Competition Effects Among Isolates of Fusarium culmorum Differing in Aggressiveness and Mycotoxin Production on Heads of Winter Rye

Fusarium culmorum is a phytopathogenic, toxigenic fungus causing seedling diseases, foot rot and head blight of cereals. For estimating competition effects in mixtures of two single-spore isolates, two winter rye single crosses were tested with either four isolates individually or four 1 : 1 mixtures of the same isolates in six field environments. Two isolates (FC46, FC64) were highly aggressive deoxynivalenol (DON) and 3-acetyl DON-producers, the other two (FC30, FC71) were medium aggressive nivalenol-producers. Rye heads were inoculated during flowering with conidia of pairs of isolates expressing similar (FC46 + FC64, FC30 + FC71) or contrary (FC46 + FC71, FC30 + FC64) levels of aggressiveness and similar or different concentrations and chemotypes of mycotoxins, respectively. Head blight rating and yield components relative to the non-inoculated plots were recorded as aggressiveness traits. Additionally, mycotoxin concentrations were measured in the rye grain. Random pathogen samples were re-isolated from heads at the onset of symptom development and analysed by molecular markers (RAPD–PCR) in one environment. Aggressiveness of the isolate mixtures was significantly lower than that of the isolates applied individually on both rye genotypes. Similarly, mycotoxin concentrations were significantly lower in the mixtures in seven out of eleven comparisons. Among the re-isolates, the component genotypes of a mixture significantly deviated from the inoculated 1 : 1 ratio when a particular isolate (FC46) was present in the mixture. This isolate displayed a superior competitive ability irrespective of the aggressiveness or mycotoxin profile of the mixing partner illustrating that pathogenic fitness is caused by additional factors that have not, as yet, been identified.     

The delay of flowering time in almond: a review of the combined effect of adaptation,mutation and breeding

Regulation of flowering time in almond, as in other Prunus species, is a complex process involving both chill and heat requirements. Following exposure to appropriate consecutive periods of cold and warm temperatures, the buds break dormancy and sprout or flower depending on bud type. To maximize flowering and subsequent vegetative growth and fruit set, chilling and ensuing warm temperature requirements have to be fully satisfied. Because of its potential for very early flowering, flowering time in almond is a major determinant of its adaptation to new environments. In colder regions, Late-flowering is often necessary to avoid frost damage during and just after flowering. Consequently, the selection of delayed flowering times remains an important objective in almond improvement programs. Flowering time is considered a quantitative though highly heritable trait. In addition, a dominant gene (Late flowering, Lb), originally identified in a spontaneous mutation of the Californian almond cultivar ‘Nonpareil’, was also described. The objective of this review is a comparative analysis of the effects of regional adaptation, breeding and mutation on the delay of flowering time in new almond cultivars. Findings indicate that the adaptation of almonds from the Mediterranean basin to colder regions in Northern Europe and America has been mainly achieved through delayed flowering. These adapted late-flowering cultivars have usually been developed by selecting desired quantitative genes within each regional germplasm. Additional progress thus appears achievable with a more comprehensive understanding of the quantitative and qualitative genetics controlling this trait. The use of molecular markers for the early selection of genes conferring late flowering, including both spontaneous mutations as well as unique regional germplasm, should allow development of even later cultivars including ultra-late cultivars flowering as into April.     

Reaction of <Emphasis Type="Italic">Phaseolus</Emphasis> spp. genotypes to ashy stem blight caused by <Emphasis Type="Italic">Macrophomina phaseolina</Emphasis>

