WP 2 – Increasing the Resilience of Cultivated Cereals

WP2-1 Drought Stress Epigenome of Cereals (TEPI)
PI – Prof. Dr. Klaus Humbeck (Dept. of Plant Physiology)
Institute of Biology, Faculty of Science 1, MLU

Postdoc – Natalia Svietlova

Periods of drought stress lead to significant yield losses worldwide, including in Central Germany. However, there are grain varieties that are drought-tolerant. Understanding the mechanisms of adaptation to drought stress is an essential prerequisite for future breeding of drought-tolerant grain varieties and their yield-reliable cultivation under changing climatic conditions. Recently, it has been shown that drought stress adaptation is controlled not only by the well-known regulation of gene expression via transcription factors but also by higher-level epigenetic mechanisms. However, research into the so-called drought stress epigenome in cereals is still in its infancy. In recent years, we have been able to establish a method to establish these epigenetic control mechanisms at the level of histone modifications and DNA methylation in the model cereal barley. Furthermore, we have identified Syrian landraces of barley that exhibit significantly increased resilience to drought stress compared to conventional grain varieties. The aim of this project proposal is to compare the drought stress epigenome of common elite varieties and tolerant varieties and to identify potential key players in drought stress resilience in cereals. The resulting data will be of crucial importance for future breeding and transgenic strategies to establish drought-resistant barley varieties.


WP2-2 NITROG(RE)EN – Establishment of Nitrogen-Fixing Associations to Optimize Productivity with Reduced Resource Use in Cereals
PI – Prof. Dr. Edgar Peiter (Dept. of Plant Nutrition)
Institute of Agricultural and Nutritional Sciences, Faculty of Science 3, MLU

Postdoc – Farheen Saifi

Crop productivity is heavily constrained by the limited availability of mineral nitrogen. The industrial production of nitrogen fertilizers via the Haber-Bosch process, converting atmospheric nitrogen (N₂) to ammonia (NH₃), is highly energy-intensive and a major source of CO₂ emissions in agriculture. Moreover, both mineral and organic nitrogen fertilizers contribute to significant environmental challenges such as eutrophication and soil degradation. This project aims to establish a sustainable, symbiotic nitrogen supply in cereal crops as an alternative to synthetic fertilization. Biological nitrogen fixation, carried out by certain bacteria and archaea via the enzyme nitrogenase, converts atmospheric N₂ into plant-usable NH₃. Agricultural symbiosis with nitrogen-fixing rhizobia is well established but is restricted to legumes, which generally exhibit lower yield stability and productivity. Attempts to engineer rhizobia symbioses in cereals using synthetic biology have faced major obstacles due to the specificity and complexity of the legume-rhizobia interaction. However, certain N₂-fixing cyanobacteria (blue-green algae) naturally form symbiotic relationships with a diverse range of plant hosts, from mosses to flowering plants. Recent findings have shown that such symbioses can occur in cereals like wheat and rice. Notably, the interaction in rice appears to involve the Common Symbiosis Signaling Pathway (CSSP), a molecular signaling route also used in mycorrhizal associations, suggesting a shared mechanism that could be leveraged in crop engineering. This project will focus on characterizing and enhancing the symbiosis between nitrogen-fixing cyanobacteria and barley as a model cereal crop. Key objectives include:

  • Monitoring colonization and symbiosis using confocal microscopy.
  • Quantifying nitrogenase activity via acetylene reduction assays and ¹⁵N₂ isotope labeling.
  • Deciphering molecular mechanisms through CRISPR/Cas9-mediated knockout of CSSP-related genes.
  • Investigating signaling dynamics using genetically encoded calcium (Ca²⁺) reporters to assess the role of oscillatory Ca²⁺ signals in symbiotic establishment.
  • Assessing genetic variability in symbiotic potential by performing a genome-wide association study (GWAS) on 250 sequenced barley genotypes from the IPK collection.

