Seed exudates from Pinus resinosa and their effects on growth and zoospore germination of Pythium afertile

1968 ◽  
Vol 46 (9) ◽  
pp. 1135-1141 ◽  
Author(s):  
V. P. Agnihotri ◽  
O. Vaartaja
Keyword(s):  
Amino Acids ◽  
Organic Acids ◽  
Germ Tube ◽  
Pinus Resinosa ◽  
Aminobutyric Acid ◽  
Seed Exudate ◽  
Germinating Seeds ◽  
Germination And Growth ◽  
Germ Tubes

The role of exudates from germinating seeds of red pine, Pinus resinosa Ait., was examined in relation to zoospore germination and growth of Pythium afertile Kanouse and Humphrey. By paper chromatography, 14 amino acids, 4 sugars, and 3 organic acids were identified in the seed exudate. Among the sugars, glucose, fructose, and sucrose were detected in large amounts and arabinose in small amounts. Of 14 amino acids identified, threonine, lysine, arginine, and glutamine were present in trace amounts; leucine, γ-aminobutyric acid, valine, asparagine, and alanine in large amounts; and proline, serine, glycine, aspartic acid, and glutamic acid in small amounts. Of three organic acids detected, malonic acid was most abundant whereas citric and fumaric acids were present in small and trace amounts, respectively.When supplied singly, all sugars and amino acids, except alanine, threonine, γ-aminobutyric acid, and arabinose stimulated mycelial growth and germ tube growth of P. afertile. Organic acids promoted no growth and inhibited zoospore germination. Mixtures of sugars and mixtures of three or four amino acids effectively stimulated growth of mycelium and germ tubes. One to three germ tubes were produced with certain amino acids and sugars but only one germ tube with others. There was no correlation between the percentage zoospore germination and length of germ tube.

ROOT EXUDATES FROM RED PINE SEEDLINGS AND THEIR EFFECTS ON PYTHIUM ULTIMUM

1967 ◽  
Vol 45 (7) ◽  
pp. 1031-1040 ◽  
Author(s):  
V. P. Agnihotri ◽  
O. Vaartaja
Keyword(s):  
Amino Acids ◽  
Root Exudates ◽  
Root Exudate ◽  
Pinus Resinosa ◽  
Pythium Ultimum ◽  
Gamma Amino Butyric Acid ◽  
Amino Butyric Acid ◽  
Pine Seedlings ◽  
Germ Tubes

The role of root exudates in interaction between pine roots (Pinus resinosa Ait.) and Pythium ultimum Trow was studied. By paper chromatographic methods three sugars and 13 amino acids were definitely identified in the root exudate. Gamma amino butyric acid was most abundant, although asparagine, glycine, serine, and alanine were also present in large amounts. Valine, leucine, glutamine, aspartic acid, glutamic acid and proline were detected in smaller quantities. Among the sugars, both glucose and fructose were abundant while traces of arabinose were detected. When supplied singly, all amino acids and sugars except serine, leucine and arabinose, stimulated growth of the pathogen and germination of sporangia. Mixtures of sugars or mixtures of three or four amino acids were very effective in stimulating mycelial growth and development of germ tubes. The kind of nutrient influenced the number of germ tubes per sporangium. Favorable nutrient combinations, viz. mixtures of sugars, mixtures of three or four amino acids or root exudate solution, produced two to nine germ tubes, while unfavorable ones, viz., glycine, arabinose and serine, etc., produced one or two germ tubes.

scholarly journals Regulation of Pathogenic Spore Germination by CgRac1 in the Fungal Plant Pathogen Colletotrichum gloeosporioides

2011 ◽  
Vol 10 (8) ◽  
pp. 1122-1130 ◽  
Author(s):  
Iris Nesher ◽  
Anna Minz ◽  
Leonie Kokkelink ◽  
Paul Tudzynski ◽  
Amir Sharon
Keyword(s):  
Cell Division ◽  
Plant Pathogen ◽  
Germ Tube ◽  
Colletotrichum Gloeosporioides ◽  
Fluorescent Protein ◽  
Nuclear Division ◽  
Simultaneous Formation ◽  
Content Type ◽  
Germ Tubes

