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This year, almost 50% of the European agricultural area suffered from drought stress. The tendency for the next years is constantly increasing. Therefore, plants develop different strategies to adapt to drought stress like in morphological, physiological and molecular pathways. In addition to drought stress, there are other challenges to handle with like the decrease of conventional plant protection products due to their negative ecological consequences. Thus, biologicals are gaining more importance because of their environment-friendly property. Biologicals are products containing natural substances and/or microorganisms leading to increasing abiotic and biotic stress tolerance. The aim of this study is to investigate drought stress tolerance in various barley genotypes (Hordeum vulgare L) and to analyse the effect of application of biologicals on these genotypes under drought stress. First, eleven diverse reacting genotypes were selected out of 200 accessions from the spring barley IPK-SB224 panel (Genobar) for greenhouse and field experiments. Drought stress was induced by 20% water capacity at the third-leaf stage for six weeks followed by a two weeks re-watering phase to investigate the recovery ability with and without treatment of biologicals. During drought stress and re-watering phase, chlorophyll content and stomatal conductance were measured and water use efficiency was calculated for this period. Flag leaves were collected to examine the osmolality, proline content and soluble sugars as well as for qRT-PCR analysis of several relevant drought stress genes. Moreover, mature plants were harvested and yield parameters like kernel biomass were acquired. Additionally, root morphology of the eleven genotypes was analysed in a hydroponic system by application of PEG6000 as an osmotic stressor. First results indicate a high significant (p<0.01) correlation of plant and kernel biomass between greenhouse and filed experiment of 0.6 and 0.54, respectively. Most significant correlation with the plant biomass was calculated for water use efficiency (0.93) and water use (0.72) under greenhouse conditions. Preliminary results of the analysis of biologicals under drought stress treatment show an increase in biomass up to 78% by applying extract of Arcitum lappa and 130% by the extract of Reynoutria sachalinensis. Results of the root analyses indicate that all root related parameters such as root biomass, length and volume are significantly (p<0.001) affected by PEG treatment and genotype. [ABSTRACT FROM AUTHOR]

Crops worldwide are threatened by drought and infectious diseases. As a result of climate change, periods of heat and drought will increase and might enhance yield losses due to increased abiotic stress and higher damage by pathogens. Barley cultivation, that has thousands of years of history, is increasingly coming under pressure. Further, the use of chemical-synthetic fungicides is increasingly questioned due to its negative effects on the environment. Therefore, there is a high demand for sustainable products, such as plant extracts and microorganisms. These products can have a direct antagonistic activity or function indirectly by promoting plant growth and resistance. The aim of the project MORGEN is to protect barley in a sustainable way from the challenges of climate change and the associated increased occurrence of powdery mildew (Blumeria graminis). In a first step, a routine method for airborne inoculation of potted barley plants with defined doses of conidia and reproducible infection results for comparative analyses could be established at the JKI Institute for Biological Control. By applying the method, a set of 50 barley accessions was analysed and accessions with high resistance to powdery mildew were successfully identified and significantly differentiated from those with medium or low resistance. In the next step the preventive effect of 18 plant strenghener/plant protection products/biostimulants (plant extracts and microorganisms) on powdery mildew infection was determined using selected genotypes of different susceptibility. The influence of drought stress on plant development and on the efficacy of some of the products examined was also investigated. Two potent preparations (plant extract/animal product) against barley powdery mildew were identified, whose excellent protective effect was independent of drought stress in our experiments. The presentation (i) shows a simple, cost-effective and statistically validated inoculation method for powdery mildew in barley, which might also be applicable/extendable to other crops, (ii) extends the knowledge on powdery mildew resistance in different barley lines and (iii) presents alternative control agents with a high efficacy against powdery mildew, which can contribute to more sustainable crop production. [ABSTRACT FROM AUTHOR]

