A D-pinitol transporter, LjPLT11, regulates plant growth and nodule development in Lotus japonicus

2021 ◽  
Author(s):  
Lu Tian ◽  
Leru Liu ◽  
Shaoming Xu ◽  
Rufang Deng ◽  
Pingzhi Wu ◽  
...  
Keyword(s):  
Plant Growth ◽  
Nitrogenase Activity ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Xenopus Laevis Oocytes ◽  
Oxygen Species ◽  
In Planta ◽  
Osmotic Balance ◽  
Infected Cells ◽  
Functional Analyses

Abstract Polyol transporters (PLTs) have been functionally characterized in yeast and Xenopus laevis oocytes as H +-symporters with broad substrate specificity, but little is known about their physiological roles in planta. To extend this knowledge we investigated roles of LjPLT11 in Lotus japonicus-Mesorhizobium symbiosis. Functional analyses of the LjPLT11 in yeast characterized this protein as an energy-independent transporter of xylitol, two O-methyl inositols, xylose and galactose. We also showed that LjPLT11 is located on peribacteroid membranes (PBMs) and functions as a facilitative transporter of D-pinitol within infected cells of L. japonicus nodules. Knockdown of LjPLT11 (LjPLT11i) in L. japonicus accelerated plant growth under nitrogen-sufficiency, but resulted in abnormal bacteroids with corresponding reductions in nitrogenase activity in nodules and plant growth in the nitrogen-fixing symbiosis. LjPLT11i nodules had higher osmotic pressure in cytosol and fewer in bacteroids than wildtype nodules both three and four weeks after inoculation of M. loti. Levels and distributions of reactive oxygen species were also perturbed in infected cells of four-week-old nodules in LjPLT11i plants. The results indicate that LjPLT11 plays a key role in adjustment of levels of its substrate pinitol, and thus maintenance of osmotic balance in infected cells and PBM stability during nodule development.

scholarly journals An Iron Uptake Operon Required for Proper Nodule Development in the Bradyrhizobium japonicum-Soybean Symbiosis

2005 ◽  
Vol 18 (9) ◽  
pp. 950-959 ◽  
Author(s):  
Heather P. Benson ◽  
Eric Boncompagni ◽  
Mary Lou Guerinot
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Iron Acquisition ◽  
Outer Membrane Proteins ◽  
Protein Characterization ◽  
Nodule Development ◽  
In Planta ◽  
Siderophore Receptors ◽  
Infected Cells ◽  
Inner Membrane Protein ◽  
Mutant Forms

Rhizobia live in the soil or enter into a nitrogen-fixing symbiosis with a suitable host plant. Each environment presents different challenges with respect to iron acquisition. The soybean symbiont Bradyrhizobium japonicum 61A152 can utilize a variety of siderophores (Fe[III]-specific ligands). Purification of iron-regulated outer membrane proteins had previously allowed the cloning of a gene, fegA, from B. ja-ponicum 61A152, whose predicted protein shares significant amino acid similarity with known TonB-dependent siderophore receptors. Here, we show that fegA is in an operon with a gene, fegB, that is predicted to encode an inner membrane protein. Characterization of fegAB and fegB mutants shows that both fegA and fegB are required for utilization of the siderophore ferrichrome. Whereas the fegB mutant forms a normal symbiosis, the fegAB mutant has a dramatic phenotype in planta. Six weeks after inoculation with a fegAB strain, soybean nodules do not contain leghemoglobin and do not fix nitrogen. Infected cells contain few symbiosomes and are filled with vesicles. As ferrichrome is a fungal siderophore not likely to be available in nodules, the symbiotic defect suggests that the fegAB operon is serving a different function in planta, possibly one involved in signaling between the two partners.

scholarly journals A Novel Fix¯ Symbiotic Mutant of Lotus japonicus, Ljsym105, Shows Impaired Development and Premature Deterioration of Nodule Infected Cells and Symbiosomes

2006 ◽  
Vol 19 (7) ◽  
pp. 780-788 ◽  
Author(s):  
Md. Shakhawat Hossain ◽  
Yosuke Umehara ◽  
Hiroshi Kouchi
Keyword(s):  
Nitrogen Deficiency ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Acetylene Reduction Activity ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Electron Microscopic ◽  
Model Legume ◽  
Mesorhizobium Loti ◽  
Infected Cells

