scholarly journals Three common symbiotic ABC-B transporters in Medicago truncatula are regulated by a NIN-independent branch of the symbiosis signalling pathway.

Author(s):  
Sonali Roy ◽  
Andrew Breakspear ◽  
Donna Cousins ◽  
Ivone Torres-Jerez ◽  
Kirsty Jean Jackson ◽  
...  

Several ATP-Binding Cassette (ABC) transporters involved in the arbuscular mycorrhizal symbiosis and nodulation have been identified. We describe three previously-unreported ABC subfamily-B transporters, named ABCB for Mycorrhization and Nodulation (AMN1, AMN2, and AMN3), that are expressed early during infection by rhizobia and arbuscular mycorrhizal fungi. These ABCB transporters are strongly expressed in symbiotically infected tissues, including in root hair cells with rhizobial infection threads and arbusculated cells. During nodulation, the expression of these genes is highly induced by rhizobia and purified Nod factors, and was dependent on DMI3, but is not dependent on other known major regulators of infection such as NIN, NSP1, or NSP2. During mycorrhization their expression is dependent on DMI3 and RAM1, but not on NSP1 and NSP2. Therefore, they may be commonly regulated through a distinct branch of the common symbiotic pathway. Mutants with exonic Tnt1-transposon insertions were isolated for all three genes. None of the single or double mutants showed any differences in colonization by either rhizobia or mycorrhizal fungi, but the triple amn1 amn2 amn3 mutant showed an increase in nodule number. Further studies are needed to identify potential substrates of these transporters and understand their roles in these beneficial symbioses.

2018 ◽  
Vol 60 (3) ◽  
pp. 575-586 ◽  
Author(s):  
Oswaldo Vald�s-L�pez ◽  
Dhileepkumar Jayaraman ◽  
Junko Maeda ◽  
Pierre-Marc Delaux ◽  
Muthusubramanian Venkateshwaran ◽  
...  

Abstract Signals and signaling pathways underlying the symbiosis between legumes and rhizobia have been studied extensively over the past decades. In a previous phosphoproteomic study on the Medicago truncatula–Sinorhizobium meliloti symbiosis, we identified plant proteins that are differentially phosphorylated upon the perception of rhizobial signals, called Nod factors. In this study, we provide experimental evidence that one of these proteins, Early Phosphorylated Protein 1 (EPP1), is required for the initiation of this symbiosis. Upon inoculation with rhizobia, MtEPP1 expression was induced in curled root hairs. Down-regulation of MtEPP1 in M. truncatula roots almost abolished calcium spiking, reduced the expression of essential symbiosis-related genes (MtNIN, MtNF-YB1, MtERN1 and MtENOD40) and strongly decreased nodule development. Phylogenetic analyses revealed that orthologs of MtEPP1 are present in legumes and specifically in plant species able to host arbuscular mycorrhizal fungi, suggesting a possible role in this association too. Short chitin oligomers induced the phosphorylation of MtEPP1 like Nod factors. However, the down-regulation of MtEPP1 affected the colonization of M. truncatula roots by arbuscular mycorrhizal fungi only moderately. Altogether, these findings indicate that MtEPP1 is essential for the establishment of the legume–rhizobia symbiosis but might plays a limited role in the arbuscular mycorrhizal symbiosis.


2018 ◽  
Author(s):  
Ivan D. Mateus ◽  
Frédéric G. Masclaux ◽  
Consolée Aletti ◽  
Edward C. Rojas ◽  
Romain Savary ◽  
...  

AbstractArbuscular mycorrhizal fungi (AMF) impact plant growth and are a major driver of plant diversity and productivity. We quantified the contribution of intra-specific genetic variability in cassava (Manihot esculenta) and Rhizophagus irregularis to gene reprogramming in symbioses using dual RNA-sequencing. A large number of cassava genes exhibited altered transcriptional responses to the fungus but transcription of most of these plant genes (72%) responded in a different direction or magnitude depending on the plant genotype. Two AMF isolates displayed large differences in their transcription, but the direction and magnitude of the transcriptional responses for a large number of these genes was also strongly influenced by the genotype of the plant host. This indicates that unlike the highly conserved plant genes necessary for the symbiosis establishment, plant and fungal gene transcriptional responses are not conserved and are greatly influenced by plant and fungal genetic differences, even at the within-species level. The transcriptional variability detected allowed us to identify an extensive gene network showing the interplay in plant-fungal reprogramming in the symbiosis. Key genes illustrated that the two organisms jointly program their cytoskeleton organisation during growth of the fungus inside roots. Our study reveals that plant and fungal genetic variation plays a strong role in shaping the genetic reprograming in response to symbiosis, indicating considerable genotype x genotype interactions in the mycorrhizal symbiosis. Such variation needs to be considered in order to understand the molecular mechanisms between AMF and their plant hosts in natural communities.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Li Cui ◽  
Feng Guo ◽  
Jialei Zhang ◽  
Sha Yang ◽  
JingJing Meng ◽  
...  

