scholarly journals High Humidity and Age-Dependent Fruit Susceptibility Promote Development of Trichothecium Black Spot on Apple

Plant Disease ◽  
2019 ◽  
Vol 103 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Pengbo Dai ◽  
Xiaofei Liang ◽  
Yajing Wang ◽  
Mark L. Gleason ◽  
Rong Zhang ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Disease Incidence ◽  
Germination Rate ◽  
Black Spot ◽  
Apple Fruit ◽  
High Humidity ◽  
Factors Affecting ◽  
Fruit Maturity ◽  
Fruit Bagging

Fruit bagging is a widely used orchard practice in China. Trichothecium black spot (TBS) is a disease highly associated with the fruit bagging. In this study, we characterized in vitro factors affecting the causal agent, Trichothecium roseum, and TBS development and infection histology on field-bagged apple fruit in situ. Under in vitro conditions, conidial germination required exogenous nutrients, and the germination rate was significantly promoted by high humidity, a condition mimicking the bag microenvironment. Germ tubes penetrated fruit via natural openings including stomata, lenticels, and surface cracks. To determine the chronology of infection by T. roseum, ‘Fuji’ fruit were inoculated in the field at different developmental stages. The earliest infection occurred 60 days after full bloom (dafb), and disease incidence increased as fruit maturity advanced. At harvest time (165 dafb), lesions on more recently inoculated fruit (105 dafb, 150 dafb) were larger than lesions from fruit inoculated on earlier dates. Histological observation showed that infection of younger fruit elicited stronger host lignification responses restricting lesion development. Taken together, our results support the hypothesis that high humidity in sealed bags and increased susceptibility associated with advancing fruit maturity are key factors promoting T. roseum infection and TBS symptom development on bagged apple fruit.

Development of an embryo germination protocol for shy-seeded grape (Vitis vinifera L.)

2021 ◽  
pp. 1-9
Author(s):  
Ashwini P. Benke ◽  
Ram Krishna ◽  
Roshni R. Samarth ◽  
Shweta S. Dhumal ◽  
Waquar A. Ansari ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Germination Rate ◽  
Germination Percentage ◽  
Vitis Vinifera L ◽  
Growth Media ◽  
Embryo Germination ◽  
Indole Butyric Acid ◽  
Grape Berries ◽  
Benzyl Amino Purine

Abstract Acquisition and germination of seeds are the most desired targets for the improvement of vegetatively propagated crops. In the present study, we developed a potential embryo germination protocol for the Red Globe grape cultivar having a low seed germination rate. Three grape berries at different developmental stages, viz. 50, 60 and 70 days after flowering (DAF), were selected for in-vitro embryo germination. Three growth media, namely Emershad and Ramming (ER), Nitsch and Nitsch (NN) and Murashige and Skoog (MS), and plant growth regulators (benzyl amino purine (BA), 0.5, 0.7 and 0.9 mg/l; indole butyric acid (IBA), 1.0, 1.5 and 2.0 mg/l; and gibberellic acid (GA), 0.1, 0.3 and 0.9 mg/l) were screened individually in different combinations with three amino acids, namely cysteine, glutamine and proline (2.0 μmol/l each). The maximum embryos germination percentage recorded at 70 DAF was 63.33, 47.78 and 45.56% in ER, NN and MS media, respectively, supplemented with 0.9 mg/l BA, 2.0 mg/l IBA, 0.9 mg/l GA and 2.0 μmol glutamine. Glutamine was found to have the most significant impact, and it improved the rescued embryos germination. The present study provides a potential recipe for a medium that can facilitate efficient germination of grape embryos.

scholarly journals Control of Sphaeropsis Rot in Stored Apple Fruit Caused by Sphaeropsis pyriputrescens with Postharvest Fungicides

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1075-1079 ◽  
Author(s):  
C. L. Xiao ◽  
Y. K. Kim ◽  
R. J. Boal
Keyword(s):  
Mycelial Growth ◽  
Disease Incidence ◽  
Apple Fruit ◽  
Conidial Germination ◽  
Fruit Rot ◽  
Mitigation Measures ◽  
The Mean ◽  
Rot Disease ◽  
Sphaeropsis Rot

