Circular RNA Vv-circCOR27 modulates thermotolerance through attenuating VvHSP90.2b-VvHsfA7a interaction in grapevine

Area of Science:

• Plant molecular biology
• RNA biology
• Stress physiology

Background:

• Circular RNAs (circRNAs) are key regulatory molecules in plants, but their functions remain largely unexplored.
• Understanding circRNA regulatory mechanisms is crucial for enhancing plant stress tolerance.

Purpose of the Study:

• To investigate the function and regulatory mechanisms of grapevine circRNA Vv-circCOR27.
• To elucidate the role of Vv-circCOR27 in plant thermotolerance.

Main Methods:

• Genetic transformation, circRNA pull-down assays, and ribonucleoprotein immunoprecipitation (RIP).
• Utilized a circRNA trimolecular fluorescence complementation (cTriFC) system.
• Overexpression of Vv-circCOR27 using a specialized expression cassette.

Main Results:

• Vv-circCOR27 expression decreased under heat stress and was lower in thermotolerant grapevine cultivars.
• Overexpression of Vv-circCOR27 enhanced thermotolerance in grapevine.
• Vv-circCOR27 directly binds to VvHSP90.2b, inhibiting VvHsfA7a interaction and downregulating small heat shock protein (sHSP) genes.

Conclusions:

• Vv-circCOR27 fine-tunes thermotolerance by competitively binding VvHSP90.2b.
• This interaction attenuates VvHsfA7a binding and subsequent transactivation of heat stress response genes.
• The study advances the understanding of circRNA regulatory mechanisms in plant heat stress response.