scholarly journals Integrative Analysis of the Wheat PHT1 Gene Family Reveals A Novel Member Involved in Arbuscular Mycorrhizal Phosphate Transport and Immunity

Cells ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 490 ◽  
Author(s):  
Yi Zhang ◽  
Lizong Hu ◽  
Deshui Yu ◽  
Kedong Xu ◽  
Ju Zhang ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Phosphate Transport ◽  
P Uptake ◽  
Mode Analysis ◽  
Fungal Colonization ◽  
Wheat Roots ◽  
Transcription Analysis ◽  
P Deficiency ◽  
Am Symbiosis ◽  
Inducible Genes

Phosphorus (P) deficiency is one of the main growth-limiting factors for plants. However, arbuscular mycorrhizal (AM) symbiosis can significantly promote P uptake. Generally, PHT1 transporters play key roles in plants’ P uptake, and thus, PHT1 genes have been investigated in some plants, but the regulation and functions of these genes in wheat (TaPHT1) during AM symbiosis have not been studied in depth. Therefore, a comprehensive analysis of TaPHT1 genes was performed, including sequence, phylogeny, cis-elements, expression, subcellular localization and functions, to elucidate their roles in AM-associated phosphate transport and immunity. In total, 35 TaPHT1s were identified in the latest high-quality bread wheat genome, 34 of which were unevenly distributed on 13 chromosomes, and divided into five groups. Sequence analysis indicated that there are 11 types of motif architectures and five types of exon-intron structures in the TaPHT1 family. Duplication mode analysis indicated that the TaPHT1 family has expanded mainly through segmental and tandem duplication events, and that all duplicated gene pairs have been under purifying selection. Transcription analysis of the 35 TaPHT1s revealed that not only known the mycorrhizal-specific genes TaPht-myc, TaPT15-4B (TaPT11) and TaPT19-4D (TaPT10), but also four novel mycorrhizal-specific/inducible genes (TaPT3-2D, TaPT11-4A, TaPT29-6A, and TaPT31-7A) are highly up-regulated in AM wheat roots. Furthermore, the mycorrhizal-specific/inducible genes are significantly induced in wheat roots at different stages of infection by colonizing fungi. Transient Agrobacterium tumefaciens-mediated transformation expression in onion epidermal cells showed that TaPT29-6A is a membrane-localized protein. In contrast to other AM-specific/inducible PHT1 genes, TaPT29-6A is apparently required for the symbiotic and direct Pi pathway. TaPT29-6A-silenced lines exhibited reduced levels of AM fungal colonization and arbuscules, but increased susceptibility to biotrophic, hemi-biotrophic and necrotrophic pathogens. In conclusion, TaPT29-6A was not only essential for the AM symbiosis, but also played vital roles in immunity.

scholarly journals The Phosphate Inhibition Paradigm: Host and Fungal Genotypes Determine Arbuscular Mycorrhizal Fungal Colonization and Responsiveness to Inoculation in Cassava With Increasing Phosphorus Supply

2021 ◽  
Vol 12 ◽  
Author(s):  
Ricardo Alexander Peña Venegas ◽  
Soon-Jae Lee ◽  
Moses Thuita ◽  
Deusdedit Peter Mlay ◽  
Cargele Masso ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
Field Trials ◽  
P Uptake ◽  
Fungal Colonization ◽  
P Availability ◽  
Terrestrial Plants ◽  
Soil Microbial ◽  
Arbuscular Mycorrhizal Fungal ◽  
P Supply