The results will provide foundational insights for establishing functional cyanobacterial symbioses in cereals, offering a scalable, low-emission alternative to synthetic nitrogen fertilization in agriculture.

WP2-3 Optimization of Natural Resistance Mechanisms of Maize Against Pests
PI- Prof. Dr. Jörg Degenhardt (Dept. of Pharmaceutical Biotechnology)
Institute of Pharmacy, Faculty of Science 1, MLU

Postdoc – Janik Telleria Marloth

Herbivorous pests are a major cause of yield loss in temperate agricultural systems. This problem is exacerbated by climate change and the prevalence of monocultures,often a result of localized agricultural planning, which leave crops increasingly vulnerable to pest infestation. This project focuses on enhancing the innate defense mechanisms of maize (corn) to improve resistance against herbivorous pests, with a particular emphasis on root-feeding species such as the Western corn rootworm (Diabrotica virgifera). Plants defend themselves against herbivory by producing toxic compounds or signaling molecules that attract natural enemies of the pests. In maize, both leaves and roots respond to herbivore attack by synthesizing defense-related compounds, including volatile mono- and sesquiterpenes. The root response is especially crucial for resistance to D. virgifera, a pest that has become established in southern Germany and is projected to spread further due to global warming. Its resilience to conventional pesticides makes the development of innate resistance particularly urgent. Despite the ecological importance of these natural defenses, the genetic regulation of defensive terpene production in maize remains poorly understood and has not been leveraged in conventional breeding programs. In previous work, we used genome-wide association studies (GWAS) to identify a basic helix-loop-helix (bHLH) transcription factor that regulates the synthesis of these terpenes. A 41-nucleotide deletion in this gene disrupts its function, highlighting its non-redundant and essential role in maize’s defense response. The current project aims to:

  • Functionally characterize the bHLH transcription factor, determining its role in regulating terpene biosynthesis during pest infestation.
  • Identify interacting proteins and downstream target genes within the regulatory network to better understand the underlying molecular cascade.
  • Elucidate the genetic basis of terpene-mediated defense responses to identify novel targets for resistance breeding in maize.

Ultimately, this work will provide a molecular framework for breeding maize varieties with enhanced resistance to root and leaf herbivores, using natural plant defense mechanisms as a sustainable alternative to chemical pesticides.


WP2-4 Investigation and Optimization of Cytoplasmic Male Sterility Lines of Barley
PIs- Dr. Etienne Meyer/Prof. Dr. Kristina Kühn (Department of Cell Physiology)
Institute of Biology, Faculty of Natural Sciences 1, MLU

Postdoc – Dr. Sarlita Dwiani

Modern plant breeding relies on hybrid seed production, which requires male-sterile parent lines. Cytoplasmic male sterility (CMS), caused by mitochondrial genes that impair pollen development, has long been used for this purpose, though its molecular basis remains poorly understood. Our research group has identified mitochondrial factors involved in CMS in field beet (Beta vulgaris) and tobacco (Nicotiana tabacum), revealing changes in the oxidative phosphorylation system. Using mitochondrial genome editing, we successfully induced CMS in tobacco, providing a model for translation to crops like barley (Hordeum vulgare). Barley already has two CMS lines (msm1 and msm2), but their use is limited by unreliable sterility at elevated temperatures, a growing concern under climate change. This project aims to identify the molecular basis of CMS and its temperature sensitivity in barley using next-generation sequencing and proteomics to compare CMS and fertile lines at different temperatures. Based on these insights, we will pursue two strategies to generate transgene-free, thermostable CMS barley:

  1. Mitochondrial genome editing in transformable barley lines.
  2. Cytoplasmic transfer and editing of the CMS locus in msm1 or msm2 backgrounds.

These improved CMS systems will then be transferred to other barley varieties via conventional breeding. The project will build on existing expertise at MLU and the university’s new plant transformation and genome editing platform.