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Jon Clements - One of the best experts on this subject based on the ideXlab platform.
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first reports of brown fruit rot on sweet cherry prunus avium and plum p domestica and shoot blight on apricot p armeniaca kwanzan cherry p serrulata and sweet cherry p avium caused by Monilinia laxa in new york rhode island and massachusetts
Plant Disease, 2011Co-Authors: Sara M Villani, Jessica J Raes, J Freier, H Faubert, Daniel R Cooley, Jon ClementsAbstract:In the eastern United States, Monilinia laxa (Aderh. & Ruhl.) Honey has only been reported on tart cherry in New York (NY) (1). As a result of considerable rain in May of 2009 and 2011, an ornamental planting of Kwanzan cherries in Middletown, Rhode Island (RI), a planting of sweet cherry cvs. Ulster, Hedelfingen, Sam, and Lapins in Lanesboro, Massachusetts (MA), and plantings of apricot cvs. Harcot and Hargrande in Albion, Aurora, and Geneva, NY, and Harogem in Lanesboro, MA developed severe shoot blight (>15 to 100% of first-year shoots). Blighted shoots were wilted with the blight encompassing the distal end and often extending into second-year tissue with a distinct sunken margin. Leaves on symptomatic shoots had flushed, but were blighted and light brown. Blossom spurs were often blighted and gummosis was frequently observed at the base. In these same years, sweet cherry cv. Black Gold in Walworth, NY and plum cv. Stanley in Olcott, NY developed severe fruit rot (35 to 70% incidence). Plantings suffe...
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first reports of brown fruit rot on sweet cherry prunus avium and plum p domestica and shoot blight on apricot p armeniaca kwanzan cherry p serrulata and sweet cherry p avium caused by Monilinia laxa in new york rhode island and massachusetts
Plant Disease, 2011Co-Authors: Kerik D Cox, Sara M Villani, Jessica J Raes, J Freier, H Faubert, Daniel R Cooley, Jon ClementsAbstract:In the eastern United States, Monilinia laxa (Aderh. & Ruhl.) Honey has only been reported on tart cherry in New York (NY) (1). As a result of considerable rain in May of 2009 and 2011, an ornamental planting of Kwanzan cherries in Middletown, Rhode Island (RI), a planting of sweet cherry cvs. Ulster, Hedelfingen, Sam, and Lapins in Lanesboro, Massachusetts (MA), and plantings of apricot cvs. Harcot and Hargrande in Albion, Aurora, and Geneva, NY, and Harogem in Lanesboro, MA developed severe shoot blight (>15 to 100% of first-year shoots). Blighted shoots were wilted with the blight encompassing the distal end and often extending into second-year tissue with a distinct sunken margin. Leaves on symptomatic shoots had flushed, but were blighted and light brown. Blossom spurs were often blighted and gummosis was frequently observed at the base. In these same years, sweet cherry cv. Black Gold in Walworth, NY and plum cv. Stanley in Olcott, NY developed severe fruit rot (35 to 70% incidence). Plantings suffering from fruit rot had fruit lesions that began as pale brown, soft lesions with indiscriminant margins that covered 15 to 85% of the fruit surface area. Many blighted spurs, shoot tissues, and infected fruit were sporulating with tan-to-buff colored conidia produced in chains. From each planting with shoot blight, shoot tips were removed for pathogen isolation. Sections of symptomatic shoots (5 cm long) were surface sterilized in 0.6% NaOCl for 1 min and rinsed in sterile dH20. From plantings displaying blighted spurs or fruit rot, isolation was attempted directly from sporulating tissue. Cross sections of sterilized shoot tissue (3 mm thick) or tufts of sporulation from fruit and spurs were placed on potato dextrose agar amended with 50 μg/ml of streptomycin sulfate. After incubation at 24°C for 5 days, colonies with lobed margins, commonly described for M. laxa (4), were obtained. Several colonies resembling M. fructicola were isolated from all locations, but the majority of isolates from spurs and shoots resembled M. laxa. Conidia from both colony morphotypes were lemon shaped, but as expected, those from putative M. laxa isolates were smaller (10.75 × 12.0 μm) compared with those from putative M. fructicola isolates (15.75 × 18.25 μm) (4). Confirmation of M. laxa was further achieved by PCR amplification of the β-tubulin gene using M. laxa-specific primers as previously described (3). Pathogenicity of M. laxa isolates was proven by inoculating fruit of the stone fruit crop from which they were isolated as previously described (2). Fruit inoculated with M. laxa developed brown, soft sporulating lesions identical to the original observations, while those inoculated with water remained healthy. M. laxa was reisolated from symptomatic shoots and spurs, but not from water-inoculated tissues. The presence of M. laxa has been reported on tart cherries in NY (1), but to our knowledge, this is the first instance of economically devastating shoot blight on apricot in NY and MA, ornamental cherry in RI, and sweet cherry in MA and fruit rot on sweet cherry and plum in NY caused by M. laxa. In wet seasons, stone fruit growers may need to revise their chemical management programs to better prepare for M. laxa epidemics on several stone fruit species. References: (1) K. D. Cox and S. M. Villani. Plant Dis. 94:783, 2010. (2) K. D. Cox and S. M. Villani. Plant Dis. 95:828, 2011. (3) Z. Ma et al. Pest Manag. Sci. 61:449, 2005. J.M. (4) G. C. M. van Leeuwen and H. A. van Kesteren. Can. J. Bot. 76:2042, 1998.
