Physiological, Biochemical and Molecular Response of Different Winter Wheat Varieties under Drought Stress at Germination and Seedling Growth Stage

Abstract

Due to climate change in recent years, there has been an increasing water deficit during the winter wheat sowing period. This study evaluated six Croatian winter wheat varieties’ physiological, biochemical, and molecular responses under two drought stress levels at the germination/seedling growth stage. Lipid peroxidation was mainly induced under both drought stress treatments, while the antioxidative response was variety-specific. The most significant role in the antioxidative response had glutathione along with the ascorbate-glutathione pathway. Under drought stress, wheat seedlings responded in proline accumulation that was correlated with the P5CS gene expression. Expression of genes encoding dehydrins (DHN5, WZY2) was highly induced under the drought stress in all varieties, while genes encoding transcription factors were differentially regulated. Expression of DREB1 was upregulated under severe drought stress in most varieties, while the expression of WRKY2 was downregulated or revealed control levels. Different mechanisms were shown to contribute to the drought tolerance in different varieties, which was mainly associated with osmotic adjustment and dehydrins expression. Identifying different mechanisms in drought stress response would advance our understanding of the complex strategies contributing to wheat tolerance to drought in the early growth stage and could contribute to variety selection useful for developing new drought-tolerant varieties.

Early Antioxidative Response to Desiccant-Stimulated Drought Stress in Field-Grown Traditional Wheat Varieties

“…[ 17 ] in the case of the exposure of wheat cultivars to severe drought stress. Decreased CAT activity in some Croatian wheat cultivars subjected to drought stress was also observed recently by Vuković et al [ 57 ]. Although the aforementioned studies demonstrated a similar response of CAT activity in wheat subjected to drought stress as the present investigation, there are a few important methodological distinctions to keep in mind.…”

“…Namely, the studies cited earlier were conducted under growth chamber conditions while this study presents the results obtained under field growing conditions. Furthermore, the study by Vuković et al [ 57 ] examined the response of wheat seedlings to drought stress, while the main focus of the present study was set to the response of flag leaf as one of the main photosynthesis sites in wheat determining the grain filling rate and yield [ 39 ]. On the contrary to CAT, APX and especially GPOD showed a higher sensitivity to drought stress, which is not surprising taking into account the higher affinity of APX for H 2 O 2 compared to CAT [ 11 ].…”

Analysis of Physiological Indicators Associated with Drought Tolerance in Wheat under Drought and Re-Watering Conditions

“…Drought stress reduces the uptake of CO 2 and subsequently reduces carbon fixation, saturating the electron transport system and forming ROS which, in turn, promote oxidative stress and lipid oxidation [ 26 , 40 ]. As the first enzyme in the antioxidant system, SOD plays a crucial role in preventing oxidative damage [ 35 ].…”

The Physiological Responses of Wheat and Maize Seedlings Grown under Water Deficit Are Modulated by Pre-Application of Auxin-Type Plant Growth Regulators

“…However, a decrease in these enzymatic activities was found in wheat. Vuković et al [ 48 ] reported different response of CAT activity depending on the genotype-specific differences and on drought intensity. Authors suggested that the lack of CAT amplification boosted lipid peroxidation in the affected varieties.…”