GENETICS OF PHYTOPATHOGENIC FUNGI: VIRULENCE OF COLOR AND NUTRITIONALLY DEFICIENT MUTANTS OF PENICILLIUM ITALICUM AND PENICILLIUM DIGITATUM

1964 ◽  
Vol 42 (4) ◽  
pp. 429-436 ◽  
Author(s):  
L. Beraha ◽  
E. D. Garber ◽  
Ø. Strømnaes
Keyword(s):  
Ultraviolet Light ◽  
Parental Strain ◽  
Citrus Fruit ◽  
Phytopathogenic Fungi ◽  
Fruit Rot ◽  
Nutritional Requirements ◽  
Penicillium Italicum ◽  
Auxotrophic Mutants ◽  
Specific Alteration ◽  
Weakly Virulent

Prototrophic color and auxotrophic mutants of Penicillium italicum and P. digitatum, causal agents of citrus fruit rot, were obtained by irradiating conidia with ultraviolet light. Avirulent mutants caused a necrosis but not an obvious rot at the site of inoculation in orange rind. Avirulence was not necessarily associated with a specific alteration in the color of sporulating colonies or with the tested nutritional requirements. Supplementing necrotic lesions with the compounds required by the avirulent auxotrophic mutants enhanced growth but did not cause an obvious rot. Although heterocaryons of P. italicum involving avirulent auxotrophic strains were weakly virulent, the corresponding diploid strains were as virulent as the haploid prototrophic parental strain. Prototrophic segregants from the diploid strains were virulent. Avirulence was not related to the inability of the avirulent mutants to grow at the site of inoculation. It is probable that more than one locus may be responsible for the loss of virulence.

scholarly journals Identification of Lasiodiplodia pseudotheobromae Causing Fruit Rot of Citrus in China

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 202
Author(s):  
Jianghua Chen ◽  
Zihang Zhu ◽  
Yanping Fu ◽  
Jiasen Cheng ◽  
Jiatao Xie ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Elongation Factor ◽  
Morphological Characteristics ◽  
Citrus Fruit ◽  
Economic Loss ◽  
Fruit Rot ◽  
Post Inoculation ◽  
Citrus Reticulata ◽  
Postharvest Diseases ◽  
Citrus Reticulata Blanco

Considering the huge economic loss caused by postharvest diseases, the identification and prevention of citrus postharvest diseases is vital to the citrus industry. In 2018, 16 decayed citrus fruit from four citrus varieties—Satsuma mandarin (Citrus unshiu), Ponkan (Citrus reticulata Blanco cv. Ponkan), Nanfeng mandarin (Citrus reticulata cv. nanfengmiju), and Sugar orange (Citrus reticulata Blanco)—showing soft rot and sogginess on their surfaces and covered with white mycelia were collected from storage rooms in seven provinces. The pathogens were isolated and the pathogenicity of the isolates was tested. The fungal strains were identified as Lasiodiplodia pseudotheobromae based on their morphological characteristics and phylogenetic analyses using the internal transcribed spacer regions (ITS), translation elongation factor 1-α gene (TEF), and beta-tubulin (TUB) gene sequences. The strains could infect wounded citrus fruit and cause decay within two days post inoculation, but could not infect unwounded fruit. To our knowledge, this is the first report of citrus fruit decay caused by L. pseudotheobromae in China.

scholarly journals Biocontrol potential of Streptomyces sp. CACIS-1.5CA against phytopathogenic fungi causing postharvest fruit diseases

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Zahaed Evangelista-Martínez ◽  
Erika Anahí Contreras-Leal ◽  
Luis Fernando Corona-Pedraza ◽  
Élida Gastélum-Martínez
Keyword(s):  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Fruit Rot ◽  
Main Body ◽  
Type I ◽  
Tropical Fruit ◽  
Habanero Pepper ◽  
Antagonistic Microorganisms

Abstract Background Fungi are one of the microorganisms that cause most damage to fruits worldwide, affecting their quality and consumption. Chemical controls with pesticides are used to diminish postharvest losses of fruits. However, biological control with microorganisms or natural compounds is an increasing alternative to protect fruits and vegetables. In this study, the antifungal effect of Streptomyces sp. CACIS-1.5CA on phytopathogenic fungi that cause postharvest tropical fruit rot was investigated. Main body Antagonistic activity was evaluated in vitro by the dual confrontation over fungal isolates obtained from grape, mango, tomato, habanero pepper, papaya, sweet orange, and banana. The results showed that antagonistic activity of the isolate CACIS-1.5CA was similar to the commercial strain Streptomyces lydicus WYEC 108 against the pathogenic fungi Colletotrichum sp., Alternaria sp., Aspergillus sp., Botrytis sp., Rhizoctonia sp., and Rhizopus sp. with percentages ranging from 30 to 63%. The bioactive extract obtained from CACIS-1.5 showed a strong inhibition of fungal spore germination, with percentages ranging from 92 to 100%. Morphological effects as irregular membrane border, deformation, shrinkage, and collapsed conidia were observed on the conidia. Molecularly, the biosynthetic clusters of genes for the polyketide synthase (PKS) type I, PKS type II, and NRPS were detected in the genome of Streptomyces sp. CACIS-1.5CA. Conclusions This study presented a novel Streptomyces strain as a natural alternative to the use of synthetic fungicides or other commercial products having antagonistic microorganisms that were used in the postharvest control of phytopathogenic fungi affecting fruits.