P Melgarejo - One of the best experts on this subject based on the ideXlab platform.
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vegetative compatibility groups and sexual reproduction among spanish Monilinia fructicola isolates obtained from peach and nectarine orchards but not Monilinia laxa
Fungal Biology, 2014Co-Authors: Antonieta De Cal, Beatriz Eguen, P MelgarejoAbstract:The frequency of occurrence of Monilinia fructicola in the Ebro Valley, Spain has increased since its first appearance in 2006, and M. fructicola has displaced Monilinia laxa, the native species which is the main cause of brown rot in peaches in this valley. In order to determine the characteristics that may be related to the displacement, we studied the capacity to generate new genotypic combinations of M. fructicola under laboratory conditions. The morphology and parasitic ability from ten field isolates of M. fructicola and M. laxa collected from three different orchards in the valley, and sampling from five different lesions were studied. Nitrate-non-utilising (nit) mutants were generated in order to test the isolates for vegetative compatibility which was done by assessing their colony growth when cultured singly or in pairs on media that contained different nitrogen sources. For the M. fructicola isolates, five vegetative compatibility groups (VCGs) were identified using the nit mutants and six VCGs were identified when they were grown on potato dextrose agar dishes. In all instances, the vegetatively compatible M. fructicola isolates came mainly from the same orchard. Only one VCG displays the same morphological and competition characteristics. No VCGs were identified among the M. laxa isolates. We did not find any apothecia of M. laxa and M. fructicola isolates in the soil of the three orchards, but we were able to produce apothecia of M. fructicola in the laboratory. Our finding of sexual reproduction and VCGs in the M. fructicola isolates suggests that the genetic variability of M. fructicola could be maintained by sexual and/or parasexual recombination.
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high chlorogenic and neochlorogenic acid levels in immature peaches reduce Monilinia laxa infection by interfering with fungal melanin biosynthesis
Journal of Agricultural and Food Chemistry, 2011Co-Authors: M Villarino, Pilar Sandinespana, P MelgarejoAbstract:Chlorogenic acid (CGA) and its isomer, neochlorogenic acid (NCGA), were found to be the major phenolic compounds in the flesh and peel of three peach cultivars. Their concentrations are especially high in immature fruits (CGA, 151−548 mg/kg; NCGA, 85−380 mg/kg), whose resistance to the brown rot fungus, Monilinia laxa, is very high. The concentrations of these two phenolic compounds decline in maturing fruits (CGA, 77−181 mg/kg; NCGA, 30−82 mg/kg), and this decline is associated with a concomitant increase in susceptibility to brown rot infection. Other phenolic compounds found in the same HPLC chromatograms at 340 nm from each peach extract at varying sampling dates in each of the three peach cultivars were not correlated with the incidence of brown rot and appeared only in some cultivars. The incidence of brown rot for each cultivar at each sampling date was significantly negatively correlated with the NCGA (r > −0.85) and CGA (r > −0.90) contents. At concentrations that are similar to those in peach fr...
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high chlorogenic and neochlorogenic acid levels in immature peaches reduce Monilinia laxa infection by interfering with fungal melanin biosynthesis
Journal of Agricultural and Food Chemistry, 2011Co-Authors: M Villarino, Pilar Sandinespana, P Melgarejo, Antonieta De CalAbstract:Chlorogenic acid (CGA) and its isomer, neochlorogenic acid (NCGA), were found to be the major phenolic compounds in the flesh and peel of three peach cultivars. Their concentrations are especially high in immature fruits (CGA, 151-548 mg/kg; NCGA, 85-380 mg/kg), whose resistance to the brown rot fungus, Monilinia laxa , is very high. The concentrations of these two phenolic compounds decline in maturing fruits (CGA, 77-181 mg/kg; NCGA, 30-82 mg/kg), and this decline is associated with a concomitant increase in susceptibility to brown rot infection. Other phenolic compounds found in the same HPLC chromatograms at 340 nm from each peach extract at varying sampling dates in each of the three peach cultivars were not correlated with the incidence of brown rot and appeared only in some cultivars. The incidence of brown rot for each cultivar at each sampling date was significantly negatively correlated with the NCGA (r > -0.85) and CGA (r > -0.90) contents. At concentrations that are similar to those in peach fruit, CGA does not inhibit spore germination or mycelial growth of M. laxa in culture but markedly inhibits the production of melanin-like pigments in the mycelia of M. laxa in culture (42% melanin reduction). Accordingly, we propose that the high concentrations of CGA and NGA in immature fruits might contribute to their reduced susceptibility or increased resistance to brown rot infection by interfering with fungal melanin production.
