scholarly journals Linnemannia elongata (Mortierellaceae) stimulates Arabidopsis thaliana aerial growth and responses to auxin, ethylene, and reactive oxygen species

2021 ◽  
Author(s):  
Natalie Vandepol ◽  
Julian Liber ◽  
Alan Yocca ◽  
Jason Matlock ◽  
Patrick Edger ◽  
...  

Harnessing the plant microbiome has the potential to improve agricultural yields and protect plants against pathogens and/or abiotic stresses, while also relieving economic and environmental costs of crop production. While previous studies have gained valuable insights into the underlying genetics facilitating plant-fungal interactions, these have largely been skewed towards certain fungal clades (e.g. arbuscular mycorrhizal fungi). Several different phyla of fungi have been shown to positively impact plant growth rates, including Mortierellaceae fungi. However, the extent of the plant growth promotion (PGP) phenotype(s), their underlying mechanism(s), and the impact of bacterial endosymbionts on fungal-plant interactions remain poorly understood for Mortierellaceae. In this study, we focused on the symbiosis between soil fungus Linnemannia elongata (Mortierellaceae) and Arabidopsis thaliana (Brassicaceae), as both organisms have high-quality reference genomes and transcriptomes available, and their lifestyles and growth requirements are conducive to research conditions. Further, L. elongata can host bacterial endosymbionts related to Mollicutes and Burkholderia . The role of these endobacteria on facilitating fungal-plant associations, including potentially further promoting plant growth, remains completely unexplored. We measured Arabidopsis aerial growth at early and late life stages, seed production, and used mRNA sequencing to characterize differentially expressed plant genes in response to fungal inoculation with and without bacterial endosymbionts. We found that L. elongata improved aerial plant growth, seed mass and altered the plant transcriptome, including the upregulation of genes involved in plant hormones and “response to oxidative stress”, “defense response to bacterium”, and “defense response to fungus”. Furthermore, the expression of genes in certain phytohormone biosynthetic pathways were found to be modified in plants treated with L. elongata . Notably, the presence of Mollicutes- or Burkholderia- related endosymbionts in Linnemannia did not impact the expression of genes in Arabidopsis or overall growth rates.

2021 ◽  
Vol 3 ◽  
Author(s):  
Michael Prabhu Inbaraj

Crop plants are continuously exposed to various abiotic stresses like drought, salinity, ultraviolet radiation, low and high temperatures, flooding, metal toxicities, nutrient deficiencies which act as limiting factors that hampers plant growth and low agricultural productivity. Climate change and intensive agricultural practices has further aggravated the impact of abiotic stresses leading to a substantial crop loss worldwide. Crop plants have to get acclimatized to various environmental abiotic stress factors. Though genetic engineering is applied to improve plants tolerance to abiotic stresses, these are long-term strategies, and many countries have not accepted them worldwide. Therefore, use of microbes can be an economical and ecofriendly tool to avoid the shortcomings of other strategies. The microbial community in close proximity to the plant roots is so diverse in nature and can play an important role in mitigating the abiotic stresses. Plant-associated microorganisms, such as endophytes, arbuscular mycorrhizal fungi (AMF), and plant growth-promoting rhizobacteria (PGPR), are well-documented for their role in promoting crop productivity and providing stress tolerance. This mini review highlights and discusses the current knowledge on the role of various microbes and it's tolerance mechanisms which helps the crop plants to mitigate and tolerate varied abiotic stresses.


2012 ◽  
Vol 77 (1) ◽  
pp. 17-27 ◽  
Author(s):  
Anna Lisek ◽  
Lidia Sas Paszt ◽  
Beata Sumorok

Summary In organic farming, mineral fertilizers are replaced by various preparations to stimulate plant growth and development. Introduction of new biopreparations into horticultural production requires an assessment of their effects on the growth and yielding of plants. Among the important indicators of the impact on plants of beneficial microorganisms contained in bioproducts is determination of their effectiveness in stimulating the growth and yielding of plants. Moreover, confirmation of the presence of arbuscular mycorrhizal (AM) fungi in the roots and plant growth promoting rhizobacteria (PGPR) in the rhizosphere is also necessary. In addition to conventional methods, molecular biology techniques are increasingly used to allow detection and identification of AM fungi in plant roots. The aim of this study was identification and initial taxonomic classification of AM fungi in the roots of ‘Elkat’ strawberry plants fertilized with various biopreparations using the technique of nested PCR. Tests were performed on DNA obtained from the roots of ‘Elkat’ strawberry plants: not fertilized, treated with 10 different biopreparations, or fertilized with NPK. Amplification of the large subunit of ribosomal gene (LSU rDNA) was carried out using universal primers, and then, in the nested PCR reaction, primers specific for the fungi of the genera Glomus, Acaulospora, and Scutellospora were used. Colonization of strawberry roots by arbuscular mycorrhizal fungi was determined on the basis of the presence of DNA fragments of a size corresponding to the types of the fungi tested for. As a result of the analyses, the most reaction products characterizing AM fungi were found in the roots of plants treated with the preparation Florovit Eko. The least fragments characteristic of AM fungi were detected in the roots of plants fertilized with NPK, which confirms the negative impact of mineral fertilizers on the occurrence of mycorrhizal fungi in the roots of strawberry plants. The roots of plants fertilized with Tytanit differed from the control plants by the presence of one of the clusters of fungi of the genus Glomus and by the absence of a cluster of fungi of the genus Scutellospora. In the roots of plants treated with other biopreparations there were reaction products indicating the presence of fungi of the genera Glomus, Scutellospora and Acaulospora, like in the roots of the control plants. The results will be used to assess the suitability of microbiologically enriched biopreparations in horticultural production.


