATP wererelated to increased RNase and protease activity and decreasedhexokinase and to a loss in capacity to incorporate amino acidinto protein.Copyright 1993, 1999 Academic Press Vigna mungo (L.), senescene, nitrogenase, leghaemoglobin, field experiments     

Structure and Expression of a-Amylase Gene from Vigna mungo

A single copy of the a-amylase gene, composed of three intronsand four exons, was found in Vigna mungo. Examination of levelsof a-amylase and its mRNA in detached cotyledons indicated thatattachment of the embryonic axis is not required for expressionof the gene in cotyledons of germinating seeds. (Received December 21, 1993; Accepted March 14, 1994)     

Change of Carbon Metabolic Activity of Rhizobium Under Carbon Starvation

One fast growing strain of Rhizobium sp (Vigna mungo) VBS 1 was tested for its metabolic activities under carbon starvation. Specific activities of the catabolic enzymes like phosphofructokinase, fructose-1,6-bisphosphate aldolase, iso-citrate dehydrogenase and malate dehydrogenase decreased remarkably whereas, induction of two anapleurotic enzymes like fructose-1,6-bisphosphatase and iso-citrate lyase took place in the cell-free extract of the strain. Almost unchanged specific activity of the enzyme glyceraldehyde-3-phosphate dehydrogenase indicated its key role in maintaining a balance between catabolic and anabolic activities under carbon starvation.     

Multiple Forms of Acid Phosphatase in Cotyledons of Vigna mungo Seedlings: Immunological Detection and Quantitation

Using a combination of column chromatography and gel electrophoresis,we have found that acid phosphatase in cotyledons of Vigna mungoseedlings is composed of at least six forms (Ia₁, Ia₂, Ib₁,Ib₂, IIa and IIb). We purified one of the major forms, Ia₁,as a polypeptide of 53 kDa. Using an antiserum raised againstthe enzyme Ia₁, we examined the immunological relationshipsbetween the multiple forms from cotyledons and the distributionof the enzyme in organs of maturing and germinating seeds. (Received December 25, 1989; Accepted July 11, 1990)     

Influence of Axis Removal on Amino-, Carboxy- and Endopeptidase Activities in Cotyledons of Germinating Vigna mungo Seeds

Endopeptidase (azocaseolytic enzyme) and carboxypeptidase activitiesin cotyledons of germinating Vigna mungo seeds increased until3 days after the onset of imbibition and decreased thereafter.In detached and incubated cotyledons, the endopeptidase activityincreased only a little while the carboxypeptidase activitycontinued increasing even after 3 days of incubation. The activitiesof leucine-aminopeptidase and alanine-aminopeptidase, exceptfor that of one leucine-aminopeptidase isoenzyme relativelyabundantly present in unimbibed dry cotyledons, increased slightlyon the first day and declined during germination. In detachedcotyledons, the activities maintained their initial levels throughoutthe incubation period. When cotyledons were detached from germinatingseedlings on days 2 and 4 then incubated, the endopeptidaseactivity started to decrease just after removal of the axisbut the carboxypeptidase activity increased more markedly thanwhen the axis remained attached. Exogenously supplied GA₃, kinetin,IAA, or their combinations, showed no significant effect onthe developmental patterns of the endopeptidase and carboxypeptidaseactivities in cotyledons. These results are discussed in relationto the role of the axis in controlling peptidase formation incotyledons of germinating V. mungo seeds. (Received November 18, 1983; Accepted February 28, 1984)     

Chromosome Banding Patterns in Some Indian Pulses

By using the Giemsa C-banding technique, chromosome bandingpatterns on the somatic chromosomes of eight important pulsecrops, pea, lentil, guar (cluster bean), chick pea, pigeon pea,mung bean (green gram), urd (black gram) and cowpea have beenstudied. Each species has a characteristic C-banding pattern.The significance of such banding patterns which correlate withthe position of pachytene knobs, in chromosome identification,and in assigning relationships at the cytological level in thepulses of genus Vigna is stressed. Chromosome banding, Giemsa C-banding, pulse crops, Pisum sativum L., garden pea, Lens culinaris Medik, lentil, Cyamopsis tetragonoloba (L.) Taub., guar, Cicer arietinum L., chick pea, gram, Cajanus cajan (L.) Millsp., pigeon pea, Vigna radiata (L.) Wilczek, mung bean, Vigna mungo (L.) Hepper, urd, Vigna unguiculata (L.) Walp, cowpea     