Nitrogen-fixing symbiosis between legume plants and rhizobia is established through complex interactions between two symbiotic partners. To identify the host legume genes that play crucial roles in such interactions, we isolated a novel Fix¯ mutant, Ljsym105, from a model legume Lotus japonicus MG-20. The Ljsym105 plants displayed nitrogen-deficiency symptoms after inoculation with Mesorhizobium loti under nitrogen-free conditions, but their growth recovered when supplied with nitrogen-rich nutrients. Ljsym105 was recessive and monogenic and mapped on the upper portion of chromosome 4. The mutant Ljsym105 formed an increased number of small and pale-pink nodules. Nitrogenase (acetylene reduction) activity per nodule fresh weight was low but retained more than 50% of that of the wild-type nodules. Light and electron microscopic observations revealed that the Ljsym105 nodule infected cells were significantly smaller than those of wild-type plants, contained enlarged symbiosomes with multiple bacteroids, and underwent deterioration of the symbiosomes prematurely as well as disintegration of the whole infected cell cytoplasm. These results indicate that the ineffectiveness of the Ljsym105 nodules is primarily due to impaired growth of infected cells accompanied with the premature senescence induced at relatively early stages of nodule development. These symbiotic phenotypes are discussed in respect to possible functions of the LjSym105 locus in the symbiotic interactions required for establishment of the nitrogen-fixing symbiosis.

scholarly journals Experimental evolution can enhance benefits of rhizobia to novel legume hosts

2021 ◽  
Vol 288 (1951) ◽  
pp. 20210812
Author(s):  
Kenjiro W. Quides ◽  
Alexandra J. Weisberg ◽  
Jerry Trinh ◽  
Fathi Salaheldine ◽  
Paola Cardenas ◽  
...  
Keyword(s):  
Root Nodules ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Nodule Formation ◽  
In Planta ◽  
Genetic Changes ◽  
Reduced Costs ◽  
Full Factorial ◽  
Host Tissues

Legumes preferentially associate with and reward beneficial rhizobia in root nodules, but the processes by which rhizobia evolve to provide benefits to novel hosts remain poorly understood. Using cycles of in planta and in vitro evolution, we experimentally simulated lifestyles where rhizobia repeatedly interact with novel plant genotypes with which they initially provide negligible benefits. Using a full-factorial replicated design, we independently evolved two rhizobia strains in associations with each of two Lotus japonicus genotypes that vary in regulation of nodule formation. We evaluated phenotypic evolution of rhizobia by quantifying fitness, growth effects and histological features on hosts, and molecular evolution via genome resequencing. Rhizobia evolved enhanced host benefits and caused changes in nodule development in one of the four host–symbiont combinations, that appeared to be driven by reduced costs during symbiosis, rather than increased nitrogen fixation. Descendant populations included genetic changes that could alter rhizobial infection or proliferation in host tissues, but lack of evidence for fixation of these mutations weakens the results. Evolution of enhanced rhizobial benefits occurred only in a subset of experiments, suggesting a role for host–symbiont genotype interactions in mediating the evolution of enhanced benefits from symbionts.

Development of an ineffective pea root nodule: morphogenesis, fine structure, and cytokinin biosynthesis

1977 ◽  
Vol 55 (14) ◽  
pp. 1891-1907 ◽  
Author(s):  
William Newcomb ◽  
Kunihiko Syono ◽  
John G. Torrey
Keyword(s):  
Rhizobium Leguminosarum ◽  
Nitrogenase Activity ◽  
Zeatin Riboside ◽  
Infection Process ◽  
Nodule Development ◽  
Cytokinin Biosynthesis ◽  
Low Frequencies ◽  
Host Cytoplasm ◽  
Host Membrane ◽  
Infected Cells

Roots of the garden pea Pisam sativum L. cv. Little Marvel inoculated with Rhizobium leguminosarum strain 1019 produce small white nodules which are ineffective in fixing atmospheric nitrogen. Analyses of cytokinin contents of the nodules at different ages using extraction, purification, and thin-layer chromatographic separation showed that the cytokinins zeatin and zeatin riboside and isopentenyladenine and its riboside were present in greatest amounts early in nodule development and decreased thereafter. A new unidentified cytokinin was present in older nodules. The early stages of the infection process in the ineffective nodules were similar to those observed in effective nodules. However, bacteria released from the bacterial thread via an unwalled droplet were not always surrounded by a host membrane. In later stages of nodule development many infected cells contained rhizobia with no enclosing membranes so that the bacteria were free within the host cytoplasm. Such cells showed very low frequencies of mitochondria, of polyribosomes, and endoplasmic reticulum. Thus, the biosynthetic capacity of the cells appeared to be impaired and membrane synthesis defective. The failure of the nodules to develop nitrogenase activity is probably related to the failure of membrane formation around the bacteria. Abnormalities in amyloplast formation were also noted, as well as structural differences in the nodule, including a higher proportion of uninfected cells and earlier cessation of mitotic activity in the nodule meristem than occurs in effective nodules of pea. Transfer cells were observed in the pericycle in both effective and ineffective nodules.

