Herbicide-induced resistance of cotton to Verticillium wilt disease and activation of host cells to produce the phytoalexin gossypol

1992 ◽  
Vol 70 (7) ◽  
pp. 1440-1444 ◽  
Author(s):  
O. A. Awadalla ◽  
I. M. El-Refai

Pretreating cotton seeds with selected herbicide markedly increased cotton resistance to vascular wilt caused by Verticillium albo-atrum. The present investigation studied the mechanism of resistance to V. albo-atrum induced by some herbicides in susceptible cotton plants. The three herbicides tested repressed mycelial growth. Prometryn and dalapon caused a marked reduction in the appearance of Verticillium wilt disease and were the most effective in controlling the disease. Phytoalexin (gossypol) production was greatly increased in herbicide-treated inoculated cotton plants. The level of gossypol was higher in the root than stem. Maximum production of gossypol was achieved in cotton plants treated with the herbicides prometryn and dalapon and inoculated with fungal spores but it was not present in uninoculated control plants. Key words: cotton, Verticillium albo-atrum, herbicides, phytoalexin, disease resistance.

1967 ◽  
Vol 20 (2) ◽  
pp. 475 ◽  
Author(s):  
TC Somers ◽  
AF Harrison

Apricot trees often recover from the "black heart" disease incited by the fungus Verticillium albo-atrum Reinke & Berthold, and a characteristic of such resistant trees is that the infected wood becomes dark brown to black in colour (Dufrenoy and Dufrenoy 1927). The fungus dies 1-6 months after it has colonized the wood (Taylor 1963). Analysis of total phenolics by the Folin-Denis assay showed an approximate fivefold increase (to about 60 mgjg wood) compared with that of uninfected wood of the same branch, and suggested their involvement in disease resistance mechanisms.


2013 ◽  
Vol 53 (2) ◽  
pp. 154-157 ◽  
Author(s):  
Mahdiyeh Mansoori ◽  
Asghar Heydari ◽  
Nader Hassanzadeh ◽  
Saeed Rezaee ◽  
Laleh Naraghi

Abstract Verticillium wilt is considered the most important disease of cotton in the world, including Iran. Cultural practices and the use of resistant varieties are the most common strategies used to control Verticillium wilt of cotton. These strategies are not always available or effective. In recent years, biological control using fungal and bacterial antagonists, has been applied to control some cotton diseases including damping-off. In this study, we investigated the possibility of biological control of Verticillium wilt of cotton using bacterial antagonists. Suspension of eight bacterial strains of Pseudomonas fluorescens and Bacillus spp. isolated from different rhizospheric soils and plant roots in the Iranian cotton fields, were prepared with a concentration of 108 cfu/ml. Ten cotton seeds (cv Varamin) were then coated with each bacterial suspension and were planted in soil pre-inoculated with Verticillium dahliae microsclerotia. The efficacy of bacterial antagonists in reducing wilt disease was evaluated by determination of the disease index in different treatments. The results indicated that most isolates were effective in reducing disease (compared to the untreated control) 90 days after sowing. Isolates B5, B6, B2, B7, and B3 were the most effective, respectively, in reducing wilt index. In contrast, isolates B1, B4, and B8 did not significantly reduce the disease. In general, P. fluorescens isolates were more effective than Bacillus isolates. This study suggests that bacterial antagonists might be potential biological control agents of cotton.


Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 129-129 ◽  
Author(s):  
G. Skarmoutsos ◽  
H. Skarmoutsou