Acid Phosphatase in Cotyledons of Germinating Vigna mungo Seeds

A marked increase in acid phosphatase activity took place incotyledons of germinating Vigna mungo seeds. The attachmentof axis organs was not required for this development of enzymeactivity in cotyledons. DEAE-cellulose column chromatographyrevealed that the phosphatase is composed of at least threeforms. (Received August 19, 1981; Accepted October 30, 1981)     

Multiple Forms of Acid Phosphatase in Cotyledons of Vigna mungo Seedlings

Acid phosphatase from cotyledons of dark-grown Vigna mungo seedlingswas separated into four forms (la, Ib, Ha and lib) by ion-exchangercolumn chromatographies. Each form of the acid phosphatase wascharacterized for its pH dependency, substrate specificity,thermal stability, activation energy, approximate molecularweight, and the effect of metal ions and other substances onits activity. Each form of the enzyme exhibited high activitytowards ATP and ADP relative to their activity towards p-nitrophenylphosphate,but showed very low activity towards phytate, a major organicphosphate reserve in cotyledons. Among the four forms, lib wasmost distinguishable by its low molecular weight and the thermalenhancement of activity.     

Isolation and Characterization of a cDNA Clone of UDP-Galactose: Flavonoid 3-0-Galactosyltransferase (UF3GaT) Expressed in Vigna mungo Seedlings

Four cDNA clones were isolated from Vigna mungo seedlings bythe screening with cDNA encoding UDP-glu-cose:flavonoid 3-0-glucosyltransferase(UF3GT) of Antirrhinum majus as a probe; the product of thegene corresponding to one cDNA was more highly expressed inthe first simple leaves than in stems. Nucleotide sequence analysisrevealed 1,691 bp (including 326 bp non-reading) containingan open reading frame of 455 amino acids. The deduced aminoacid sequence showed 42% and 23% identity with those of A. majusUDP-glucose:flavonoid 3-O-glucosyltransferase (UF3GT) and Petuniahybrida UDP-rhamnose:anthocyanidin 3-0-glucoside rhamnosyltrans-ferase(RT), respectively. One region of the cDNA (amino acids 325to 387) showed similarity to ceramide UDP-galac-tosyltransferasesof mice, rats and humans. A crude extract from Escherichia coli,in which the protein was expressed from the cDNA, showed highUF3GaT activity but low UF3GT activity, and was similar in K_m,optimal pH and substrate specificity to UF3GaT from V. mungo.We conclude that we have obtained UDP-galactose:flavonoid 3-0-galactosyltransferase(UF3GaT) cDNA from V. mungo. 4 Deceased.     

Studies with phorate,an organophosphate insecticide,on some enzymes of nitrogen metabolism inVigna mungo (L.) Hepper

Effects of phorate (Thimet-10 G) on the activities of enzymes of nitrogen metabolism,viz., glutamine synthetase (GS), glutamate dehydrogenase (GDH), and glutamate synthase (GOGAT) in the primary leaves, nitrogenase (N₂-ase) in detached root nodules, and protein concentration in the primary leaves ofVigna mungo (L.) Hepper have been studied. Phorate stimulated the activities of these enzymes and protein concentration in primary leaves at lower concentrations (50 to 200 mg per pot), but inhibited at higher concentrations (400 to 600 mg per pot). Although, the V_max for each enzyme with different treatments varied, the K_m value of each enzyme in the control and the treated plants remained unaltered.     

