scholarly journals Ectopic or Over-Expression of Class 1 Phytoglobin Genes Confers Flooding Tolerance to the Root Nodules of Lotus japonicus by Scavenging Nitric Oxide

Antioxidants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 206 ◽  
Author(s):  
Mitsutaka Fukudome ◽  
Eri Watanabe ◽  
Ken-ichi Osuki ◽  
Nahoko Uchi ◽  
Toshiki Uchiumi

Flooding limits biomass production in agriculture. Leguminous plants, important agricultural crops, use atmospheric dinitrogen gas as nitrogen nutrition by symbiotic nitrogen fixation with rhizobia, but this root-nodule symbiosis is sometimes broken down by flooding of the root system. In this study, we analyzed the effect of flooding on the symbiotic system of transgenic Lotus japonicus lines which overexpressed class 1 phytoglobin (Glb1) of L. japonicus (LjGlb1-1) or ectopically expressed that of Alnus firma (AfGlb1). In the roots of wild-type plants, flooding increased nitric oxide (NO) level and expression of senescence-related genes and decreased nitrogenase activity; in the roots of transgenic lines, these effects were absent or less pronounced. The decrease of chlorophyll content in leaves and the increase of reactive oxygen species (ROS) in roots and leaves caused by flooding were also suppressed in these lines. These results suggest that increased levels of Glb1 help maintain nodule symbiosis under flooding by scavenging NO and controlling ROS.

Science ◽  
2019 ◽  
Vol 366 (6468) ◽  
pp. 1021-1023 ◽  
Author(s):  
Takashi Soyano ◽  
Yoshikazu Shimoda ◽  
Masayoshi Kawaguchi ◽  
Makoto Hayashi

Legumes develop root nodules in symbiosis with nitrogen-fixing rhizobial bacteria. Rhizobia evoke cell division of differentiated cortical cells into root nodule primordia for accommodating bacterial symbionts. In this study, we show that NODULE INCEPTION (NIN), a transcription factor in Lotus japonicus that is essential for initiating cortical cell divisions during nodulation, regulates the gene ASYMMETRIC LEAVES 2-LIKE18/LATERAL ORGAN BOUNDARIES DOMAIN16a (ASL18/LBD16a). Orthologs of ASL18/LBD16a in nonlegume plants are required for lateral root development. Coexpression of ASL18a and the CCAAT box–binding protein Nuclear Factor-Y (NF-Y) subunits, which are also directly targeted by NIN, partially suppressed the nodulation-defective phenotype of L. japonicusdaphne mutants, in which cortical expression of NIN was attenuated. Our results demonstrate that ASL18a and NF-Y together regulate nodule organogenesis. Thus, a lateral root developmental pathway is incorporated downstream of NIN to drive nodule symbiosis.


2021 ◽  
Vol 36 (3) ◽  
pp. n/a
Author(s):  
Mitsutaka Fukudome ◽  
Yuta Shimokawa ◽  
Shun Hashimoto ◽  
Yusuke Maesako ◽  
Nahoko Uchi-Fukudome ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Takahashi ◽  
Kaori Shiojiri ◽  
Akira Yamawo

AbstractAboveground communication between plants is well known to change defense traits in leaves, but its effects on belowground plant traits and soil characteristics have not been elucidated. We hypothesized that aboveground plant-to-plant communication reduces root nodule symbiosis via induction of bactericidal chemical defense substances and changes the soil nutrient environment. Soybean plants were exposed to the volatile organic compounds (VOCs) from damaged shoots of Solidago canadensis var. scabra, and leaf defense traits (total phenolics, saponins), root saponins, and root nodule symbiosis traits (number and biomass of root nodules) were measured. Soil C/N ratios and mineral concentrations were also measured to estimate the effects of resource uptake by the plants. We found that total phenolics were not affected. However, plants that received VOCs had higher saponin concentrations in both leaves and roots, and fewer root nodules than untreated plants. Although the concentrations of soil minerals did not differ between treatments, soil C/N ratio was significantly higher in the soil of communicated plants. Thus, the aboveground plant-to-plant communication led to reductions in root nodule symbiosis and soil nutrient concentrations. Our results suggest that there are broader effects of induced chemical defenses in aboveground plant organs upon belowground microbial interactions and soil nutrients, and emphasize that plant response based on plant-to-plant communications are a bridge between above- and below-ground ecosystems.


2002 ◽  
Vol 68 (11) ◽  
pp. 5217-5222 ◽  
Author(s):  
Raul Rivas ◽  
Encarna Velázquez ◽  
Anne Willems ◽  
Nieves Vizcaíno ◽  
Nanjappa S. Subba-Rao ◽  
...  

ABSTRACT Rhizobia are the common bacterial symbionts that form nitrogen-fixing root nodules in legumes. However, recently other bacteria have been shown to nodulate and fix nitrogen symbiotically with these plants. Neptunia natans is an aquatic legume indigenous to tropical and subtropical regions and in African soils is nodulated by Allorhizobium undicola. This legume develops an unusual root-nodule symbiosis on floating stems in aquatic environments through a unique infection process. Here, we analyzed the low-molecular-weight RNA and 16S ribosomal DNA (rDNA) sequence of the same fast-growing isolates from India that were previously used to define the developmental morphology of the unique infection process in this symbiosis with N. natans and found that they are phylogenetically located in the genus Devosia, not Allorhizobium or Rhizobium. The 16S rDNA sequences of these two Neptunia-nodulating Devosia strains differ from the only species currently described in that genus, Devosia riboflavina. From the same isolated colonies, we also located their nodD and nifH genes involved in nodulation and nitrogen fixation on a plasmid of approximately 170 kb. Sequence analysis showed that their nodD and nifH genes are most closely related to nodD and nifH of Rhizobium tropici, suggesting that this newly described Neptunia-nodulating Devosia species may have acquired these symbiotic genes by horizontal transfer.