Abstract Peanut yield is severely affected by exchangeable calcium ion (Ca2+) deficiency in the soil. Arbuscular mycorrhizal (AM) symbiosis increases the absorption of Ca2+ for host plants. Here, we analyzed the physiological and transcriptional changes in the roots of Arachis hypogaea L. colonized by Funneliformismosseae under Ca2+-deficient and -sufficient conditions. The results showed that exogenous Ca2+ application increased arbuscular mycorrhizal fungi (AMF) colonization, plant dry weight, and Ca content of AM plants. Simultaneously, transcriptome analysis showed that Ca2+ application further induced 74.5% of differentially expressed gene transcripts in roots of AM peanut seedlings. These genes are involved in AM symbiosis development, hormone biosynthesis and signal transduction, and carotenoid and flavonoid biosynthesis. The transcripts of AM-specific marker genes in AM plants with Ca2+ deprivation were further up-regulated by Ca2+ application. Gibberellic acid (GA3) and flavonoid contents were higher in roots of AM- and Ca2+-treated plants, but salicylic acid (SA) and carotenoid contents specifically increased in roots of the AM plants. Thus, these results suggest that the synergy of AM symbiosis and Ca2+ improves plant growth due to the shared GA- and flavonoid-mediated pathway, whereas SA and carotenoid biosynthesis in peanut roots are specific to AM symbiosis.


2012 ◽  
Vol 518-523 ◽  
pp. 5381-5384
Author(s):  
Song Mei Shi ◽  
Bo Tu ◽  
Dai Jun Liu ◽  
Xiao Hong Yang

Physic nut (Jatropha curcas Linn., Euphorbiaceae) is one of the hottest biomass energy plant studied by scientists. This paper first reviewed the symbiosis relationship between physic nut and arbuscular mycorrhizal fungi. The researches have showed that diversity of arbuscular mycorrhizal fungi (AMF) exists around the rhizosphere of physic nut. The AMF hyphae colonize root tips of physic nut to develop arbuscular mycorrhizae. The construction of mycorrhizal symbiosis relationship improves the nutritional absorption, promotes the growth and development of seedlings, and enhance the stress tolerance capacity of physic nut. This paper also displays a prospect for mycorrhizal physic nut research in the future, such as mycorrhizal system, the molecular mechanism for stress resistance and gene engineering. As an important resource of biomass energy, mycorrhizal physic nut has a huge exploitation potential and practical value.


2008 ◽  
Vol 56 (5) ◽  
pp. 802-813 ◽  
Author(s):  
Luis Cárdenas ◽  
Adán Martínez ◽  
Federico Sánchez ◽  
Carmen Quinto

2013 ◽  
Vol 281 ◽  
pp. 664-669
Author(s):  
En Wu ◽  
Guo Rong Xin ◽  
Kazuo Sugawara

With the aggravation of volcanic ash Andosol acidification, artificial forage grass Dactylis glomerata L. gradual degradation, replaced by weed plant Anthoxanthum odoratum L., but the mechanism is unclear. In order to reveal the mechanism, this study used Andosol soil as matrix, explored the effects of arbuscular mycorrhizal fungi on D. glomerata and A. odoratum at different pH gradients in acidic Andosol by glasshouse experiment. The results show that the mycorrhizal colonization of D. glomerata strongly affected by soil pH, but the A. odoratum was not yet. The mycorrhizal symbiosis led to a positive effect on growth and P uptake of D. glomerata and A. odoratum. Consider to invasion and expansion of A. odoratum in severity acidic pasture is origin of this specificity on arbuscular mycorrhizal symbiosis in acidic soil other than D. glomerata.


