Effects of water stress on chestnut blight

1995 ◽  
Vol 25 (6) ◽  
pp. 1030-1035 ◽  
Author(s):  
S. Gao ◽  
L. Shain
Keyword(s):  
Water Stress ◽  
Osmotic Potential ◽  
Virulent Strain ◽  
Moisture Stress ◽  
Companion Paper ◽  
Culture Collection ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Dormant Season ◽  
Stem Segments

A range of moisture stress was induced in American chestnut (Castaneadentata (Marsh.) Borkh.) stem segments by incubating them in chambers maintained at humidities of 100%, 90%, or 70% or by soaking their unsealed lower ends in water. Stems then were inoculated with mycelial discs or conidial suspensions of a virulent strain of the chestnut blight fungus (Cryphonectriaparasitica (Murr.) Barr, Ep 155 (American Type Culture Collection No. 38755)). Bark osmotic potential and relative turgidity were monitored on these stems during the development of chestnut blight cankers. Canker expansion was greatest on the stem segments that were lowest in bark osmotic potential (−1.8 MPa) and relative turgidity (56.3%), whereas expansion was least on those stems that were highest in bark osmotic potential (−1.1 MPa) and relative turgidity (68.4%). Water stress, however, had little effect on conidial infection of wounds on stems collected during the growing season, but fewer conidial inoculations of wounds were successful on water-stressed stems collected during the dormant season. Bark osmotic potential of living trees ranged from −0.8 to −2.0 MPa in monthly samplings during the year. Mycelial growth and conidial germination of C. parasitica generally was not affected at osmotic potentials above −2.0 MPa (see companion paper). These results indicate that canker expansion, but not necessarily canker initiation, is favored by water stress and that the effects of water stress are greater on the host than on the pathogen.

Effects of osmotic potential on virulent and hypovirulent strains of the chestnut blight fungus

1995 ◽  
Vol 25 (6) ◽  
pp. 1024-1029 ◽  
Author(s):  
S. Gao ◽  
L. Shain
Keyword(s):  
Osmotic Potential ◽  
Mycelial Growth ◽  
Companion Paper ◽  
Conidial Germination ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Virulent Strains ◽  
Agar Media ◽  
Cornmeal Agar ◽  
Osmotic Potentials

Mycelial growth and conidial germination of two virulent and four isogenic hypovirulent strains of Cryphonectriaparasitica (Murr.) Barr were monitored on cornmeal agar media osmotically adjusted with NaCl, KCl, sucrose, or a salt mixture of NaCl–KCl–Na2SO4 of 5:3:2. Mycelial growth generally was not inhibited on KCl or sucrose adjusted media with an osmotic potential above −2.0 MPa. Mycelial growth generally was inhibited at this osmotic potential, however, on those media that contained sodium in the osmoticum. While conidial germination was more sensitive than mycelial growth to sodium, conidia were more tolerant than mycelia to osmotic potentials less than −2.0 MPa when media were adjusted with KCl or sucrose. Conidia of all strains germinated on media adjusted to −6.0 MPa with these two osmotica after incubation for 48 h but not 24 h at 25 °C. Hypovirulent strains generally reacted similarly to their isogenic virulent strains with regard to reduced osmotic potential. Because the lowest osmotic potential of chestnut (Castaneadentata (Marsh.) Borkh.) bark observed in monthly samples was −2.0 MPa (see companion paper), it appears that water stress has little direct impact on the pathogen during pathogenesis.

scholarly journals Cutinase in Cryphonectria parasitica, the chestnut blight fungus: suppression of cutinase gene expression in isogenic hypovirulent strains containing double-stranded RNAs.

1992 ◽  
Vol 12 (10) ◽  
pp. 4539-4544 ◽  
Author(s):  
D A Varley ◽  
G K Podila ◽  
S T Hiremath
Keyword(s):  
Gene Expression ◽  
Fusarium Solani ◽  
Virulent Strain ◽  
Pathogenic Fungi ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Plant Pathogenic Fungi ◽  
Chestnut Blight Fungus ◽  
Plant Cuticles ◽  
Isogenic Strains

Plant-pathogenic fungi produce cutinase, an enzyme required to degrade plant cuticles and facilitate penetration into the host. The absence of cutinase or a decrease in its production has been associated with a decrease in pathogenicity of the fungus. A set of isogenic strains of Cryphonectria parasitica, the chestnut blight fungus, was tested for the presence and amounts of cutinase activity. The virulent strain of C. parasitica produced and secreted significantly higher amounts of cutinase than the hypovirulent strains. Use of both nucleic acid and polyclonal antibody probes for cutinase from Fusarium solani f. sp. pisi showed that cutinase in C. parasitica is 25 kDa in size and is coded by a 1.1-kb mRNA. Both mRNA and protein were inducible by cutin hydrolysate, while hypovirulence agents suppressed the level of mRNA and the enzyme. Since all the strains had the cutinase gene, the suppression of expression was due to the hypovirulence agents. The data presented are the first report indicating that hypovirulence agents in C. parasitica regulate a gene associated with pathogenicity in other plant-pathogenic fungi.

