Endophytic Fungi from Plums (Prunus domestica) and Their Antifungal Activity against Monilinia fructicola

2012 ◽  
Vol 75 (10) ◽  
pp. 1883-1889 ◽  
Author(s):  
RAPHAEL SANZIO PIMENTA ◽  
JULIANA F. MOREIRA da SILVA ◽  
JEFFREY S. BUYER ◽  
WOJCIECH J. JANISIEWICZ

Enophytic fungi were isolated from plum (Prunus domestica) leaves, identified with ITS1 and ITS4 primers, and their antagonistic activity was tested against Monilinia fructicola, which causes brown rot, blossom blight, and twig blight of stone fruits, and Colletotrichum gloeosporioides, which causes anthracnose on a variety of fruit crops. The production of antifungal compounds was determined in agar-diffusion and volatile inverted-plate tests. A total of 163 fungi were recovered from 30 plum trees, representing 22 cultivars. Twenty-nine morphotypes were detected, but only 14 species were identified genetically. The most frequently isolated species was Phaeosphaeria nodorum, constituting 86.5% of the total isolates. Four isolates produced inhibitory volatiles to M. fructicola; however, no isolate produced volatiles inhibitory to C. gloeosporioides. The volatiles produced by these fungi were identified as ethyl acetate, 3-methyl-1-butanol, acetic acid, 2-propyn-1-ol, and 2-propenenitrile. The fungal volatiles inhibited growth and reduced width of the hyphae, and caused disintegration of the hyphal content. This is the first study describing fungal endophytes in stone fruits. The P. nodorum strains producing inhibitory volatiles could play a significant role in reduction of M. fructicola expansion in plum tissues. Potential of these strains for biological control of this pathogen on stone fruits warrants further investigation.

1965 ◽  
Vol 16 (2) ◽  
pp. 141 ◽  
Author(s):  
PT Jenkins

A fungus with the cultural characteristics of Sclerotinia laxa Aderh. & Ruhl. has been determined as a cause of blossom and twig blight and fruit rot of stone fruits in southern Victoria. This is the first report of a brown rot species other than S. fructicola (Wint.) Rehm. occurring in Australia. European plum (Prunus domestica) is the host most severely affected, and there is evidence that the disease has spread from this host to adjacent cherry, peach, and apricot varieties. The distribution of S. laxa appears to be restricted to the Wandin, Tyabb, and Red Hill districts of southern Victoria. S. fructicola also is a cause of blossom blight and fruit rot in these districts, and is the only brown rot fungus which causes losses of stone fruits in the major canning fruit districts of northern Victoria.


Plant Disease ◽  
2010 ◽  
Vol 94 (9) ◽  
pp. 1166-1166 ◽  
Author(s):  
A. Munda ◽  
M. Viršček Marn

Monilinia fructicola, the causal agent of brown rot, is a destructive fungal pathogen that affects mainly stone fruits (Prunoideae). It causes fruit rot, blossom wilt, twig blight, and canker formation and is common in North and South America, Australia, and New Zealand. M. fructicola is listed as a quarantine pathogen in the European Union and was absent from this region until 2001 when it was detected in France. In August 2009, mature peaches (Prunus persica cv. Royal Glory) with brown rot were found in a 5-year-old orchard in Goriška, western Slovenia. Symptoms included fruit lesions and mummified fruits. Lesions were brown, round, rapidly extending, and covered with abundant gray-to-buff conidial tufts. The pathogen was isolated in pure culture and identified based on morphological and molecular characters. Colonies on potato dextrose agar (PDA) incubated at 25°C in darkness had an average daily growth rate of 7.7 mm. They were initially colorless and later they were light gray with black stromatal plates and dense, hazel sporogenous mycelium. Colony margins were even. Sporulation was abundant and usually developed in distinct concentric zones. Limoniform conidia, produced in branched chains, measured 10.1 to 17.7 μm (mean = 12.1 μm) × 6.2 to 8.6 μm (mean = 7.3 μm) on PDA. Germinating conidia produced single germ tubes whose mean length ranged from 251 to 415 μm. Microconidia were abundant, globose, and 3 μm in diameter. Morphological characters resembled those described for M. fructicola (1). Morphological identification was confirmed by amplifying genomic DNA of isolates with M. fructicola species-specific primers (2–4). Sequence of the internal transcribed spacer (ITS) region (spanning ITS1 and ITS 2 plus 5.8 rDNA) of a representative isolate was generated using primers ITS1 and ITS4 and deposited in GenBank (Accession No. GU967379). BLAST analysis of the 516-bp PCR product revealed 100% identity with several sequences deposited for M. fructicola in NCBI GenBank. Pathogenicity was tested by inoculating five mature surface-sterilized peaches with 10 μl of a conidial suspension (104 conidia ml–1) obtained from one representative isolate. Sterile distilled water was used as a control. Peaches were wounded prior to inoculation. After 5 days of incubation at room temperature and 100% relative humidity, typical brown rot symptoms developed around the inoculation point, while controls showed no symptoms. M. fructicola was reisolated from lesion margins. Peach and nectarine orchards in a 5-km radius from the outbreak site were surveyed in September 2009 and M. fructicola was confirmed on mummified fruits from seven orchards. The pathogen was not detected in orchards from other regions of the country, where only the two endemic species M. laxa and M. fructigena were present. To our knowledge, this is the first report of M. fructicola associated with brown rot of stone fruits in Slovenia. References: (1) L. R. Batra. Page 106 in: World Species of Monilinia (Fungi): Their Ecology, Biosystematics and Control. J. Cramer, Berlin, 1991. (2) M.-J. Côté et al. Plant Dis. 88:1219, 2004. (3) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000. (4) R. Ioos and P. Frey. Eur. J. Plant Pathol. 106:373, 2000.