ABSTRACT Colletotrichum gloeosporioides is a facultative plant pathogen: it can live as a saprophyte on dead organic matter or as a pathogen on a host plant. Different patterns of conidial germination have been recognized under saprophytic and pathogenic conditions, which also determine later development. Here we describe the role of CgRac1 in regulating pathogenic germination. The hallmark of pathogenic germination is unilateral formation of a single germ tube following the first cell division. However, transgenic strains expressing a constitutively active CgRac1 (CA-CgRac1) displayed simultaneous formation of two germ tubes, with nuclei continuing to divide in both cells after the first cell division. CA-CgRac1 also caused various other abnormalities, including difficulties in establishing and maintaining cell polarity, reduced conidial and hyphal adhesion, and formation of immature appressoria. Consequently, CA-CgRac1 isolates were completely nonpathogenic. Localization studies with cyan fluorescent protein (CFP)-CgRac1 fusion protein showed that the CgRac1 protein is abundant in conidia and in hyphal tips. Although the CFP signal was equally distributed in both cells of a germinating conidium, reactive oxygen species accumulated only in the cell that produced a germ tube, indicating that CgRac1 was active only in the germinating cell. Collectively, our results show that CgRac1 is a major regulator of asymmetric development and that it is involved in the regulation of both morphogenesis and nuclear division. Modification of CgRac1 activity disrupts the morphogenetic program and prevents fungal infection.

Interaction of culture age and temperature on germination and growth of Curvularia geniculata and on virulence

1972 ◽  
Vol 50 (11) ◽  
pp. 2093-2096 ◽  
Author(s):  
Clinton F. Hodges
Keyword(s):  
Germ Tube ◽  
Culture Age ◽  
Germination And Growth ◽  
Germ Tubes

Germination of conidia of Curvularia geniculata from 20-, 40-, and 60-day-old cultures increased as temperature was increased to 15C. At 25C, maximum germination occurred among conidia from 20-day-old cultures, but germination from 40- and 60-day-old cultures decreased at and above 25C. Number and length of germ tubes and primary germ-tube branches increased on all conidia as temperature was increased from 5C to 25C and decreased above 25C. Germination also was influenced by culture age. Total and rate of germination decreased among conidia from older cultures at all temperatures; number and length of germ tubes and germ-tube branches also decreased on conidia from older cultures. Pathogenicity of C. geniculata was not clearly established.

Corrigendum to Role of Plasma Amino Acids and Urinary Organic Acids in Diagnosis of Mitochondrial Diseases in Children

2015 ◽  
Vol 52 (4) ◽  
pp. 470
Author(s):  
Hamed M. Shatla ◽  
Hoda Y. Tomoum ◽  
Solaf M. Elsayed ◽  
Iman A. Elagouza ◽  
Rania H. Shatla ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Acids ◽  
Mitochondrial Diseases ◽  
Plasma Amino Acids ◽  
Urinary Organic Acids

Role of Plasma Amino Acids and Urinary Organic Acids in Diagnosis of Mitochondrial Diseases in Children

2014 ◽  
Vol 51 (6) ◽  
pp. 820-825 ◽  
Author(s):  
Hamed M. Shatla ◽  
Hoda Y. Tomoum ◽  
Solaf M. Elsayed ◽  
Iman A. Elagouza ◽  
Rania H. Shatla ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Acids ◽  
Mitochondrial Diseases ◽  
Plasma Amino Acids ◽  
Urinary Organic Acids

scholarly journals Contribution of Individual Chemoreceptors to Sinorhizobium meliloti Chemotaxis Towards Amino Acids of Host and Nonhost Seed Exudates

2016 ◽  
Vol 29 (3) ◽  
pp. 231-239 ◽  
Author(s):  
Benjamin A. Webb ◽  
Richard F. Helm ◽  
Birgit E. Scharf
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sinorhizobium Meliloti ◽  
Wild Type ◽  
Chemotaxis Assay ◽  
Plant Seeds ◽  
Single Deletion ◽  
Seed Exudate ◽  
Type Response

Plant seeds and roots exude a spectrum of molecules into the soil that attract bacteria to the spermosphere and rhizosphere, respectively. The alfalfa symbiont Sinorhizobium meliloti utilizes eight chemoreceptors (McpT to McpZ and IcpA) to mediate chemotaxis. Using a modified hydrogel capillary chemotaxis assay that allows data quantification and larger throughput screening, we defined the role of S. meliloti chemoreceptors in sensing its host, Medicago sativa, and a closely related nonhost, Medicago arabica. S. meliloti wild type and most single-deletion strains displayed comparable chemotaxis responses to host or nonhost seed exudate. However, while the mcpZ mutant responded like wild type to M. sativa exudate, its reaction to M. arabica exudate was reduced by 80%. Even though the amino acid (AA) amounts released by both plant species were similar, synthetic AA mixtures that matched exudate profiles contributed differentially to the S. meliloti wild-type response to M. sativa (23%) and M. arabica (37%) exudates, with McpU identified as the most important chemoreceptor for AA. Our results show that S. meliloti is equally attracted to host and nonhost legumes; however, AA play a greater role in attraction to M. arabica than to M. sativa, with McpZ being specifically important in sensing M. arabica.