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enhancing the adhesion of epicoccum nigrum conidia to peach surfaces and its relationship to the biocontrol of brown rot caused by Monilinia laxa
Journal of Applied Microbiology, 2010Co-Authors: Inmaculada Larena, A De Cal, P MelgarejoAbstract:Aims: To find a formulation of Epicoccum nigrum conidia that enhances its adhesion to peach surfaces and improves its biocontrol efficacy against brown rot caused by Monilinia laxa. Methods and Results: The stickers, glycerol, sodium alginate and methylcellulose; the desiccants, silica powder and talc; and a commercial adhesive (NU FILM 17®) were added at two different points during the production of an E. nigrum conidial formulation to improve conidial adhesion to peach surfaces. Conidial adhesion levels were determined from the number of E. nigrum conidia that adhered to glass slides or peach surfaces and conidial viability of adherent E. nigrum conidia was determined from the number of colony-forming units of glass or peach-adherent E. nigrum that grew on Petri dishes that contained potato dextrose agar. Compared to dried E. nigrum conidia without additives, the adhesion and viability of adherent E. nigrum conidia to peach surfaces were enhanced when either 1·25% sodium alginate or 2·5% methylcellulose was added to the conidial mass after fluid-bed drying, and when 2·5% methylcellulose was added to the conidial mass after its production and before fluid-bed drying. Epicoccum nigrum conidial formulations with 2·5% methylcellulose were more effective than dried E. nigrum conidia without additives in reducing the incidence of brown rot in peaches caused by M. laxa. Conclusions: When 2·5% methylcellulose is incorporated into an E. nigrum conidial formulation, the adhesion of E. nigrum conidia to peach surfaces improves and results in efficacious biocontrol of brown rot. Significance and Impact of the Study: A new improved formulation of a biocontrol agent has been developed to improve the control of M. laxa on peaches.
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mass production of conidia of penicillium frequentans a biocontrol agent against brown rot of stone fruits
Biocontrol Science and Technology, 2002Co-Authors: A De Cal, Inmaculada Larena, Belen Guijarro, P MelgarejoAbstract:Conidial production of Penicillium frequentans , a biocontrol agent of the fungal pathogen Monilinia laxa , was tested in liquid and solid-state fermentation. Conidial production of P. frequentans in solid-state fermentation was higher than in liquid-state fermentation. Solidstate fermentation was made in specially designed plastic bags (VALMIC ® ) containing peat:vermiculite (1:1 w/w). Addition of nutrients to the peat:vermiculite increased conidial production of P. frequentans , especially when lentil meal was added. The number of conidia obtained in this solid-state fermentation was maintained in the range of 10 8 -10 9 conidia g -1 from 5 to 120 days after inoculation. Germinability of these conidia was > 90% until 90 days of incubation and declined at 120 days. Optimal initial moisture content in the substrate was 30-40% (v/w). At lower moisture contents, significant reductions in conidial production and germinability were observed, particularly at 10% (v/w). Conidial production was similar when...
Marta Mari - One of the best experts on this subject based on the ideXlab platform.
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molecular characterization of the two postharvest biological control agents aureobasidium pullulans l1 and l8
Biological Control, 2018Co-Authors: Alessandra Di Francesco, Marta Mari, Annibale Folchi, Matteo Calassanzio, C Ratti, Elena BaraldiAbstract:Abstract L1 and L8 are Aureobasidium pullulans strains previously shown to effectively act as biocontrol agents (BCA) against fruit postharvest pathogens. Here, L1 and L8 strains were tested in vivo against Monilinia laxa of peaches showing the ability to reduce the brown rot incidence by 95% and by 80% respectively. To develop future bioformulation and allow commercial use of these biocontrol agents (BCAs) it is necessary to develop specific identification tools. Since A. pullulans strains share very similar morphological features and are not distinguishable by visual analysis, the RAPD (Random Amplified Polymorphic DNA) technique was applied to genomic DNA of L1 and L8 and of other 40 different A. pullulans strains, and SCAR markers were developed from a L1 and L8 specific RAPD fragment of 984 bp. These primers amplify a fragment of 137 bp exclusively in L1 and L8, and can be used to distinguish the two yeasts strains from other A. pullulans strains with high specificity. The droplet digital PCR, used to determine the precise limit of detection (LOD), showed that these markers allow to detect up to 43 and 215 cells of L1 and L8 respectively.