2019 ◽  
Vol 20 (2) ◽  
pp. 235 ◽  
Author(s):  
Izabela Sańko-Sawczenko ◽  
Dominika Dmitruk ◽  
Barbara Łotocka ◽  
Elżbieta Różańska ◽  
Weronika Czarnocka

Auxins are postulated to be one of the pivotal factors in nodulation. However, their transporters in Lotus japonicus, the model species for the study of the development of determinate-type root nodules, have been scarcely described so far, and thus their role in nodulation has remained unknown. Our research is the first focusing on polar auxin transporters in L. japonicus. We analyzed and compared expression of PINs in 20 days post rhizobial inoculation (dpi) and 54 dpi root nodules of L. japonicus by real-time quantitative polymerase chain reaction (qPCR) along with the histochemical β-glucuronidase (GUS) reporter gene assay in transgenic hairy roots. The results indicate that LjPINs are essential during root nodule development since they are predominantly expressed in the primordia and young, developing nodules. However, along with differentiation, expression levels of several PINs decreased and occurred particularly in the nodule vascular bundles, especially in connection with the root’s stele. Moreover, our study demonstrated the importance of both polar auxin transport and auxin intracellular homeostasis during L. japonicus root nodule development and differentiation.


Science ◽  
2020 ◽  
Vol 369 (6504) ◽  
pp. 663-670 ◽  
Author(s):  
Zoltan Bozsoki ◽  
Kira Gysel ◽  
Simon B. Hansen ◽  
Damiano Lironi ◽  
Christina Krönauer ◽  
...  

Plants evolved lysine motif (LysM) receptors to recognize and parse microbial elicitors and drive intracellular signaling to limit or facilitate microbial colonization. We investigated how chitin and nodulation (Nod) factor receptors of Lotus japonicus initiate differential signaling of immunity or root nodule symbiosis. Two motifs in the LysM1 domains of these receptors determine specific recognition of ligands and discriminate between their in planta functions. These motifs define the ligand-binding site and make up the most structurally divergent regions in cognate Nod factor receptors. An adjacent motif modulates the specificity for Nod factor recognition and determines the selection of compatible rhizobial symbionts in legumes. We also identified how binding specificities in LysM receptors can be altered to facilitate Nod factor recognition and signaling from a chitin receptor, advancing the prospects of engineering rhizobial symbiosis into nonlegumes.


2020 ◽  
Author(s):  
Akira Akamatsu ◽  
Miwa Nagae ◽  
Yuka Nishimura ◽  
Daniela Romero Montero ◽  
Satsuki Ninomiya ◽  
...  

2010 ◽  
Vol 23 (6) ◽  
pp. 784-790 ◽  
Author(s):  
Marion Koch ◽  
Nathanaël Delmotte ◽  
Hubert Rehrauer ◽  
Julia A. Vorholt ◽  
Gabriella Pessi ◽  
...  

Rhizobia are able to infect legume roots, elicit root nodules, and live therein as endosymbiotic, nitrogen-fixing bacteroids. Host recognition and specificity are the results of early programming events in bacteria and plants, in which important signal molecules play key roles. Here, we introduce a new aspect of this symbiosis: the adaptive response to hosts. This refers to late events in bacteroids in which specific genes are transcribed and translated that help the endosymbionts to meet the disparate environmental requirements imposed by the hosts in which they live. The host-adaptation concept was elaborated with Bradyrhizobium japonicum and three different legumes (soybean, cowpea, and siratro). Transcriptomes and proteomes in root-nodule bacteroids were analyzed and compared, and genes and proteins were identified which are specifically induced in only one of the three hosts. We focused on those determinants that were congruent in the two data sets of host-specific transcripts and proteins: seven for soybean, five for siratro, and two for cowpea. One gene cluster for a predicted ABC-type transporter, differentially expressed in siratro, was deleted in B. japonicum. The respective mutant had a symbiotic defect on siratro rather than on soybean or cowpea. This result demonstrates the value of the applied approach and corroborates the host-specific adaptation concept.


1992 ◽  
Vol 38 (6) ◽  
pp. 577-583 ◽  
Author(s):  
J. K. Ladha ◽  
Minviluz Garcia ◽  
R. P. Pareek ◽  
G. Rarivoson

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.


eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Martina Katharina Ried ◽  
Meritxell Antolín-Llovera ◽  
Martin Parniske

Symbiosis Receptor-like Kinase (SYMRK) is indispensable for the development of phosphate-acquiring arbuscular mycorrhiza (AM) as well as nitrogen-fixing root nodule symbiosis, but the mechanisms that discriminate between the two distinct symbiotic developmental fates have been enigmatic. In this study, we show that upon ectopic expression, the receptor-like kinase genes Nod Factor Receptor 1 (NFR1), NFR5, and SYMRK initiate spontaneous nodule organogenesis and nodulation-related gene expression in the absence of rhizobia. Furthermore, overexpressed NFR1 or NFR5 associated with endogenous SYMRK in roots of the legume Lotus japonicus. Epistasis tests revealed that the dominant active SYMRK allele initiates signalling independently of either the NFR1 or NFR5 gene and upstream of a set of genes required for the generation or decoding of calcium-spiking in both symbioses. Only SYMRK but not NFR overexpression triggered the expression of AM-related genes, indicating that the receptors play a key role in the decision between AM- or root nodule symbiosis-development.


Sign in / Sign up

Export Citation Format

Share Document