Ashy stem blight (ASB) caused by Macrophomina phaseolina (Tassi) Goidanich (Mp) is a devastating seed-transmitted disease in common bean in the tropics. The identification of resistant cultivars throughout the cropping season contributes to disease management. Resistance is found in the primary and tertiary gene pools. Our objectives were to determine (1) the reaction of Phaseolus spp. genotypes to two Mp isolates at vegetative and reproductive stages, (2) the area under disease progress curve (AUDPC), and (3) resistant plants per genotype at harvest. Twenty-three genotypes from different origins were planted in the greenhouse in 2016 and 2017. One less-aggressive Mp (PRJD16) and one more-aggressive (PRI16) isolate were inoculated one and three times, respectively, by the cut-stem method. ‘Beníquez’, ‘Othello’, and ‘Verano’ were highly susceptible (mean scores >8.0, and AUDPC values from 264.6 to 300.8) to both isolates. BAT 477 and NY6020-4 were intermediate (5.6 and 6.2; AUDPC: 161.6 and 187.1) to PRJD16 and susceptible (7.4 and 8.2; AUDPC: 209.4 and 235.1) to PRI16. Resistant genotypes (mean scores ≤3) were not identified in this study. However, A 195, ‘Badillo’, and ‘PC 50’ possessed lower mean scores (4.3–5.4) and AUDPC values (126.4–150.9) to both isolates. Furthermore, A 195 had the highest percentage of resistant plants (55.6%) followed by PC 50, I9365-31, and PI 321637 (27.8%) to PRJD16 at harvest. Thus, the identification of resistant parents across Phaseolus species is necessary to increase the levels of ASB resistance in common bean cultivars throughout the entire cropping season.     

The value of incorporating carcass trait phenotypes in terminal sire selection indexes to improve carcass weight and quality of heavy lambs

Genetic selection for carcass traits is paramount to maximize the profitability and long‐term sustainability of any meat‐producing livestock species. The main objectives of this research were to evaluate the efficiency of indicator traits for the genetic improvement of lamb carcass traits and to determine the value of including carcass traits into terminal sire selection indexes for the Canadian sheep industry. The carcass traits included hot carcass weight (HCW), fat depth at the GR site (FATGR) and average carcass conformation score (AVGCONF), and were measured on heavy lambs (slaughter age less than 365 days and HCW greater than 16.3 kg) in commercial abattoirs. Growth traits were found to be moderately efficient indicator traits for the genetic improvement of HCW but selection on ultrasound traits was necessary to substantially improve the carcass quality traits (FATGR and AVGCONF). Economic selection indexes were designed by adding various combinations of carcass traits into the Canadian Sheep Genetic Evaluation System terminal indexes. Records measured on individuals and progeny were assumed to be the sources of information for live animal and carcass traits, respectively. The changes in index accuracy, efficiency and expected correlated response were used to assess the value of their inclusion. HCW was found to have a large economic value, and its inclusion into terminal selection indexes was expected to substantially increase their accuracy (0.08–0.12 points) and efficiency (20%–30%). However, further including FATGR (measured 110 mm from the carcass midline over the 12th rib) and AVGCONF had little impact on the accuracy (≤0.03) and efficiency (1%–7%) of the proposed indexes. Thus, the inclusion of carcass traits into the existing terminal selection indexes could be beneficial for the genetic improvement of HCW, but further research is needed to determine optimal methods of increasing carcass fatness and muscularity.     

Leiomyoma of the third eyelid in a dog

A 14‐year‐old neutered male Dachshund presented for the evaluation of oculus dexter (OD) third eyelid elevation ongoing for approximately 2 months. Complete ophthalmic examination revealed a large, nonpainful, well‐demarcated, soft mass at the base of the right third eyelid causing elevation and mild hyperemia. The mass was freely moveable with the third eyelid, and no right globe deviation was noted. No other abnormalities were noted on physical examination, routine blood chemistry, complete blood count, serum T4, urinalysis, or urine cortisol/creatinine ratio. Ocular B‐mode ultrasonography showed an anechoic, well‐demarcated, homogenous, soft tissue mass at the base of the third eyelid with no orbital extension. A leiomyoma was diagnosed after multiple punch biopsies were obtained from the palpebral surface of the mass. The right third eyelid was excised surgically. Histopathology confirmed a completely excised, nodular, unencapsulated, expansile mass within the third eyelid. Positive smooth muscle actin and negative S‐100 immunohistochemistry confirmed a leiomyoma. Bundles of normal smooth muscle were also present adjacent to the mass. The mass was compressing the adjacent lacrimal gland and associated with moderate dacryoadenitis. Twelve months postoperatively, the right globe position and motility remain normal with no evidence of mass regrowth. To the author's knowledge, this is the first reported case of a leiomyoma of the third eyelid in any species. In this case, the mass was completely excised and no regrowth has occurred twelve months after surgery. This case along with independently reviewed canine third eyelids clearly demonstrates the presence of smooth muscle within the canine third eyelid.     

