The formation of root nodules, increase of their mass, formation of harvest and its structure in soybean of cultivar Mariana inoculated by Tn5-mutants created by means transposon mutagenesis with the use of plasmid pSUP2021 was studied in conditions of field experiment. It has been found that the investigated transposon mutants specifically influenced the forming of soybean symbiotic apparatus: Tn5-mutant 17–2 was marked by the highest nodular ability, 31–2 formed the largest biomass of nodule roots, while 9–2 was characterized by the highest general and specific nitrogen-fixing activities. The seeds inoculation by transposon mutants 9–1, 9–2, 17–2 and 33–2 was marked to cause an increase of the seed productivity in comparison with inoculation by commercial strain 634b. All Tn5-mutants proved to cause an increase of the seed harvest in comparison with the commercial strain 634b, while mutants 9–2, 17–2 and 33–2 in comparison with the initial strain 646. Bacterization of seeds by high-activity transposon mutants 9–2 and 17–2 provided the largest harvest growth of soybean in comparison with the control. In perspective these Tn5-mutants could be the initial material for subsequent selection of soybean rhizobia production strains.

The paper covers the role of lectins of legumes in the establishing of nitrogen fixing symbiosis with nodule bacteria. The positive influence of these proteins in initiation of rhizobia binding to the roots of legume plants was proved. It was established that level of hemagglutination activity of lectins of soybean and lupine nodules directly relate on the activity of nitrogen fixation. Treatment of soybean seeds with the rhizobial suspension combined with homologous lectin promoted nitrogen fixation in nodules and has considerably increased crop yield thus indicating perceptiveness of use of legumes lectins in compositions of bacterial fertilizers for legume plants.

The efficiency of the presowing soybean inoculation with nodule bacteria at direct seeds bacterization or introduction of inoculum to the soil at presowing cultivation as well as the ability of rhizobia remained in the soil to the next year to form active symbioses with soybean plants was studied. The liquid bacterial cultures of production strain Bradyrhizobium japonicum 634b and three perspective Tn5-mutants of B. japonicum 646 were used. The introduction of the inoculum to soil was shown to be more efficient during both years of investigations as compared with the seeds inoculation which resulted in higher number of nodules formed, their nitrogenase activity and greater soybean seeds yield. Two of three studied Tn5-mutants had surpassed the standard strain by the efficiency indices.

Viability of soybean nodule bacteria under various technologies of production of bacterial preparations and influence of homologous lectin on their efficiency had been studied. It is shown that perlite and vermiculite are equivalent carriers in terms of technology for product¬ion of bacterial preparations. The findings indicate perspectiveness of homologous lectin ме as a component of bacterial preparations.

Plant growth experiments were conducted to assess symbiotic efficiency, photosynthetic rates, and the development of soybean (Glycine max (L.) Merrill) seedlings after seed inoculation with active and inactive strains of root nodule bacteria Bradyrhizobium japonicum preincubated in the presence homologous and heterologous proteins. The properties of active and inactive symbiotic strains were differentially modulated by homologous soybean lectin, which had a marked influence on plant physiological condition. The incubation of active rhizobia with a homologous lectin, i.e., lectin of the respective plant, increased the nitrogen-fixing activity of nodules and, consequently, elevated photosynthetic rates and weight increments in soybean plants. At the same time, the homologous lectin suppressed the symbiotic properties of inactive strain of nodule bacteria. The preincubation of rhizobia with a heterologous pea lectin had virtually no effect on functioning of symbiotic apparatus and photosynthetic rate, whereas the preincubation of root nodule bacteria with human albumin exerted an effect similar to that induced by a homologous lectin on symbiotic productivity.

Nodule bacteria (Bradyrhizobium japonicum) of various activities were preincubated with homologous lectin and then used for inoculating soybean (Glycine max (L.) Merrill) seeds. The effect of this inoculation on the photosynthetic rate, lectin activity in leaves, and plant development at different supply of mineral nitrogen was investigated under the conditions of pot experiments. There was a positive relationship between the photosynthetic rate and the lectin activity of proteins isolated from soybean leaves. Under the conditions of effective symbiosis, activation of functioning of the symbiotic apparatus by preincubation of the rhizobia with lectin exerted an additional stimulating effect on the photosynthetic rate. It is suggested that a relationship between the effectiveness of legume-rhizobium symbiosis and the lectin activity in leaves is mediated by the regulation of photosynthesis through a demand for assimilates in the source-sink system of soybean plants.

The protein and amino acid compositions of non-nodulating soybean root extract (NNSRE) as well as capability of haemagglutinating protein from NNSRE to interact with Bradyrhizobium lipopolysaccharides have been studied. Small number of protein bands on gel plate was revealed as a result of SDS-PAAG electrophoresis of NNSRE protein pool. Moreover, some of these protein bands were located in area of soybean seed lectin (SBL) disposition. Amino acid analysis of root extract protein fractions from both nodulating and non-nodulating soybean did not show significant differences in their amino acid composition. It was determined that the carbohydrate-binding protein from the NNSRE could bind some of slow-growing nodule bacteria lipopolysaccharides when polysaccharide molecules were used at low concentrations.

The effect of lectins from leguminous plants, lupine (Lupinus luteus L.) and soybean (Glycine max (L.) Merr., on the symbiotic activity of nodule bacteria from the Bradyrhizobium genus, their virulence and efficiency, was investigated. It was found that preincubation of rhizobia with the lectin isolated from a specific host plant resulted in both enhancement of nodulation and stimulation of the nitrogen-fixing activity of fully developed nodules. In contrast, the lectin isolated from a nonspecific host plant had no such effect.

Native PAGE was used to identify qualitative and quantitative changes in apoplastic enzymes extracted from bean leaves during a hypersensitive response (HR) resulting from inoculation with an avirulent race of P. s. pv.phaseolicola.A burst of apoplastic peroxidase (EC-POX) activity was identified 2 h after inoculation.There was an apparent increase in the activity of an extracellular isoenzyme of superoxide dismutase (EC-SOD 2).In addition a second extracellular SOD isoenzyme (EC-SOD 1) was detected after 5 h.Contamination of the apoplast by cytoplasmic constituents was excluded as glucose-6-phosphate dehydrogenase activity was not detectable in apoplastic fluids during this period.This represents the fgst report of the involvement of an apoplastie SOD in the HR.The possibility that EC-POX may generate activated oxygen species via NAD(P)H oxidation is discussed.In vitro studies on the generation of activated oxygen species by microsomes isolated from potato tubers identified the existence of two distinct NADH oxidase activities, with pH optima of 6 and 7.8.At pH 6, NADH oxidase activity was stimulated by Mn 2+, 4-hydroxy phenolics and 3,4-dihydroxy cimlamic acid and was sensitive to inhibition by SOD and catalase (CAT).It is suggested that this activity is the result of ~ membrane associated peroxidase.