Sphaeropsis rot caused by Sphaeropsis pyriputrescens is a recently reported postharvest fruit rot disease of apple grown in Washington State. The objective of this study was to develop chemical-based mitigation measures for Sphaeropsis rot in stored apple fruit. To determine in vitro sensitivity of S. pyriputrescens to the three registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil, 30 isolates of S. pyriputrescens obtained from various sources were tested for mycelial growth and conidial germination on fungicide-amended media. Golden Delicious apple fruit were inoculated with the pathogen in the orchard at 2 or 5 weeks before harvest. After harvest, fruit were either nontreated or dipped in thiabendazole, fludioxonil, or pyrimethanil solutions, stored at 0°C, and monitored for decay development for up to 9 months after harvest. The mean effective concentration of a fungicide that inhibits mycelial growth or spore germination by 50% relative to the nonamended control (EC50) values of thiabendazole, fludioxonil, and pyrimethanil on mycelial growth were 0.791, 0.0005, and 2.829 μg/ml, respectively. Fludioxonil and pyrimethanil also were effective in inhibiting conidial germination of the fungus with EC50 values of 0.02 μg/ml for fludioxonil and 5.626 μg/ml for pyrimethanil. All three postharvest fungicides applied at label rates immediately after harvest were equally effective in controlling Sphaeropsis rot in stored apple fruit, reducing disease incidence by 92 to 100% compared with the nontreated control. The results indicated that Sphaeropsis rot may be effectively controlled by the currently registered postharvest fungicides thiabendazole, fludioxonil, and pyrimethanil.

scholarly journals VARIATION IN AGGRESSIVENESS OF FUSARIUM HEAD BLIGHT SPECIES TOWARDS BARLEY PLANTS DETERMINED USING THREE IN VITRO ASSAYS

2019 ◽  
Vol 31 (1) ◽  
pp. 19-33 ◽  
Author(s):  
Nachaat Sakr
Keyword(s):  
Fusarium Head Blight ◽  
Disease Incidence ◽  
Germination Rate ◽  
Field Conditions ◽  
In Vitro Assays ◽  
Lesion Length ◽  
Head Blight ◽  
Coleoptile Length ◽  
Progress Curve

Aggressiveness is the most important fungal trait affecting Fusarium head blight (FHB) disease invasion and stability of host resistance. Until recently, in vitro methodologies have proved to be very useful in analyzing disease responses in barley plants to FHB infection. To update our knowledge, the variation in aggressiveness for 16 isolates of four FHB species was assessed towards two barley cultivars varying in resistance to FHB. Nine aggressiveness criteria involved in three in vitro assays were used: incubation period, latent period (LP), lesion length (of detached leaf and clip-dipping inoculations), germination rate reduction, standardized area under disease progress curve (AUDPCstandard), coleoptile length reduction of Petri-dish inoculation, and percentage of infected seedlings (of foliar-spraying and pin-point inoculations). Differences in inoculated treatment were observed on young plant parts relative to water controls. Inter and intraspecific differences in aggressiveness were observed towards barley plants as measured by LP and AUDPCstandard. Nevertheless, the other seven criteria did not differentiate FHB isolates. Results indicted that a cultivar-specific aggressiveness do not exist among barley plants and pathogens for LP and AUDPCstandard. Significant correlation coefficients were obtained between the data of LP and AUDPCstandard. Moreover, the values of LP and AUDPCstandard were significantly correlated with the data of disease incidence generated under controlled and field conditions. It seems that LP and AUDPCstandard are indicators of aggressiveness occurring in the whole plant during FHB infection. To our best knowledge, this is the first in vitro research full analyzing aggressiveness of four FHB species on barley plants. In addition, our study investigates the potential use of in vitro indices in predicting FHB data generated under controlled and field conditions.

Factors affecting the infection of sweet cherry (Prunus avium) fruit by Podosphaera cerasi

Plant Disease ◽  
2021 ◽  
Author(s):  
Claudia Probst ◽  
Binod Pandey ◽  
Prashant Swamy ◽  
Gary Glenn Grove
Keyword(s):  
Powdery Mildew ◽  
Prunus Avium ◽  
Developmental Stages ◽  
Disease Incidence ◽  
The United States ◽  
In Planta ◽  
Full Bloom ◽  
Symptomatic Disease ◽  
Conidial Concentration