Host–endophyte interactions in effective and ineffective nodules induced by the endophyte of Myrica gale

1983 ◽  
Vol 61 (11) ◽  
pp. 2898-2909 ◽  
Author(s):  
Kathryn A. VandenBosch ◽  
John G. Torrey
Keyword(s):  
Nitrogenase Activity ◽  
Root Nodules ◽  
Seedling Development ◽  
Nodule Development ◽  
Nodule Formation ◽  
Cortical Tissue ◽  
Intercellular Spaces ◽  
Cortical Cells ◽  
Myrica Gale ◽  
Infected Cells

Suspensions of crushed root nodules of Myrica gale containing the actinomycete Frankia induced nodule formation on roots of seedlings of M. gale and Comptonia peregrina grown in nutrient water culture. Nodules formed on M. gale were normal in structure and exhibited nitrogenase activity (measured as acetylene reduction) and provided the necessary nitrogen for seedling development. These effective nodules showed typical external and internal structure with the endophyte developing both vesicles and sporangia within cortical cells of the host tissue. Small nodules formed on C. peregrina representing the primary nodule stage. They lacked nitrogenase activity and were termed ineffective. Vesicles failed to develop within these ineffective nodules. However, sporangia were formed in infected cells and within intercellular spaces of the nodule cortical tissue. In addition, prominent amyloplasts occurred in infected cells of the ineffective nodules, a feature lacking in effective nodules. Exogenously supplied combined nitrogen increased seedling growth but did not improve nodule development or endophyte morphogenesis in the ineffective nodules.

scholarly journals Recapitulation of the Function and Role of ROS Generated in Response to Heat Stress in Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 371
Author(s):  
Emily Medina ◽  
Su-Hwa Kim ◽  
Miriam Yun ◽  
Won-Gyu Choi
Keyword(s):  
Heat Stress ◽  
Plant Growth ◽  
Intracellular Signaling ◽  
Oxygen Species ◽  
Natural Ecosystems ◽  
Signaling Molecule ◽  
Signaling Systems ◽  
Cell Compartments ◽  
Tropical Area

In natural ecosystems, plants are constantly exposed to changes in their surroundings as they grow, caused by a lifestyle that requires them to live where their seeds fall. Thus, plants strive to adapt and respond to changes in their exposed environment that change every moment. Heat stress that naturally occurs when plants grow in the summer or a tropical area adversely affects plants’ growth and poses a risk to plant development. When plants are subjected to heat stress, they recognize heat stress and respond using highly complex intracellular signaling systems such as reactive oxygen species (ROS). ROS was previously considered a byproduct that impairs plant growth. However, in recent studies, ROS gained attention for its function as a signaling molecule when plants respond to environmental stresses such as heat stress. In particular, ROS, produced in response to heat stress in various plant cell compartments such as mitochondria and chloroplasts, plays a crucial role as a signaling molecule that promotes plant growth and triggers subsequent downstream reactions. Therefore, this review aims to address the latest research trends and understandings, focusing on the function and role of ROS in responding and adapting plants to heat stress.

scholarly journals Multifarious Indigenous Diazotrophic Rhizobacteria of Rice (Oryza sativa L.) Rhizosphere and Their Effect on Plant Growth Promotion

2022 ◽  
Vol 8 ◽  
Author(s):  
Mohammad Imran Mir ◽  
Bee Hameeda ◽  
Humera Quadriya ◽  
B. Kiran Kumar ◽  
Noshin Ilyas ◽  
...  
Keyword(s):  
Plant Growth ◽  
Phosphate Solubilization ◽  
Nitrogenase Activity ◽  
Hydrolytic Enzymes ◽  
Seed Vigor ◽  
Bacterial Isolates ◽  
Diazotrophic Bacteria ◽  
Pgp Traits ◽  
Rice Plants