scholarly journals Survival and mutant production induced by mutagenic agents in Metarhizium anisopliae

1995 ◽  
Vol 52 (3) ◽  
pp. 548-554 ◽  
Author(s):  
V. Kava - Cordeiro ◽  
E.A. Luna - Alves - Lima ◽  
J.L. Azevedo
Keyword(s):  
Gamma Radiation ◽  
Ultraviolet Light ◽  
Metarhizium Anisopliae ◽  
Entomopathogenic Fungus ◽  
Nitrous Acid ◽  
Wild Strain ◽  
Wild Type ◽  
Survival Curves ◽  
Auxotrophic Mutants ◽  
Morphological Mutants

A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12%) and nitrous acid (0.06%).The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed.

Phytophthora nicotianae var. parasitica. [Descriptions of Fungi and Bacteria].

1964 ◽  
Author(s):  
G. M. Waterhouse
Keyword(s):  
Geographical Distribution ◽  
Citrus Fruit ◽  
Heavy Rain ◽  
Drainage Water ◽  
Phytophthora Nicotianae ◽  
Crown Rot ◽  
Fruit Rot ◽  
Piper Betle ◽  
Wide Range ◽  
Southern Rhodesia

Abstract A description is provided for Phytophthora nicotianae var. parasitica. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a very wide range of host plants comprising 58 families including: avocado, castor, Cinchona spp., citrus, cotton, eggplant, guava, lucerne, papaw, parsley, pineapple, Piper betle, rhubarb, sesame, strawberry, tomato. DISEASES: Damping-off of seedlings (tomato, castor, citrus, cotton); root rot (citrus, avocado, strawberry, lucerne); crown rot (parsley, rhubarb, strawberry, lucerne); brown stem rot of tobacco; stem canker and tip blight of Cinchona spp. ; leaf blight (castor, sesame, pineapple, Piper betle) and fruit rot (citrus, tomato, guava, papaw, eggplant). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Mali, Madagascar, Mauritius, Morocco, Nigeria, Sierra Leone, Southern Rhodesia, Tanganyika); Asia (Burma, Ceylon, China, Formosa, India, Israel, Japan, Java, Malaya, Philippines); Australia & Oceania (Australia, Hawaii, Tasmania); Europe (Cyprus, France, Germany, Great Britain, Holland, Ireland, Italy, Poland, Portugal, U.S.S.R.); North America (Bermuda, Canada, Mexico, U.S.A.); Central America & West Indies (Costa Rica, Cuba, El Salvador, Guatemala, Jamaica, Montserrat, Puerto Rico, Trinidad);. South America (Argentina, Brazil, British Guiana, Colombia, Paraguay, Peru, Venezuela). TRANSMISSION: Soil-borne, spreading rapidly after heavy rain or where soil remains moist or water-logged (40: 470). Also recorded in drainage water in India and in reservoirs and canals supplying citrus groves in U.S.A. (23: 45; 39: 24). A method for determining a disease potential index in soil using lemon fruit has been described (38: 4). Also present in testas of seeds from diseased citrus fruit which may infect nursery seedbeds (37: 165).

Nutritional requirements ofCytophaga johnsonae and some of its auxotrophic mutants

1981 ◽  
Vol 5 (4) ◽  
pp. 235-240 ◽  
Author(s):  
Li-Yen Edward Chang ◽  
Jack L. Pate
Keyword(s):  
Nutritional Requirements ◽  
Auxotrophic Mutants

A nonsclerotial pathogenic mutant of Sclerotinia sclerotiorum

1989 ◽  
Vol 35 (4) ◽  
pp. 517-520 ◽  
Author(s):  
R. Vincent Miller ◽  
Eugene J. Ford ◽  
David C. Sands
Keyword(s):  
Ultraviolet Light ◽  
Plant Species ◽  
Sclerotinia Sclerotiorum ◽  
Parental Strain ◽  
Wild Type ◽  
Physiological Studies ◽  
Sclerotial Development

A nonsclerotial mutant of Sclerotinia sclerotiorum was produced by mutagenesis with 8-methoxypsoralen and ultraviolet light. The mutant, SL-1, failed to produce sclerotia on artificial media, infested grain, or on infected plants. The mutant remained pathogenic to eight plant species susceptible to the wild-type parental strain of the fungus. The mutant, SL-1, is potentially useful for physiological studies on sclerotial development and for investigation of its potential for biological weed control.Key words: Sclerotinia, mutant, sclerotialess, biocontrol, weeds.

scholarly journals POSTHARVEST QUALITY OF SWEET CHERRY FRUITS AS AFFECTED BY BIOREGULATORS

