Pathogen-mediated priming induces intergenerational immunity against spot blotch in wheat.

Area of Science:

• Plant Pathology
• Crop Science
• Plant Immunology

Background:

• Spot blotch, caused by Bipolaris sorokiniana, significantly reduces wheat yield (Triticum aestivum) in warm, humid regions.
• Over-reliance on fungicides poses sustainability and environmental concerns, necessitating alternative disease management strategies.
• Defense priming, induced by mild stimuli, enhances plant resistance to subsequent stresses.

Purpose of the Study:

• To investigate the potential of attenuated Bipolaris sorokiniana spores as a priming stimulus to enhance wheat resistance against spot blotch.
• To evaluate 'green vaccination' using pathogen-mediated priming as a sustainable strategy for crop resilience.
• To assess the impact of priming on biochemical defenses, photosynthetic pigments, and yield traits.

Main Methods:

• Wheat plants were treated with a low-dose suspension of attenuated Bipolaris sorokiniana spores to induce pathogen-mediated defense priming.
• Disease severity was quantified by measuring the percent disease index.
• Biochemical analyses assessed photosynthetic pigments, antioxidant enzyme activities, lipid peroxidation, phenolic content, and PAL/POX activity. Yield traits and intergenerational effects were also evaluated.

Main Results:

• Primed plants (P+B) exhibited a 2.6-fold reduction in disease severity compared to non-primed controls (B).
• Significant increases were observed in photosynthetic pigments (chlorophylls, carotenoids), antioxidant defenses (SOD, CAT, APX, ascorbic acid, proline), and phenolic content.
• Yield traits, including spike number, spikelet fertility, and thousand grain weight (TGW), were enhanced, with benefits observed in the F1 generation (intergenerational immune priming).

Conclusions:

• Pathogen-mediated defense priming using attenuated Bipolaris sorokiniana spores is an effective 'green vaccination' strategy against wheat spot blotch.
• This approach enhances plant immunity, improves photosynthetic efficiency, boosts antioxidant capacity, and increases crop yield sustainably.
• The observed intergenerational immune priming highlights the potential for durable, transgenerational disease resistance in wheat.