Climatic change shows a spiraling trend of scarce rainfall mirrored with a fall of majority produced cereals such as barley. Thus, finding solutions through crop management and cultivar selection has become crucial to minimize crop losses and stabilize the dropping trends. In this study, we test the effects of irriga-tion and sowing patterns on five geno-types. We conducted the experiment in 2021 at the experimental fields of Julius Kuehn Institute in Berlin. We applied three irrigation treatments: Rainfed, supplementary irrigation (irrigation is applied when plant available water capacity (PAWC) < 30% and refilled to 70%), and non-limiting irrigation (irrigation is applied when PAWC < 50% and refilled to 100%). We tested four genotypes, which are promising to feature high drought stress tolerance, i.e., Morex, Golden Promise, BCC1589, HOR7985, and we used RGT Planet as a reference. We further tested two sowing patterns with a sowing density of 290 seeds/m², i.e., equidistant sowing in a triangular pattern with 6 cm distance between single plants vs. conventional row drilling at 11 cm row distance. The main traits we assessed during the growing season are plant spacing, above-ground biomass, and weekly, we assessed crop phenology, canopy height, leaf area index (LAI), as well as multi-spectral indices such as normal-ized differential vegetation index (NDVI), soil adjusted vegetative index (SAVI), crop water stress index (CWSI), etc. using the MicaSense-Altum camera, mounted on a copter. At harvest, we assessed yield and yield components. The uniform sowing pattern showed substantially stronger canopy coverage and significantly higher NDVI than conventional drill seeding for all five genotypes in early vegetative stages (39 days after sowing (DAS)). Later in the season, i.e., from 61 DAS to 91 DAS, we experienced a drought period that coincided with the flowering and beginning of the grain filling stage, resulting in a significant difference between irrigated and rainfed treatments. We observed the highest values of LAI under the irrigated treatments for the genotypes Golden Promise, BCC1589, and RGT planet. Under all irrigated treatments, we recorded a significantly higher grain yield for all genotypes, except for Morex. We observe a significant effect of sowing pattern on yield of the reference cultivar RGT Planet under rainfed and supplementary irrigation. The genotype Morex expresses drought tolerance traits, as it does not underperform under water stress; however, it generates significantly lower yields compared to the reference cultivar. Although we aim to identify drought tolerance traits, it is important that these traits do not relate negatively with yield and quality traits. [ABSTRACT FROM AUTHOR]

Comparative biology includes the comparison of transcriptome and quantitative real-time RT-PCR (qRT-PCR) data sets in a range of species to detect evolutionarily conserved and divergent processes. Transcript abundance analysis of target genes by qRT-PCR requires a highly accurate and robust workflow. This includes reference genes with high expression stability (i.e. low intersample transcript abundance variation) for correct target gene normalization. Cross-species qRT-PCR for proper comparative transcript quantification requires reference genes suitable for different species. We addressed this issue using tissue-specific transcriptome data sets of germinating Lepidium sativum seeds to identify new candidate reference genes. We investigated their expression stability in germinating seeds of L.   sativum and Arabidopsis thaliana by qRT-PCR, combined with in silico analysis of Arabidopsis and Brassica napus microarray data sets. This revealed that reference gene expression stability is higher for a given developmental process between distinct species than for distinct developmental processes within a given single species. The identified superior cross-species reference genes may be used for family-wide comparative qRT-PCR analysis of Brassicaceae seed germination. Furthermore, using germinating seeds, we exemplify optimization of the qRT-PCR workflow for challenging tissues regarding RNA quality, transcript stability, and tissue abundance. Our work therefore can serve as a guideline for moving beyond Arabidopsis by establishing high-quality cross-species qRT-PCR. [ABSTRACT FROM AUTHOR]

Heterobasidion annosum is a very destructive fungal pathogen causing massive losses on forest trees in the northern hemisphere. Tree infection usually takes place through the cut surface after felling. Phlebiopsis gigantea is commonly used as a biological control agent, applied directly after cutting on the stump surface. We investigated the interaction between both fungi in different gas compositions with lowered O2 (0.1% and 0.4%) and enhanced CO2 (15%) concentrations, imitating conditions as present on the wood surface and inside living wood tissue. When grown under 0.1% O2 and 15% CO2, fungal development of both species was altered, growth rate of P. giganteawas decreased and of H. parviporum slightly increased. Low O2 and high CO2 induced the formation of highly hydrophilic tissue with impaired conidia formation and germination capacity. In H. parviporum,this effect was more striking after 7 dpi with 45% reduced vitality, in P. gigantea after 14 dpi with 89% vitality reduction. These observations suggest that entering the tree through the cut surface is accompanied by altering fungal tissue to be more hydrophilic with a concurrent reduction of conidia formation and germination. Expression of the hydrophobin genes HAH1 and HAH2 of H. parviporum at ambient air decreased significantly in response to fungal interaction with P. gigantea. Gene expression was also influenced by O2 and CO2 content. Reduction of O2to 0.4% led to significantly decreased transcription rate of both HAH1 and HAH2 in single and dual cultures. [ABSTRACT FROM AUTHOR]