Powdery mildew caused by Podosphaera cerasi is the most important fungal disease of sweet cherries in the Pacific Northwest of the United States. In this study, several factors related to disease epidemiology were evaluated. The experiments were conducted to investigate flower susceptibility to P. cerasi infection by in planta and in vitro inoculation. The susceptibility of fruit at various developmental stages was investigated using defined concentrations of P. cerasi conidia. Furthermore, the threshold of conidial concentration required for fruit infection was determined. The pathogen activity during full bloom was limited and not related to fruit disease incidence and severity at harvest. Foliar infections always preceded fruit infections by an average of 42 days during the three years of the study. The onset of fruit infection followed, on average, 66 days after full bloom and appeared simultaneously on all susceptible cherry cultivars in the research orchard. Disease symptoms were only observed on fruit in Biologische Bundesanstalt, Bundessortenamt, and Chemical industry (BBCH) scale 8 (maturity) in all cultivars examined. During this stage, a concentration of 500 conidia/ ml was sufficient to cause fruit infection at harvest. Interaction between the inoculation dates and inoculum conidial concentration revealed a dependency of disease development on the host stage at the time of conidial inoculation; the younger the fruit, the more conidia are needed to cause disease at harvest. Molecular studies showed a rapid increase in conidia viability at the transition from asymptomatic to the symptomatic disease of fruit. No evidence of ontogenic resistance of fruit to powdery mildew infection was observed.

scholarly journals Effect of the age of the pupal holotissue on the nutritional quality of artificial diets for Trichogramma spp. (Hymenoptera: Trichogrammatidae)

2000 ◽  
Vol 29 (3) ◽  
pp. 555-563 ◽  
Author(s):  
Fernando L. Cônsoli ◽  
José R.P. Parra
Keyword(s):  
Nutritional Quality ◽  
Developmental Stages ◽  
Egg Yolk ◽  
Artificial Diets ◽  
Age Classes ◽  
Factors Affecting ◽  
Fetal Serum ◽  
Bovine Fetal Serum

The nutritional quality of artificial diets composed of pupal holotissues of Diatraea saccharalis (Fabr.) (Lep.: Crambidae) from three different age classes (1-2, 3-4 and 5-6 days old) were tested for rearing Trichogramma galloi Zucchi and T. pretiosum Riley (Hym.: Trichogrammatidae) in vitro. Pupal holotissues were added to egg yolk, bovine fetal serum, lactoalbumine hydrolysate and preservatives, and offered to the parasitoids into artificial eggs. The quality of these diets in supporting the development of both parasitoids was evaluated by assessing the acceptance and parasitism of the artificial host eggs, larval and pupal survival, size, parasitism capacity and longevity of the in vitro-reared females, and the presence of deformed adults. Diets composed of 5-6 d old pupal holotissues did not support the larval development of both parasitoids as well as reduced the acceptance and/or parasitism of artificial eggs by T. galloi and T. pretiosum. The factors affecting the nutritional quality of pupal holotissues collected from different developmental stages are discussed.

scholarly journals 291 EFFECT OF DIFFERENT TRANSPORT TEMPERATURES (+4°C, +32°C) ON IN VITRO MATURATION OF OOCYTES COLLECTED FROM CATTLE AND SHEEP OVARIES

2005 ◽  
Vol 17 (2) ◽  
pp. 296
Author(s):  
O.B. Ozdas ◽  
M. Tas ◽  
U. Cirit ◽  
M. Evecen ◽  
K. Demir ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Developmental Stages ◽  
Chi Square ◽  
Medium Temperature ◽  
Factors Affecting ◽  
Group I ◽  
Significant Difference ◽  
Temperature Group ◽  
C 32

At present, blastocyst rates in embryos obtained from in vitro maturation of oocytes, and their fertilization and culture, is still not at the desired level. One of the most important problems encountered in in vitro culture studies is seen in the maturation period of oocytes until they reach the fertilizable level. Transport time of the ovaries and, in particular, temperature of the transport medium used are among the factors affecting complete maturation. The aim of this study was to determine the effects of different transport temperatures (4°C, 32°C) of sheep and cattle ovaries on the in vitro maturation of oocytes. Two experimental groups were formed in the study. Sheep and cattle ovaries were put into saline solution at 32°C. The ovaries were transported at the same temperature (Group I) or at 4°C following a 10-min incubation at room temperature (Group II), in 2–4 h to the laboratory (n = 6). For each group, oocytes were collected from ovaries using the dissection method and selected oocytes were matured in their own group in 700 μL TCM-199 (supplemented with pyruvate, LH, FCS) for 23 h at a gas atmosphere of 5% CO2, 5% O2, 90% N2 and at 38.8°C. At the end of maturation, oocytes were cleansed from their cumulus oophorus cells and fixed in acetic acid-ethyl alcohol (1:3) for 48 h. The developmental stages until MII of oocytes stained with aceto-orcein were then examined under the phase contrast microscope. The chi-square test was used for statistical analysis (Table 1). While oocytes obtained from sheep ovaries transported at +32°C reached the MII stage at a faster rate compared to those at +4°C (P < 0.001), no statistically significant difference was observed between the maturation to the MII stage of oocytes obtained from cattle ovaries transported at +4°C and +32°C. As a result of this study, while it was established that cattle ovaries could be transported at both +4°C and +32°C and that there was no difference in oocyte maturation, a medium temperature of +4°C was determined to be unsuitable for transporting sheep ovaries. Table 1. Stages of development in sheep and cattle oocytes after 23 h of culture This work was supported by Istanbul University.