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biocontrol of Monilinia laxa by aureobasidium pullulans strains insights on competition for nutrients and space
International Journal of Food Microbiology, 2017Co-Authors: Alessandra Di Francesco, Luisa Ugolini, Salvatore Daquino, Eleonora Pagnotta, Marta MariAbstract:Abstract Two Aureobasidium pullulans strains (L1 and L8), able to prevent postharvest fruit decay, were evaluated in order to elucidate how the competition for nutrients and space was involved in their activity against Monilinia laxa, the causal agent of peach brown rot. The competition for nutrients was studied by co-culturing pathogen conidia and antagonists in different conditions of nutrient availability and avoiding contact between them. Both antagonists prevented the germination of conidia of M. laxa in water, reducing germination rate by > 35%. However, L1 and L8 showed the lowest inhibition of conidial germination in peach juice at 5%, with a reduction of 12.6% and 13.9% respectively. HPLC amino acid analysis of peach juice revealed that the addition of the yeast suspension greatly modified their composition: asparagine was completely depleted soon after 12 h of incubation and was probably hydrolyzed to aspartic acid by the yeasts, as aspartic acid content markedly increased. Pure asparagine and aspartic acid were tested by in vitro trials at the concentrations found in peach juice: both influenced M. laxa growth, but in opposite ways. Asparagine stimulated pathogen growth; conversely, amended medium with aspartic acid significantly inhibited the conidia germination and mycelial development of M. laxa. Scanning Electron Microscopy revealed that both strains showed a great capability to compete with M. laxa for space (starting 8 h after treatment), colonizing the wound surface and inhibiting pathogen growth. This study clearly showed that A. pullulans L1 and L8 strains could compete with M. laxa for nutrients and space; this mode of action may play an important role in the antagonistic activity, especially in the first hours of tritrophic host-pathogen-antagonist interaction, although several other mechanisms can interact each other.
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postharvest biocontrol of Monilinia laxa Monilinia fructicola and Monilinia fructigena on stone fruit by two aureobasidium pullulans strains
Biological Control, 2012Co-Authors: Marta Mari, Camilla Martini, Michela Guidarelli, F NeriAbstract:Abstract The antagonistic effects of yeasts, L1 and L8, isolated from carposphere of ‘Redhaven’ peaches were tested for the first time in the same experiment against three Monilinia species ( Monilinia laxa , Monilinia fructicola and Monilinia fructigena ) in in vitro and in vivo trials. The two antagonists were selected after preliminary assays for their ability to reduce brown rot in peaches and nectarines, and both were identified by molecular and morphological tools as Aureobasidium pullulans . In in vivo trials, neither the autoclaved cells, nor the sterile culture filtrates of either antagonist showed any significant reduction of rot incidence produced by inocula of the three Monilinia species, while the washed cells of L1 and L8 completely inhibited M. laxa and M. fructicola rots and reduced M. fructigena infections by 70% and 90%, respectively. In other trials, nectarines treated with antagonist cells and inoculated with the pathogens were stored at 0 °C for 21 days, plus 7 days at 20 °C. The low temperature reduced brown rot development, since all fruit were free from disease symptoms on removal from cold storage. However after 7 d at 20 °C, untreated fruit were rotted over 45% depending on the Monilinia species but the antagonists completely inhibited M. laxa and M. fructicola , while M. fructigena infections were reduced by 89.8% and 91.2% by L1 and L8, respectively. For both strains, 10 8 CFU ml −1 was the most active concentration, although L1 showed good activity at a concentration of 10 7 CFU ml −1 . Isolate L8 at the concentration of 10 7 CFU ml −1 was ineffective against M. fructicola and M. fructigena , showing no difference between treated fruit and the control, excepting the case of nectarines inoculated with M. laxa , where L8 at the concentration of 10 7 CFU ml −1 reduced the brown rot infections with respect to the control. The increase in population density of A. pullulans strains L1 and L8 in the wounds of nectarines stored at 0° or 20 °C was low but sufficient to control brown rot. In conclusion, the present preliminary study identified two antagonistic strains of A. pullulans as active ingredients for the development of biofungicides for postharvest application against three Monilinia species that are responsible for high economic losses in stone fruit crops.
