Identification of a system that allows a Rhizobium tropici dctA mutant to grow on succinate, but not on other C4-dicarboxylates

2001 ◽  
Vol 47 (6) ◽  
pp. 509-518 ◽  
Author(s):  
Silvia Batista ◽  
Ana I Catalán ◽  
Ismael Hernández-Lucas ◽  
Esperanza Martínez-Romero ◽  
O Mario Aguilar ◽  
...  
Keyword(s):  
Transport System ◽  
Biochemical Characterization ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Insertion Mutant ◽  
Rhizobium Tropici ◽  
Gene Encoding ◽  
Shoot Dry Weight ◽  
Reduction Activity ◽  
Bean Plants

A defined insertion mutant of a gene encoding a homolog of the rhizobial C4-dicarboxylate permease (dctA) was constructed in Rhizobium tropici strain CIAT899. This mutant (GA1) was unable to grow on fumarate or malate; however, in contrast with other rhizobial dctA mutants, it retained a limited ability to grow on succinate with ammonia as a nitrogen source. Our results suggest the presence of a novel succinate-specific transport system in R. tropici. Biochemical characterization indicated that this alternative transport system in GA1 is active and dependent on an energized membrane. It was also induced by succinate and aspartate, and was repressed by glucose and glycerol. Bean plants inoculated with GA1 showed a reduced nitrogen-fixing ability, achieving only 29% of the acetylene reduction activity determined in CIAT899 strain nodules, 33 days after inoculation. Also, bean plants inoculated with GA1 had reduced shoot dry weight compared with plants inoculated with the wild-type strain.Key words: succinate transport, Rhizobium tropici, C4-dicarboxylate uptake.

scholarly journals Changes in N2 fixation in Stylosanthes scabra derived from tissue culture

1997 ◽  
Vol 20 (4) ◽  
pp. 713-716 ◽  
Author(s):  
Maria José Valarini ◽  
Ivani Pozar Otsuk ◽  
Maria Lucia Carneiro Vieira
Keyword(s):  
Tissue Culture ◽  
Nitrogen Fixation ◽  
N2 Fixation ◽  
Acid Soils ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Shoot Dry Weight ◽  
Reduction Activity ◽  
Randomized Design ◽  
Stylosanthes Scabra

Plants were regenerated from leaf-derived callus culture of Stylosanthes scabra, a polyploid legume tolerant to drought and adapted to acid soils. A total of 168 regenerants were planted out in Leonard jars in a complete randomized design. Nitrogen fixation and vegetative growth were indirectly evaluated by shoot dry weight, root dry weight, shoot N content and acetylene reduction activity. The results showed higher variation in the regenerants than in controls not submitted to tissue culture. Significant differences were found for all nitrogen fixation related-traits

Effects of an Autoregulatory Senescence-inhibitor Gene Construct on Nicotiana alata Link and Otto.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 519d-519 ◽  
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Plant Height ◽  
Dry Weight ◽  
Nicotiana Alata ◽  
Wild Type ◽  
Gene Encoding ◽  
Delayed Senescence ◽  
Gene Construct ◽  
Shoot Dry Weight ◽  
Inhibitor System

Nicotiana alata Link and Otto. was transformed via Agrobacterium tumefaciens encoding a senescence-specific promoter SAG12 cloned from Arabidopsis thaliana fused to a Agrobacterium tumefaciens gene encoding isopentenyl transferase (IPT) that catalyzes cytokinin synthesis. This was considered an autoregulatory senescence-inhibitor system. In 1996, we reported delayed senescence of intact flowers by 2 to 6 d and delayed leaf senescence of transgenic vs. wild-type N. alata. Further evaluations in 1997 revealed several other interesting effects of the SAG12-IPT gene construct. Measurement of chlorophyll content of mature leaves showed higher levels of both chlorophyll a and b in transgenic material under normal fertilization and truncated fertilization regimes. At 4 to 5 months of age transgenic plants expressed differences in plant height, branching, and dry weight. Plant height was reduced by 3 to 13 cm; branch counts increased 2 to 3 fold; and shoot dry weight increased up to 11 g over wild-type N. alata. These observations indicate the system is not tightly autoregulated and may prove useful to the floriculture industry for producing compact and more floriferous plants.

scholarly journals Seedling treatments and phosphorus solution concentrations affect nodulation and nodule functions in soybean (Glycine max L.)

