White-fruited strawberry genotypes are not per se hypoallergenic

Green Roof Gardens - Selecting Allergy-Friendly Vegetation: A Global Allergy and Asthma Excellence Network (GA²LEN) Position Paper

Green roof gardens are important for planetary health by mitigating the effects of urbanization. Because of the nature of green roof gardens, only particular plants can be used. The allergologic impact of these plants remains ill-characterized and guidance on building allergy-friendly green roof gardens is missing. To address this gap, we investigated the plant spectrum of several German green roof companies and categorized plants based on their primary pollination mechanism. Except for grasses, most plants were insect-pollinated and of low allergenicity. In addition, we conducted a review on the allergologic impact of plants used for green roof gardens. Our aim was to provide landscape architects with guidance on how to develop allergy-friendly green roof gardens. We highlight the need for universally accepted standards for assessing the allergenicity of roof top plants. Also, we recommend the joint development, by green roof producers and allergists, of criteria for allergy-friendly roof gardens. Their implementation may help to reduce the risk of allergen sensitization and allergy exacerbation, such as by avoiding the use of wind-pollinated plants of proven allergenicity including grasses. Green infrastructure, such as green roofs, should benefit planetary health without increasing the prevalence and burden of allergies.

Insights into the microbiome assembly during different growth stages and storage of strawberry plants

BACKGROUND

Microbiome assembly was identified as an important factor for plant growth and health, but this process is largely unknown, especially for the fruit microbiome. Therefore, we analyzed strawberry plants of two cultivars by focusing on microbiome tracking during the different growth stages and storage using amplicon sequencing, qPCR, and microscopic approaches.

RESULTS

Strawberry plants carried a highly diverse microbiome, therein the bacterial families Sphingomonadaceae (25%), Pseudomonadaceae (17%), and Burkholderiaceae (11%); and the fungal family Mycosphaerella (45%) were most abundant. All compartments were colonized by high number of bacteria and fungi (10⁷-10¹⁰ marker gene copies per g fresh weight), and were characterized by high microbial diversity (6049 and 1501 ASVs); both were higher for the belowground samples than in the phyllosphere. Compartment type was the main driver of microbial diversity, structure, and abundance (bacterial: 45%; fungal: 61%) when compared to the cultivar (1.6%; 2.2%). Microbiome assembly was strongly divided for belowground habitats and the phyllosphere; only a low proportion of the microbiome was transferred from soil via the rhizosphere to the phyllosphere. During fruit development, we observed the highest rates of microbial transfer from leaves and flowers to ripe fruits, where most of the bacteria occured inside the pulp. In postharvest fruits, microbial diversity decreased while the overall abundance increased. Developing postharvest decay caused by Botrytis cinerea decreased the diversity as well, and induced a reduction of potentially beneficial taxa.

CONCLUSION

Our findings provide insights into microbiome assembly in strawberry plants and highlight the importance of microbe transfer during fruit development and storage with potential implications for food health and safety.

Genotype-Dependent Gene Expression in Strawberry (Fragaria x ananassa) Plants Under High Temperature Stress

The differences in tolerance to high temperatures were investigated on the basis of gene expressions in two strawberry (Fragaria x ananassa Duch) cultivars which were previously determined as high temperature tolerant (Redlands Hope = R. Hope) and sensitive (Festival). Plants were exposed incrementally to 35, 40, 45, and finally 50 °C for 24 h. qRT-PCR analyses were carried out with 19 known sequences from the databases. Protein expression analyses were based on SDS-PAGE results, sequenced and then separated due to their isoelectric points. Expression levels were determined at 35, 40, and 45 °C. According to the results, tolerance of 'R. Hope' to high temperature stress can be explained with the coordination of Hsp70, Hsp90, and small heat shock proteins (sHsps) having a vital and supplementary role in stress response. Sensitive cultivar 'Festival' can respond to high temperatures only with the low molecular weight protein and transcripts that do not take a central role in high temperature stress response. Moreover, allergen gene expression triggered by high temperature were detected in both cultivars with different expression levels. The greater expression level in allergen genes observed in the sensitive cultivar 'Festival' under high temperature indicates that there is possibly a negative correlation between expression level in allergen genes and heat stress tolerance. Future studies addressing allergen gene expression under high temperature stress are required to confirm on these findings and to expand on the potential use as a molecular marker in breeding process for enhanced tolerance to high temperature.