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fungicidal activity of plant volatile compounds for controlling Monilinia laxa in stone fruit
Plant Disease, 2007Co-Authors: Fiorella Neri, Marta Mari, Stefano Brigati, Paolo BertoliniAbstract:ABSTRACT Nine plant-volatile compounds were tested for their activity against Monilinia laxa, the cause of brown rot in stone fruit. In vitro trials on conidial germination and mycelial growth showed a consistent fungicidal activity of trans-2-hexenal, carvacrol, and citral, whereas trans-cinnamaldehyde, hexanal, (-)-carvone, eugenol, 2-nonanone, and p-anisaldehyde exhibited a progressively lower inhibition. The best inhibitor of conidial germination was trans-2-hexenal (effective dose for 50 and 90% inhibition [ED50 and ED95] = 7.53 and 9.4 μl/liter, respectively; minimal inhibitory concentration [MIC] = 12.3 μl/liter], whereas carvacrol was the best inhibitor of mycelial growth (ED50 and ED95 = 2 and 3.4 μl/liter, respectively; MIC = 6.1 μl/liter). The three most active compounds in in vitro studies also were tested in vivo as postharvest biofumigants. The best control of brown rot was with trans-2-hexenal (efficacy ranging from 46.2 to 80.3%, depending on cultivar), whereas citral and carvacrol resulte...
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postharvest control of Monilinia laxa and rhizopus stolonifer in stone fruit by peracetic acid
Postharvest Biology and Technology, 2004Co-Authors: Marta Mari, R Gregori, I DonatiAbstract:Abstract Peracetic acid (PAA) treatment of stone fruit (sweet cherry, apricot, peach and nectarine) reduced the incidence of brown rot caused by Monilinia laxa and soft rot caused by Rhizopus stolonifer . The efficacy of the treatment depended on the length of time. Fruit, neither wounded nor inoculated and dipped for 1 min in a 125 mg L −1 PAA solution, showed a significant reduction of Monilinia rots with respect to control. Significant inhibition was also observed on fruit wounded and inoculated with R. stolonifer and treated for 1 min with 250 mg L −1 PAA solution. Sodium bicarbonate (SBC), sodium propionate (Na-Pro) and potassium sorbate (K-Sorb), substances generally regarded as safe (GRAS), were also evaluated. Phytotoxic effects appeared on fruit treated with SBC at the minimum effective concentration (3%). Any rot reduction was observed in Na-Pro fruit treated, only K-Sorb at 1.5% was able to significantly reduce Monilinia infections in sweet cherries (61.6%), apricots (78%) and nectarines (31.8%) with respect to the controls, without any visible damage on the skin. Similar results were obtained on apricot wounded and inoculated with R. stolonifer . Fruit hydro-refrigeration significantly reduced the incidence of brown rot in Nero I and Van sweet cherries; disease control was improved by addition of PAA (125 mg L −1 ) in cold water. PAA efficacy on pre-existing infections can be very useful to control stone fruit diseases that can spread during shipping and marketing.
Sara M Villani - One of the best experts on this subject based on the ideXlab platform.
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first reports of brown fruit rot on sweet cherry prunus avium and plum p domestica and shoot blight on apricot p armeniaca kwanzan cherry p serrulata and sweet cherry p avium caused by Monilinia laxa in new york rhode island and massachusetts
Plant Disease, 2011Co-Authors: Sara M Villani, Jessica J Raes, J Freier, H Faubert, Daniel R Cooley, Jon ClementsAbstract:In the eastern United States, Monilinia laxa (Aderh. & Ruhl.) Honey has only been reported on tart cherry in New York (NY) (1). As a result of considerable rain in May of 2009 and 2011, an ornamental planting of Kwanzan cherries in Middletown, Rhode Island (RI), a planting of sweet cherry cvs. Ulster, Hedelfingen, Sam, and Lapins in Lanesboro, Massachusetts (MA), and plantings of apricot cvs. Harcot and Hargrande in Albion, Aurora, and Geneva, NY, and Harogem in Lanesboro, MA developed severe shoot blight (>15 to 100% of first-year shoots). Blighted shoots were wilted with the blight encompassing the distal end and often extending into second-year tissue with a distinct sunken margin. Leaves on symptomatic shoots had flushed, but were blighted and light brown. Blossom spurs were often blighted and gummosis was frequently observed at the base. In these same years, sweet cherry cv. Black Gold in Walworth, NY and plum cv. Stanley in Olcott, NY developed severe fruit rot (35 to 70% incidence). Plantings suffe...