A vast majority of terrestrial plants are dependent on arbuscular mycorrhizal fungi (AMF) for their nutrient acquisition. AMF act as an extension of the root system helping phosphate uptake. In agriculture, harnessing the symbiosis can potentially increase plant growth. Application of the AMF Rhizophagus irregularis has been demonstrated to increase the yields of various crops. However, there is a paradigm that AMF colonization of roots, as well as the plant benefits afforded by inoculation with AMF, decreases with increasing phosphorus (P) supply in the soil. The paradigm suggests that when fertilized with sufficient P, inoculation of crops would not be beneficial. However, the majority of experiments demonstrating the paradigm were conducted in sterile conditions without a background AMF or soil microbial community. Interestingly, intraspecific variation in R. irregularis can greatly alter the yield of cassava even at a full application of the recommended P dose. Cassava is a globally important crop, feeding 800 million people worldwide, and a crop that is highly dependent on AMF for P uptake. In this study, field trials were conducted at three locations in Kenya and Tanzania using different AMF and cassava varieties under different P fertilization levels to test if the paradigm occurs in tropical field conditions. We found that AMF colonization and inoculation responsiveness of cassava does not always decrease with an increased P supply as expected by the paradigm. The obtained results demonstrate that maximizing the inoculation responsiveness of cassava is not necessarily only in conditions of low P availability, but that this is dependent on cassava and fungal genotypes. Thus, the modeling of plant symbiosis with AMF under different P levels in nature should be considered with caution.

scholarly journals Conservation and diversity in transcriptional responses among host plants forming distinct arbuscular mycorrhizal morphotypes

2021 ◽  
Author(s):  
Takaya Tominaga ◽  
Chihiro Miura ◽  
Yuuka Sumigawa ◽  
Yukine Hirose ◽  
Katsushi Yamaguchi ◽  
...  
Keyword(s):  
Host Plants ◽  
Molecular Mechanisms ◽  
Lotus Japonicus ◽  
Arbuscular Mycorrhizal ◽  
Fungal Colonization ◽  
Intermediate Type ◽  
Transcriptional Responses ◽  
Eustoma Grandiflorum ◽  
Signal Molecule ◽  
Am Symbiosis

The morphotype of arbuscular mycorrhizal (AM) roots is distinct mostly depending on AM host species: Arum, Paris, and Intermediate types. We previously reported that gibberellin (GA) promotes the establishment of Paris-type AM symbiosis in Eustoma grandiflorum despite its negative effects on Arum-type AM symbiosis in model plants. However, the molecular mechanisms underlying the differential effects of GA on different morphotypes, including Intermediate-type AM symbiosis, remain elusive. Comparative transcriptomics revealed that several symbiosis-related genes were transcriptionally promoted upon AM fungal colonization in Lotus japonicus (Arum-type), Daucus carota (Intermediate-type), and E. grandiflorum (Paris-type). Interestingly, upon GA treatment, the fungal colonization levels and expression of symbiosis-related genes were suppressed in L. japonicus and D. carota but were promoted in E. grandiflorum. Exogenous GA transcriptionally inhibited the biosynthetic process of a host-derived signal molecule involved in AM symbiosis, strigolactone, in L. japonicus and E. grandiflorum. Additionally, disaccharides mainly metabolized in AM roots would be different between L. japonicus and D. carota/ E. grandiflorum. This study uncovered the conserved transcriptional responses during mycorrhization and diverse responses to GA in AM roots with distinct morphotypes among phylogenetically distant host plants.

scholarly journals Correlative evidence for co-regulation of phosphorus and carbon exchanges with symbiotic fungus in the arbuscular mycorrhizal Medicago truncatula

2019 ◽  
Author(s):  
Jan Konečný ◽  
Hana Hršelová ◽  
Petra Bukovská ◽  
Martina Hujslová ◽  
Jan Jansa
Keyword(s):  
Medicago Truncatula ◽  
De Novo ◽  
Arbuscular Mycorrhizal ◽  
P Uptake ◽  
Specific Marker ◽  
Fungus Infection ◽  
Symbiotic Fungus ◽  
Plant Symbiont ◽  
Am Symbiosis ◽  
Key Questions

ABSTRACTIn the research of arbuscular mycorrhizal (AM) symbiosis a considerable progress was made. But despite that, key questions still remain unanswered – for example it is well known that biotrophic fungus release phosphate (P) to- and recieves carbon (C) from the plant symbiont, but the particular genes, and their products, responsible for this exchange are still not fully understood. Here, we made a de novo quest for such genes involved in C transfer. Using physiological intervention of 90% shading and the correlation of expression levels of MtPT4, the AM-specific marker, and our candidate genes we demonstrate that several novel genes may be involved in AM symbiosis in Medicago truncatula. Also, we examined the expression of phosphate transporters (MtPT1-6) and we discuss the balance of “direct” and “mycorrhizal” P uptake pathways upon symbiotic fungus infection and C deprivation.