2021 ◽  
pp. 339-355
Author(s):  
Michel Ruiz Sánchez ◽  
Juan Adriano Cabrera Rodríguez ◽  
José M. Del'Anico Rodríguez ◽  
Yaumara Muñoz Hernández ◽  
Ricardo Aroca Álvarez ◽  
...  

Introduction. The water deficit negatively affects rice plants and limits their productivity. Arbuscular mycorrhizal symbiosis has been shown to improve rice productivity in drought conditions. Objective. To propose a new categorization for the state of water stress of rice plants inoculated (AM) or not with arbuscular mycorrhizal fungi (nonAM) and exposed to water deficit (D) during the vegetative phase. Materials and methods. The experiment was carried out under controlled greenhouse conditions during the years 2009 and 2010 at the Zaidín Experimental Station, Granada, Spain. The rice transplantation was carried out fourteen days after germination to pots with a 5 cm water sheet and at 30, 40, or 50 days after transplantation (DAT) they were subjected to water deficit during a period of 15 days, at which time the water sheet was restored. The control treatment was maintained throughout the cycle under flood conditions (ww). Evaluations were performed at 45, 55, 65 DAT and after recovery at 122 DAT. The harvest was carried out at 147 DAT. Results. The reduction in water supply demonstrated water stress in the plants, manifested by the decrease in the water potential of the leaves. Arbuscular mycorrhizal symbiosis always favored the water status of the plant. Four categories of water status of plants were proposed taking into account water potentials and agricultural yield: no stress (≥-0.67 MPa); light stress (<-0.67 to -1.20 MPa); moderate stress (<-1.20 to -1.60 MPa), and severe stress (<-1.60 MPa). Conclusion. The categorization of stress due to the water deficit is a tool of high scientific value for the specific case of rice, since this plant has the capacity to adapt to tolerate the presence of a sheet of water throughout its biological cycle and is highly susceptible to water deficit.


Author(s):  
Poonam Jaiswal ◽  
Suresh Singh Rajpurohit

Mycorrhizal symbiosis occurs between arbuscular mycorrhizal fungi and most of the vascular plants and is a highly evolved mutually beneficial relationship occurring within the rhizosphere of the vascular plants. The host plants are directly conferred benefits to the growth and development due to this symbiotic association. Their function ranges from stress alleviation to bioremediation in polluted soils besides their importance in the restoration of degraded wastelands. In this investigation colonization percentage and spore density of VAM fungi were studied in industrial waste dump sites and soil having natural vegetation. Industrial waste dump sites are characteristically dominated by Glomus. Mycorrhizal association and spore formation potential of AMF was significantly lowered in soil disturbed due to industrial waste dumping.


2001 ◽  
Vol 79 (10) ◽  
pp. 1175-1180 ◽  
Author(s):  
R Azcón ◽  
J M Ruiz-Lozano ◽  
R Rodríguez

The objective of this study was to determine how the uptake and transport of nitrate by two species of arbuscular mycorrhizal (AM) fungi is affected by its concentration in the medium and by the age of the AM symbiosis. Tracer amounts of15N nitrate were applied at two plant growth periods to mycorrhizal or nonmycorrhizal lettuce plants, which had been grown in soil supplied with nitrate to provide a total of 84, 168, or 252 mg N/kg. At both injection times, Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe and Glomus fasciculatum (Thaxter sensu Gerd.) Gerd. and Trappe reached the highest values of nitrogen derived from the fertilizer (NdfF) at 84 mg N/kg. Glomus mosseae also reached the highest values of labeled fertilizer N utilization at 84 mg N/kg, whereas G. fasciculatum reached the highest values at 168 mg N/kg in the medium. The highest N level in the medium (252 mg N/kg) had a negative effect on % NdfF and % labeled fertilizer utilization for all mycorrhizal plants. Regarding the time of15N fertilizer application, G. fasciculatum-colonized plants had a minimum change in % NdfF and % labeled fertilizer utilization during the growth period (60 days application vs. 30 days application). In contrast, G. mosseae-colonized plants growing at 168 mg N/kg in the medium, decreased these two values in the latest application. The present results confirm that mycorrhizal symbiosis may be particularly important for nitrogen nutrition in plants growing in neutral-alkaline soils.Key words: arbuscular mycorrhizae, nitrate assimilation, nitrate uptake,15N-labeled fertilizer.


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