Characteristic Dissection of Xanthomonas oryzae pv. oryzae Responsive MicroRNAs in Rice

Area of Science:

• Plant Pathology
• Molecular Biology
• Genetics

Background:

• MicroRNAs (miRNAs) are key regulators in plant-pathogen interactions.
• The specific roles of rice miRNAs in defense against Xanthomonas oryzae pv. oryzae (Xoo) require further elucidation.

Purpose of the Study:

• To investigate the dynamic changes in rice miRNAs during Xoo infection.
• To identify miRNA-target regulatory units involved in rice-Xoo interplay.
• To functionally validate the role of specific miRNAs and their targets in rice immunity.

Main Methods:

• Small RNA sequencing and degradome technology were employed to profile miRNAs and their targets in rice varieties IR24 and IRBB5 post-Xoo infection.
• Quantitative real-time stem-loop reverse transcription-polymerase chain reaction (RT-PCR) validated sequencing data.
• Bioinformatic analysis identified differentially expressed miRNAs and regulatory units.

Main Results:

• A total of 80 regulatory units, comprising 29 differentially expressed known miRNAs and 38 cleaved targets, were identified during infection.
• Differentially expressed miRNAs were categorized into three immunity-related clusters.
• Overexpression and disruption experiments confirmed the functional roles of osa-miR164a, osa-miR167d, and osa-miR159b in regulating rice defense against Xoo.

Conclusions:

• Specific miRNA-target interactions, such as osa-miR164a/OsNAC60, osa-miR167d-5p/OsWD40-174, and osa-miR159b/OsMYBGA, OsLRR-RLK2, OsMPK20-4, play critical roles in rice-Xoo interactions.
• Modulating these regulatory units offers a potential strategy to control rice defense responses against Xoo infestation.
• This study provides novel insights into the complex regulatory network of miRNAs in rice immunity.