scholarly journals Chemical identification of 18-hydroxycarlactonoic acid as an LjMAX1 product and conversion of 18-hydroxylcarlactonoates to canonical and non-canonical strigolactones in Lotus japonicus

2019 ◽  
Author(s):  
Narumi Mori ◽  
Aika Sado ◽  
Xiaonan Xie ◽  
Kaori Yoneyama ◽  
Kei Asami ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Plant Architecture ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Insertion Mutant ◽  
Methyl Ester Derivative ◽  
Model Legume ◽  
Plant Feeding ◽  
Feeding Experiments ◽  
Endogenous Compound

AbstractStrigolactones (SLs) are a group of plant apocarotenoids that act as rhizosphere signaling molecules for both arbuscular mycorrhizal fungi and root parasitic plants. They also regulate plant architecture as phytohormones. The model legume Lotus japonicus produces canonical 5-deoxystrigol (5DS) and non-canonical lotuslactone (LL). The biosynthesis pathways of the two SLs remain elusive. In this study, we characterized the L. japonicus MAX1 homolog, LjMAX1, found in the Lotus japonicus genome assembly build 2.5. The L. japonicus max1 LORE1 insertion mutant was deficient in 5DS and LL production. A recombinant LjMAX1 protein expressed in yeast microsomes converted carlactone (CL) to 18-hydroxycarlactonoic acid (18-HO-CLA) via carlactonoic acid (CLA). Identity of 18-HO-CLA was confirmed by comparison of the methyl ester derivative of the MAX1 product with the chemically synthesized methyl 18-hydroycarlactonoate (18-HO-MeCLA) using LC-MS/MS. (11R)-CL was detected as an endogenous compound in the root of L. japonicus.13C-labeled CL, CLA, and 18-HO-MeCLA were converted to [13C]-5DS and LL in plant feeding experiments using L. japonicus WT. These results showed that LjMAX1 is the crucial enzyme in the biosynthesis of Lotus SLs and that 18-hydroxylated carlactonoates are precursors for SL biosynthesis in L. japonicus.

scholarly journals Gibberellins Interfere with Symbiosis Signaling and Gene Expression and Alter Colonization by Arbuscular Mycorrhizal Fungi in Lotus japonicus

2014 ◽  
Vol 167 (2) ◽  
pp. 545-557 ◽  
Author(s):  
Naoya Takeda ◽  
Yoshihiro Handa ◽  
Syusaku Tsuzuki ◽  
Mikiko Kojima ◽  
Hitoshi Sakakibara ◽  
...  
Keyword(s):  
Gene Expression ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal

scholarly journals Artificial intelligence enables the identification and quantification of arbuscular mycorrhizal fungi in plant roots

2021 ◽  
Author(s):  
Edouard Evangelisti ◽  
Carl Turner ◽  
Alice McDowell ◽  
Liron Shenhav ◽  
Temur Yunusov ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Plant Root ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Root Systems ◽  
Experimental Conditions ◽  
Root Colonisation ◽  
Fungal Colonisation ◽  
Identification And Quantification

Soil fungi establish mutualistic interactions with the roots of most vascular land plants. Arbuscular mycorrhizal (AM) fungi are among the most extensively characterised mycobionts to date. Current approaches to quantifying the extent of root colonisation and the relative abundance of intraradical hyphal structures in mutant roots rely on staining and human scoring involving simple, yet repetitive tasks prone to variations between experimenters. We developed the software AMFinder which allows for automatic computer vision-based identification and quantification of AM fungal colonisation and intraradical hyphal structures on ink-stained root images using convolutional neural networks. AMFinder delivered high-confidence predictions on image datasets of colonised roots of Medicago truncatula, Lotus japonicus, Oryza sativa and Nicotiana benthamiana obtained via flatbed scanning or digital microscopy enabling reproducible and transparent data analysis. A streamlined protocol for sample preparation and imaging allowed us to quantify dynamic increases in colonisation in whole root systems over time. AMFinder adapts to a wide array of experimental conditions. It enables accurate, reproducible analyses of plant root systems and will support better documentation of AM fungal colonisation analyses. AMFinder can be accessed here: https://github.com/SchornacklabSLCU/amfinder.git

scholarly journals The Medicago truncatula Sucrose Synthase Gene MtSucS1 Is Activated Both in the Infected Region of Root Nodules and in the Cortex of Roots Colonized by Arbuscular Mycorrhizal Fungi

2003 ◽  
Vol 16 (10) ◽  
pp. 903-915 ◽  
Author(s):  
Natalija Hohnjec ◽  
Andreas M. Perlick ◽  
Alfred Pühler ◽  
Helge Küster
Keyword(s):  
Medicago Truncatula ◽  
Mycorrhizal Fungi ◽  
Sucrose Synthase ◽  
Root Nodules ◽  
Arbuscular Mycorrhizal ◽  
Grain Legume ◽  
Sink Strength ◽  
Cortical Cells ◽  
Model Legume ◽  
Microbial Symbionts