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first reports of brown fruit rot on sweet cherry prunus avium and plum p domestica and shoot blight on apricot p armeniaca kwanzan cherry p serrulata and sweet cherry p avium caused by Monilinia laxa in new york rhode island and massachusetts
Plant Disease, 2011Co-Authors: Kerik D Cox, Sara M Villani, Jessica J Raes, J Freier, H Faubert, Daniel R Cooley, Jon ClementsAbstract:In the eastern United States, Monilinia laxa (Aderh. & Ruhl.) Honey has only been reported on tart cherry in New York (NY) (1). As a result of considerable rain in May of 2009 and 2011, an ornamental planting of Kwanzan cherries in Middletown, Rhode Island (RI), a planting of sweet cherry cvs. Ulster, Hedelfingen, Sam, and Lapins in Lanesboro, Massachusetts (MA), and plantings of apricot cvs. Harcot and Hargrande in Albion, Aurora, and Geneva, NY, and Harogem in Lanesboro, MA developed severe shoot blight (>15 to 100% of first-year shoots). Blighted shoots were wilted with the blight encompassing the distal end and often extending into second-year tissue with a distinct sunken margin. Leaves on symptomatic shoots had flushed, but were blighted and light brown. Blossom spurs were often blighted and gummosis was frequently observed at the base. In these same years, sweet cherry cv. Black Gold in Walworth, NY and plum cv. Stanley in Olcott, NY developed severe fruit rot (35 to 70% incidence). Plantings suffering from fruit rot had fruit lesions that began as pale brown, soft lesions with indiscriminant margins that covered 15 to 85% of the fruit surface area. Many blighted spurs, shoot tissues, and infected fruit were sporulating with tan-to-buff colored conidia produced in chains. From each planting with shoot blight, shoot tips were removed for pathogen isolation. Sections of symptomatic shoots (5 cm long) were surface sterilized in 0.6% NaOCl for 1 min and rinsed in sterile dH20. From plantings displaying blighted spurs or fruit rot, isolation was attempted directly from sporulating tissue. Cross sections of sterilized shoot tissue (3 mm thick) or tufts of sporulation from fruit and spurs were placed on potato dextrose agar amended with 50 μg/ml of streptomycin sulfate. After incubation at 24°C for 5 days, colonies with lobed margins, commonly described for M. laxa (4), were obtained. Several colonies resembling M. fructicola were isolated from all locations, but the majority of isolates from spurs and shoots resembled M. laxa. Conidia from both colony morphotypes were lemon shaped, but as expected, those from putative M. laxa isolates were smaller (10.75 × 12.0 μm) compared with those from putative M. fructicola isolates (15.75 × 18.25 μm) (4). Confirmation of M. laxa was further achieved by PCR amplification of the β-tubulin gene using M. laxa-specific primers as previously described (3). Pathogenicity of M. laxa isolates was proven by inoculating fruit of the stone fruit crop from which they were isolated as previously described (2). Fruit inoculated with M. laxa developed brown, soft sporulating lesions identical to the original observations, while those inoculated with water remained healthy. M. laxa was reisolated from symptomatic shoots and spurs, but not from water-inoculated tissues. The presence of M. laxa has been reported on tart cherries in NY (1), but to our knowledge, this is the first instance of economically devastating shoot blight on apricot in NY and MA, ornamental cherry in RI, and sweet cherry in MA and fruit rot on sweet cherry and plum in NY caused by M. laxa. In wet seasons, stone fruit growers may need to revise their chemical management programs to better prepare for M. laxa epidemics on several stone fruit species. References: (1) K. D. Cox and S. M. Villani. Plant Dis. 94:783, 2010. (2) K. D. Cox and S. M. Villani. Plant Dis. 95:828, 2011. (3) Z. Ma et al. Pest Manag. Sci. 61:449, 2005. J.M. (4) G. C. M. van Leeuwen and H. A. van Kesteren. Can. J. Bot. 76:2042, 1998.
Antonieta De Cal - One of the best experts on this subject based on the ideXlab platform.