scholarly journals Influence of arbuscular mycorrhizal fungi on uptake of Zn and P by two contrasting rice genotypes

2009 ◽  
Vol 55 (No. 3) ◽  
pp. 93-100 ◽  
Author(s):  
R. Hajiboland ◽  
N. Aliasgharzad ◽  
R. Barzeghar
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Arbuscular Mycorrhizal ◽  
P Uptake ◽  
Genotypic Difference ◽  
Genotypic Differences ◽  
Nutrient Deficiencies ◽  
P Deficiency ◽  
Rice Genotypes ◽  
Amf Inoculation

There is little experimental evidence about the functional significance of arbuscular mycorrhizal fungi (AMF) colonization in providing nutrients for lowland rice. This study was undertaken to examine whether growth and nutrient deficiencies may affect plants benefit from AMF inoculation. Two contrasting rice (<I>Oryza sativa</I> L.) genotypes and two AMF species (<I>Glomus mosseae</I> and <I>G. intraradices</I>) were used in this experiment. Under P starvation, P uptake in the genotype tolerant to P deficiency (Fajr), declined significantly up to 36% (<I>P</I> < 0.05) in response to AMF inoculation, while it enhanced by about 70% (<I>P</I> < 0.01) in susceptible genotype (Shafagh). Under Zn starvation, Zn uptake of Zn-efficient genotype (Shafagh) increased by about 2 fold (<I>P</I> < 0.01), but a reduction of 52% (<I>P</I> < 0.05) was observed in the Zn-inefficient genotype (Fajr) upon mycorrhization. Greater genotypic differences were observed for –P–Zn plants. Our results imply that genotypic difference in responsiveness to inoculation with AMF is attributable to different contribution of mechanisms for increased nutrient uptake in mycorrhizal plants depending on nutrient, nutritional status and nutrient efficiency of genotypes.

Gibberellin Promotes Fungal Entry and Colonization during Paris-Type Arbuscular Mycorrhizal Symbiosis in Eustoma grandiflorum

2019 ◽  
Vol 61 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Takaya Tominaga ◽  
Chihiro Miura ◽  
Naoya Takeda ◽  
Yuri Kanno ◽  
Yoshihiro Takemura ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Arbuscular Mycorrhizas ◽  
Mycorrhizal Symbiosis ◽  
Fungal Colonization ◽  
Eustoma Grandiflorum ◽  
Root Cortex ◽  
Contrasting Effect ◽  
Am Fungus ◽  
Am Symbiosis ◽  
Ga Biosynthesis

Abstract Arbuscular mycorrhizas (AMs) are divided into two types according to morphology: Arum- and Paris-type AMs. Gibberellins (GAs) mainly inhibit the establishment of Arum-type AM symbiosis in most model plants, whereas the effects of GAs on Paris-type AM symbiosis are unclear. To provide insight into the mechanism underlying this type of symbiosis, the roles of GAs were investigated in Eustoma grandiflorum when used as the host plant for Paris-type AM establishment. Eustoma grandiflorum seedlings were inoculated with the model AM fungus, Rhizophagus irregularis, and the effects of GA and the GA biosynthesis inhibitor uniconazole-P on the symbiosis were quantitatively evaluated. Exogenous GA significantly increased hyphopodium formation at the epidermis, thus leading to the promotion of fungal colonization and arbuscule formation in the root cortex. By contrast, the suppression of GA biosynthesis and signaling attenuated fungal entry to E. grandiflorum roots. Moreover, the exudates from GA-treated roots strongly induced the hyphal branching of R. irregularis. Our results show that GA has an contrasting effect on Paris-type AM symbiosis in E. grandiflorum compared with Arum-type AM symbiosis. This finding could be explained by the differential regulation of the early colonization stage, where fungal hyphae make contact with and penetrate the epidermis.