The MtSucS1 gene encodes a sucrose synthase (EC 2.4.1.13) in the model legume Medicago truncatula. To determine the expression pattern of this gene in different organs and in particular during root endosymbioses, we transformed M. truncatula with specific regions of MtSucS1 fused to the gusAint reporter gene. These fusions directed an induction to the vasculature of leaves, stems, and roots as well as to flowers, developing seeds, young pods, and germinating seedlings. In root nodules, strong promoter activity occurred in the infected cells of the nitrogen-fixing zone but was additionally observed in the meristematic region, the prefixing zone, and the inner cortex, including the vasculature. Concerning endomycorrhizal roots, the MtSucS1 promoter mediated strongest expression in cortical cells harboring arbuscules. Specifically in highly colonized root sections, GUS-staining was furthermore detected in the surrounding cortical cells, irrespective of a direct contact with fungal structures. In accordance with the presence of an orthologous PsSus1 gene, we observed a comparable regulation of MtSucS1 expression in the grain legume Pisum sativum in response to microbial symbionts. Unlike other members of the MtSucS gene family, the presence of rhizobial or Glomus microsymbionts significantly altered and enhanced MtSucS1 gene expression, leading us to propose that MtSucS1 is involved in generating sink-strength, not only in root nodules but also in mycorrhizal roots.

scholarly journals A Mycorrhizal-Specific Ammonium Transporter from Lotus japonicus Acquires Nitrogen Released by Arbuscular Mycorrhizal Fungi

2009 ◽  
Vol 150 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Mike Guether ◽  
Benjamin Neuhäuser ◽  
Raffaella Balestrini ◽  
Marek Dynowski ◽  
Uwe Ludewig ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Ammonium Transporter

scholarly journals Receptor-mediated chitin perception in legume roots is functionally separable from Nod factor perception

2017 ◽  
Vol 114 (38) ◽  
pp. E8118-E8127 ◽  
Author(s):  
Zoltan Bozsoki ◽  
Jeryl Cheng ◽  
Feng Feng ◽  
Kira Gysel ◽  
Maria Vinther ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Oxygen Species ◽  
Binding Studies ◽  
Root Cells ◽  
Nod Factor ◽  
Defense Response Genes ◽  
Root Tissues ◽  
Molecular Patterns

The ability of root cells to distinguish mutualistic microbes from pathogens is crucial for plants that allow symbiotic microorganisms to infect and colonize their internal root tissues. Here we show thatLotus japonicusandMedicago truncatulapossess very similar LysM pattern-recognition receptors,LjLYS6/MtLYK9 andMtLYR4, enabling root cells to separate the perception of chitin oligomeric microbe-associated molecular patterns from the perception of lipochitin oligosaccharide by theLjNFR1/MtLYK3 andLjNFR5/MtNFP receptors triggering symbiosis. Inactivation of chitin-receptor genes inLjlys6,Mtlyk9, andMtlyr4mutants eliminates early reactive oxygen species responses and induction of defense-response genes in roots.Ljlys6,Mtlyk9, andMtlyr4mutants were also more susceptible to fungal and bacterial pathogens, while infection and colonization by rhizobia and arbuscular mycorrhizal fungi was maintained. Biochemical binding studies with purifiedLjLYS6 ectodomains further showed that at least six GlcNAc moieties (CO6) are required for optimal binding efficiency. The 2.3-Å crystal structure of theLjLYS6 ectodomain reveals three LysMβααβmotifs similar to other LysM proteins and a conserved chitin-binding site. These results show that distinct receptor sets in legume roots respond to chitin and lipochitin oligosaccharides found in the heterogeneous mixture of chitinaceous compounds originating from soil microbes. This establishes a foundation for genetic and biochemical dissection of the perception and the downstream responses separating defense from symbiosis in the roots of the 80–90% of land plants able to develop rhizobial and/or mycorrhizal endosymbiosis.

scholarly journals Role of Cell Wall Polyphosphates in Phosphorus Transfer at the Arbuscular Interface in Mycorrhizas

2021 ◽  
Vol 12 ◽  
Author(s):  
Cuc Thi Nguyen ◽  
Katsuharu Saito
Keyword(s):  
Mycorrhizal Fungi ◽  
Cell Walls ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Distribution Patterns ◽  
Phosphorus Release ◽  
Symbiotic Association ◽  
Fungal Cell ◽  
Main Site ◽  
Fine Branch