2008 ◽  
Vol 53 (No. 2) ◽  
pp. 65-71 ◽  
Author(s):  
S.J. Miao ◽  
X.Z. Han ◽  
X.B. Liu ◽  
Y.F. Qiao
Keyword(s):  
Glycine Max ◽  
Plant Biomass ◽  
Dry Weight ◽  
Solution Culture ◽  
Acetylene Reduction Activity ◽  
Nodule Size ◽  
Reduction Activity ◽  
P Content ◽  
Significant Difference ◽  
Nutrient Solution Culture

The effect of three seedling treatments: T<sub>0</sub>, normal germination; T<sub>1</sub>, cotyledons removed; T<sub>2</sub>, cotyledons removed 5 days earlier than in T<sub>1</sub>; and two phosphorus levels (P<sub>0</sub> and P<sub>30</sub>) on nodulation and nodule function in soybean [<i>Glycine max</i> (L.) Merr.] were investigated in nutrient solution culture. The number of nodules formed at P<sub>0</sub> was in the order T<sub>2</sub> > T<sub>0</sub> > T<sub>1</sub>, but it was T<sub>0</sub> > T<sub>2</sub> > T<sub>1</sub> at P<sub>30</sub>. Nodule dry weight per plant had the same tendency as the nodule number. Nodule size (dry weight per nodule) in seedlings ranged from 0.601 to 1.089 mg in the order T<sub>0</sub> > T<sub>1</sub> > T<sub>2</sub>, regardless of P level. For example, nodule size in T<sub>0</sub> was larger by 86% and 52% than T<sub>2</sub> at P<sub>0</sub> and P<sub>30</sub>, respectively. Furthermore, regardless of P level, a specific acetylene reduction activity (ARA, &micro;M C<sub>2</sub>H<sub>4</sub>/h/g nodule) increased with P content in seedlings, but no significant difference was found (<i>P</i> < 0.05). Leghemoglobin (Lb) content was not significantly affected by P level; however, seedlings (T<sub>0</sub> and T<sub>1</sub>) significantly affected the Lb content per unit plant biomass (<i>P</i> < 0.05). All these results suggest that seedling P content plays a key role in nodulation and nodule function of soybean.

scholarly journals Diversity and Effectivity of Indigenous Mesorhizobium Strains for Chickpea (Cicer arietinum L.) in Myanmar

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 287 ◽  
Author(s):  
Khin Myat Soe ◽  
Aung Zaw Htwe ◽  
Kyi Moe ◽  
Abiko Tomomi ◽  
Takeo Yamakawa
Keyword(s):  
Sequence Analysis ◽  
Cicer Arietinum ◽  
Acetylene Reduction ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Rrna Gene ◽  
Cicer Arietinum L ◽  
Reduction Activity ◽  
Legume Production ◽  
High Level

Chickpea (Cicer arietinum L.) is one of the world’s main leguminous crops that provide chief source of food for humans. In the present study, we characterized thirty isolates of indigenous chickpea rhizobia from Myanmar based on the sequence analysis of the bacterial 16S rRNA gene. The sequence analysis confirmed that all isolates were categorized and identified as the genus Mesorhizobium and they were conspecific with M. plurifarium, M. muliense, M. tianshanense, and M. sp. This is the first report describing M. muliense, M. tianshanense, and M. plurifurium from different geographical distribution of indigenous mesorhizobia of chickpea in Myanmar. In order to substitute the use of chemical fertilizers in legume production, there is a need for the production of Biofertilizers with rhizobial inoculants. The effectiveness of Myanmar Mesorhizobim strains isolated from soil samples of major chickpea growing areas of Myanmar for plant growth and nitrogen fixation were studied in pot experiments. The nodule dry weight and acetylene reduction activity of the plant inoculated with Mesorhizobium tianshanense SalCP19 was significantly higher than the other tested isolates in Yezin-4 chickpea variety. But, Mesorhizobium sp. SalCP17 was showed high level of acetylene reduction activity per plant in Yezin-6 chickpea variety.

