The Transferability of Spectral Grain Yield Prediction in Wheat Breeding across Years and Trial Locations.

Grain yield (GY) prediction based on non-destructive UAV-based spectral sensing could make screening of large field trials more efficient and objective. However, the transfer of models remains challenging, and is affected by location, year-dependent weather conditions and measurement dates. Therefore, this study evaluates GY modelling across years and locations, considering the effect of measurement dates within years. Based on a previous study, we used a normalized difference red edge (NDRE1) index with PLS (partial least squares) regression, trained and tested with the data of individual dates and date combinations, respectively. While strong differences in model performance were observed between test datasets, i.e., different trials, as well as between measurement dates, the effect of the train datasets was comparably small. Generally, within-trials models achieved better predictions (max. R2 = 0.27-0.81), but R2-values for the best across-trials models were lower only by 0.03-0.13. Within train and test datasets, measurement dates had a strong influence on model performance. While measurements during flowering and early milk ripeness were confirmed for within- and across-trials models, later dates were less useful for across-trials models. For most test sets, multi-date models revealed to improve predictions compared to individual-date models.

Metabolite profiling of barley flag leaves under drought and combined heat and drought stress reveals metabolic QTLs for metabolites associated with antioxidant defense.

Barley (Hordeum vulgare L.) is among the most stress-tolerant crops; however, not much is known about the genetic and environmental control of metabolic adaptation of barley to abiotic stresses. We have subjected a genetically diverse set of 81 barley accessions, consisting of Mediterranean landrace genotypes and German elite breeding lines, to drought and combined heat and drought stress at anthesis. Our aim was to (i) investigate potential differences in morphological, physiological, and metabolic adaptation to the two stress scenarios between the Mediterranean and German barley genotypes and (ii) identify metabolic quantitative trait loci (mQTLs). To this end, we have genotyped the investigated barley lines with an Illumina iSelect 9K array and analyzed a set of 57 metabolites from the primary C and N as well as antioxidant metabolism in flag leaves under control and stress conditions. We found that drought-adapted genotypes attenuate leaf carbon metabolism much more strongly than elite lines during drought stress adaptation. Furthermore, we identified mQTLs for flag leaf γ-tocopherol, glutathione, and succinate content by association genetics that co-localize with genes encoding enzymes of the pathways producing these antioxidant metabolites. Our results provide the molecular basis for breeding barley cultivars with improved abiotic stress tolerance.

Efficient Noninvasive FHB Estimation using RGB Images from a Novel Multiyear, Multirater Dataset.

Fusarium head blight (FHB) is one of the most prevalent wheat diseases, causing substantial yield losses and health risks. Efficient phenotyping of FHB is crucial for accelerating resistance breeding, but currently used methods are time-consuming and expensive. The present article suggests a noninvasive classification model for FHB severity estimation using red-green-blue (RGB) images, without requiring extensive preprocessing. The model accepts images taken from consumer-grade, low-cost RGB cameras and classifies the FHB severity into 6 ordinal levels. In addition, we introduce a novel dataset consisting of around 3,000 images from 3 different years (2020, 2021, and 2022) and 2 FHB severity assessments per image from independent raters. We used a pretrained EfficientNet (size b0), redesigned as a regression model. The results demonstrate that the interrater reliability (Cohen's kappa, κ) is substantially lower than the achieved individual network-to-rater results, e.g., 0.68 and 0.76 for the data captured in 2020, respectively. The model shows a generalization effect when trained with data from multiple years and tested on data from an independent year. Thus, using the images from 2020 and 2021 for training and 2022 for testing, we improved the F1w score by 0.14, the accuracy by 0.11, κ by 0.12, and reduced the root mean squared error by 0.5 compared to the best network trained only on a single year's data. The proposed lightweight model and methods could be deployed on mobile devices to automatically and objectively assess FHB severity with images from low-cost RGB cameras. The source code and the dataset are available at https://github.com/cvims/FHB_classification.

Delayed release phosphatidylcholine in chronic-active ulcerative colitis: a randomized, double-blinded, dose finding study.

