S‐locus diversity and cross‐compatibility of wild Prunus avium for timber breeding

Prunus avium is primarily cultivated for its fruit, sweet cherries. However, it is also used to produce high‐quality timber. In a P. avium seed orchard, gametophytic self‐incompatibility is a restriction for free pollen flow and should be considered when establishing basic forest materials. In this study, S‐locus diversity and cross‐incompatibility of wild cherry individuals in clonal banks established for breeding for timber production were investigated. Wild cherry trees (140) with outstanding forest growth habit, collected in northern Spain, grafted and planted in two clonal banks, were genotyped at the S‐locus. The self‐incompatibility S‐locus genes, S‐RNase and SFB, were analysed by PCR. Twenty‐two S‐haplotypes, resulting in 72 different S‐genotypes, were identified. The genotypes were grouped into 33 incompatibility groups and 39 unique genotypes. This initial S‐locus analysis revealed large genetic diversity of wild cherry trees from the Spanish northern deciduous forest, and provides useful information for seed orchard design. Wild P. avium displays significantly more genetic diversity than what is detected in local cultivars, revealing a narrowing of genetic diversity during local domestication.     

Quantifying the effect of Managed Aquifer Recharge on the microbiological human health risks of irrigating crops with recycled water

Managed Aquifer Recharge (MAR) is increasingly being used for water recycling via aquifers and recovery for irrigation. Quantitative Microbial Risk Assessment (QMRA) was used to assess the human health risks from irrigation using reclaimed water and to evaluate the reduction in risk where MAR is used for irrigation management. Four MAR sites (Shafdan, Israel; Nardò, Italy; Bolivar, Australia; and Sabadell, Spain) that use reclaimed water for crop and/or park irrigation were evaluated, and the risk to human health was quantified in terms of DALYs (Disability Adjusted Life Years). The results indicated that median risks for all scenarios and pathogens evaluated were acceptable (<10⁻⁶ DALYs) with the exception of risks from accidental aerosol ingestion and bacterial pathogens at the Nardò site. MAR was found to be one of the most important treatment barriers in terms of log₁₀ inactivation credits and hence a useful tool for recycled water irrigation management. The Shafdan site relied almost completely on the MAR treatment to reduce the human health risks from irrigation to acceptable levels. For the Nardò site MAR was also an important barrier, where if MAR had not been used as part of the irrigation system the risk would be unacceptable for protozoa and viruses. The Bolivar and Sabadell sites had much larger and more technologically complex recycled water treatment systems and as such MAR was not a critical barrier in managing human health risks.     

Polybrominated diphenyl ethers (PBDEs) in foodstuffs: human exposure through the diet

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in a variety of materials, including synthetic polymers and textiles. Although these chemicals have been detected in environmental samples and human tissues, there is little information about human exposure to PBDEs through the diet. In the present study, we determined the concentrations of PBDEs in a number of food samples acquired in Catalonia (Spain) during 2000. The dietary intake of PBDEs was estimated for the general population living in this Spanish region. The highest PBDE concentrations were found in oils and fats, fish and shellfish, meat and meat products, and eggs, while the lowest levels corresponded to fruits, vegetables, and tubers. The dietary intake of PBDEs for an adult male was 97.3 ng/day (assuming not detected (ND) = (1)/(2) limit of detection (LOD)) or 81.9 ng/day (assuming ND = 0) The greatest contribution to these values corresponded to fish and shellfish, with approximately one-third of the total intake. TetraBDEs and pentaBDEs were the homologues showing the highest percentages of contribution to the sum of total PBDEs. The comparison of the current dietary intake with the suggested lowest observed adverse effect level value of 1 mg/kg/day for the most sensitive endpoints for toxic effects of PBDEs results in a safety factor over 5 orders of magnitude in relation to PBDE exposure from food.     

Control of postharvest diseases on citrus fruit by preharvest applications of biocontrol agent Pantoea agglomerans CPA-2: Part II. Effectiveness of different cell formulations

Infection of citrus fruit by postharvest pathogens often occurs in the field prior to harvest; therefore, it could be advantageous to apply biocontrol agents before harvest, which would reduce initial infection and then remain active and control pathogens in storage and under commercial conditions. The objective of the present work was to evaluate the effectiveness of different formulations of Pantoea agglomerans applied preharvest for controlling postharvest diseases on citrus. Results confirmed the protective effect of the additive Fungicover (FC) on populations of P. agglomerans exposed to non-conducive field conditions. In general, when osmotic-adapted and lyophilised P. agglomerans cells were used in bacterial treatments, these treatments showed greater survival rates than treatments with non-osmotic-adapted or fresh cells under field conditions. However, this superiority was only found when Fungicover was also added to suspensions of bacterial treatments. Therefore, bacterial treatments with Fungicover had population levels of P. agglomerans cells 1.2 and 2.8 log CFU cm⁻² higher than bacterial treatments without Fungicover during field experiments. These results allowed us to conclude that it is possible to improve environmental stress tolerance and ecological competence of P. agglomerans cells by integrating certain formulation strategies. Consequently, the improved formulation of P. agglomerans provided an effective control for orange fruit against natural postharvest pathogen infections and artificial infections of Penicillium digitatum with values of decay reduction higher than 50%. These latter results also demonstrated that it is possible to control postharvest pathogens using bacterial preharvest treatments.     

Insecticidal activity of Maytenus species (Celastraceae) nortriterpene quinone methides against codling moth, Cydia pomonella (L.) (Lepidoptera: tortricidae)

The insecticidal effects of nortriterpene quinone methides (pristimerin, tingenonee, and 20-alpha-hydroxytingenone) are reported for the first time. The natural products were isolated from Maytenus sp. (Celastraceae) and their effects tested on larvae of codling moth (Cydia pomonella, Lepidoptera: Tortricidae). The three metabolites produce the same effects on codling moth larvae that azadirachtin does, although at higher concentrations. 20-alpha-Hydroxytingenone was the most active compound, showing lethal, antifeedant, and insect growth regulation activities. Pristimerin showed also a high antifeedant activity together with its molt effect suppression. Tingenone showed the lowest activity. The differences in the activity of the three products are related to the structure of the E ring.     

Control of Blue Mold of Apples by Preharvest Application of Candida sake Grown in Media with Different Water Activity

ABSTRACT Unmodified and low water activity (a(w))-tolerant cells of Candida sake CPA-1 applied before harvest were compared for ability to control blue mold of apples ('Golden Delicious') caused by Penicillium expansum under commercial storage conditions. The population dynamics of strain CPA-1 on apples were studied in the orchard and during storage following application of 3 x 10(6) CFU/ml of each treatment 2 days prior to harvest. In the field, the population size of the unmodified treatment remained relatively unchanged, while the population size of the low-a(w)-modified CPA-1 cells increased. During cold storage, the populations in both treatments increased from 10(3) to 10(5) CFU/g of apple after 30 days, and then declined to about 2.5 x 10(4) CFU/g of apple. In laboratory studies, the low-a(w)-tolerant cells provided significantly better disease control as compared with the unmodified cells and reduced the number of infected wounds and lesion size by 75 and 90%, respectively, as compared with the non-treated controls. After 4 months in cold storage, both unmodified and low-a(w)-tolerant cells of C. sake were equally effective against P. expansum on apple (>50% reduction in size of infected wounds).