VIGS for Dissecting Mechanisms Involved in the Symbiotic Interaction of Microbes with Plants

Author(s):  
Mette Grønlund
1991 ◽  
Vol 23 (4-6) ◽  
pp. 973-980 ◽  
Author(s):  
M. Takahashi ◽  
S. Kyosai

A Multi-stage Reversing flow Bioreactor (MRB) was developed by the Public Works Research Institute in 1986. It utilizes the symbiotic interaction between anaerobic bacteria (sulfate reducing bacteria) and microaerobic bacteria (Beggiatoa=filamentous sulfur oxidizing bacteria) for self-granulated pellet formation. A MRB Pilot plant for domestic wastewater treatment (design capacity was 225 m3/day) was constructed in 1988. After several modifications of the initial design, stable pellet formation and high performance were achieved. This paper describes the results of the pilot plant operation.


2021 ◽  
Vol 9 (1) ◽  
pp. 140
Author(s):  
Ruying Wang ◽  
Simin Luo ◽  
Bruce B. Clarke ◽  
Faith C. Belanger

Strong creeping red fescue (Festuca rubra subsp. rubra) is a commercially important low-maintenance turfgrass and is often naturally infected with the fungal endophyte Epichloë festucae. Epichloë spp. are endophytes of several cool-season grass species, often conferring insect resistance to the grass hosts due to the production of toxic alkaloids. In addition to insect resistance, a unique feature of the strong creeping red fescue/E. festucae symbiosis is the endophyte-mediated disease resistance to the fungal pathogen Clarireedia jacksonii, the causal agent of dollar spot disease. Such disease resistance is not a general feature of other grass/ Epichloë interactions. E. festucae isolates infecting red fescue have an antifungal protein gene Efe-afpA, whereas most other Epichloë spp. do not have a similar gene. The uniqueness of this gene suggests it may, therefore, be a component of the unique disease resistance seen in endophyte-infected red fescue. Here, we report the generation of CRISPR-Cas9 Efe-afpA gene knockouts with the goal of determining if absence of the protein in endophyte-infected Festuca rubra leads to disease susceptibility. However, it was not possible to infect plants with the knockout isolates, although infection was possible with the wild type E. festucae and with complemented isolates. This raises the interesting possibility that, in addition to having antifungal activity, the protein is required for the symbiotic interaction. The antifungal protein is a small secreted protein with high expression in planta relative to its expression in culture, all characteristics consistent with effector proteins. If Efe-AfpA is an effector protein it must be specific to certain interactions, since most Epichloë spp. do not have such a gene in their genomes.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Osamu Kagawa ◽  
◽  
Shota Uchida ◽  
Daishi Yamazaki ◽  
Yumiko Osawa ◽  
...  

AbstractEnvironmental factors promote symbiosis, but its mechanism is not yet well understood. The alga Pseudocladophora conchopheria grows only on the shell of an intertidal gastropod Lunella correensis, and these species have a close symbiotic relationship which the alga reduces heat stress of the gastropod. In collaboration with general public, we investigated how environmental conditions alter the symbiotic interaction between the alga and the gastropod. Information about the habitats of each gastropod and images of shells was obtained from the Japanese and Korean coasts via social media. We constructed the hierarchical Bayesian model using the data. The results indicated that the proportion of shell area covered by P. conchopheria increased as the substrate size utilized by the gastropod increased. Meanwhile, temperature did not affect the proportion of P. conchopheria on the shell. These suggested that the alga provides no benefits for the gastropod on small substrates because gastropod can reduce the heat stress by diving into the small sediment. Further, the gastropod’s cost incurred by growing the alga on the shell seems to be low as the algae can grow even in cooler places where no benefits of heat resistance for gastropods. Different environments can yield variable conditions in symbiosis.


Plant Biology ◽  
2021 ◽  
Author(s):  
V. L. Muñoz ◽  
M. S. Figueredo ◽  
H. Reinoso ◽  
A. Fabra

2006 ◽  
Vol 19 (12) ◽  
pp. 1444-1450 ◽  
Author(s):  
Fabien Lombardo ◽  
Anne B. Heckmann ◽  
Hiroki Miwa ◽  
Jillian A. Perry ◽  
Koji Yano ◽  
...  