BACKGROUND: In 2 preceding studies, delayed release phosphatidylcholine (rPC) was found to (a) improve disease activity and (b) withdraw steroids in patients with chronic-active ulcerative colitis. GOAL: Objective of the study was to determine the most effective rPC dose with least adverse events. STUDY: A randomized, dose-controlled, double-blinded study. Four groups of 10 patients each with nonsteroid-treated, chronic-active ulcerative pancolitis with a clinical activity index (CAI) and endoscopic activity index (EAI) >or=7. Patients were treated with oral rPC at doses of 0.5, 1, 3, and 4 g daily over 12 weeks. RESULTS: The CAI changes from baseline to the end of the study were 2.5 (0.5 g), 7.0 (1 g), 5.5 (3 g), and 6.0 (4 g dose arm). Significant improvement of the CAI was registered between the lowest rPC dose of 0.5 g (control group) and all higher doses of 1.0, 3.0, and 4.0-g rPC (Por=50% CAI improvement) were 70% in all of the effective dose groups (1 to 4 g, P=0.003). This was paralleled by the EAI improvement and by the rates of mucosal healing. Median time to clinical response was 5 (IQR 2 to 8) weeks. Bloating was registered in 40% of the patients irrespective of the treatment dose. Three of the 10 patients in the 4 g dose group reported nausea. CONCLUSION: We found a saturable dose response of rPC in the treatment of chronic-active ulcerative colitis with effective doses >or=1 g per day; doses of 3 and 4 g seem to be superior in achieving remission.

Phosphatidylcholine (lecithin) and the mucus layer: Evidence of therapeutic efficacy in ulcerative colitis?

Colonic mucus protects against attacks from bacteria in stool. One component of mucus is phosphatidylcholine (PC) which is thought to be arranged as continuous lamellar layer in the apical mucus and to be responsible for establishing a protective hydrophobic surface. This 'intestinal surfactant' plays a key role in mucosal defense. Thus, a defective PC layer contributes to the development of inflammation. Analysis of rectoscopically acquired mucus aliquots revealed a 70% decrease in PC content in ulcerative colitis (UC) compared to Crohn's disease (CD) and healthy controls - independent of disease activity. Accordingly, we propose that lack of mucus PC is a key pathogenetic factor in UC. In clinical studies a delayed-release oral PC preparation (rPC) was found to substitute the lack of PC in rectal mucus. Indeed, in non-steroid-treated active UC, 53% of rPC patients reached remission [clinical activity index (CAI) ≤3] compared to 10% of placebo patients (p ≤ 0.001). Endoscopic and histologic findings improved concomitantly. A second trial with 60 chronic-active, steroid-dependent UC patients was conducted to test for steroid-sparing effects. Complete steroid withdrawal with a concomitant achievement of remission (CAI ≤3) or clinical response (≥50% CAI improvement) was reached in 15 PC-treated patients (50%) but only in 3 (10%) placebo patients (p = 0.002). In conclusion, intrinsic reduction of PC (lecithin) in colonic mucus may be a key pathogenetic feature of UC. Topical supplement of PC by a delayed-released oral PC preparation is effective in resolving inflammatory activity of UC and may develop to a first-choice therapy for this disease.

Fine mapping, physical mapping and development of diagnostic markers for the Rrs2 scald resistance gene in barley.

The Rrs2 gene confers resistance to the fungal pathogen Rhynchosporium secalis which causes leaf scald, a major barley disease. The Rrs2 gene was fine mapped to an interval of 0.08 cM between markers 693M6_6 and P1D23R on the distal end of barley chromosome 7HS using an Atlas (resistant) x Steffi (susceptible) mapping population of 9,179 F(2)-plants. The establishment of a physical map of the Rrs2 locus led to the discovery that Rrs2 is located in an area of suppressed recombination within this mapping population. The analysis of 58 barley genotypes revealed a large linkage block at the Rrs2 locus extending over several hundred kb which is present only in Rrs2 carrying cultivars. Due to the lack of recombination in the mapping population and the presence of a Rrs2-specific linkage block, we assume a local chromosomal rearrangement (alien introgression or inversion) in Rrs2 carrying varieties. The variety analysis led to the discovery of eight SNPs which were diagnostic for the Rrs2 phenotype. Based on these SNPs diagnostic molecular markers (CAPS and pyrosequencing markers) were developed which are highly useful for marker-assisted selection in resistance gene pyramiding programmes for Rhynchosporium secalis resistance in barley.