Plant Disease ◽  
1998 ◽  
Vol 82 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Chuanxue Hong ◽  
Themis J. Michailides

Naturally growing apothecia of Monilinia fructicola were collected from two commercial plum orchards near Reedley and Sanger, both in Fresno County, California. Ascospore discharges from 90 (1996) and 86 (1997) apothecia were monitored individually using spore traps at four constant temperatures. The period of discharge decreased as temperature increased from 10 to 25°C. However, daily discharge increased as temperature increased from 10 to 15°C and remained high at 20 and 25°C. The greatest discharge occurred with apothecia at 15°C, followed by those incubated at 20, 10, and 25°C. The germination of ascospores of M. fructicola and the length of germ tubes increased as temperature increased from 7 to 15°C; however, increasing temperatures above 15°C did not increase either ascospore germination or length of germ tubes. This information may help in the development of warning systems and management strategies for brown rot blossom blight of stone fruits.


1969 ◽  
Vol 20 (2) ◽  
pp. 317 ◽  
Author(s):  
PF Kable

Blossom blight is of economic importance in apricots on the Murrumbidgee Irrigation Areas (MIA), but fruit rot is not. Monilinia fructicola generally does not overwinter effectively in apricot trees in the MIA, the inocula for primary infections coming from nearby peach plantations. Blighted blossoms in apricot trees, which flower a week before peaches, may provide inoculum for blighting of flowers in the latter crop. In apricot trees, unlike peach, there is a continuous infection chain from flowering till harvest. Inoculum may pass from apricot to peach in December and January, thus bridging a gap in the infection chain in peach. The infection chain in apricot is described. Latent and quiescent infections were observed. The implications of the exchange of inoculum between peach and apricot are discussed.


Plant Disease ◽  
1997 ◽  
Vol 81 (12) ◽  
pp. 1416-1424 ◽  
Author(s):  
Themis J. Michailides ◽  
David P. Morgan

In eight commercial prune (Prunus domestica cv. French) orchards, 43 to 69% of brown rot (caused by Monilinia fructicola or M. laxa) infections occurred in clustered fruit as opposed to solitary fruit. Fruit-to-fruit contact surfaces had cracked and thin cuticles and larger microcracks (up to 2,255 μm in length) surrounding the lenticels than those of non-contact surfaces (cracks up to 351 μm in length). Furthermore, fruit-to-fruit contact surfaces retained greater proportions of methylene blue, indicating absence of epicuticular wax, than the non-contact surfaces. Carbohydrate content of exudates in water placed on fruit-to-fruit contact surfaces was 15 and 22 mg/ml, while those of non-contact surfaces were 13 and 19 mg/ml after 15 and 28 h, respectively. Conidia of M. fructicola germinated faster and at higher rates, and the incidence of infection was significantly higher on fruit-to-fruit contact than on non-contact surfaces. Densities of fungal CFU were greater (27 to 98 CFU/cm2) on fruit-to-fruit contact compared to those of non-contact surfaces (7 to 29 CFU/cm2). In four experiments, after spraying to runoff with distilled water, surfaces of solitary fruit dried after 7 to 8 h at 23 ± 1°C compared to 12 to 14 h for groups of 5 to 6 fruit. After spraying the same mature fruit with 1.2 × 105 conidia/ml of M. fructicola and incubating at 24°C and >97% relative humidity, 26 to 70% and 38 to 100% of fruit placed in groups of 5 to 6 were infected after 3 days and 5 days, respectively, whereas only 2 to 13% and 21 to 65% of solitary fruit became infected. These results suggest that fruit-to-fruit contact surfaces predispose prune fruit to infection by M. fructicola, and that it might be possible to reduce fruit losses from brown rot in prune orchards by thinning fruit to reduce fruit clustering, applying early summer fungicide sprays before fruit contact occurs, and ultimately, by selection for non-clustering cultivars in prune breeding programs.