A diverse group of rhizobacteria persists in the rhizospheric soil, on the surface of roots, or in association with rice plants. These bacteria colonize plant root systems, enhance plant growth and crop yield. Indigenous rhizobacteria are known to promote soil health, grain production quality and serve as sustainable bioinoculant. The present study was aimed to isolate, identify and characterize indigenous plant growth promoting (PGP) diazotrophic bacteria associated with the rhizosphere of rice fields from different areas of Jammu and Kashmir, India. A total of 15 bacteria were isolated and evaluated for various PGP traits, antagonistic activity against phytopathogens, production of hydrolytic enzymes and biofilm formation under in-vitro conditions. The majority of the isolated bacteria were Gram-negative. Out of 15 bacterial isolates, nine isolates produced IAA (12.24 ± 2.86 to 250.3 ± 1.15 μg/ml), 6 isolates exhibited phosphate solubilization activity (36.69 ± 1.63 to 312.4 ± 1.15 μg/ml), 7 isolates exhibited rock phosphate solubilization while 5 isolates solubilized zinc (10–18 mm), 7 isolates showed siderophore production, 8 isolates exhibited HCN production, 6 isolates exhibited aminocyclopropane-1-carboxylate (ACC) deaminase activity, 13 isolates exhibited cellulase activity, nine isolates exhibited amylase and lipase activity and six isolates exhibited chitinase activity. In addition, 5 isolates showed amplification with the nifH gene and showed a significant amount of nitrogenase activity in a range of 0.127–4.39 μmol C2H4/mg protein/h. Five isolates viz., IHK-1, IHK-3, IHK-13, IHK-15 and IHK-25 exhibited most PGP attributes and successfully limited the mycelial growth of Rhizoctonia solani and Fusarium oxysporum in-vitro. All the five bacterial isolates were identified based on morphological, biochemical and 16S rDNA gene sequencing study, as Stenotrophomonas maltophilia, Enterobacter sp., Bacillus sp., Ochrobactrum haematophilum and Pseudomonas aeruginosa. Rice plants developed from seeds inoculated with these PGP strains individually had considerably higher germination percentage, seed vigor index and total dry biomass when compared to control. These findings strongly imply that the PGP diazotrophic bacteria identified in this work could be employed as plant growth stimulators in rice.

scholarly journals SCREENING OF SOIL BACTERIA FOR PLANT GROWTH PROMOTION ACTIVITIES IN VITRO

2016 ◽  
Vol 4 (1) ◽  
pp. 27 ◽  
Author(s):  
Edi Husen
Keyword(s):  
Plant Growth ◽  
Soil Bacteria ◽  
Phosphate Solubilization ◽  
Azotobacter Vinelandii ◽  
Growth Promotion ◽  
Nitrogenase Activity ◽  
Chelating Agent ◽  
Plant Growth Promoting Rhizobacteria ◽  
Iaa Production

Fourteen isolates of soil bacteria, including two known plant growth promoting rhizobacteria (PGPR) strains, Azotobacter vinelandii Mac 259 and Bacillus cereus UW 85, were tested in vitro. Parameters assessed were indoleacetic acid (IAA) production, phosphate solubilization, dinitrogen fixation, and siderophore (Fe-III chelating agent) production. IAA production was assayed colorimetrically using ferric chlorideperchloric acid reagent. Phosphate-solubilization and siderophore production were tested qualitatively by plating the bacteria in Pikovskaya and chrome azurol S agar, respectively. The ability to fix dinitrogen was measured based on nitrogenase activity of the bacteria by gas chromatography. The results showed that twelve isolates produced IAA, ranged from 2.09 to 33.28 µmol ml-1. The ability to solubilize precipitated phosphate was positively exhibited by four isolates (BS 58, BTS, TCaR 61, and BTCaRe 65). Seven isolates including Mac 259 positively produced siderophore. None of the isolates showed nitrogenase activity. Only one isolate (TS 3) did not exhibit any of the traits tested. Isolate TCeRe 60 and reference strain Mac 259 were found to have IAA- and siderophore-producing traits. Four P-solubilizing bacteria (BS 58, BTS, TCaR 61, and BTCaRe 65) were also IAA- and siderophore-producing bacteria. Potential use of these PGPR isolates needs further test in enhancing plant growth.

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