scholarly journals Addition of high C:N crop residues to a P-limited substrate constrains the benefits of arbuscular mycorrhizal symbiosis for wheat P and N nutrition

Mycorrhiza ◽  
2021 ◽  
Author(s):  
Rosolino Ingraffia ◽  
Sergio Saia ◽  
Antonio Giovino ◽  
Gaetano Amato ◽  
Giuseppe Badagliacca ◽  
...  
Keyword(s):  
Plant Growth ◽  
Nutrient Uptake ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
P Uptake ◽  
Mycorrhizal Symbiosis ◽  
N Recovery ◽  
Positive Effects ◽  
Plant P Uptake ◽  
Am Symbiosis

AbstractMany aspects concerning the role of arbuscular mycorrhizal (AM) fungi in plant nutrient uptake from organic sources remain unclear. Here, we investigated the contribution of AM symbiosis to N and P uptake by durum wheat after the addition of a high C:N biomass to a P-limited soil. Plants were grown in pots in the presence or absence of a multispecies AM inoculum, with (Org) or without (Ctr) the addition of 15N-labelled organic matter (OM). A further treatment, in which 15N was applied in mineral form (Ctr+N) in the same amount as that supplied in the Org treatment, was also included. Inoculation with AM had positive effects on plant growth in both control treatments (Ctr and Ctr+N), mainly linked to an increase in plant P uptake. The addition of OM, increasing the P available in the soil for the plants, resulted in a marked decrease in the contribution of AM symbiosis to plant growth and nutrient uptake, although the percentage of mycorrhization was higher in the Org treatment than in the controls. In addition, mycorrhization drastically reduced the recovery of 15N from the OM added to the soil whereas it slightly increased the N recovery from the mineral fertiliser. This suggests that plants and AM fungi probably exert a differential competition for different sources of N available in the soil. On the whole, our results provide a contribution to a better understanding of the conditions under which AM fungi can play an effective role in mitigating the negative effects of nutritional stresses in plants.

scholarly journals Mycorrhizal symbiosis alleviates plant drought stress within and across plant generations via plasticity

2020 ◽  
Author(s):  
Javier Puy ◽  
Carlos Perez Carmona ◽  
Inga Hiiesalu ◽  
Maarja Opik ◽  
Mari Moora ◽  
...  
Keyword(s):  
Drought Stress ◽  
Phenotypic Plasticity ◽  
Water Availability ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Mycorrhizal Symbiosis ◽  
Fungal Colonization ◽  
Transgenerational Effects ◽  
Two Generations ◽  
Am Symbiosis

Phenotypic plasticity is essential for organisms to adapt to local ecological conditions. Little is known about how mutualistic interactions, such as arbuscular mycorrhizal (AM) symbiosis, mediate plant phenotypic plasticity and to what extent this plasticity may be heritable (i.e. transgenerational effects). We tested for plant plasticity within- and across-generations in response to AM symbiosis and varying water availability in a full factorial experiment over two generations, using the perennial apomictic herb Taraxacum brevicorniculatum. We examined changes in phenotype, performance, and AM fungal colonization of the offspring throughout plant development. AM symbiosis and water availability triggered phenotypic changes during the life cycle of plants. Additionally, both triggered adaptive transgenerational effects, especially detectable during the juvenile stage. Drought stress and absence of AM fungi caused concordant plant phenotypic modifications towards a stress-coping phenotype within- and across-generations. AM fungal colonization of offspring was also affected by the parental environment. AM symbiosis can trigger transgenerational effects, including changes in functional traits related to resource-use acquisition and AM fungal colonization of the offspring, in turn affecting the biotic interaction. Thus, transgenerational effects of mycorrhizal symbiosis are not limited to plant fitness, but also improve plants ability to cope with environmental stress.

scholarly journals Molecular signal communication during arbuscular mycorrhizal formation induces significant transcriptional reprogramming of wheat (Triticum aestivum) roots

