Soybean GmSUT1 transporter participates in sucrose transport to nodules during rhizobial symbiosis

This paper originates from a presentation at the IIIrd International Congress on Crassulacean Acid Metabolism, Cape Tribulation, Queensland, Australia, August 2001. In Ananas comosus L. (Merr.) (pineapple), a widely cultivated bromeliad that exhibits crassulacean acid metabolism (CAM), much of the carbohydrate synthesized during the daytime appears to accumulate as soluble sugars in the vacuole. To investigate the mechanism of sugar transport into the vacuole, microsomal extracts were prepared from deacidifying leaves harvested during Phase III of the CAM cycle. The vesicle preparations exhibited features expected for a fraction highly enriched in vacuolar membranes (tonoplast), i.e. the ATPase activity of 16 ±�2�nkat mg-1 protein was inhibited 96% by 50 mm KNO3, an inhibitor of vacuolar ATPases, and was only 7% inhibited by 100μm NaN3 plus 100μm Na3VO4, inhibitors of mitochondrial and plasma membrane ATPases, respectively. Further, the microsomal ATPase activity showed a pH optimum between 7.0 and 8.0, typical of a vacuolar ATPase. When presented with Mg-ATP, vesicles established H+ gradients that could be maintained for at least 25 min. The vesicles were able to take up [14C]sucrose from an external medium. Sucrose uptake exhibited saturable kinetics with an apparent Km of 50 m sucrose and apparent Vmax of 171 ± 5 pkat mg-1 protein. Sucrose uptake was not dependent upon, nor stimulated by, Mg-ATP, suggesting that the mechanism of sucrose transport into the vacuole in A. comosus does not involve H+-coupled cotransport. However, the initial rates of sucrose uptake from the external medium were stimulated when vesicles were preloaded with sucrose. This trans-stimulation is consistent with characteristics expected for a sucrose uniporter capable of operating in an exchange mode. It is proposed that the accumulation of glucose and fructose in leaf vacuoles of Ananas during the light period involves at least two steps - transport of sucrose into the vacuole by a mechanism exhibiting characteristics of a sucrose uniporter, followed by cleavage of sucrose by a vacuolar acid invertase to form glucose and fructose.

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Identification of an isoflavonoid transporter required for the nodule establishment of the Rhizobium-Fabaceae symbiotic interaction

10.1101/2021.07.30.452494 ◽

2021 ◽

Author(s):

Wanda Biala-Leonhard ◽

Laura Zanin ◽

Stefano Gottardi ◽

Rita de Brito Francisco ◽

Silvia Venuti ◽

...

Keyword(s):

Functional Characterization ◽

Crop Productivity ◽

Signaling Cascades ◽

Nutritional Deficiencies ◽

White Lupin ◽

Symbiotic Interaction ◽

Phosphate Availability ◽

Rhizobial Symbiosis

Nitrogen (N) as well as Phosphorus (P) are key nutrients determining crop productivity. Legumes have developed strategies to overcome nutrient limitation by e.g., forming a symbiotic relationship with N-fixing rhizobia and the release of P-mobilizing exudates and are thus able to grow without supply of N or P fertilizers. The legume-rhizobial symbiosis starts with root release of isoflavonoids, that act as signaling molecules perceived by compatible bacteria. Subsequently, bacteria release nod factors, which induce signaling cascades allowing the formation of functional N-fixing nodules. We report here the identification and functional characterization of a plasma membrane-localized MATE-type transporter (LaMATE2) involved in the release of genistein from white lupin roots. The LaMATE2 expression in the root is upregulated under N deficiency as well as low phosphate availability, two nutritional deficiencies that induce the release of this isoflavonoid. LaMATE2 silencing reduced genistein efflux and even more the formation of symbiotic nodules, supporting the crucial role of LaMATE2 in isoflavonoid release and nodulation. Furthermore, silencing of LaMATE2 limited the P-solubilization activity of lupin root exudates. Transport assays in yeast vesicles demonstrated that LaMATE2 acts as a proton-driven isoflavonoid transporter.

