scholarly journals Populus trichocarpa and Populus deltoides Exhibit Different Metabolomic Responses to Colonization by the Symbiotic Fungus Laccaria bicolor

2014 ◽  
Vol 27 (6) ◽  
pp. 546-556 ◽  
Author(s):  
Timothy J. Tschaplinski ◽  
Jonathan M. Plett ◽  
Nancy L. Engle ◽  
Aurelie Deveau ◽  
Katherine C. Cushman ◽  
...  

Within boreal and temperate forest ecosystems, the majority of trees and shrubs form beneficial relationships with mutualistic ectomycorrhizal (ECM) fungi that support plant health through increased access to nutrients as well as aiding in stress and pest tolerance. The intimate interaction between fungal hyphae and plant roots results in a new symbiotic “organ” called the ECM root tip. Little is understood concerning the metabolic reprogramming that favors the formation of this hybrid tissue in compatible interactions and what prevents the formation of ECM root tips in incompatible interactions. We show here that the metabolic changes during favorable colonization between the ECM fungus Laccaria bicolor and its compatible host, Populus trichocarpa, are characterized by shifts in aromatic acid, organic acid, and fatty acid metabolism. We demonstrate that this extensive metabolic reprogramming is repressed in incompatible interactions and that more defensive compounds are produced or retained. We also demonstrate that L. bicolor can metabolize a number of secreted defensive compounds and that the degradation of some of these compounds produces immune response metabolites (e.g., salicylic acid from salicin). Therefore, our results suggest that the metabolic responsiveness of plant roots to L. bicolor is a determinant factor in fungus–host interactions.

1997 ◽  
Vol 07 (01n02) ◽  
pp. 93-100 ◽  
Author(s):  
SATOSHI YOKOTA ◽  
JUN-ICHI INOUE ◽  
KEISUKE MUROZONO ◽  
SIGEO MATSUYAMA ◽  
HIROMICHI YAMAZAKI ◽  
...  

Elemental composition of living cells and tissues reflects their physiological function and status. However, it has been difficult to know in-situ elemental distribution by conventional analytical methods. In-air PIXE seems suitable for surface analysis of living cells and tissues because any treatment (e.g. freeze drying, digestion) is not required before and during measurement. We applied Via (vertical-beam in-air) PIXE to surface analysis of plant roots exposed to aluminum ( Al ). Aluminum stress is a major factor that limits elongation of plant roots in acid soils. We previously reported decrease in atomic ratio of potassium to phosphorus (K/P ratio) of dried root-tip of alfalfa (Medicago sativa L.) under Al stress using in-vacuum PIXE. In Via PIXE, 5 to 7-minute irradiation by 3 MeV proton beams of 200 pA was sufficient to obtain X-ray spectra without drying root samples. Decrease in K/P ratio in surface cells of root-tips was observed by short-term (6-8 h) exposure of root to Al . Via PIXE is recognized as a powerful tool for in-situ surface analysis of plant material.


2017 ◽  
Vol 10 (1) ◽  
pp. 35-45
Author(s):  
N.F. Lunkova ◽  
N.A. Burmistrova ◽  
M.S. Krasavina

Background:A growing part of the root is one of the most active sinks for sucrose coming from source leaves through the phloem. In the root, sucrose is unloaded from conducting bundles and is distributed among the surrounding cells. To be involved in the metabolism, sucrose should disintegrate into hexoses by means of degrading enzymes.Aims:The aim of this research was to explore the possibility of the involvement of one such enzymes, invertase, in phloem unloading as well as distribution of its activity in the functionally different tissues of the plant root tips.Method:To estimate the enzyme activities in root tissues, we applied two techniques: the histochemical method using nitro blue tetrazolium. The localization of phloem unloading was studied with carboxyfluorescein, a fluorescent marker for symplastic transport.Results:Invertase activity was not detected in the apical part of the meristem. It appeared only between the basal part of this zone and the beginning of the elongation zone. There is the root phloem unloading in that area. Invertase activity increased with increasing the distance from the root tip and reached the highest values in the region of cell transition to elongation and in the elongation zone. The activities of the enzyme varied in different tissues of the same zone and sometimes in the neighboring cells of the same tissue. Biochemical determination of invertase activity was made in the maize root segments coincident to the zones of meristem, cell elongation and differentiation. The results of both methods of determination of invertase activity were in agreement.Conclusion:It was concluded that phloem unloading correlated with invertase activity, possibly because of the activation of invertase by unloaded sucrose. Invertase is one of the factors involved in the processes preparing the cells for their transition to elongation because the concentration of osmotically active hexoses increases after cleavage of sucrose, that stimulates water entry into the cells, which is necessary for elongation growth.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tina Unuk Nahberger ◽  
Gian Maria Niccolò Benucci ◽  
Hojka Kraigher ◽  
Tine Grebenc

AbstractSpecies of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.


2003 ◽  
Vol 69 (1) ◽  
pp. 327-333 ◽  
Author(s):  
Renske Landeweert ◽  
Paula Leeflang ◽  
Thom W. Kuyper ◽  
Ellis Hoffland ◽  
Anna Rosling ◽  
...  