Clinical features and heritability of hypoadrenocorticism in Nova Scotia Duck Tolling Retrievers: 25 cases (1994-2006)

OBJECTIVE: To evaluate the clinical features and heritability of naturally occurring hypoadrenocorticism in Nova Scotia Duck Tolling Retrievers (NSDTRs). DESIGN: Retrospective case series. ANIMALS: 25 NSDTRs with hypoadrenocorticism. PROCEDURES: Questionnaires completed by owners of NSDTRs with hypoadrenocorticism and medical records from veterinarians were reviewed for information regarding diagnosis, age at diagnosis, concurrent diseases, age at death, and cause of death. Pedigrees were analyzed for heritability and mode of inheritance of hypoadrenocorticism (including complex segregation analysis of pedigrees of 1,515 dogs). RESULTS: On the basis of results of ACTH stimulation testing, hypoadrenocorticism was diagnosed in 16 female and 9 male NSDTRs (including 6 full siblings). Median age at diagnosis was 2.6 years; the diagnosis was made prior to 2 years of age in 11 dogs. Seventeen dogs had hyponatremia, hyperkalemia, or both, and serum electrolyte concentrations were within reference ranges for 8 dogs at the time of diagnosis. Median survival time after diagnosis for 4 dogs that died or were euthanized as a result of medical causes was 1.6 years. Heritability was calculated at 0.98 with no sex effect, and complex segregation analysis fit a major gene model with an autosomal recessive mode of inheritance. CONCLUSIONS AND CLINICAL RELEVANCE: In NSDTRs, hypoadrenocorticism was diagnosed at an earlier age, compared with published reports of age at diagnosis among the general dog population. Among the study dogs, 32% had no serum electrolyte abnormalities at the time of diagnosis, and the disease appeared to have an autosomal recessive mode of inheritance in the breed.     

Expression of porcine endogenous retroviruses (PERVs) in melanomas of Munich miniature swine (MMS) Troll

Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pig breeds. Since some of them are able to infect human cells, they might represent a risk for xenotransplantation using pig cells or organs. However, the expression and biological role of PERVs in healthy pigs as well as in porcine tumours is largely unknown. Since we and others have recently shown overexpression of a human endogenous retrovirus, HERV-K, in human melanomas, we studied the expression of PERVs in melanomas of selectively bred Munich miniature swine (MMS) Troll. This breeding herd of MMS Troll is characterised by a high prevalence of melanomas, which histologically resemble various types of cutaneous melanomas in humans. Several genetic factors have been defined when studying inheritance of melanomas and melanocytic nevi in MMS Troll. Here we show that the polytropic PERV-A and PERV-B as well as the ecotropic PERV-C are present in the genome of all melanoma bearing MMS Troll investigated. Most interestingly, in the spleen, but not in other organs, recombinant PERV-A/C proviruses were found. PERV expression was found elevated in melanomas when compared to normal skin and viral proteins were expressed in melanomas and pulmonary metastasis-derived melanoma cell cultures. During passaging of these cells in vitro the expression of PERV mRNA and protein increased and virus particles were released as shown by RT activity in the supernatant and by electron microscopy. Genomic RNA of PERV-A, -B and -C were found in pelleted virus particles. Although PERV expression was elevated in melanomas and pulmonary metastasis-derived cell cultures, the function of the virus in tumour development is still unclear.