Harnessing drought-induced immune priming for intergenerational resistance to spot blotch in wheat

Abstract

Drought priming has proven to be an effective strategy in modern agriculture for enhancing crop resistance to pathogens. However, the biochemical and metabolic mechanisms underlying these protective effects under biotic stress remain insufficiently understood, offering a valuable opportunity for further research. This study demonstrates that drought-induced priming in wheat (Triticum aestivum) not only improves resistance to Bipolaris sorokiniana (spot blotch) but also transfers this protection to the subsequent generation (G1). Using growth metrics, disease assessments, biochemical analysis, and yield evaluations, we found that progeny of drought-primed plants showed enhanced defense responses under pathogen stress, despite no morphological differences in stress-free conditions. Significant increases in photosynthetic pigments-chlorophyll a (3.80-fold), chlorophyll b (3.27-fold), and carotenoids (2.69-fold) were observed, along with key stress markers like proline (1.78-fold), total phenolics (1.30-fold), and ascorbic acid (2.30-fold). The progeny also exhibited an 8.37-fold reduction in malondialdehyde (MDA) levels, indicating reduced oxidative damage. Under biotic stress, drought-primed progeny displayed increased activities of antioxidant enzymes, including superoxide dismutase (2.35-fold), catalase (2.48-fold), and ascorbate peroxidase (3.37-fold), along with upregulated defense enzymes like peroxidase (1.44-fold), phenylalanine ammonia-lyase (1.97-fold) and chitinase (1.88-fold). These biochemical adjustments optimized resource allocation for both growth and defense. Additionally, drought-primed progeny showed improved yield performance compared to non-primed progeny under stress.

Our findings highlight drought-induced intergenerational priming as a sustainable, chemical-free strategy for long-term crop protection, offering a path toward resilient crop varieties in the face of global climate challenges.