Chemotactic responses of Phytophthora sojae zoospores to amino acids and sugars in root exudates

Isoflavones in soybean seed and root exudates are host specific signal molecules for Phytophthora sojae to recognize host soybean. G protein and calcium signaling pathway are involved in the chemotaxis of zoospores in the recognition of isoflavones. To investigate the role of host non-specific signaling molecules (sugars and amino acids) in seed and root exudates in zoospore chemotaxis and mycelial growth, the transcriptome of P. sojae responding to aspartic acid (Asp) and glucose (Glc) was analyzed by RNA-seq method. We found that the relative in situ concentrations of amino acids and sugars significantly promoted zoospore chemotaxis, as do isoflavones. Transcriptomics showed that both similarity and difference existed in response mechanisms of P. sojae to Asp and Glc. Asp and Glc activated MAPK signaling pathway and phosphatidylinositol signaling system but not G-protein signaling pathway, which have been reported to be responsible for zoospore chemotaxis. In addition, ubiquitin mediated proteolysis and ABC transporters were also activated by Asp and Glc. Meanwhile, glutathione signaling pathway uniquely participated in the response of P. sojae to Asp but not involved in the response process to Glc, which is waiting for further study. Our results provide new insights into the molecular mechanism of zoospore response to Asp and Glc.

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Chemotaxis response of Erwinia carotovora on sugars and amino acids of root exudates of Panax ginseng

China Journal of Chinese Materia Medica ◽

10.4268/cjcmm20162109 ◽

2016 ◽

Keyword(s):

Amino Acids ◽

Panax Ginseng ◽

Root Exudates ◽

Erwinia Carotovora

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Role of proteinaceous amino acids released in root exudates in nutrient acquisition from the rhizosphere

Plant and Soil ◽

10.1007/bf00009493 ◽

1994 ◽

Vol 158 (2) ◽

pp. 183-192 ◽

Cited By ~ 58

Author(s):

D. L. Jones ◽

A. C. Edwards ◽

K. Donachie ◽

P. R. Darrah

Keyword(s):

Amino Acids ◽

Root Exudates ◽

Nutrient Acquisition

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Chemistry of root exudates and rhizosphere soils of prairie plants

Canadian Journal of Botany ◽

10.1139/b79-181 ◽

1979 ◽

Vol 57 (13) ◽

pp. 1473-1477 ◽

Cited By ~ 18

Author(s):

U. G. Bokhari ◽

D. C. Coleman ◽

Amy Rubink

Keyword(s):

Amino Acids ◽

Nutrient Cycling ◽

Root Exudates ◽

Microbial Growth ◽

Rhizosphere Soil ◽

Soluble Sugars ◽

The Other ◽

Blue Grama ◽

Rhizosphere Soils ◽

Prairie Plants

Root exudates may have important effects on microbial growth and nutrient cycling in many ecosystems. We examined exudation patterns of two dominant plants in the shortgrass prairie.Root exudates of mature blue grama plants contained greater amounts of carbohydrates than younger plants, whereas the latter exuded slightly more amino N than the older plants. Axenic seedlings exuded larger amounts of sugars than normal seedlings; however, there was no difference in the amounts of amino N exuded. Among the amino acids exuded by axenic seedlings the levels of proline, methionine, and glutamic acids were higher than those of the other amino acids. The rhizosphere soil of both blue grama and fringed sagewort had more soluble sugars than the nonrhizosphere soil while the latter had more nonsoluble sugars. Both soluble and nonsoluble amino N were in greater concentrations in the nonrhizosphere soil of blue grama and fringed sagewort than in the rhizosphere soil of the same species. Rhizosphere soil of the above two species contained more polyphenols than the nonrhizosphere soil. Trace amounts of terpenes were found only in the soil associated with fringed sagewort.

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The Role of Root Exudates of Barley Colonized by Pseudomonas fluorescens in Enhancing Root Colonization by Fusarium culmorum

Plants ◽

10.3390/plants9030366 ◽

2020 ◽

Vol 9 (3) ◽

pp. 366

Author(s):

Nadezhda Vishnevskaya ◽

Vlada Shakhnazarova ◽

Alexander Shaposhnikov ◽

Olga Strunnikova

Keyword(s):