Arbuscular mycorrhizal fungi provide plants with soil mineral nutrients, particularly phosphorus. In this symbiotic association, the arbuscular interface is the main site for nutrient exchange. To understand phosphorus transfer at the interface, we analyzed the subcellular localization of polyphosphate (polyP) in mature arbuscules of Rhizophagus irregularis colonizing roots of Lotus japonicus wild-type (WT) and H+-ATPase ha1-1 mutant, which is defective in phosphorus acquisition through the mycorrhizal pathway. In both, the WT and the ha1-1 mutant, polyP accumulated in the cell walls of trunk hyphae and inside fine branch modules close to the trunk hyphae. However, many fine branches lacked polyP. In the mutant, most fine branch modules showed polyP signals compared to the WT. Notably, polyP was also observed in the cell walls of some fine branches formed in the ha1-1 mutant, indicating phosphorus release from fungal cells to the apoplastic regions. Intense acid phosphatase (ACP) activity was detected in the periarbuscular spaces around the fine branches. Furthermore, double staining of ACP activity and polyP revealed that these had contrasting distribution patterns in arbuscules. These observations suggest that polyP in fungal cell walls and apoplastic phosphatases may play an important role in phosphorus transfer at the symbiotic interface in arbuscules.

scholarly journals Role of strigolactones: Signalling and crosstalk with other phytohormones

2020 ◽  
Vol 15 (1) ◽  
pp. 217-228
Author(s):  
Mohammad Faizan ◽  
Ahmad Faraz ◽  
Fareen Sami ◽  
Husna Siddiqui ◽  
Mohammad Yusuf ◽  
...  
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Growth And Development ◽  
Plant Architecture ◽  
Abiotic Factors ◽  
Arbuscular Mycorrhizal ◽  
Plant Growth And Development ◽  
Wide Range ◽  
Physiological Reactions

AbstractPlant hormones play important roles in controlling how plants grow and develop. While metabolism provides the energy needed for plant survival, hormones regulate the pace of plant growth. Strigolactones (SLs) were recently defined as new phytohormones that regulate plant metabolism and, in turn, plant growth and development. This group of phytohormones is derived from carotenoids and has been implicated in a wide range of physiological functions including regulation of plant architecture (inhibition of bud outgrowth and shoot branching), photomorphogenesis, seed germination, nodulation, and physiological reactions to abiotic factors. SLs also induce hyphal branching in germinating spores of arbuscular mycorrhizal fungi (AMF), a process that is important for initiating the connection between host plant roots and AMF. This review outlines the physiological roles of SLs and discusses the significance of interactions between SLs and other phytohormones to plant metabolic responses.

Temporal dynamics of mycorrhizal fungal communities and co-associations with grassland plant communities following experimental manipulation of rainfall

2019 ◽  
Author(s):  
Coline Deveautour ◽  
Sally Power ◽  
Kirk Barnett ◽  
Raul Ochoa-Hueso ◽  
Suzanne Donn ◽  
...  
Keyword(s):  
Community Composition ◽  
Plant Community ◽  
Plant Communities ◽  
Fungal Community ◽  
Mycorrhizal Fungi ◽  
Temporal Dynamics ◽  
Arbuscular Mycorrhizal ◽  
Fungal Communities ◽  
Plant Responses ◽  
Rainfall Regimes

Climate models project overall a reduction in rainfall amounts and shifts in the timing of rainfall events in mid-latitudes and sub-tropical dry regions, which threatens the productivity and diversity of grasslands. Arbuscular mycorrhizal fungi may help plants to cope with expected changes but may also be impacted by changing rainfall, either via the direct effects of low soil moisture on survival and function or indirectly via changes in the plant community. In an Australian mesic grassland (former pasture) system, we characterised plant and arbuscular mycorrhizal (AM) fungal communities every six months for nearly four years to two altered rainfall regimes: i) ambient, ii) rainfall reduced by 50% relative to ambient over the entire year and iii) total summer rainfall exclusion. Using Illumina sequencing, we assessed the response of AM fungal communities sampled from contrasting rainfall treatments and evaluated whether variation in AM fungal communities was associated with variation in plant community richness and composition. We found that rainfall reduction influenced the fungal communities, with the nature of the response depending on the type of manipulation, but that consistent results were only observed after more than two years of rainfall manipulation. We observed significant co-associations between plant and AM fungal communities on multiple dates. Predictive co-correspondence analyses indicated more support for the hypothesis that fungal community composition influenced plant community composition than vice versa. However, we found no evidence that altered rainfall regimes were leading to distinct co-associations between plants and AM fungi. Overall, our results provide evidence that grassland plant communities are intricately tied to variation in AM fungal communities. However, in this system, plant responses to climate change may not be directly related to impacts of altered rainfall regimes on AM fungal communities. Our study shows that AM fungal communities respond to changes in rainfall but that this effect was not immediate. The AM fungal community may influence the composition of the plant community. However, our results suggest that plant responses to altered rainfall regimes at our site may not be resulting via changes in the AM fungal communities.

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