Invasion of clear-cuttings by the actinorhizal plant Comptoniaperegrina

1986 ◽  
Vol 16 (4) ◽  
pp. 872-874 ◽  
Author(s):  
O. Q. Hendrickson
Keyword(s):  
Forest Floor ◽  
Mineral Soil ◽  
Dry Weight ◽  
Significant Negative Correlation ◽  
Acetylene Reduction Activity ◽  
Total N ◽  
Reduction Activity ◽  
Site Disturbance ◽  
Harvest Site ◽  
Whole Tree

Three years after harvesting a mixed conifer–hardwood forest in Ontario, the density of sweet fern (Comptoniaperegrina (L.) Coult.) was far greater on a whole-tree harvest site (logging slash removed) than on an adjacent conventional harvest site (logging slash present). These differences were related to the degree of site disturbance, particularly forest floor removal. Nodule fixation rates also appeared to reflect the degree of disturbance, being highest in plants growing along a logging road where the sandy, nitrogen-poor mineral soil was exposed, and exceptionally low on the conventional harvest site (0.67 μmol C2H4 g dry weight−1 h−1). Overall, acetylene reduction activity showed a significant negative correlation (r = −0.77, p < 0.001) with total N.

Relative contributions to nitrogenase (acetylene reducing) activity of stem and root nodules in Sesbania rostrata

1992 ◽  
Vol 38 (6) ◽  
pp. 577-583 ◽  
Author(s):  
J. K. Ladha ◽  
Minviluz Garcia ◽  
R. P. Pareek ◽  
G. Rarivoson
Keyword(s):  
Acetylene Reduction ◽  
Root Nodule ◽  
Nitrogenase Activity ◽  
Root Nodules ◽  
Dry Weight ◽  
Acetylene Reduction Activity ◽  
Sesbania Rostrata ◽  
Reduction Activity ◽  
Acetylene Reducing Activity ◽  
Aerial Stem

Six experiments, two each in the phytotron, greenhouse, and field, were conducted to assess the contribution of nitrogenase activity (acetylene reduction) by stem nodules in the presence and absence of root nodules of Sesbania rostrata (Brem & Oberm). In a greenhouse experiment, the effect of detaching already formed aerial stem nodules on the restoration of root nodules and nitrogenase activity was studied. The field experiment compared nodulation and acetylene-reduction activity by dual-nodulating S. rostrata and root-nodulating Sesbania cannabina. Acetylene-reduction activity expressed per gram of nodule dry weight was higher for stem nodules than for root nodules. Root nodule dry weight and acetylene-reduction activity failed to increase after stem inoculation, but root nodule dry weight and acetylene-reduction activity increased several fold within 15 days of detachment of aerial stem nodules. Stem nodulation, which occurred without inoculation under lowland field condition, suppressed root nodulation, thus accounting for more than 75% of total nitrogenase activity. Sesbania rostrata showed higher acetylene-reduction activity than S. cannabina. In dual-nodulating plants, root and stem nodules appeared to strike a balance in competition for energy, which may be controlled by stem nodulation. Key words: Sesbania rostrata, Azorhizobium caulinodans, stem nodule, root nodule, acetylene-reducing activity.

scholarly journals Characterization of Two Inducible Phosphate Transport Systems in Rhizobium tropici