ABSTRACT Molecular identification techniques based on total DNA extraction provide a unique tool for identification of mycelium in soil. Using molecular identification techniques, the ectomycorrhizal (EM) fungal community under coniferous vegetation was analyzed. Soil samples were taken at different depths from four horizons of a podzol profile. A basidiomycete-specific primer pair (ITS1F-ITS4B) was used to amplify fungal internal transcribed spacer (ITS) sequences from total DNA extracts of the soil horizons. Amplified basidiomycete DNA was cloned and sequenced, and a selection of the obtained clones was analyzed phylogenetically. Based on sequence similarity, the fungal clone sequences were sorted into 25 different fungal groups, or operational taxonomic units (OTUs). Out of 25 basidiomycete OTUs, 7 OTUs showed high nucleotide homology (≥99%) with known EM fungal sequences and 16 were found exclusively in the mineral soil. The taxonomic positions of six OTUs remained unclear. OTU sequences were compared to sequences from morphotyped EM root tips collected from the same sites. Of the 25 OTUs, 10 OTUs had ≥98% sequence similarity with these EM root tip sequences. The present study demonstrates the use of molecular techniques to identify EM hyphae in various soil types. This approach differs from the conventional method of EM root tip identification and provides a novel approach to examine EM fungal communities in soil.


2014 ◽  
Vol 44 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Amy L. Klocko ◽  
Richard Meilan ◽  
Rosalind R. James ◽  
Venkatesh Viswanath ◽  
Cathleen Ma ◽  
...  

The stability and value of transgenic pest resistance for promoting tree growth are poorly understood. These data are essential for determining if such trees could be beneficial to commercial growers in the face of substantial regulatory and marketing costs. We investigated growth and insect resistance in hybrid poplar expressing the cry3Aa transgene in two field trials. An initial screening of 502 trees comprising 51 transgenic gene insertion events in four clonal backgrounds (Populus trichocarpa × Populus deltoides, clones 24-305, 50-197, and 198-434; and P. deltoides × Populus nigra, clone OP-367) resulted in transgenic trees with greatly reduced insect damage. A large-scale study of 402 trees from nine insertion events in clone OP-367, conducted over two growing seasons, demonstrated reduced tree damage and significantly increased volume growth (mean 14%). Quantification of Cry3Aa protein indicated high levels of expression, which continued after 14 years of annual or biannual coppice in a clone bank. With integrated management, the cry3Aa gene appears to be a highly effective tool for protecting against leaf beetle damage and improving yields from poplar plantations.


2014 ◽  
Vol 21 (12) ◽  
pp. 1308-1319
Author(s):  
Setsuko Komatsu ◽  
Myeong W. Oh ◽  
Hee Y. Jang ◽  
Soo J. Kwon ◽  
Hye R. Kim ◽  
...  

Plant root systems form complex networks with the surrounding soil environment and are controlled by both internal and external factors. To better understand the function of root tips of soybean during germination, three proteomic techniques were used to analyze the protein profiles of root tip cells. Proteins were extracted from the root tips of 4-dayold soybean seedlings and analyzed using two-dimensional (2D) gel electrophoresis-based proteomics, SDS-gel based proteomics, and gel-free proteomics techniques. A total of 121, 862, and 341 proteins were identified in root tips using the 2D gel-based, SDS gel-based, and gel-free proteomic techniques, respectively. The proteins identified by 2D gel-based proteomic analysis were predominantly localized in the cytoplasm, whereas nuclear-localized proteins were most commonly identified by the SDS gel-based and gel-free proteomics techniques. Of the 862 proteins identified in the SDS gelbased proteomic analysis, 190 were protein synthesis-related proteins. Furthermore, 24 proteins identified using the 2Dgel based proteomic technique shifted between acidic and basic isoelectric points, and 2 proteins, heat shock protein 70.2 and AAA-type ATPase, displayed two different molecular weights at the same isoelectric point. Taken together, these results suggest that a number of proteins related to protein synthesis and modification are activated in the root tips of soybean seedlings during germination.


2021 ◽  
Vol 22 (19) ◽  
pp. 10248
Author(s):  
Katja Witzel ◽  
Andrea Matros ◽  
Uwe Bertsch ◽  
Tariq Aftab ◽  
Twan Rutten ◽  
...  

Salt stress tolerance of crop plants is a trait with increasing value for future food production. In an attempt to identify proteins that participate in the salt stress response of barley, we have used a cDNA library from salt-stressed seedling roots of the relatively salt-stress-tolerant cv. Morex for the transfection of a salt-stress-sensitive yeast strain (Saccharomyces cerevisiae YSH818 Δhog1 mutant). From the retrieved cDNA sequences conferring salt tolerance to the yeast mutant, eleven contained the coding sequence of a jacalin-related lectin (JRL) that shows homology to the previously identified JRL horcolin from barley coleoptiles that we therefore named the gene HvHorcH. The detection of HvHorcH protein in root extracellular fluid suggests a secretion under stress conditions. Furthermore, HvHorcH exhibited specificity towards mannose. Protein abundance of HvHorcH in roots of salt-sensitive or salt-tolerant barley cultivars were not trait-specific to salinity treatment, but protein levels increased in response to the treatment, particularly in the root tip. Expression of HvHorcH in Arabidopsis thaliana root tips increased salt tolerance. Hence, we conclude that this protein is involved in the adaptation of plants to salinity.


1956 ◽  
Vol 2 (1) ◽  
pp. 87-92 ◽  
Author(s):  
William A. Jensen ◽  
Leroy G. Kavaljian

The intracellular distribution of ascorbic acid was studied in frozen-dried root tips of Allium cepa and Vicia faba by the silver nitrate procedure. The sites of the ascorbic acid as indicated by the deposited silver appear as spherical (0.2 to 0.6 µ in diameter) cytoplasmic particles. The site appears to have small amounts of lipides and to be rich in ribonucleic acid. These particles are concluded to be submicroscopic in size and associated, in the elongating cell, with the cell surface. In the meristematic cells they appear fewer in number and are distributed throughout the cytoplasm.


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