Abstract
With the aim of providing genetic materials for breeding drought-resistant wheat varieties, the physiological and metabolic plasticity of three drought-resistant wheat multiple synthetic derivative lines (MSDLs) and their backcross parent “Norin 61” (N61) were evaluated in response to drought stress. The results indicated that the D-genome introgressions from Aegilops tauschii into the MDSLs improved their drought-adaptive traits. Specifically, MNH5 and MSD345 showed higher photosynthesis rates and triose phosphate utilization than N61 under control conditions, resulting in greater accumulation of glucose and sucrose in the shoots. However, under drought stress, MNH5 and MSD345 had higher intrinsic water use efficiency than MSD53 and N61. The total antioxidant capacity and superoxide dismutase activity increased in all three MSDLs, whereas no significant changes were found in N61 in response to drought stress. Metabolome analysis identified six common drought-induced metabolites in all of the investigated genotypes. However, four metabolites (adenine, gamma aminobutyric acid, histidine, and putrescine) each specifically accumulated in an MSDL in response to drought stress, suggesting that these metabolites are important for MSDL drought resistance. In conclusion, MNH5 and MSD345 showed better adaptive responses to drought stress than MSD53 and N61, suggesting that these two MSDLs could be explored for breeding drought-resistant wheat lines.
Highlights
Persistent droughts and reductions in the quantity and quality of water resources are considered major environmental constraints affecting global wheat (Triticum aestivum) production [1].Drought episodes are not limited to dryland regions, but are increasingly impacting European farmlands due to the current climate change scenario [2]
MSD53 had high yield under control and drought conditions compared with Norin 61 (N61), a local Sudanese cultivar (Imam), and MSD345
MSD53 had low drought tolerance efficiency compared with MSD345
Summary
Persistent droughts and reductions in the quantity and quality of water resources are considered major environmental constraints affecting global wheat (Triticum aestivum) production [1].Drought episodes are not limited to dryland regions, but are increasingly impacting European farmlands due to the current climate change scenario [2]. To maintain sustainable wheat productivity under water-deficit conditions, it is imperative to improve wheat drought resistance. Drought resistance has been categorized into four mechanisms: escape, avoidance, tolerance, Agronomy 2020, 10, 1588; doi:10.3390/agronomy10101588 www.mdpi.com/journal/agronomy. Drought escape involves the reprogramming of plant phenology, resulting in a short lifecycle or increased developmental plasticity [5]. Drought avoidance comprises physiological and morphological responses such as stomatal closure and root elongation, which maintain high water status by improving water uptake or reducing water loss under dry conditions [4]. Drought tolerance refers to the capacity of plants to maintain cellular function under water-deficit conditions by improving the osmotic adjustment, antioxidant capacity, and metabolic homeostasis [3]
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