2000 ◽  
Vol 66 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Lina M. Botero ◽  
Thamir S. Al-Niemi ◽  
Timothy R. McDermott
Keyword(s):  
Transport System ◽  
Response Regulator ◽  
Insertion Site ◽  
Dry Weight ◽  
Type Systems ◽  
Phosphate Transport ◽  
Transport Systems ◽  
Atpase Inhibitor ◽  
Rhizobium Tropici ◽  
High Affinity

ABSTRACT Rhizobium tropici forms nitrogen-fixing nodules on the roots of the common bean (Phaseolus vulgaris). Like other legume-Rhizobium symbioses, the bean-R. tropiciassociation is sensitive to the availability of phosphate (Pi). To better understand phosphorus movement between the bacteroid and the host plant, Pi transport was characterized in R. tropici. We observed two Pitransport systems, a high-affinity system and a low-affinity system. To facilitate the study of these transport systems, a Tn5B22 transposon mutant lacking expression of the high-affinity transport system was isolated and used to characterize the low-affinity transport system in the absence of the high-affinity system. TheKm and V max values for the low-affinity system were estimated to be 34 ± 3 μM Pi and 118 ± 8 nmol of Pi · min−1 · mg (dry weight) of cells−1, respectively, and the Km andV max values for the high-affinity system were 0.45 ± 0.01 μM Pi and 86 ± 5 nmol of Pi · min−1 · mg (dry weight) of cells−1, respectively. Both systems were inducible by Pi starvation and were also shock sensitive, which indicated that there was a periplasmic binding-protein component. Neither transport system appeared to be sensitive to the proton motive force dissipator carbonyl cyanide m-chlorophenylhydrazone, but Pi transport through both systems was eliminated by the ATPase inhibitor N,N′-dicyclohexylcarbodiimide; the Pi transport rate was correlated with the intracellular ATP concentration. Also, Pi movement through both systems appeared to be unidirectional, as no efflux or exchange was observed with either the wild-type strain or the mutant. These properties suggest that both Pi transport systems are ABC type systems. Analysis of the transposon insertion site revealed that the interrupted gene exhibited a high level of homology withkdpE, which in several bacteria encodes a cytoplasmic response regulator that governs responses to low potassium contents and/or changes in medium osmolarity.

scholarly journals Effects of Phosphate Solubilizing Fungi on Growth and Yield of Haricot Bean (Phaseolus vulgaris L.) Plants

2016 ◽  
Vol 8 (10) ◽  
pp. 204 ◽  
Author(s):  
Firew Elias ◽  
Diriba Muleta ◽  
Delelegn Woyessa
Keyword(s):  
Phaseolus Vulgaris ◽  
Dry Weight ◽  
Growth And Yield ◽  
Fresh Weight ◽  
Shoot Height ◽  
Shoot Dry Weight ◽  
Standard Procedures ◽  
Bean Plants ◽  
Phosphate Solubilizing

<p>Haricot bean (<em>Phaseolus vulgaris</em> L.) is one of the most important cash crops and export commodities besides its use in human food and soil fertility improvement. Phosphorus (P) is one of the major bio-elements that limits agricultural production. However, phosphate-solubilizing fungi play a noteworthy role in increasing the bioavailability of soil phosphates for plants. The purpose of this study was to evaluate the effects phosphate solubilizing fungi on the growth of haricot bean plants. Cultural and morphological features were used to tentatively identify the fungal isolates to genus level. Based <em>In vitro</em> phosphate solubilization efficieny conducted in both solid and liquid PVK medium following standard procedures, two best isolates were selected and evaluated under greenhouse for their performance on haricot bean. Under greenhouse experiment, shoot height (47.31 cm plant<sup>-1</sup>), root length (41.01 cm plant<sup>-1</sup>), nodule number (65.67 plant<sup>-1</sup>), nodule dry weight (0.59 g plant<sup>-1</sup>), shoot fresh weight (62.73 g plant<sup>-1</sup>), shoot dry weight (14.33 g plant<sup>-1</sup>), number of pod (12.89 plant<sup>-1</sup>), 50-seed weight (35.89 g plant<sup>-1</sup>), P content (0.59%) and N content (1.96%) were significantly increased by co-inoculation of two isolates (PSFAP) in the soil amended with rock phosphate (RP) compared to control. Moreover, the highest number of leaves (59.55 leaves plant<sup>-1</sup>) and root fresh weight (14.19 g plant<sup>-1</sup>) were recorded as a result of inoculation with isolate PSFP compared to control. The present study indicated the presence of potential plant associated fungi that possess phytobeneficial traits for extending their use as microbial biofertilizers after testing their suitability for the desired purpose.</p>