2019 ◽  
Author(s):  
Hui Tian ◽  
Runze Wang ◽  
Mengjiao Li ◽  
Haiyan Dang ◽  
Zakaria M Solaiman
Keyword(s):  
High Throughput Sequencing ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Physical Contact ◽  
Nitrogen And Phosphorus ◽  
Wheat Roots ◽  
Transcriptional Profiles ◽  
Am Symbiosis ◽  
Molecular Signal ◽  
Pass Through

Abstract Background and Aims Arbuscular mycorrhizal (AM) symbiosis begins with molecular signal communication (MSC) between AM fungi and the roots of the host plant. We aimed to test the hypothesis that the transcriptional profiles of wheat roots can be changed significantly by AM symbiotic signals, without direct contact. Methods Non-mycorrhizal (NM) and MSC treatments involved burying filter membrane bags containing sterilized and un-sterilized inoculum of the AM fungus Rhizophagus irregularis, respectively. The bags physically separated roots and AM structures but allowed molecular signals to pass through. Extracted RNA from wheat roots was sequenced by high-throughput sequencing. Results Shoot total nitrogen and phosphorus content of wheat plants was decreased by the MSC treatment. A total of 2360 differentially expressed genes (DEGs), including 1888 up-regulated DEGs and 472 down-regulated DEGs, were found dominantly distributed on chromosomes 2A, 2B, 2D, 3B, 5B and 5D. The expression of 59 and 121 genes was greatly up- and down-regulated, respectively. Only a portion of DEGs could be enriched into known terms during gene ontology analysis, and were mostly annotated to ‘catalytic activity’, ‘protein metabolic process’ and ‘membrane’ in the molecular function, biological process and cellular component ontology categories, respectively. More than 120 genes that may be involved in key processes during AM symbiosis development were regulated at the pre-physical contact stages. Conclusions The transcriptional profiles of wheat roots can be changed dramatically by MSC. Much of the information provided by our study is of great importance for understanding the mechanisms underlying the development of AM symbiosis.

scholarly journals Medicago SPX1 and SPX3 regulate phosphate homeostasis, mycorrhizal colonization, and arbuscule degradation

2021 ◽  
Author(s):  
Peng Wang ◽  
Roxane Snijders ◽  
Wouter Kohlen ◽  
Jieyu Liu ◽  
Ton Bisseling ◽  
...  
Keyword(s):  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Mineral Nutrients ◽  
Fungal Colonization ◽  
Phosphate Homeostasis ◽  
Pi Starvation ◽  
Biosynthesis Gene ◽  
Am Symbiosis ◽  
Phosphate Response ◽  
Inner Cortex

Abstract To acquire sufficient mineral nutrients such as phosphate (Pi) from the soil, most plants engage in symbiosis with arbuscular mycorrhizal (AM) fungi. Attracted by plant-secreted strigolactones (SLs), the fungi colonize the roots and form highly branched hyphal structures called arbuscules inside inner cortex cells. The host plant must control the different steps of this interaction to maintain its symbiotic nature. However, how plants sense the amount of Pi obtained from the fungus, and how this determines the arbuscule lifespan, are far from understood. Here, we show that Medicago truncatula SPX-domain containing proteins SPX1 and SPX3 regulate root Pi starvation responses, in part by interacting with PHOSPHATE RESPONSE REGULATOR2, as well as fungal colonization and arbuscule degradation. SPX1 and SPX3 are induced upon Pi starvation but become more restricted to arbuscule-containing cells upon the establishment of symbiosis. This induction in arbuscule-containing cells is associated with the presence of cis-regulatory AW-boxes and transcriptional regulation by the WRINKLED1-like transcription factor WRI5a. Under Pi-limiting conditions, SPX1 and SPX3 facilitate the expression of the SL biosynthesis gene DWARF27, which could help explain the increased fungal branching in response to root exudates. Later, in arbuscule-containing cells, SPX1 and SPX3 redundantly control arbuscule degradation. Thus, SPX proteins play important roles as phosphate sensors to maintain a beneficial AM symbiosis.

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