Evaluation of Fructan metabolism enzymes in contrasting barley (<i>Hordeum vulgare</i>) genotypes under drought stress

Abstract

In terminal drought conditions, the limitations on current photosynthesis can improve the influence of cereal stem carbohydrate reserves on preserving grain yield. This study investigated how the remobilization of stem fructans affects barley yield under drought conditions. The present study performed comparative physiological and gene expression analyses using flag leaf, penultimate, and peduncle tissues from four barley genotypes (G1, G2, G3, and G4). We examined the expression levels of fructan metabolism genes in drought-stressed leaf, stem penultimate, and peduncle tissues during the grain-filling stage, comparing them to those under normal conditions. Notably, genetic variability among the cultivars influences the expression of drought-responsive genes associated with tolerance. Specifically, genotypes 1 and 3 showed an up-regulation of fructan metabolism genes in response to drought, while genotypes 2 and 4 exhibited a down-regulation. Our findings indicated that increased fructan accumulation and its subsequent remobilization significantly contribute to the yield stability of G1 and G3 under drought stress conditions. Barley genotypes that demonstrate a strong capacity for fructan production and remobilization in response to terminal drought stress could serve as valuable resources for breeding programs aimed at improving drought tolerance through the selection of these traits.