scholarly journals Microbial-Induced Carbon Competition in the Spermosphere Leads to Pathogen and Disease Suppression in a Municipal Biosolids Compost

2012 ◽  
Vol 102 (6) ◽  
pp. 588-596 ◽  
Author(s):  
Mei-Hsing Chen ◽  
Eric B. Nelson
Keyword(s):  
Linoleic Acid ◽  
Microbial Communities ◽  
Germ Tube ◽  
Disease Suppression ◽  
Cucumber Seed ◽  
Seed Exudate ◽  
Municipal Biosolids ◽  
Carbon Competition ◽  
Germ Tubes ◽  
Biosolids Compost

The aim of this study was to understand whether competition for fatty acids in plant seed exudates by compost-derived seed-colonizing microbial communities could explain the suppression of plant infections initiated by sporangia of Pythium ultimum. The germination behavior of P. ultimum sporangia in response to cucumber seeds was measured to determine the impact of seed-colonizing microbes on pathogen suppression. Seed-colonizing microbial communities from municipal biosolids compost utilized cucumber seed exudates and linoleic acid in vitro, reducing the respective stimulatory activity of these elicitors to P. ultimum sporangial germination. However, when sporangia were observed directly in the spermosphere of seeds sown in the compost medium, levels of germination and sporangial emptying did not differ from the responses in sand. The percentage of aborted germ tubes was greater after incubating sporangia in compost medium for 12-h than the level of germ tube abortion when sporangia were incubated in sand. Abortion did not occur if previously germinated sporangia were supplemented with cucumber seed exudate. Furthermore, removal of cucumber seed exudate after various stages of germ tube emergence resulted in an increase in aborted germ tubes over time. Adding increasing levels of glucose directly to the compost medium alleviated germ tube abortion in the spermosphere and also eliminated disease suppression. These data fail to support a role for linoleic acid competition in Pythium seedling disease suppression but provide evidence for general carbon competition mediated by seed-colonizing microbial communities as a mechanism for the suppression of Pythium seed infections in municipal biosolids compost.

The effect of pea root exudate on the germination of Pythium aphanidermatum zoospore cysts

1970 ◽  
Vol 48 (9) ◽  
pp. 1501-1514 ◽  
Author(s):  
Yung Chang-Ho
Keyword(s):  
Organic Acids ◽  
Germ Tube ◽  
Root Exudate ◽  
Pythium Aphanidermatum ◽  
Tube Growth ◽  
Percentage Germination ◽  
Pea Root ◽  
Low Concentrations ◽  
Germination And Growth ◽  
Germ Tube Growth

Zoospore cysts of Pythium aphanidermatum germinated well without external nutrient supply, but pea root exudate increased percentage germination and germ tube growth. Zoospore cyst germination and growth varied with different concentrations of the substrate supplied. Alone, the neutral fraction (sugars) increased percentage germination but had little effect on germ tube growth; the cationic fraction (amino acids) suppressed germination and growth somewhat, except at very low concentrations; the anionic fraction (organic acids) mildly stimulated both processes. Neutral and anionic fractions combined approached the stimulatory effect of root exudate. Amongst the components of root exudate tested as pure chemicals, fructose, histidine, homoserine, proline, and tartaric acid promoted germination and growth at low concentrations. Alpha-alanine, glutamine, serine, and valine became stimulatory at high concentrations. A combination of glucose with one of the organic acids was more effective than either alone.

scholarly journals In Candida albicans, the Nim1 kinases Gin4 and Hsl1 negatively regulate pseudohypha formation and Gin4 also controls septin organization

2004 ◽  
Vol 164 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Raymond Wightman ◽  
Steven Bates ◽  
Pat Amornrrattanapan ◽  
Peter Sudbery
Keyword(s):  
Candida Albicans ◽  
Germ Tube ◽  
Ectopic Expression ◽  
Tube Formation ◽  
Septin Ring ◽  
Germ Tubes ◽  
Developmental Switch

In the development of hyphal germ tubes of Candida albicans, a band of septin forms at the base of the germ tube (basal septin band). Later, a septin ring forms, which organizes the first septum within the germ tube (septin ring). We have investigated the role of the Nim1 kinases, Gin4 and Hsl1, in the formation of these septin structures. We show that during germ tube formation, Gin4 is required for the organization of the septin ring but not the basal septin band. Hsl1 is not required for the formation of either septin rings or basal bands. Unexpectedly, we found that both gin4Δ and hsl1Δ mutants form pseudohyphae constitutively, in a fashion that in the case of gin4Δ, is partly independent of Swe1. Gin4-depleted pseudohyphae are unable to form hyphae when challenged with serum, but this can be overcome by ectopic expression of Gin4 from the MET3 promoter. Thus, Gin4 may regulate the developmental switch from pseudohyphae to hyphae.

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