Deciphering the genetic basis for vitamin E accumulation in leaves and grains of different barley accessions.

Tocopherols and tocotrienols, commonly referred to as vitamin E, are essential compounds in food and feed. Due to their lipophilic nature they protect biomembranes by preventing the propagation of lipid-peroxidation especially during oxidative stress. Since their synthesis is restricted to photosynthetic organisms, plant-derived products are the major source of natural vitamin E. In the present study the genetic basis for high vitamin E accumulation in leaves and grains of different barley (Hordeum vulgare L.) accessions was uncovered. A genome wide association study (GWAS) allowed the identification of two genes located on chromosome 7H, homogentisate phytyltransferase (HPT-7H) and homogentisate geranylgeranyltransferase (HGGT) that code for key enzymes controlling the accumulation of tocopherols in leaves and tocotrienols in grains, respectively. Transcript profiling showed a correlation between HPT-7H expression and vitamin E content in leaves. Allele sequencing allowed to decipher the allelic variation of HPT-7H and HGGT genes corresponding to high and low vitamin E contents in the respective tissues. Using the obtained sequence information molecular markers have been developed which can be used to assist smart breeding of high vitamin E barley varieties. This will facilitate the selection of genotypes more tolerant to oxidative stress and producing high-quality grains.

Are PECTIN ESTERASE INHIBITOR Genes Involved in Mediating Resistance to Rhynchosporium commune in Barley?

A family of putative PECTIN ESTERASE INHIBITOR (PEI) genes, which were detected in the genomic region co-segregating with the resistance gene Rrs2 against scald caused by Rhynchosporium commune in barley, were characterized and tested for their possible involvement in mediating resistance to the pathogen by complementation and overexpression analysis. The sequences of the respective genes were derived from two BAC contigs originating from the susceptible cultivar 'Morex'. For the genes HvPEI2, HvPEI3, HvPEI4 and HvPEI6, specific haplotypes for 18 resistant and 23 susceptible cultivars were detected after PCR-amplification and haplotype-specific CAPS-markers were developed. None of the tested candidate genes HvPEI2, HvPEI3 and HvPEI4 alone conferred a high resistance level in transgenic over-expression plants, though an improvement of the resistance level was observed especially with OE-lines for gene HvPEI4. These results do not confirm but also do not exclude an involvement of the PEI gene family in the response to the pathogen. A candidate for the resistance gene Rrs2 could not be identified yet. It is possible that Rrs2 is a PEI gene or another type of gene which has not been detected in the susceptible cultivar 'Morex' or the full resistance reaction requires the presence of several PEI genes.

Delayed release phosphatidylcholine as new therapeutic drug for ulcerative colitis--a review of three clinical trials.

IMPORTANCE OF THE FIELD: As the pathogenesis of ulcerative colitis (UC) is unknown, a causative therapy is lacking. Therefore, some UC patients suffer from disease activity despite symptomatic anti-inflammatory treatment strategies. We claim that reduction of phosphatidylcholine (PC) in colonic mucus impairs the mucosal barrier and, thus, causes attacks of the commensal bacterial flora to induce colitis. Thus, mucus PC substitution could provide a causal therapy for UC. AREAS COVERED IN THIS REVIEW: A delayed released oral PC preparation (rPC) was found to substitute for the lack of PC in rectal mucus. In non-steroid-treated active UC, 53% of rPC-treated patients reached remission compared with 10% of placebo patients (p < 0.001). In a second trial with chronic-active, steroid-dependent UC patients, steroid withdrawal with a concomitant achievement of remission (CAI ≤ 3) or clinical response (≥ 50% CAI improvement) was reached in 15 rPC-treated patients (50%) but only in 3 (10%) placebo patients (p = 0.002). WHAT THE READER WILL GAIN: The concept that missing PC in colonic mucus is the main pathogenetic factor for development of UC. PC can be substituted by rPC, which cures the disease in the majority of patients. TAKE HOME MESSAGE: rPC is, to our knowledge, the first causative therapeutic option for patients with UC.