Amino Acids ◽

Pseudomonas Fluorescens ◽

Root Exudates ◽

Fusarium Culmorum ◽

Ultra Performance Liquid Chromatography ◽

Root Surface ◽

Phytopathogenic Fungus ◽

Quantitative Composition ◽

Experimental Conditions ◽

In The Beginning

The aim of this study was to find out why after joint inoculation of the substrate with the phytopathogenic fungus Fusarium culmorum and the antagonistic bacterium Pseudomonas fluorescens the amount of the fungus on the root surface in the beginning of the colonization was greater on the roots colonized by the bacterium than on control roots. This phenomenon is especially interesting because joint inoculation with P. fluorescens was always followed by a considerable decrease in the incidence of Fusarium root rot. In two experiments barley was grown in sterile vermiculite inoculated only with F. culmorum, only with P. fluorescens and jointly with the fungus and the bacterium. In the control, vermiculite was not inoculated with any microorganisms. After the removal from the vermiculite, barley plants were transferred into deionized water for the collection of root exudates. The duration of barley growth in the vermiculite and in the water was different in the two experiments. The exudates were tested for their ability to elicit chemotropism in F. culmorum and influence its growth. We did not observe any chemotropism of F. culmorum towards barley root exudates. However, the exudates of the barley colonized by the bacterium stimulated the growth of fungal germ tubes. Using an ultra-performance liquid chromatography system, we found that experimental conditions influenced the quantitative composition of the exudates. The amount of amino acids in the solution of exudates decreased considerably after a prolonged growth of control barley in water, while the presence of P. fluorescens resulted in a considerably increase of the amount of amino acids in the exudates. The exudates of barley colonized by P. fluorescens contained much more glucose, lactic acid and several amino acids than the exudates of control barley. These components are known to be necessary for the growth of F. culmorum. Their presence in the exudates of barley colonized by P. fluorescens seems to be the reason of a more active colonization by the fungus of barley roots colonized by the bacterium.

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Amino acids in root exudates of cotton

Plant and Soil ◽

10.1007/bf01381342 ◽

1962 ◽

Vol 16 (3) ◽

pp. 312-326 ◽

Cited By ~ 13

Author(s):

Miss C. B. Sulochana

Keyword(s):

Amino Acids ◽

Root Exudates

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Short-Term Effects of Salt Stress on the Amino Acids of Phragmites australis Root Exudates in Constructed Wetlands

Water ◽

10.3390/w12020569 ◽

2020 ◽

Vol 12 (2) ◽

pp. 569 ◽

Cited By ~ 2

Author(s):

En Xie ◽

Xuejing Wei ◽

Aizhong Ding ◽

Lei Zheng ◽

Xiaona Wu ◽

...

Keyword(s):

Amino Acids ◽

Salt Stress ◽

Amino Acid ◽

Phragmites Australis ◽

Root Exudates ◽

Amino Acid Content ◽

Total Amino Acid ◽

Control Group ◽

Short Term ◽

Short Term Effects

In this study, the short-term effects of NaCl stress on the free amino acid content and composition of root exudates of Phragmites australis were evaluated. Nineteen amino acid types were detected in all samples. The results indicated that NaCl significantly influenced the total amino acid (TotAA) content. The TotAA content at 6‰ salinity (1098.79 μM g−1 DW) was up to 24 times higher than that in the control group (45.97 μM g−1 DW) but decreased to 106.32 μM g−1 DW at 6‰ salinity in the first hour. The stress period also significantly affected the TotAA content. After 4 h of stress, the TotAA content of the control and 1‰ salinity groups increased by approximately 30- and 14-fold, and those of the 3‰ and 6‰ groups decreased to 60% and 37%, respectively. The increase in TotAA content was primarily caused by the increase in proline content; the proportion of proline accounted for 58.05% of the TotAA content at 3‰ salinity level in 2 h. Most amino acids showed a significant positive correlation with each other, but proline and methionine showed a different trend. Therefore, the proline level is a useful indicator of salt stress in Phragmites australis, especially in saltwater wetlands.

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Stimulation of Waitea circinata by root exudates of Pinus cembroides

Canadian Journal of Microbiology ◽

10.1139/m69-239 ◽

1969 ◽

Vol 15 (11) ◽

pp. 1319-1323 ◽

Cited By ~ 3

Author(s):

V. P. Agnihotri ◽

O. Vaartaja

Keyword(s):

Amino Acids ◽

Glutamic Acid ◽

Root Exudates ◽

Germination Percentage ◽

Extension Growth ◽

Initial Growth ◽

Waitea Circinata ◽

Carbohydrate Components ◽

Germination And Growth ◽

Control Water

Effects of root exudates from Pinus cembroides to Waitea circinata were studied by using paper chromatography. Each of 14 seedlings liberated an average of 175 μg of ninhydrin-positive substance and 133 μg of sugars in 35 days. From these, 14 amino acids, 4 sugars, and 3 organic acids were identified. The root exudate induced greatly increased mycelial growth over a wide temperature range, but sclerotia were produced only after 20 days between 15 and 20 °C. Each amino acid and carbohydrate, except threonine, valine, glycine, glutamic acid, lysine, γ-aminobutyric acid, and citric acid, stimulated vegetative growth. Neither basidia nor sclerotia developed on any nutrient medium. The sclerotia did not require exogenous nutrition for germination and initial growth. Germination percentage remained between 95 and 100 with each exudate component. All carbohydrate components, either singly or in combination, stimulated extension growth from sclerotia. Of 14 amino acids, only aspartic acid, glutamic acid, and leucine supported faster extension growth than the control (water agar). Temperature and pH influenced germination and growth, the optima being at 25 to 30 °C and pH 5 to 6.

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