Serological evidence confirming the assignment of phaseolus aureus and P. mungo to the genus vigna

Endopeptidase activity was detected in extracts of cotyledons of 11 species of Vigna and Phaseolus Antibodies against the purified protease isolated from the cotyledons of 5-day-old P.aureus seedlings inhibited the activity of that enzyme in crude extracts of cotyledons. A similar inhibition was obtained with P. mungo, P. adenanthus and 4 species of Vigna, while there was no inhibition of endopeptidase activity in extracts of cotyledons of 4 species of Phaseolus. Immunodiffusion tests proved that the protease of Vigna is distinct from that of Phaseolus. The evidence supports the reassignment of P. aureus and P. mungo to the genus Vigna and indicates that the names Vigna radiata and Vigna mungo are more appropriate than P. aureus and P. mungo for green gram and black gram respectively.     

Distribution and Redistribution of Molybdenum in Black Gram (Vigna mungo L. Hepper) in Relation to Molybdenum Supply

The effect of seven rates of molybdenum (Mo) supply on the distributionand redistribution of Mo in Vigna mungo (black gram) cv. Reguron a Mo-deficient sandy loam was examined from flower bud appearanceto pod set in one experiment and during pod filling to maturityin another. At the three lowest Mo supply rates, N deficiency symptoms typicalof Mo deficiency appeared, and shoot dry matter and shoot nitrogencontent were depressed. Increasing Mo supply increased Mo concentrationsin all plant parts but the response varied with Mo supply andwith plant part. In leaf blades and petioles, Mo concentrationsincreased slightly when the Mo supply increased from severelydeficient to deficient levels but further increases in Mo supplymarkedly increased the Mo concentrations, particularly in immatureand recently matured leaves. In petioles, Mo concentrationsgenerally exceeded those in the blades which they supportedat all levels of Mo supply. At Mo rates greater than that requiredfor maximum growth, Mo concentrations in basal stem segmentsexceeded those in petioles. Molybdenum concentrations in nodulesexceeded those in above ground plant parts except at the highestlevel of Mo supply where the concentrations in basal stem segmentsexceeded those in nodules. In Mo-adequate plants, Mo contents in the trifoliolate leavesdecreased with time suggesting that Mo was readily remobilized.By contrast, in stem segments at all levels of Mo supply, andin trifoliolate leaves in Mo-deficient plants, Mo contents remainedconstant or increased with time suggesting that Mo was not remobilizedin all plant parts or at all levels of Mo supply. Thus, theresults suggest that in black gram Mo was variably mobile, beingphloem immobile at low Mo supply, but phloem-mobile in all plantparts with the possible exception of stem segments at adequateMo supply. The relevance of these results for the developmentof plant tests for Mo deficiency diagnosis is discussed.Copyright1994, 1999 Academic Press Molybdenum, phloem-mobility, redistribution, black gram, Vigna mungo L. Hepper     

Partial Purification and Some Properties of Flavonol 3-O-Glycosyltransferases from Seedlings of Vigna mungo, with Special Reference to the Formation of Kaempferol 3-O-Galactoside and 3-O-Glucoside

A novel enzyme, UDP-D-galactose:flavonol 3-O-galactosyltransferase(F3GaT), catalyzing the transfer of D-galactose from UDP-D-galactoseto the 3 position of 5,7,4'-trihydroxyflavonol (kaempferol),was detected in and purified about 404-fold from seedlings ofVigna mungo by precipitation with ammonium sulfate, chromatographyon Sephadex G-100 and chromatofocusing. The enzyme was separatedby this procedure from a coexisting UDP-D-glucose:flavonol 3-O-glucosyltransferase(F3GT), which was simultaneously purified about 189-fold. F3GaTwas isolated as a soluble enzyme with pH optima of 8.0 in imidazole-HClbuffer and 7.5 in histidine-HCl buffer. F3GT had the same pHoptima. The M_r of both F3GaT and F3GT, which had isoelectricpoints of 5.1 and 6.1, respectively, was estimated by elutionfrom a column of Sephadex G-100 to be about 43,000. The activitiesof F3GaT and F3GT were stimulated by 14 mM 2-mercaptoethanoland strongly inhibited by 1 mM Cu²⁺, 1 mM Zn²⁺, and variousreagents that react with sulfhydryl groups. Among various possiblesubstrates for F3GaT that were tested, kaempferol, isorhamnetinand quercetin were the best. The K_m values for kaempferol andUDP-D-galactose were determined to be 0.40 µM and 125µM, respectively. Similarly, F3GT had low K_m values of0.69 µM for kaempferol and 1.67 mM for UDP-D-glucose.F3GaT and F3GT mediated the transfer of galactose and glucose,respectively, to the 3-hydroxyl groups exclusively of kaempferol,isorhamnetin and quercetin. Rhamnetin also functioned as a galactosylacceptor though less efficiently. (Received October 12, 1992; )     

