SP1: Effect of Stress by Genotype Interactions on Above- and Below-Ground Carbon Allocation, Nutrient Use Efficiency and Root-Zone Processes

Climate change increases the likelihood of crops facing multiple stresses concurrently, yet research to date has largely focused on responses to individual stress factors. This subproject investigates how crops allocate their resources above- and below-ground under combined stresses conditions, establishing a link between plant traits and gene expression. The results will support the breeding of more resilient crop varieties and improve stress response models.

Project description

We have a fundamental lack of understanding of how resource use efficienciy and its allocation between above- and below-ground parts respond to concurrent, multiple stresses, which are likely to occur more frequently in the future due to accelerated climate change.

SP1 aims to establish an improved scientific basis for future advances in breeding by identifying key traits for good crop performance under favourable conditions, as well as those that contribute to tolerance to individual and combined stress factors.

Whilst the phenotypic plasticity of above-ground crop traits has been in the focus of modern agronomic studies for more than a century, similar approaches targeting root traits remain scarce. Detailed phenotyping of above-ground (chlorophyll fluorescence, stomatal conductance, nitrogen nutrition index, δ¹³C and δ¹⁵N) and below-ground traits (root morphology, anatomy, osmolytes, mycorrhization, mucilage secretion, rhizomicrobial enzyme activities), will be utilised in systematic field and greenhouse studies to investigate the distribution of carbon (C) and dry matter, as well as nutrient use efficiency above- and below-ground, including defence traits that influence the quality of above-ground biomass.

A person kneels between rows of maize plants, collecting a soil sample for MultiStress Research using a clear tube, with bottles and sampling equipment placed nearby on the ground.

The analysis of all traits will be linked to gene expression level parameters, such as mRNAseq and metabolome profiles, in order to link genotype and phenotype and to gain important insights into the mechanisms of stress response under tropical and temperate climatic conditions. Characterising the distribution of dry matter above- and below-ground, as well as and quantifying resource use under contrasting environmental factors and multiple stresses, will enable the derivation of crop and soil parameters required to describe genotype-specific responses to multiple concomitant stresses in the novel MultiStress model, thereby supporting model evaluation.

This is particularly important in maize cultivation, as maize occupies around 23% of arable land in Germany and 40% of arable land in Kenya, making it one of the most important crops in both countries.