scholarly journals Sweet Orange Fruit Age and Inoculum Concentration Affect the Expression of Citrus Black Spot Symptoms

Plant Disease ◽  
2019 ◽  
Vol 103 (5) ◽  
pp. 913-921 ◽  
Author(s):  
Guilherme F. Frare ◽  
Geraldo J. Silva-Junior ◽  
Fabrício E. Lanza ◽  
Renato B. Bassanezi ◽  
Thiago G. Ramires ◽  
...  
Keyword(s):  
Incubation Period ◽  
Sweet Orange ◽  
Disease Incidence ◽  
Black Spot ◽  
Conidial Germination ◽  
Inoculum Concentration ◽  
Factors Affecting ◽  
Citrus Black Spot ◽  
Incubation Periods ◽  
Orange Fruit

Citrus black spot (CBS), caused by Phyllosticta citricarpa, affects different citrus species worldwide. CBS is mainly expressed as false melanose and hard spot symptoms. There is no consensus in the literature about the period when fruit are susceptible to P. citricarpa infection and the length of the CBS incubation period. Therefore, this study aimed to assess the influence of sweet orange variety, fruit age, and inoculum concentration on the incubation period and the expression of different CBS symptoms. Attached fruit of Hamlin, Pera, and Valencia sweet orange at 1.5, 3.0, 5.0, and 7.0 cm diameter were inoculated with suspensions containing 103 and 105 conidia/ml of P. citricarpa. The percent conidial germination was quantified using scanning electron microscopy. The CBS symptoms on fruit were assessed monthly. The four diameters did not significantly affect conidial germination on the inoculated fruit, although CBS incidences were lower when larger fruit were inoculated. Hard spot symptoms on sweet orange fruit did not develop from the false melanose symptoms and vice versa. The incubation periods for false melanose were shorter than those observed for hard spot. False melanose began to appear 44 days after inoculation, but hard spot only formed at 113 days or later. Incubation periods were shorter and incidences of false melanose were higher following inoculation with higher inoculum concentration and smaller fruit diameter. The incubation period of hard spot varied among varieties and fruit diameters. However, there was no relationship between hard spot incidence and variety. This study provides a better understanding of the factors affecting the variation in the CBS incubation period and disease incidence on fruit.

scholarly journals In Vitro Culture of ‘Myrobalan’ (Prunus cerasifera Ehrh.) Embryos

HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1672-1674 ◽  
Author(s):  
Arancha Arbeloa ◽  
Ma Elena Daorden ◽  
Elena García ◽  
Pilar Andreu ◽  
Juan A. Marín
Keyword(s):  
Culture Media ◽  
Germination Rate ◽  
Interspecific Crosses ◽  
In Vitro Germination ◽  
Embryo Germination ◽  
Breeding Programs ◽  
Factors Affecting ◽  
Embryo Size ◽  
Prunus Cerasifera

In vitro embryo culturing has arisen as a powerful tool for embryo germination of low-viability seeds. This tool has been used to germinate seeds of early-maturing or hybrid Prunus species. ‘Myrobalan’ (Prunus cerasifera Ehrh.) is a widely used rootstock for plum and apricot cultivars and its interspecific hybrids have a clear potential for breeding purposes. However, early seed abortion is often a problem in interspecific crosses because no protocol has been established yet for ‘Myrobalan’ seeds. In this work, we developed a procedure for in vitro germination of embryos of different sizes. Various factors affecting embryo germination such as the culture media, the presence of cotyledons, the stratification temperature, and the embryo size were tested in three different ‘Myrobalan’ clones. The developed protocol includes the use of full embryos that were stratified at 4 °C and cultured in C2d culture medium. The germination rate was strongly affected by the embryo size and reached 90% germination with intermediate- to large-sized embryos (6.5 to 10 mm). However, smaller embryos could also be germinated, and up to 30% germination was achieved with 0.5- to 2-mm long embryos. The results obtained here provide a protocol for in vitro germination of ‘Myrobalan’ embryos that will likely be helpful in breeding programs.