2001 ◽  
Vol 91 (8) ◽  
pp. 759-768 ◽  
Author(s):  
Y. Luo ◽  
D. P. Morgan ◽  
T. J. Michailides

Experiments under controlled environmental conditions were conducted during bloom of prune (Prunus domestica, L.) in 1999 and 2000 to assess the effects of inoculum concentration (IC), wetness duration (WD), temperature, and bloom stages on development of brown rot blossom blight of prunes. Branches from trees of a prune orchard were inoculated with Monilinia fructicola at different bloom stages and incubated at different temperatures with different periods of WD. The proportion of blighted blossoms (PBB) for each inoculated branch was determined. Bloom stage, IC, temperature, and WD significantly affected blossom blight of prunes. PBB at popcorn and full bloom stages was significantly greater than PBB at later bloom stages (P ≤0.05). The optimal temperatures for blossom blight development were 22 to 26°C, and Gaussian functions were used to describe the relationship between PBB and temperature. PBB linearly increased with increased IC. Linear regressions of PBB on WD were obtained for each combination of bloom stage, IC, and temperature. The parameters of these regressions were used in a computer program to produce the possible maximum PBB with 90% probability (PBB90) using stochastic simulations. Early bloom stages with a higher IC at temperatures from 20 to 25°C were associated with more severe blossom blight than late stages with a lower IC at nonoptimal temperatures. Blossom blight did not occur at <10 or >30°C and less than 4-h WD. However, longer than 4-h WD linearly increased incidence of blossom blight. A risk assessment table of blossom blight was produced for different environmental conditions to guide the control of prune brown rot.


Plant Disease ◽  
2011 ◽  
Vol 95 (10) ◽  
pp. 1284-1291 ◽  
Author(s):  
Xiao-qiong Zhu ◽  
Xiao-yu Chen ◽  
Li-yun Guo

In total, 455 Monilinia isolates from stone fruits collected from several provinces (cities) in China from 2003 to 2009 were identified to species based on morphological characteristics, molecular identification, and the sequence of the internal transcribed spacer (ITS) regions 1 and 2 and the 5.8S gene of the ribosomal RNA. Overall, four species were detected (Monilinia fructicola, M. fructigena, M. laxa, and Monilia polystroma). M. fructicola was the most prevalent (93.0%) followed by M. fructigena (4.8%), M. laxa (2.0%), and Monilia polystroma (0.2%). M. fructicola and M. fructigena were found on peach, plum, and apricot; M. laxa was found only on apricot, cherry (in an organic orchard), and wild peach; and Monilia polystroma was found only on plum in Heilongjiang. The pathogenicity of Monilinia fructicola, M. laxa, and M. fructigena did not significantly differ on wounded nectarine and apricot, indicating that the differences in frequency of occurrence were not linked to virulence. Phylogenetic analysis based on ITS sequences showed that the isolates of M. laxa and M. fructigena from China differed from isolates of these species from other countries, and that the difference led to the separation of the isolates from China and those from other countries into different phylogenetic groups. Further study is needed to determine whether they are cryptic species.


2012 ◽  
Vol 39 (No. 3) ◽  
pp. 116-122 ◽  
Author(s):  
Sz. Sződi ◽  
H. Komjáti ◽  
Gy. Turóczi

Monilinia laxa (Monilia laxa), Monilinia fructicola (Monilia fructicola) and Monilinia fructigena (Monilia fructigena) are the causal agents of brown rot on pome and stone fruits in Hungary. Forty-five isolates collected from different hosts, different years in several orchards were used for characterization of the M. laxa and M. fructigena population in Hungary. The isolates were identified on species level based on morphological and molecular biological methods; out of these 24 were M. laxa, 20 were M. fructigena and 1 was M. fructicola. Populations of the three Monilinia species were studied with microsatellite primers and the degree of genetic diversity within the species was measured. The population structure analysis revealed that genetic diversity within M. laxa subpopulations was H<sub>S</sub>= 0.1599, while within M. fructigena subpopulations was H<sub>S</sub>= 0.2551. The total genetic diversity was H<sub>T</sub>= 0.3846, while genetic diversity between M. laxa and M. fructigena subpopulations was D<sub>ST</sub>= 0.1771. No clustering relationship was observed among isolates by the different years or hosts.


2001 ◽  
Vol 91 (5) ◽  
pp. 428-439 ◽  
Author(s):  
E. W. A. Boehm ◽  
Z. Ma ◽  
T. J. Michailides

A set of molecular diagnostics was developed for Monilinia fructicola, causal agent of brown rot of stone fruits, capable of sensitive detection of the pathogen in planta. Species-specific repetitive sequences were identified from a partial library of 312 recombinant clones hybridized with total DNA, followed by subsequent screening for specificity. One hundred isolates, comprising 12 fungal species common to California stone fruits, were surveyed for specificity. Three clones hybridized to 60 geographically diverse M. fructicola isolates (California, Michigan, Georgia, Oregon, and Australia) to the exclusion of all other fungi surveyed, including the closely related M. laxa (n = 12). Two clones were identical and of extrachromosomal origin (pMF73 and pMF150), whereas the third (pMF210) migrated with uncut DNA. The sensitivity of all three was comparable and capable of detecting 50 pg of fungal DNA in dot blot hybridizations. Six species-specific primer pair sets were designed. They maintained the same specificity patterns observed in the initial hybridization surveys and were sensitive enough to detect 50 fg of fungal DNA template, approximately equivalent to 10 spores. The species-specific clones were capable of detecting the pathogen in planta, specifically from infected plum flowers and nectarine fruit tissue, using both hybridization- and polymerase chain reaction-based methodologies.


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