The IbmiRn01-IbSEN1-Ibcirc560 module regulates chilling tolerance in sweetpotato

Area of Science:

• Plant Molecular Biology
• Stress Physiology
• Agricultural Science

Background:

• Chilling stress significantly limits sweetpotato yield and productivity.
• Understanding cold signal perception is key to enhancing sweetpotato's low-temperature resilience.

Purpose of the Study:

• To identify novel regulatory elements involved in sweetpotato chilling stress response.
• To elucidate the molecular mechanisms underlying chilling tolerance in sweetpotato.

Main Methods:

• Identification of a novel chilling-induced microRNA (IbmiRn01).
• Analysis of gene regulation involving IbSEN1 (RNA helicase family) and Ibcirc560 (circular RNA).
• Generation of transgenic sweetpotato plants (overexpression, RNAi, STTM) to assess chilling tolerance phenotypes.

Main Results:

• IbmiRn01 enhances chilling tolerance by targeting and cleaving IbSEN1 mRNA; IbSEN1 acts as a negative regulator.
• Overexpression of IbmiRn01 or knockdown of IbSEN1 improved chilling tolerance, modulated cold signaling genes, and increased antioxidant activity.
• IbSEN1 promotes IbACD5 transcription, interacts with IbHSP90, and represses Ibcirc560 expression, while Ibcirc560 overexpression increases chilling sensitivity.

Conclusions:

• A novel regulatory network (IbmiRn01-IbSEN1-Ibcirc560) fine-tunes chilling tolerance in sweetpotato.
• This network provides potential genetic targets for breeding improved chilling-tolerant sweetpotato varieties.