scholarly journals Aspergillus terreus Inhibits Growth and Induces Morphological Abnormalities in Pythium aphanidermatum and Suppresses Pythium-Induced Damping-Off of Cucumber

2018 ◽  
Vol 9 ◽  
Author(s):  
Boshra A. Halo ◽  
Rashid A. Al-Yahyai ◽  
Abdullah M. Al-Sadi
PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7884 ◽  
Author(s):  
Hanaa Al-Shibli ◽  
Sergey Dobretsov ◽  
Abdulrahman Al-Nabhani ◽  
Sajeewa S.N. Maharachchikumbura ◽  
Velazhahan Rethinasamy ◽  
...  

A study was conducted to investigate the potential of Aspergillus terreus obtained from Avicennia marina mangrove roots in inhibiting Pythium aphanidermatum and damping-off disease of cucumber. Aspergillus terreus exhibited in vitro inhibition of Pythium aphanidermatum growth. Electron microscope examination revealed that the antagonistic fungal isolate resulted in shrinking and groves in Pythium hypha. When Aspergillus terreus culture filtrate was added to Pythium aphanidermatum, it resulted in a significant increase (by 73%) in electrolyte leakage from Pythium hypha compared to the control, as well as significant reduction (by 71%) in oospore production. The Aspergillus terreus culture was also found to produce a cellulase enzyme, which is suggested to be involved in the antagonism against Pythium aphanidermatum. Adding Aspergillus terreus to soil infested with Pythium aphanidermatum significantly reduced percent mortality in cucumber seedlings by 70%. Aspergillus terreus, when applied alone on cucumber seedlings, did not show any suppressive effects on cucumber growth (length and fresh and dry weight). This appears to be the first report of isolation from mangrove of Aspergillus terreus with antagonistic activity against Pythium aphanidermatum-induced damping-off of cucumber. The study indicates that fungal isolates obtained from marine environments may serve as potential biocontrol agents against some plant pathogens.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 788
Author(s):  
Shaban R. M. Sayed ◽  
Shaimaa A. M. Abdelmohsen ◽  
Hani M. A. Abdelzaher ◽  
Mohammed A. Elnaghy ◽  
Ashraf A. Mostafa ◽  
...  

The role of Pythium oligandrum as a biocontrol agent against Pythium aphanidermatum was investigated to avoid the harmful impacts of fungicides. Three isolates of P. oligandrum (MS15, MS19, and MS31) were assessed facing the plant pathogenic P. aphanidermatum the causal agent of Glycine max damping-off. The tested Pythium species were recognized according to their cultural and microscopic characterizations. The identification was confirmed through sequencing of rDNA-ITS regions including the 5.8 S rDNA. The biocontrol agent, P. oligandrum, isolates decreased the mycelial growth of the pathogenic P. aphanidermatum with 71.3%, 67.1%, and 68.7% through mycoparasitism on CMA plates. While the half-strength millipore sterilized filtrates of P. oligandrum isolates degrade the pathogenic mycelial linear growth by 34.1%, 32.5%, and 31.7%, and reduce the mycelial dry weight of the pathogenic P. aphanidermatum by 40.1%, 37.4%, and 36.8%, respectively. Scanning electron microscopy (SEM) of the most effective antagonistic P. oligandrum isolate (MS15) interaction showed coiling, haustorial parts of P. oligandrum to P. aphanidermatum hyphae. Furthermore, P. oligandrum isolates were proven to enhance the germination of Glycine max seedling to 93.3% in damping-off infection using agar pots and promote germination of up to 80% during soil pot assay. On the other hand, P. oligandrum isolates increase the shoot, root lengths, and the number of lateral roots.