2018 ◽  
Author(s):  
Whitney L. Dolan ◽  
Clint Chapple

ABSTRACTThe Mediator complex is a central component of transcriptional regulation in Eukaryotes. The complex is structurally divided into four modules known as the head, middle, tail and kinase modules, and in Arabidopsis thaliana, comprises 28-34 subunits. Here, we explore the functions of four Arabidopsis Mediator tail subunits, MED2, MED5a/b, MED16, and MED23, by comparing the impact of mutations in each on the Arabidopsis transcriptome. We find that these subunits affect both unique and overlapping sets of genes, providing insight into the functional and structural relationships between them. The mutants primarily exhibit changes in the expression of genes related to biotic and abiotic stress. We find evidence for a tissue specific role for MED23, as well as in the production of alternative transcripts. Together, our data help disentangle the individual contributions of these MED subunits to global gene expression and suggest new avenues for future research into their functions.


2003 ◽  
Vol 54 (10) ◽  
pp. 969 ◽  
Author(s):  
D. K. Singh ◽  
V. Singh

In a glasshouse study, two experiments were conducted to understand how inherent variability, such as the seed size or mass, and formation of adventitious nodal roots might influence the tolerance of various wheat and triticale cultivars at different growth stages to waterlogging. Waterlogging at germination resulted in 11% seedling mortality, but the waterlogged seedlings had a 19% increase in shoot mass per plant, with no difference in root mass compared with non-waterlogged seedlings. Waterlogging at the 3-leaf stage was deleterious to only a few cultivars. On average, larger seed resulted in greater plant growth for most of the cultivars, and seed mass was positively related to the plant biomass and adventitious nodal root mass under waterlogged conditions. A decreasing oxygen concentration with increasing duration of waterlogging and soil depth did not affect the plant growth and visual stress symptoms, chlorosis, until the oxygen concentration decreased to less than 10% in the bottom depths. The highest yielding triticale cultivar, Muir, and wheat cultivars Brookton and Frame had the greatest seed mass, plant biomass, and relative growth rates under waterlogged conditions, compared with the lowest yielding wheat cultivars, Amery, Silverstar, and More. However, the degree of 'waterlogging tolerance', expressed as the percent ratio of plant biomass or growth rates under waterlogged conditions relative to the non-waterlogged control conditions, appeared to be greatest for the low-yielding cultivars, indicating a 'cautious approach' when screening tolerant cultivars.


1991 ◽  
Vol 69 (12) ◽  
pp. 2597-2602 ◽  
Author(s):  
S. P. Bentivenga ◽  
B. A. D. Hetrick

The impact of benomyl fungicide and spring burning on mycorrhizal activity and plant growth was assessed in tallgrass prairie in Kansas. We report for the first time that the productivity of mycotrophic plants can be reduced by inhibition of indigenous vesicular–arbuscular mycorrhizal fungi under field conditions. A vital stain, nitro blue tetrazolium, used to assess active mycorrhizal colonization, proved to be a more sensitive measure of treatment effects than the cell wall stain, trypan blue. Burning stimulated both plant growth and active mycorrhizal colonization. However, by 32 days after burning no differences in colonization were detected. Our observations support the hypothesis that mycorrhizal fungi play an important role in the growth of warm-season tallgrass prairie grasses and may contribute to enhanced plant growth of warm-season tallgrass prairie grasses and may contribute to enchanced plant growth following spring burning. Key words: burning, benomyl fungicide, phosphorus, tallgrass prairie, VA mycorrhizae, warm-season grasses.


Author(s):  
Ouattara Brahima ◽  
Abo Kouabenan ◽  
Tuo Seydou ◽  
Silue Nakpalo ◽  
Kone N’golo Abdoulaye ◽  
...  