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Light-Photoreceptors and Proteins Related to Monilinia laxa Photoresponses
'MDPI AG', 2021Co-Authors: Rodríguez-píres Silvia, Espeso, Eduardo A., Rasiukevičiūtė Neringa, Melgarejo Paloma, Antonieta De CalAbstract:Light represents a ubiquitous source of information for organisms to evaluate their environment. The influence of light on colony growth and conidiation was determined for three Monilinia laxa isolates. The highest mycelial growth rate was observed under red light for the three M. laxa isolates, followed by green light, daylight or darkness. However, reduced sporulation levels were observed in darkness and red light, but conidiation enhancement was found under daylight, black and green light with more hours of exposure to light. Putative photoreceptors for blue (white-collar and cryptochromes), green (opsins), and red light (phytochromes) were identified, and the photoresponse-related regulatory family of velvet proteins. A unique ortholog for each photoreceptor was found, and their respective domain architecture was highly conserved. Transcriptional analyses of uncovered sets of genes were performed under daylight or specific color light, and both in time course illumination, finding light-dependent triggered gene expression of MlVEL2, MlPHY2, MlOPS2, and MlCRY2, and color light as a positive inductor of MlVEL3, MlVEL4, MlPHY1, and MlCRY1 expression. M. laxa has a highly conserved set of photoreceptors with other light-responsive fungi. Our phenotypic analyses and the existence of this light-sensing machinery suggest transcriptional regulatory systems dedicated to modulating the development and dispersion of this pathogen.This study was funded by grants AGL2014-55287-C2-1-R, RTI2018-094263-B-I00, and AGL2017-84389-C2-2-R from the Ministry of Science, Innovation and Universities (MCIU, Spain), Agencia Estatal de Investigación (AEI), and the Fondo Europeo de Desarrollo Regional (FEDER, EU). S. Rodríguez-Pires received a Ph.D. fellowship from the Ministry of Science, Innovation and Universities (Spain)Peer reviewe
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Influence of light on the Monilinia laxa–stone fruit interaction
'Wiley', 2021Co-Authors: Rodríguez-píres Silvia, Espeso, Eduardo A., Melgarejo Paloma, Garcia-companys Marina, Antonieta De CalAbstract:28 p.-5 fig.Light represents a signal for the regulation of virulence in many microbial pathogens. Two stone fruits, nectarines and cherries, were used to investigate the influence of light on brown rot caused by Monilinia laxa. Three single-spore strains were inoculated on nectarines and incubated under different white lights, red light, blue light, greenight, and black light with two photoperiods. In addition, to understand the effect of daylight irradiance on brown rot, M. laxa was inoculated on different cherry cultivars and incubated under two simulated solar irradiations. Significantly higher disease severity and sporulation were reported on inoculated nectarines incubated under 58 W white light for 12 hr light/12 hr darkness than on nectarines incubated in continuous darkness. Only red light caused a significant increase in the incidence and severity of the disease in nectarines inoculated with the three M. laxa isolates, compared to fruit incubated under white light. High light intensity (185.45 W/m2), caused greater brown rot severity in all cherry cultivars, both early and late varieties, than low irradiance (145.85 W/m2). Significant up-regulation of the pathogenicity-related MlPNL2 gene was observed as an early response after cherry inoculation under high-intensity light, especially in late cherry cultivars, while MlPG1 expression did not show any changes under different light irradiances. M. laxa was shown to be a light-responsive fungal pathogen, and light seemed to play an active role in brown rot development.This study was funded by grants AGL2014-55287-C2-1-R and AGL2017-84389-C2-2-R from the Ministry of Science, Innovation and Universities (MCIU, Spain), Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER, EU).Peer reviewe
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Depicting the battle between nectarine and Monilinia laxa: the fruit developmental stage dictates the effectiveness of the host defenses and the pathogen’s infection strategies
Horticulture Research, 2020Co-Authors: Marta Balsells-llauradó, Neus Teixidó, Antonieta De Cal, Christian J. Silva, Josep Usall, Núria Vall-llaura, Sandra Serrano-prieto, Saskia D. Mesquida-pesci, Barbara Blanco-ulate, Rosario TorresAbstract:Infections by the fungus Monilinia laxa , the main cause of brown rot in Europe, result in considerable losses of stone fruit. Herein, we present a comprehensive transcriptomic approach to unravel strategies deployed by nectarine fruit and M. laxa during their interaction. We used M. laxa -inoculated immature and mature fruit, which was resistant and susceptible to brown rot, respectively, to perform a dual RNA-Seq analysis. In immature fruit, host responses, pathogen biomass, and pathogen transcriptional activity peaked at 14–24 h post inoculation (hpi), at which point M. laxa appeared to switch its transcriptional response to either quiescence or death. Mature fruit experienced an exponential increase in host and pathogen activity beginning at 6 hpi. Functional analyses in both host and pathogen highlighted differences in stage-dependent strategies. For example, in immature fruit, M. laxa unsuccessfully employed carbohydrate-active enzymes (CAZymes) for penetration, which the fruit was able to combat with tightly regulated hormone responses and an oxidative burst that challenged the pathogen’s survival at later time points. In contrast, in mature fruit, M. laxa was more dependent on proteolytic effectors than CAZymes, and was able to invest in filamentous growth early during the interaction. Hormone analyses of mature fruit infected with M. laxa indicated that, while jasmonic acid activity was likely useful for defense, high ethylene activity may have promoted susceptibility through the induction of ripening processes. Lastly, we identified M. laxa genes that were highly induced in both quiescent and active infections and may serve as targets for control of brown rot.