Ailanthus glandulosa is an introduced tree species in Greece used as ornamental and is considered resistant to both fungal and insect attacks. However, since 1992, a great number of A. glandulosa plants of different ages and in different parts of northern Greece have been dying. The phenomenon appeared either in single trees or in groups, and the number of affected plants increased from year to year. The symptoms were characteristic of a wilt disease. Dieback started on one or more branches and gradually spread, or whole trees were affected from the beginning. Death may occur during spring when trees do not resume their activity or later in the summer. Leaves wilt, turn yellow and fall in a short time. Trees may die in 1 to 3 years depending on their age. In cross sections of branches a continuous discoloured ring or arc was present in the outermost sapwood. Isolations made from dying trees from 25 different locations have yielded V. dahliae, a pathogen known to cause vascular wilt on many plant hosts, including Ailanthus (1). Isolations made from healthy trees did not yield the fungus. Abundant mycelium developed in the host vessels of infected trees; the hyphae were cylindrical, hyaline, and septate. On malt agar fungal cultures developed quickly and were initially a whitish to cream color that later turned black due to the formation of microsclerotia. In culture, microsclerotia started to form centrally and were dark brown to black, consisting of swollen globular cells that formed irregular masses variable in shape. The fungus also produced abundant verticillate conidiophores with phialides and conidia. This is a first report of Verticillium wilt on A. glandulosa in Greece. Reference: (1) G. Arnaud et al. Rev. Pathol. Veg. Entomol. Agric. Fr. 17:227, 1930.


1958 ◽  
Vol 36 (3) ◽  
pp. 297-299 ◽  
Author(s):  
W. Newton ◽  
M. C. J. van Adrichem

The F1 generation of selfed plants of Fragaria chiloensis, F. ovalis, and F. yukonensis contained seedlings resistant to the verticillium wilt disease. Selfed F. orientalis plants yielded seedlings that carried considerable tolerance but selfed F. vesca, F. bracteata, and F. virginiana plants yielded neither tolerant nor resistant seedlings. Asexually propagated plants of the seven species were all susceptible to the disease.


Author(s):  
C. Booth

Abstract A description is provided for Fusarium oxysporum f.sp. vasinfectum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Gossypium spp., and species of Cajanus, Coffea, Hevea, Hibiscus, Medicago, Ricinus, Solanum and Vigna. DISEASE: Vascular wilt or Fusariosis of cotton is a disease affecting its host at all stages of its growth. Early symptoms on seedlings consist of vein clearing of the leaves followed by necrosis of the interveinal tissue and death of the leaves. On older plants leaves become chlorotic and the vascular tissues show a brown discolouration. Growth is retarded and the plant eventually wilts. GEOGRAPHICAL DISTRIBUTION: Africa: Congo, Central African Republic, Egypt, Ethiopia, Madagascar, Senegal, Somalia, Sudan, South Africa, Tanganyika, Uganda; Asia: Burma, China, Formosa, India, Indo-China, Iran, Iraq, Pakistan, U.S.S.R. ; Europe: France, Greece, Italy, Romania, Yugoslavia; North America, Mexico, U.S.A. (cotton belt); Central America & West Indies: Guatemala, Nevis, Nicaragua, Puerto Rico, Salvador, St. Vincent; South America: Argentina, Brazil, Chile, Colombia, Peru, Venezuela. (C.M.I. Map 362). TRANSMISSION: Soil-borne, but may also be transmitted by water and seed. The pathogen has been recovered from delineated seed obtained from infected cotton plants in the Central African Republic, Congo, Tanganyika and Brazil (32: 186; 33: 143; 40: 754; 41: 389). The percentage infection ranged from 0.2 to 5.0.


2021 ◽  
Author(s):  
Timothy D. Murray

Abstract H. cerealis is a pathogen that causes a vascular wilt disease of gramineous hosts known as Cephalosporium stripe. It is the only known vascular wilt of small grasses and small cereal grains with a fungal aetiology. It causes what is referred to as a 'single-cycle' disease because it does not have an airborne, repeating phase. As such, it is not an invasive species per se.


2001 ◽  
Vol 2 (1) ◽  
pp. 15 ◽  
Author(s):  
J. B. Ochoa ◽  
B. Yangari ◽  
V. Galarza ◽  
J. Fiallos ◽  
M. A. Ellis

Farmers have generally abandoned production of “common naranjilla” in many areas mainly due to uncontrollable epidemics of an apparent vascular wilt disease. Naranjilla vascular wilt (NVW) and is currently the major constraint to the production of naranjilla in Ecuador, where losses due to NVW may reach up to 80%. Accepted for publication 13 September 2001. Published 18 September 2001.


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