Data on tomato fitness improvement by arbuscular mycorrhizal fungi (AMF) remain patchy. The present study was initiated to evaluate the effect of the period of AMF inoculation as well as the level of mineral manure on tomato growth. The experiment took place from June to October 2016, in the West African Science Service Center on Climate Change and Adapted Land Use greenhouse. AMF inocula were applied to seeds and/or transplants, each receiving three different levels of chemical fertilizer. The impact of the inoculation period and the level of fertilization, were assessed on plant growth parameters, including height, number of functional leaves, root-collar diameter, and root length. Observation of hyphae, arbuscules and vesicles was carried out by roots staining method and anabled the determination of mycorrhization parameters. Plants Mycorrhizal dependence was assessed with their fresh and dry mass. An analysis of variance and post ANOVA analysis was performed using the Newman-Keuls test (P= .05) for the comparison of means. The findings pointed that, when transplanting, the difference between mycorrhized plants and non-mycorrhized ones was very highly significant in terms of the height of the stem (P= .00), the length of the taproot, and the root collar diameter. The lower the level of manure was, the higher the frequency of infection has been (73.33% for MS1 and MSR1; 76.67% for MR1).Transplants growing without a supply of mineral manure expressed greater mycorrhizal dependence (66% for MSR1). Arbuscular mycorrhization of the tomato is profitable for its optimal development. The endomycorrhization of tomato can be done during sowing or transplanting with the same benefits but, with a low level of fertilizer. So, it’s necessary to controll the intake of mineral manure because it influences the natural mycorrhization of plants.


The rhizosphere is the slim region of soil that’s directly influenced by root secretions and accompanying soil microorganisms known as root microbiome. The rhizosphere involving the soil pores comprises numerous beneficial bacterium and others different microorganisms. Microbial communities play a vital role within the functioning of plants by stimulating their morphology, physiology and development. Several species of the rhizosphere microorganism are helpful to plant growth and overall productivity. The useful plant-microbe associations within the rhizosphere are the principal determinants of plant and soil health (SH). Rhizobacteria comprise mycorrhization helper microorganism and plant growth promoting rhizobacteria (PGPR) are support arbuscular mycorrhizal fungi (AM fungi) to colonize the plant roots. Tomato is the second most common cultivated vegetable within the world for biological process and functions. Tomato has high values in soluble fat, vitamin A, B, C, lycopene, flavonoids, and β-carotene and is of course low in calories. Tomato consumption are extremely useful to human health (HH) because of several crucial nutrients are accessible. In current study, the impact of inoculating tomato with consortium AM fungi and PGPR on growth, fruit quality and productivity was estimated. The inoculated AM fungi are containing Aculospora logula-15%, Glomus fasciculatum-20%, Glomus intraradices-40%, Gigaspora margarita-15% and Scutellospora heterogama-10% infective propagules in inoculum. The consortium PGPR treatments were inoculated with Azotobacter chroococcum, Pseudomonas fluoresces and Fraturia aurantia (10-9CFU/g) and also the Control [100% Recommended Rate of fertilizers (RRF)] treatment was without microbial inoculated. Phyto-morpho-chemical factors, containing Lycopene, β-carotene, antioxidant activity, growth, fruit yield, fruit potassium (K) and macro and micro nutrients uptake in shoot were improved by AM fungi and PGPR mediated tomato as compared with control (100% RRF). Maximum lycopene, β-carotene, fruit K and antioxidant activity (AA) were recorded in plants treated with multiple biostimulants of AM fungi + PGPR treatment. Maximum height, biomass and marketable yield were observed in AM fungi + PGPR treated plants and minimum in control (100% RRF). A correlational statistics between lycopene, β-carotene, AA with fruit and shoot K (P


Mycorrhiza ◽  
2021 ◽  
Author(s):  
Verena Säle ◽  
Javier Palenzuela ◽  
Concepción Azcón-Aguilar ◽  
Iván Sánchez-Castro ◽  
Gladstone Alves da Silva ◽  
...  

AbstractAlmost all land plants form symbiotic associations with arbuscular mycorrhizal fungi (AMF). Individual plants usually are colonized by a wide range of phylogenetically diverse AMF species. The impact that different AMF taxa have on plant growth is only partly understood. We screened 44 AMF isolates for their effect on growth promotion and nutrient uptake of leek plants (Allium porrum), including isolates that have not been tested previously. In particular, we aimed to test weather AMF lineages with an ancient evolutionary age differ from relatively recent lineages in their effects on leek plants. The AMF isolates that were tested covered 18 species from all five AMF orders, eight families, and 13 genera. The experiment was conducted in a greenhouse. A soil–sand mixture was used as substrate for the leek plants. Plant growth response to inoculation with AMF varied from − 19 to 232% and depended on isolate, species, and family identity. Species from the ancient families Archaeosporaceae and Paraglomeraceae tended to be less beneficial, in terms of stimulation plant growth and nutrient uptake, than species of Glomeraceae, Entrophosporaceae, and Diversisporaceae, which are considered phylogenetically more recent than those ancient families. Root colonization levels also depended on AMF family. This study indicates that plant benefit in the symbiosis between plants and AMF is linked to fungal identity and phylogeny and it shows that there are large differences in effectiveness of different AMF.


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