Roles of Non-Coding RNA in Sugarcane-Microbe Interaction

Area of Science:

• Plant molecular biology
• Genomics
• Biochemistry

Background:

• Non-coding RNAs, including microRNAs (miRNAs), are crucial regulators in plant-microbe interactions.
• The specific roles of sugarcane miRNAs in disease response remain largely unexplored.

Purpose of the Study:

• To investigate the function of sugarcane miRNAs in response to pathogenic bacteria, specifically *Acidovorax avenae*.
• To identify novel miRNAs and understand their regulatory mechanisms in sugarcane immunity.

Main Methods:

• Small RNA (sRNA) transcriptome sequencing of sugarcane infected with *A. avenae*.
• Bioinformatic analysis of miRNA and small interfering RNA (siRNA) sequences.
• Quantitative reverse transcription-PCR (qRT-PCR) for miRNA expression validation.
• 5' rapid amplification of cDNA ends (5'RACE) assay to confirm miRNA target cleavage.

Main Results:

• Identified conserved and novel miRNAs and siRNAs in sugarcane infected with *A. avenae*.
• Observed differential regulation of miR408, a copper-microRNA, which was downregulated during pathogen infection but upregulated with beneficial bacteria.
• Confirmed miR408 targets, including a laccase, demonstrating its role in post-transcriptional gene silencing.
• siRNAs targeting a copper-transporter gene were repressed upon *A. avenae* infection.

Conclusions:

• Sugarcane employs specific miRNA-mediated regulatory mechanisms to distinguish between pathogenic and beneficial microorganisms.
• miR408 is a key regulator in sugarcane's response to microbial stimuli, influencing disease resistance and beneficial interactions.
• This study provides insights into the complex non-coding RNA-based defense strategies in plants.