Cryptosporidiumcell culture infectivity assay design

Parasitology ◽  
2011 ◽  
Vol 138 (6) ◽  
pp. 671-681 ◽  
Author(s):  
B. J. KING ◽  
A. R. KEEGAN ◽  
B. S. ROBINSON ◽  
P. T. MONIS
Keyword(s):  
Developmental Stages ◽  
Gastrointestinal Disease ◽  
Cell Monolayer ◽  
Data Interpretation ◽  
Host Cells ◽  
Specific Gene ◽  
Factors Affecting ◽  
Number Of Factors ◽  
Life Cycle Development

SUMMARYMembers of the genusCryptosporidium, which cause the gastrointestinal disease cryptosporidiosis, still represent a significant cause of water-borne disease worldwide. While intensive efforts have been invested in the development of techniques for parasite culture,in vitrogrowth has been hampered by a number of factors including low levels of infectivity as well as delayed life-cycle development and poor synchronicity. In this study we examined factors affecting the timing of contact between excysted sporozoites and target host cells and the subsequent impact of this upon the establishment of infection. We demonstrate that excystation rate impacts upon establishment of infection and that in our standard assay format the majority of sporozoites are not close enough to the cell monolayer when they are released from the oocyst to successfully establish infection. However, this can be easily overcome by centrifugation of oocysts onto the cell monolayer, resulting in approximately 4-fold increases in sporozoite attachment and subsequent infection. We further demonstrate that excystation procedures can be tailored to control excystation rate to match the assay end purpose and that excystation rate can influence data interpretation. Finally, the addition of both a centrifugation and washing step post-sporozoite attachment may be appropriate when considering the design ofin vitroculture experiments for developmental analysis and stage-specific gene expression as this appears to increase the synchronicity of early developmental stages.

scholarly journals The Effects of Postharvest Hot Water and Fungicide Treatments on Guignardia citricarpa Growth and the Development of Citrus Black Spot Symptoms on ‘Valencia’ Orange Fruit

HortScience ◽  
2016 ◽  
Vol 51 (12) ◽  
pp. 1555-1560 ◽  
Author(s):  
Jiaqi Yan ◽  
Megan M. Dewdney ◽  
Pamela D. Roberts ◽  
Mark A. Ritenour
Keyword(s):  
Disease Severity ◽  
Mycelial Growth ◽  
Disease Incidence ◽  
Black Spot ◽  
Hot Water ◽  
Lesion Development ◽  
Guignardia Citricarpa ◽  
Citrus Black Spot ◽  
Orange Fruit

Citrus black spot (CBS), caused by Guignardia citricarpa, is a fungal disease that was first described in Australia in the 1890s and has since been discovered in Southwest Florida in 2010. The current study evaluated the effects of hot water treatments on mycelial growth of G. citricarpa in vitro and also evaluated postharvest hot-water dips and fungicide treatments on CBS development on ‘Valencia’ oranges. In vitro exposure to 56 °C for 120 seconds, 59 °C for 60 seconds, or 62 °C for 30 seconds suppressed mycelial growth of all three G. citricarpa isolates by >30%. These treatments did not significantly reduce disease incidence or severity of CBS lesion development on whole ‘Valencia’ oranges from CBS-infected trees when the fruit already had visible CBS symptoms before treatment. On asymptomatic fruit, while the treatments did not significantly reduce the incidence of CBS lesion development, fruit dipped in 56 °C water for 120 seconds significantly reduced disease severity after 2 weeks of storage compared with the control. None of the treatments caused peel scalding or fruit quality deterioration. Postharvest application of azoxystrobin, imazalil, or thiabendazole significantly reduced CBS disease severity on fruit that were asymptomatic at harvest, but did not affect disease incidence. These fungicides were not effective on fruit harvested later in the season (April), possibly because most lesion expression had already occurred before harvest, with little left to develop after harvest. On fruit showing CBS symptoms at harvest, postharvest fungicide treatments did not significantly affect disease incidence or severity after storage. Heating the fungicide solutions did not significantly improve fungicide effectiveness. These results demonstrated that fungicide azoxystrobin, imazalil, or thiabendazole could reduce CBS severity, but not incidence, on orange fruit that are still asymptomatic at harvest.

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