Ionome profiling discriminate genotype-dependent responses to drought in durum wheat

Abstract

Low-resource environments, such as dry or infertile soils, result in limited plant growth and development, which in turn constrain crop productivity. Water shortage is a significant threat to agricultural productivity all over the world. Drought may also affect plant nutrient uptake and assimilation capability causing nutrient deficiencies even in fertilized fields. Durum wheat is an important staple food crop for ensuring food security in the Mediterranean area, which is increasingly subjected to periods of severe drought due to global changes. Thus, identifying wheat cultivars/genotypes able to cope with suboptimal water, and with unbalanced nutrient availability deriving from drought is crucial to mitigate climate change's adverse effects on agriculture.

In this study, a detailed analysis of the phenome, including biomass production, proline production, and characterization of root system architecture, and the ionome, was performed on a panel of 15 Triticum turgidum genotypes, differing for drought tolerance, in order to understand the genotype-specific physiological responses to drought and to identify those genotypes characterised by a positive correlation between ion homeostasis and drought response. The characterization of root system architecture helped our understanding of the morphological responses of wheat plants to drought. Our findings demonstrated that drought exposure for 7 days significantly impacted the ionomic profiles of most genotypes in both shoot and root tissues, albeit to varying degrees. The Lcye A⁻B^- genotype showed the highest accumulation efficiency for most nutrients in shoots, while Bulel tritordeum and Karim in roots. It is also important to understand how micronutrients interact with each other and with macronutrients. Thus, we performed a nutrient correlation network analysis, which showed that drought altered the interactions between nutrients in most genotypes. These findings underscore the importance of understanding the mechanisms regulating nutrient homeostasis, as these mechanisms can either mitigate or exacerbate the impact of drought stress.

Understanding the interplay between ionomic profiles and environmental conditions can provide valuable insights into developing more resilient crops that can thrive in challenging environments, ultimately contributing to global food security in the face of climate change.