2019 ◽  
Vol 18 (5) ◽  
pp. 189-199 ◽  
Author(s):  
Jelena Kalajdžić ◽  
Biserka Milić ◽  
Mladen Petreš ◽  
Aleksandra Stankov ◽  
Mila Grahovac ◽  
...  
Keyword(s):  
Weight Loss ◽  
Sweet Cherry ◽  
Titratable Acidity ◽  
Phytopathogenic Fungi ◽  
Fruit Weight ◽  
Fruit Rot ◽  
Postharvest Quality ◽  
Naphthaleneacetic Acid ◽  
Disease Occurrence ◽  
Sweet Cherry Cultivars

During the cold storage of sweet cherry, severe losses can occur due to the water loss, phytopathogenic fungi and physiological disorders. The aim of this research was to assess the effects of treatments with NAA (α-naphthaleneacetic acid), BA (6-benzyladenine), and GA3 (gibberellic acid) on fruit quality at harvest and after 21 days of storage under two regimes, including 0°C, RH (relative humidity) 90% and 3°C, RH 70%, and after additional shelf life exposure. Sweet cherry cultivars – ‘Summit’, ‘Kordia’ and ‘Regina’ – were treated with bioregulators at the end of flowering. NAA significantly increased the fruit weight at harvest compared to the control in all cultivars assessed. BA stimulated the fruit growth in ‘Kordia’ and ‘Regina’, while it was ineffective in ‘Summit’. GA3 caused significant increase in fruit weight by 8.3% in ‘Kordia’ only. Moreover, BA and GA3 induced a higher firmness of fruits at harvest. Weight loss of fruits during storage at 0°C, RH 90%, was increased with NAA and reduced with GA3 in ‘Regina’ only. BA and GA3 reduced the weight loss of sweet cherry fruits stored at 3°C, RH 70%. Bioregulator treatments increased TA (titratable acidity) in fruits at harvest, while the effects on TA during storage were variable depending on the cultivar. ‘Summit’ had the highest sensitivity to storage fruit rot. BA and GA3 decreased the disease occurrence on fruits stored at 0°C in ‘Summit’ and ‘Kordia’.

Penicillium digitatum. [Descriptions of Fungi and Bacteria].

1966 ◽  
Author(s):  
A. H. S. Onions
Keyword(s):  
Geographical Distribution ◽  
Citrus Fruit ◽  
Penicillium Digitatum ◽  
Penicillium Italicum ◽  
White Mould ◽  
Light Soil ◽  
Green Mould ◽  
Fruit Disease ◽  
Fallen Fruit ◽  
Fruit Surface

Abstract A description is provided for Penicillium digitatum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On decaying citrus fruit. DISEASE: Green mould of citrus fruit. Growth is rapid atter infection, the fruit surface becoming covered in a white mould which quickly becomes olive due to the production of the conidia. The fruit then softens and begins to shrink and if exposed to the air becomes a hollow mummified shell. Distinct from Penicillium italicum (see CMI Descript. 99) which is blue-green and finally reduces the fruit to a slimy mass. GEOGRAPHICAL DISTRIBUTION: Common in all citrus producing areas, but widespread as a storage rot of citrus fruit. TRANSMISSION: Common in soil of citrus producing areas and enters the fruit as a wound parasite but will not penetrate undamaged fruit. Said to occur more frequently than P. italicum on fallen fruit on light soil in Israel (31: 603). Spores also particularly abundant in air of citrus packing houses and fruit conditioning rooms (40: 400; 41: 89).

A visual indicator of heterokaryosis in Fusarium oxysporum from celery

1984 ◽  
Vol 62 (3) ◽  
pp. 540-545 ◽  
Author(s):  
John E. Puhalla
Keyword(s):  
Fusarium Oxysporum ◽  
Ultraviolet Light ◽  
Minimal Medium ◽  
Genetic Complementation ◽  
Wild Type ◽  
Uv Treatment ◽  
Formae Speciales ◽  
Auxotrophic Mutants ◽  
Pale Pink ◽  
Type Strains

Wild-type isolates of Fusarium oxysporum f. sp. apii (celery pathogens) were white or pale pink. Ultraviolet-light (UV) treatment of conidia, however, yielded stable orange mutants, which in turn gave rise to yellow and white mutants after a second UV treatment. Some pairings between these yellow and white mutants developed an orange line where they touched. This orange line developed only if the two mutants formed heterokaryons with each other. In contrast, attempts to demonstrate heterokaryons between complementary auxotrophic mutants on minimal medium failed. The color heterokaryon was a mosaic of homokaryotic and heterokaryotic cells, the latter being confined to the area of anastomosis between the two mutants. Genetic complementation was also confined to this area. In pairings among color mutants of five wild-type strains two vegetative (heterokaryon) compatibility (VC) groups were defined. VC groups in other formae spéciales of F. oxysporum should also be detectable by this method.

Sign in / Sign up

Export Citation Format

Share Document