Nitrogenase activity, nodulation and seed production inVicia fabaas affected by methabenzthiazuron

1996 ◽  
Vol 127 (3) ◽  
pp. 319-324 ◽  
Author(s):  
J. Martínez ◽  
D. Vidal ◽  
E. Simón
Keyword(s):  
Seed Production ◽  
Vegetative Growth ◽  
Nitrogenase Activity ◽  
Dry Weight ◽  
Inhibitory Effect ◽  
Acetylene Reduction Activity ◽  
N Recovery ◽  
N Fixation ◽  
N Content ◽  
Reduction Activity

SUMMARYThe effects of recommended application rates of the herbicide methabenzthiazuron (MBT) (2·5 and 4 kg ha-1) on vegetative growth, nodulation and N2fixation in faba bean plants were studied in the field at Barcelona during 1990 and 1991. Nodulation, specific nitrogenase activity (SNA) of excised nodules, dry weight of plants and seed nitrogen content at harvest were compared in MBT-treated, hand-weeded (HW) and control plants. In 1990 the higher MBT application (4 kg ha-1) caused a decrease in nodulation and acetylene reduction activity (ARA) per plant during the mid-period of pod-fill, and also in vegetative growth, seed production and N content of seeds, whereas the lower rate (2·5 kg ha-1) did not have a significant effect on any of these factors. However, in 1991, growth and herbicide effects were different from those in the previous year. No inhibitory effect of MBT on nodulation, SNA or ARA per plant was observed and vegetative growth, seed production and N content of seeds were not significantly different from those of plants from HW plots. In 1991, both 4 kg ha-1of MBT and the HW treatment caused a stimulatory effect on seed N recovery and yield compared to control plants. Rates of ARA per plant at late pod-fill were positively related to N recovery by seeds. These differences could have been due to the low rainfall in 1990, which may have permitted MBT to remain in the soil for a longer period and to inhibit N fixation and plant growth in theVicia fabacrop.

Effect of inoculation of Zea mays with Azospirillum brasilense strains under temperate conditions

1981 ◽  
Vol 27 (9) ◽  
pp. 871-877 ◽  
Author(s):  
G. W. O'Hara ◽  
M. R. Davey ◽  
J. A. Lucas
Keyword(s):  
Zea Mays ◽  
Nitrogen Content ◽  
Acetylene Reduction ◽  
Azospirillum Brasilense ◽  
Dry Weight ◽  
Yield Response ◽  
Acetylene Reduction Activity ◽  
Reduction Activity ◽  
Mutant Strains ◽  
Nitrogen Concentrations

Seven strains of Azospirillum brasilense were compared for their effect on the growth of Zea mays grown under temperate conditions in sand–vermiculite pot cultures. Inoculation with all seven strains tested, including Fix− mutant strains, increased dry weight and total nitrogen content of shoots, but nitrogen concentrations were unaffected. Low and variable rates of acetylene reduction activity were observed from excised roots of inoculated plants without preincubation. Estimates of N2-fixing A. brasilense associated with inoculated roots showed differences between strains in establishing themselves in the rhizosphere and endorhizosphere. In some strains enrichment in the endorhizosphere of roots occurred following inoculation, but the relative numbers and location of the strains did not appear to affect the yield response.

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