Author(s):  
G. M. Waterhouse

Abstract A description is provided for Pythium aphanidermatum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a wide range of hosts, often similar to those attacked by P. butleri, but inducing different symptoms, represented in the following families: Amaranthaceae, Amaryllidaceae, Araceae, Basellaceae, Bromeliaceae, Cactaceae, Chenopodiaceae, Compositae, Coniferae, Convolvulaceae, Cruciferae, Cucurbitaceae, Euphorbiaceae, Gramineae, Leguminosae, Linaceae, Malvaceae, Moraceae, Passifloraceae, Rosaceae, Solanaceae, Umbelliferae, Violaceae, Vitaceae, Zingiberaceae. DISEASES: Damping-off of various seedlings; 'cottony-leak' of cucurbit fruit in storage; 'cottony blight' of turf grasses; root and stalk rot of maize. Other hosts: tobacco, sugar-beet, sugar-cane, papaw, pineapple, ginger, bean and cotton. GEOGRAPHICAL DISTRIBUTION: Africa (Central African Republic, Fernando, Ghana, Kenya, Malawi, Mali, Nigeria, Sierra Leone, South Africa, Southern Rhodesia, Sudan, Togo, Zambia); Asia (Ceylon, China, Formosa, India, Indonesia, Israel, Japan, Java, Malaya, Philippines, Sumatra); Australasia & Oceania (Australia, Hawaii, New Caledonia); North America (Canada, Mexico); Central America & West Indies (Antilles, Jamaica, Puerto Rico); South America (Argentina, Brazil, Peru, Venezuela); Europe Austria, Cyprus, Czechoslovakia, Great Britain, Greece, Holland, Italy, Poland, U.S.S.R., Yugoslavia). (CMI Map 309) TRANSMISSION: Soil-borne. Eggplant fruit become infected when blossom end is in contact with soil (5: 465). Readily isolated from soil using fresh potato cubes treated with streptomycin and pimaricin as baits (43, 1519; 43, 46) or seedling papaw roots in soil containing papaw tissue (43, 1720). Also recorded as seed-borne on tomato and cucurbits but doubtful whether seed-transmitted (see Noble et al., An Annotated List of Seed-Borne Diseases, 1958, pp. 23, 25, 124).


2007 ◽  
pp. 371-374
Author(s):  
K. Al Kiyoomi ◽  
M. Deadman ◽  
Y. Al Maqbali ◽  
S. Al Jabri ◽  
J. Perret ◽  
...  

2001 ◽  
Vol 91 (4) ◽  
pp. 383-391 ◽  
Author(s):  
K. Heungens ◽  
J. L. Parke

Burkholderia cepacia AMMDR1 is a biocontrol agent that reduces Pythium damping-off and Aphanomyces root rot severity on peas in the field. We studied the effect of B. cepacia AMMDR1 on post-infection stages in the life cycles of these pathogens, including mycelial colonization of the host, production of oogonia, and production of secondary zoospore inoculum. We used Burkholderia cepacia 1324, a seed and rootcolonizing but antibiosis-deficient Tn5 mutant of B. cepacia AMMDR1, to study mechanisms of biological control other than antibiosis. B. cepacia AMMDR1 significantly reduced Pythium aphanidermatum postinfection colonization and damping-off of pea seeds, even when the bacteria were applied 12 h after zoospore inoculation. B. cepacia AMMDR1 also significantly reduced colonization of taproots by Aphanomyces euteiches mycelium, but only when the bacteria were applied at high population densities at the site of zoospore inoculation. The antibiosisdeficient mutant, B. cepacia 1324, had no effect on mycelial colonization of seeds or roots by Pythium aphanidermatum nor A. euteiches, suggesting that antibiosis is the primary mechanism of biological control. B. cepacia AMMDR1, but not B. cepacia 1324, reduced production of A. euteiches oogonia. This effect occurred even when the population size of B. cepacia AMMDR1 was too small to cause a reduction in lesion length early on in the infection process and may result from in situ antibiotic production. B. cepacia AMMDR1 had no effect on the production of secondary zoospores of A. euteiches from infected roots. The main effects of B. cepacia AMMDR1 on postinfection stages in the life cycles of these pathogens therefore were reductions in mycelial colonization by Pythium aphanidermatum and in formation of oogonia by A. euteiches. No mechanism other than antibiosis could be identified.


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