During the symbiotic interaction between legumes and rhizobia, the host cell plasma membrane and associated plant cell wall invaginate to form a tunnel-like infection thread, a structure in which bacteria divide to reach the plant root cortex. We isolated four Lotus japonicus mutants that make infection pockets in root hairs but form very few infection threads after inoculation with Mesorhizobium loti. The few infection threads that did initiate in the mutants usually did not progress further than the root hair cell. These infection-thread deficient (itd) mutants were unaffected for early symbiotic responses such as calcium spiking, root hair deformation, and curling, as well as for the induction of cortical cell division and the arbuscular mycorrhizal symbiosis. Complementation tests and genetic mapping indicate that itd2 is allelic to Ljsym7, whereas the itd1, itd3, and itd4 mutations identified novel loci. Bacterial release into host cells did occur occasionally in the itd1, itd2, and itd3 mutants suggesting that some infections may succeed after a long period and that infection of nodule cells could occur normally if the few abnormal infection threads that were formed reached the appropriate nodule cells.


2008 ◽  
Vol 21 (6) ◽  
pp. 781-790 ◽  
Author(s):  
Alberto Ferrarini ◽  
Matteo De Stefano ◽  
Emmanuel Baudouin ◽  
Chiara Pucciariello ◽  
Annalisa Polverari ◽  
...  

Nitric oxide (NO) is involved in diverse physiological processes in plants, including growth, development, response to pathogens, and interactions with beneficial microorganisms. In this work, a dedicated microarray representing the widest database available of NO-related transcripts in plants has been produced with 999 genes identified by a cDNA amplified fragment length polymorphism analysis as modulated in Medicago truncatula roots treated with two NO donors. The microarray then was used to monitor the expression of NO-responsive genes in M. truncatula during the incompatible interaction with the foliar pathogen Colletotrichum trifolii race 1 and during the symbiotic interaction with Sinorhizobium meliloti 1021. A wide modulation of NO-related genes has been detected during the hypersensitive reaction or during nodule formation and is discussed with special emphasis on the physiological relevance of these genes in the context of the two biotic interactions. This work clearly shows that NO-responsive genes behave differently depending on the plant organ and on the type of interaction, strengthening the need to consider regulatory networks, including different signaling molecules.


2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Jéssica Dutra Vieira ◽  
Paulo Roberto Diniz Da Silva ◽  
Valdir Marcos Stefenon

The indoleacetic acid produced by symbiotic bacteria is an important phytohormone signaling microbe-plant interaction, being therefore essential for rhizoremediation. In this study, the effect of different concentrations of copper ions on the bacterial growth and indoleacetic acid production was investigated in two strains of Mesorhizobium loti in in vitro conditions, aiming to determine critical concentrations of this heavy metal for rhizoremediation of contaminated soils using this bacterium. The experiment consisted on a control culture without copper and three treatments supplemented with 10 mg.L-1, 20 mg.L-1 or 50 mg.L-1 of CuSO4. For both strains, the growth stopped after 48h and no significant difference was observed across treatments. The production of indoleacetic acid by the control treatment without copper was significantly higher in comparison to the copper- containing treatments. Mesorhizobium loti SEMIA806 and SEMIA816 are resistant to up to 50 mg.L-1 of CuSO4 in the culture medium, presenting effective growth. The synthesis of indoleacetic acid was strongly reduced but not excluded by ions copper in the medium. So, it is expected that environmental copper found in the soil up to the concentration of 50 mg.L-1 will not preclude the symbiotic interaction between M. loti and leguminous host plant in rhizoremediation enterprises.


2021 ◽  
Author(s):  
Wanda Biala-Leonhard ◽  
Laura Zanin ◽  
Stefano Gottardi ◽  
Rita de Brito Francisco ◽  
Silvia Venuti ◽  
...  

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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