Overexpression of Myo-Inositol Oxygenase (TaMIOXA) Enhances the Drought and High-Temperature Resistance of Triticum aestivum L.

Wheat (Triticum aestivum L.) is the most widely cultivated staple food crop globally. As a primary food source for 35–40% of the world’s population, the stability of its yield is directly linked to global food security. However, extreme weather events triggered by climate change have led to reductions in wheat yield, resulting in an urgent need to enhance the stress tolerance of wheat against drought and high temperatures. In this study, we successfully isolated and cloned a myo-inositol oxygenase gene from wheat. Further research revealed that high temperatures and drought stress significantly increased the expression level of the TaMIOXA gene in wheat leaves. A batch of overexpressing lines was obtained via Agrobacterium-mediated transformation. Compared to the control group, wheat plants with molecularly modified TaMIOXA overexpression exhibited stronger resistance to high temperatures and drought. This significantly increased their survival rates by 10% to 40%. The cumulative amount of hydrogen peroxide decreased from 7.86 × 10−4 to 1.54 × 10−2 mmol/g, and that of malondialdehyde decreased from 8.42 × 10−7 to 2.21 × 10−6 mmol/g. This confirms that overexpression of myo-inositol oxygenase significantly enhances wheat’s tolerance to drought and high temperatures. This study offers valuable genetic resources for wheat stress tolerance.