Conidia of hypovirulent strains of Cryphonectriaparasitica differ in their potential for biocontrol of chestnut blight

1992 ◽  
Vol 22 (9) ◽  
pp. 1338-1342 ◽  
Author(s):  
K.L. Scibilia ◽  
F.V. Hebard ◽  
L. Shain
Keyword(s):  
Virulent Strain ◽  
Culture Collection ◽  
American Chestnut ◽  
American Type Culture Collection ◽  
Chestnut Blight ◽  
Virulent Strains ◽  
Hypovirulent Strain

Conidia from eight hypovirulent strains of Cryphonectriaparasitica (Murr.) Barr were suspended in water and applied to the bark of American chestnut (Castaneadentata (Marsh.) Borkh.) trees. Cankers were initiated with mycelium of virulent strains isogenic to the applied conidia. Hypovirulent strains differed significantly in the ability of their conidia to putatively convert isogenic virulent strains in cankers, as indicated by the recovery of cultures with hypovirulent morphology from challenged cankers. A tank mix of conidia from two hypovirulent strains in different conversion groups putatively converted significantly more cankers initiated by isogenic virulent strains than did separate applications of conidia from these strains, particularly when the second application was delayed by 2 weeks. Cankers initiated on excised stems with virulent strain Ep 155 (American Type Culture Collection 38755) yielded cultures with hypovirulent morphology after application of conidia from isogenic hypovirulent strain Ep 780 at densities as low as 50 and 700 conidia/cm2 for inoculations sealed or not sealed with latex caulk, respectively.

Cutinase in Cryphonectria parasitica, the chestnut blight fungus: suppression of cutinase gene expression in isogenic hypovirulent strains containing double-stranded RNAs

1992 ◽  
Vol 12 (10) ◽  
pp. 4539-4544
Author(s):  
D A Varley ◽  
G K Podila ◽  
S T Hiremath
Keyword(s):  
Gene Expression ◽  
Fusarium Solani ◽  
Virulent Strain ◽  
Pathogenic Fungi ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Plant Pathogenic Fungi ◽  
Chestnut Blight Fungus ◽  
Plant Cuticles ◽  
Isogenic Strains

Plant-pathogenic fungi produce cutinase, an enzyme required to degrade plant cuticles and facilitate penetration into the host. The absence of cutinase or a decrease in its production has been associated with a decrease in pathogenicity of the fungus. A set of isogenic strains of Cryphonectria parasitica, the chestnut blight fungus, was tested for the presence and amounts of cutinase activity. The virulent strain of C. parasitica produced and secreted significantly higher amounts of cutinase than the hypovirulent strains. Use of both nucleic acid and polyclonal antibody probes for cutinase from Fusarium solani f. sp. pisi showed that cutinase in C. parasitica is 25 kDa in size and is coded by a 1.1-kb mRNA. Both mRNA and protein were inducible by cutin hydrolysate, while hypovirulence agents suppressed the level of mRNA and the enzyme. Since all the strains had the cutinase gene, the suppression of expression was due to the hypovirulence agents. The data presented are the first report indicating that hypovirulence agents in C. parasitica regulate a gene associated with pathogenicity in other plant-pathogenic fungi.

The chestnut blight fungus world tour: successive introduction events from diverse origins in an invasive plant fungal pathogen

2012 ◽  
Vol 21 (16) ◽  
pp. 3931-3946 ◽  
Author(s):  
C. DUTECH ◽  
B. BARRÈS ◽  
J. BRIDIER ◽  
C. ROBIN ◽  
M. G. MILGROOM ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Invasive Plant ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus ◽  
Plant Fungal Pathogen

Comparative vesicle proteomics reveals selective regulation of protein expression in chestnut blight fungus by a hypovirus

2013 ◽  
Vol 78 ◽  
pp. 221-230 ◽  
Author(s):  
Jinzi Wang ◽  
Fangzhen Wang ◽  
Youjun Feng ◽  
Ke Mi ◽  
Qi Chen ◽  
...  
Keyword(s):  
Protein Expression ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus

Crypt1, an active Ac-like transposon from the chestnut blight fungus, Cryphonectria parasitica

2001 ◽  
Vol 265 (4) ◽  
pp. 730-738 ◽  
Author(s):  
D. Linder-Basso ◽  
R. Foglia ◽  
P. Zhu ◽  
B.I. Hillman
Keyword(s):  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Chestnut Blight Fungus

scholarly journals The Morphology and the Biological Control of Cryphonectria parasitica

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Carmen Emilia PUIA ◽  
Daniela Andreea GRIGORESCU ◽  
Raluca Vasilica MICLEA
Keyword(s):  
Biological Control ◽  
Virulent Strain ◽  
Morphological Characteristics ◽  
Castanea Sativa ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Dual Culture ◽  
Natural Form ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Cryphonectria parasitica  (Murr.) Bar [syn. Endothia parasitica (Murr. And.] (anamorf: Endothiella sp .) is the causal agent of chestnut bark disease or chestnut blight, disease which produced great damages throughout the world, for example, in Europe, the European chestnut tree ( Castanea sativa (P.) Mill) was heavily affected. Environmental concerns have focused attention on natural forms of disease control as an effective alternative to chemical pesticides. In the chestnut blight fungus, Cryphonectria parasitica deals with a natural form of biological control in which the virulence of a fungal pathogen is attenuated by an endogenous viral RNA genetic element- the hypovirulent strain. In our researches we picked samples of chestnut bark from different areas in Maramures county. We’ve isolated the fungus on PDA medium and we’ve studied the morphological characteristics of the usual virulent strain and we looked for a possible hypovirulent strain in order to study its capacity for biological control. The fungus develops in the bark and in cambium where forms a yellowish or brownish stroma and produces both conidia and ascospores. The pycnidia stromata break through the lenticels producing conidia and later in the same stroma develop the perithecia which produce ascospores. Both strains of the fungus were found in the research area. The hypovirulent strain had a slower development, showed no sporu lation and pigmentation “white cultural strain” and was tested in vitro for the capacity to convert the virulent isolates by dual culture tests.

Sign in / Sign up

Export Citation Format

Share Document