Novel cuticle regulators in maize and their impact on abiotic and biotic stress responses

• Applicant: Dr. Susanne Matschi
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2017 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 380688791

The cuticle is the outer physical barrier of the aerial plant parts and establishes an important interaction surface with the environment. This impregnating epidermal coat, consisting of the lipid polymer cutin embedded with and covered by a wide range of cuticular waxes, provides protection against a multitude of environmental stresses like desiccation, UV radiation or pathogen attack. Thickness, structure, and chemical composition of the cuticle vary widely between different organs, developmental stages, or growth conditions, and between species. The potential functional consequences of such differences are poorly understood. The goal of this project is the identification and elucidation of new key components responsible for functional cuticle development in maize. In crop plants, the identity and in planta roles of many genes involved in cuticular wax biosynthesis, transport, and their regulation remain elusive. The functional contribution of the maize cuticle and its components to abiotic and biotic stress responses of the maize plant have been rarely studied so far, and especially the genetic regulation and impact of the cuticle on the adult, agronomically most important growth phase is completely unknown. The proposed project uses a dual approach to address these issues. Firstly, it aims to identify and characterize new key players of cuticular wax deposition in a forward genetics approach. Several new mutants with defects in cuticular wax deposition have been isolated, which will be characterized, and identification of the causal mutation will be achieved via next-generation sequencing methods. Secondly, for the first time, the biological functions of these and other cuticle genes and mutations will be analyzed with a focus on the adult leaf cuticle biogenesis, utilizing a collection of diverse cuticle mutants. Biochemical and structural changes of the cuticle will be correlated with functional consequences in cuticle-related agronomically important traits like drought tolerance and pathogen resistance. Next to the analysis of cuticular permeability and specific water loss across the cuticle, comparisons will be made with respect to drought tolerance and resistance to pathogens infecting the plant via cuticle penetration. The functional characterization of juvenile and adult growth stages allows extensive comparisons for the importance of the respective components in the different growth stages. The aim of this project is the further elucidation of cuticle biosynthesis in maize and to gain knowledge about the function of specific cuticular components with a particular focus on the adult growth stage of maize. These findings can contribute to the development of strategies for crop plant optimization in environmental challenges such as water limitation or pathogen attack, in order to ultimately serve growing requirements for agricultural production and to ensure food security in the future.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Laurie G. Smith