The Interaction between Antioxidants Content and Allergenic Potency of Different Raspberry Cultivars

Food allergies are a very serious problem among consumers. The most common food allergies involve animal products, but they can also involve fruits such as berries. We aimed to determine whether organic farming is useful for the production of high-quality and safe fruits. Three varieties of raspberries 'Laszka', 'Glen Ample' and 'Polka' from organic and conventional production (neighboring farms) were collected over the two years of the experiment. Quantitative and qualitative analysis of phenolic compounds was carried out, and the content of Bet v1 and profilin was determined. The organic raspberries contained a lower level of phenolic compounds, especially anthocyanins. Conventional fruits were characterized by a higher allergenic potency than organic ones. We found a strong link between their anthocyanin content and the allergy status of conventional raspberry fruits. Therefore, organically produced raspberries are safer for consumers.

Evaluation of basophil activation caused by transgenic rice seeds expressing whole T cell epitopes of the major Japanese cedar pollen allergens

Background

Japanese cedar (JC) pollinosis is a serious type I allergic disease in Japan. Although subcutaneous immunotherapy and sublingual immunotherapy have been applied to treat JC pollinosis, high doses of allergens may cause IgE-mediated allergic reactions. The transgenic rice seeds that contain genetically modified Cry j 1 and Cry j 2, the two major allergens of JC pollen, have been developed as candidates for oral immunotherapy. Although the antigens in the transgenic rice seeds (Tg-rice seeds) were engineered such that they decrease binding ability with IgE and they are of insufficient length to cross-link IgE on the surface of mast cells or basophils, the safety of Tg-rice seeds for patients with JC pollinosis was unclear.

Methods

To verify the safety of Tg-rice seeds in terms of allergies, we investigated the percentage of activated basophils induced by Tg-rice seed extract in the basophil activation test. Blood samples from 29 patients with JC pollinosis were collected. Tg-rice seed extract, non-transgenic wild-type rice seed extract, and Cry j 1 and Cry j 2 were mixed with the blood with reagents. The percentage of activated basophils was assessed by CD203c expression, a basophil activation marker.

Results

The percentage of activated basophils after the stimulation with Tg-rice seed extract was 4.5 ± 1.6% (mean ± SD) compared with 62.9 ± 20.2% after Cry j 1- and Cry j 2-stimulation (difference 58.4%, P < 0.001, 95% confidence interval 51.0–65.9%).

Conclusions

The results will contribute to the safety of Tg-rice seeds in terms of allergies.

Effect of the Strawberry Genotype, Cultivation and Processing on the Fra a 1 Allergen Content

Birch pollen allergic patients show cross-reactivity to vegetables and fruits, including strawberries (Fragaria × ananassa). The objective of this study was to quantify the level of the Fra a 1 protein, a Bet v 1-homologous protein in strawberry fruits by a newly developed ELISA, and determine the effect of genotype, cultivation and food processing on the allergen amount. An indirect competitive ELISA using a specific polyclonal anti-Fra a 1.02 antibody was established and revealed high variability in Fra a 1 levels within 20 different genotypes ranging from 0.67 to 3.97 µg/g fresh weight. Mature fruits of red-, white- and yellow-fruited strawberry cultivars showed similar Fra a 1 concentrations. Compared to fresh strawberries, oven and solar-dried fruits contained slightly lower levels due to thermal treatment during processing. SDS-PAGE and Western blot analysis demonstrated degradation of recombinant Fra a 1.02 after prolonged (>10 min) thermal treatment at 99 °C. In conclusion, the genotype strongly determined the Fra a 1 quantity in strawberries and the color of the mature fruits does not relate to the amount of the PR10-protein. Cultivation conditions (organic and conventional farming) do not affect the Fra a 1 level, and seasonal effects were minor.