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Pectin as carbon source for Monilinia laxa, exoproteome and expression profiles of related genes
'Scientific Societies', 2020Co-Authors: Rodríguez-píres Silvia, Antonieta De Cal, Melgarejo Paloma, Espeso, Eduardo A.Abstract:73 p.-6 fig.-2 tab.-1 fig. supl.-4 tab.supl.Pectin, as part of the fruit cell wall, can be degraded by brown rot fungi by coordinating the production, secretion, and action of extracellular enzymes. In this study, pectin utilization by the necrotroph Monilinia laxa 8L was studied by in vitro and in silico approaches. A total of 403 genes encoding carbohydrate-active enzymes (CAZymes) were identified, including 38 coding a predicted pectin-degrading activity. Analyzing the differences between M. laxa 8L exoproteomes in media containing glucose and pectin as sole carbon sources, we identified 107 pectin-specific proteins, among them, 64.48% harbor a classical secretory activity, including 42 CAZymes and six pectin-degrading proteins. Analyzing the gene-expression patterns of some pectinase families revealed their possible sequential action in pectin disassembly. We found, in vitro, an early pectin-dependent induction of MlRGAE1, MlPG1, and three members of the rhamnosidase family (MlαRHA2, MlαRHA3, and MlαRHA6) and late response of MlPG2 and MlPNL3. M. laxa 8L has the ability to use both pectin and byproducts as carbon sources, based on a functional pectinolytic machinery encoded in its genome, subjected to pectin-dependent regulation and appropriate secretion mechanisms of these pectinolytic enzymes. Differences in the secretion and transcription profile of M. laxa 8L provided insights into the different mechanisms that contribute to brown rot development.Ministry of Science, Innovation and Universities (MCIU, Spain), Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER, EU): AGL2014-55287-C2-1-R, BFU2015-66806-R, RTI2018- 094263-B-I00 and AGL2017-84389-C2-2-RPeer reviewe
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Proteomic studies to understand the mechanisms of peach tissue degradation by Monilinia laxa
'Frontiers Media SA', 2020Co-Authors: Rodríguez-píres Silvia, Antonieta De Cal, Melgarejo Paloma, Espeso, Eduardo A.Abstract:12 p.-5 fig.Monilinia laxa is a necrotrophic plant pathogen able to infect and produce substantial losses on stone fruit. Three different isolates of M. laxa were characterized according to their aggressiveness on nectarines. M. laxa 8L isolate was the most aggressive on fruit,33L isolate displayed intermediated virulence level, and 5L was classified as a weak aggressive isolate. Nectarine colonization process by the weak isolate 5L was strongly delayed. nLC-MS/MS proteomic studies using in vitro peach cultures provided data on exoproteomes of the three isolates at equivalent stages of brown rot colonization; 3 days for 8L and 33L, and 7 days for 5L. A total of 181 proteins were identified from 8L exoproteome and 289 proteins from 33L at 3 dpi, and 206 proteins were identified in 5L exoproteome at 7 dpi. Although an elevated number of proteins lacked a predicted function, the vast majority of proteins belong to OG group “metabolism”, composed of categories such as “carbohydrate transport and metabolism” in 5L, and “energy production and conversion” most represented in 8L and 33L. Among identified proteins, 157 that carried a signal peptide were further examined and classified. Carbohydrate-active enzymes and peptidases were the main groups revealing different protein alternatives with the same function among isolates. Our data suggested a subset of secreted proteins as possible markers of differential virulence in more aggressive isolates, MlPG1 MlPME3, NEP-like, or endoglucanase proteins. A core-exoproteome among isolates independently of their virulence but time-dependent was also described. This core included several well-known virulence factors involved in host-tissue factors like cutinase, pectin lyases, and acid proteases. The secretion patterns supported the assumption that M. laxa deploys an extensive repertoire of proteins to facilitate the host infection and colonization and provided information for further characterization of M.laxa pathogenesis.This study was funded by grants AGL2014-55287-C2-1-R, BFU2015-66806-R, RTI2018-094263-B-I00 and AGL2017-84389-C2-2-R from the Ministry of Science, Innovation and Universities (MCIU, Spain), Agencia Estatal de Investigación (AEI), and the Fondo Europeo de Desarrollo Regional (FEDER, EU).Peer reviewe