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ATBS1-INTERACTING FACTOR 2 Negatively Modulates Pollen Production and Seed Formation in Arabidopsis

Frontiers in Plant Science ◽

10.3389/fpls.2021.704958 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yoon Kim ◽

Sun-Ho Kim ◽

Dong-Min Shin ◽

Soo-Hwan Kim

Keyword(s):

Pollen Grains ◽

Starch Accumulation ◽

Bhlh Transcription Factor ◽

Pollen Production ◽

Sucrose Transport ◽

Seed Formation ◽

Helix Loop Helix ◽

Knockout Mutants ◽

Auxin Signalling ◽

Genes Encoding

ATBS1-INTERACTING FACTOR 2 (AIF2) is a non-DNA-binding basic-helix-loop-helix (bHLH) transcription factor. Here, we demonstrate that AIF2 negatively modulates brassinosteroid (BR)-induced, BRASSINAZOLE RESISTANT 1 (BZR1)-mediated pollen and seed formation. AIF2-overexpressing Arabidopsis plants (AIF2ox) showed defective pollen grains and seed production while two AIF2 knockout mutants, aif2-1 and aif2-1/aif4-1, displayed opposite phenotypes. Genes encoding BZR1-regulated positive factors of seed size determination (SHB1, IKU1, MINI3) were suppressed in AIF2ox and genes for negative factors (AP2 and ARF2) were enhanced. Surprisingly, BZR1-regulated pollen genes such as SPL, MS1, and TDF1 were aberrantly up-regulated in AIF2ox plants. This stage-independent abnormal expression may lead to a retarded and defective progression of microsporogenesis, producing abnormal tetrad microspores and pollen grains with less-effective pollen tube germination. Auxin plays important roles in proper development of flower and seeds: genes for auxin biosynthesis such as TCPs and YUCCAs as well as for positive auxin signalling such as ARFs were suppressed in AIF2ox flowers. Moreover, lipid biosynthesis- and sucrose transport-related genes were repressed, resulting in impaired starch accumulation. Contrarily, sucrose and BR repressed ectopic accumulation of AIF2, thereby increasing silique length and the number of seeds. Taken together, we propose that AIF2 is negatively involved in pollen development and seed formation, and that sucrose- and BR-induced repression of AIF2 positively promotes pollen production and seed formation in Arabidopsis.

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Sulla carnosamodulates root invertase activity in response to the inhibition of long-distance sucrose transport under magnesium deficiency

Plant Biology ◽

10.1111/plb.12489 ◽

2016 ◽

Vol 18 (6) ◽

pp. 1031-1037 ◽

Cited By ~ 3

Author(s):

N. Farhat ◽

A. Smaoui ◽

L. Maurousset ◽

B. Porcheron ◽

R. Lemoine ◽

...

Keyword(s):

Magnesium Deficiency ◽

Invertase Activity ◽

Sucrose Transport ◽

Long Distance

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Sucrose transport at the tonoplast

Phytochemistry ◽

10.1016/0031-9422(73)80541-2 ◽

1973 ◽

Vol 12 (6) ◽

pp. 1211-1219 ◽

Cited By ~ 26

Author(s):

Thomas E. Humphreys

Keyword(s):

Sucrose Transport

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Temperature as a key factor for successful inoculation of soybean with Bradyrhizobium spp. under cool growing conditions in Belgium

The Journal of Agricultural Science ◽

10.1017/s0021859618000515 ◽

2018 ◽

Vol 156 (4) ◽

pp. 493-503 ◽

Cited By ~ 3

Author(s):

J. Pannecoucque ◽

S. Goormachtigh ◽

J. Ceusters ◽

J. Debode ◽

C. Van Waes ◽

...

Keyword(s):

Field Trials ◽

Protein Yield ◽

Control Treatment ◽

Rhizobial Symbiosis ◽

Key Factor ◽

Growing Conditions ◽

Set Up ◽

Biological Nitrogen ◽

Intermediate Performance

AbstractBacterial inoculation of soybean seeds to improve biological nitrogen fixation is a well-known practice to achieve higher seed and protein yield with reduced fertilization. The optimal inoculation strategy in temperate regions is unknown because soybeans are rarely cultivated under colder growing conditions. The aim of the present work was to determine the most suitable inoculation strategy for soybean cultivation in Belgium. Field trials were set up with four Bradyrhizobium inoculants (HiStick, Force 48, Biodoz and Optimize) at two locations over 2 years (2014–2015) and compared with a non-inoculated control treatment. In addition, HiStick was tested at three doses and Optimize at two time periods prior to sowing. Under Belgian conditions, all inoculants were effective in establishing rhizobial symbiosis, resulting in increased yield, protein content, protein yield and thousand-grain weight compared with the non-inoculated control. A single dose of HiStick was sufficient to establish symbiosis. Pre-inoculation with Optimize 2 weeks before sowing gave an intermediate performance for most parameters between the non-inoculated control treatment and inoculation with Optimize 24 h prior to sowing. Among the four products tested, Biodoz seemed the best product for inoculation under cool growing conditions. Based on the atpD gene, the bacterial strain of Biodoz showed complete similarity with Bradyrhizobium diazoefficiens, while strains of other products were identified as Bradyrhizobium japonicum. In vitro growing capacity of the Biodoz strain at 8 °C was higher compared with the other strains. Better cold adaptation of the Biodoz strain might be a possible explanation for the better performance of Biodoz in Belgium.

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