Monitoring Primary Response to Chilling Stress in Etiolated Vigna radiata and V. mungo Seedlings Using Thermal Hysteresis of Water Proton NMR Relaxation Times

Thermal hysteresis of longitudinal relaxation times (T₁) ofwater protons in hypocotyls of etiolated Vigna radiata and V.mungo seedlings was investigated by pulse nuclear magnetic resonance(NMR) spectroscopy. Various lengths of chilling exposures duringa cool-warm cycle between 20 and 0?C (below 10?C, about 4 h)for the T₁ hysteresis measurement did not cause any visibleinjury symptoms in hypocotyls. However, the profiles of T₁ hysteresisvaried as a result of different chilling exposures. The sumsof the T₁ ratio (for detail see Introduction) reflecting T₁prolongation or shortening upon the warming process were a goodquantitative index for the extent of T₁ hysteresis, and thewide dispersion of this value ranging on the "minus" side (T₁prolongation upon warming) suggested the occurrence of a primaryresponse of cells to chilling stress before obvious visiblesymptoms occur while the T₁ ratio sums on the "plus" side (T₁shortening upon warming) corresponded to a response of seriousvisible injury. Therefore, the sums of the T₁ ratio can be usedas a non-destructive diagnostic tool for monitoring the primaryevent of chilling injury when lacking any visible injury symptoms.The data indicate that the critical temperature for the occurrenceof primary response for chilling stress was around 7.5?C forV. radiata and 12.5?C for V. mungo. (Received February 1, 1988; Accepted June 1, 1988)     

Surface Charge Density Estimation of Vigna mungo Protoplasts Using a Fluorescent Dye, 9-Aminoacridine

We showed that the surface charge density of protoplasts canbe estimated by the 9-aminoacridine method. The estimated surfacecharge density of the protoplasts isolated from elongating regionsof Vigna mungo root was – 39 ? 8 mC/m². The negative surfacecharge density increased when protoplasts were treated withglutaraldehyde or when EDTA was added to the protoplast suspensionmedium. These results support the validity of our estimationof the surface charge density of protoplasts by the 9-aminoacridinemethod. The concentration of amino groups at the surface ofthe protoplasts was estimated to be 34 mC/m². (Received June 19, 1987; Accepted April 11, 1988)     

Synthesis and Turnover of {alpha}-Amylase in Cotyledons of Germinating Vigna mungo Seeds: Effects of Exogenously Applied End-Products and Plant Hormones

Pulse-chase experiments indicated that the higher levels ofa-amylase in detached and incubated cotyledons of Vigna mungothan those in cotyledons attached to the embryonic axis weredue to both faster synthesis and slower degradation of the enzymein the detached cotyledons than in the attached cotyledons.Levels of a-amylase in the cotyledons were examined in termsof possible effects of end-products and the effects of exogenouslyapplied plant hormones and growth regulators. Levels of a-amylaseactivity and content were reduced by high concentrations ofglucose and sucrose, and it is suggested that this effect wascaused mostly by osmotic stress and partly by end-product repression.The level of a-amylase was nearly twice that in controls after1 to 10µM GA₃ had been applied to the cotyledons. In addition,0.1 mM kinetin, 0.1 mM 2,4-D and 0.1 to 0.S mM naphthaleneaceticacid also increased the level by 34% to 66% as compared to thecontrol. ABA and uniconazole both prevented the synthesis ofa-amylase. (Received July 4, 1994; Accepted November 14, 1994)