Distinct Evolutionary Profiles and Functions of microRNA156 and microRNA529 in Land Plants

Area of Science:

• Plant molecular biology
• Genomics
• Evolutionary biology

Background:

• MicroRNA156 (miR156) and miR529 share high sequence similarity and target the same SQUAMOSA promoter binding protein-like (SPL) genes.
• Distinguishing the specific roles of miR156 and miR529 in plant regulatory networks is challenging due to their overlapping targets.

Purpose of the Study:

• To dissect the evolutionary and functional differences between miR156 and miR529 family members in land plants.
• To develop a method for rapid identification of miR156 and miR529 family members.
• To provide insights into their distinct regulatory roles in plant development.

Main Methods:

• Comparative sequence analysis of miR156 and miR529 family members.
• Phylogenetic analysis to determine evolutionary patterns.
• Small RNA sequencing and Parallel Analysis of RNA Ends (PARE) to identify targets and expression patterns.

Main Results:

• miR156 and miR529 exhibit differences in mismatch-sensitive regions crucial for target recognition.
• Precursor conservation patterns differ: miR156 precursors are conserved in the hairpin region, while miR529 precursors are conserved outside the hairpin.
• Phylogenetic analysis indicates independent evolution of MIR156 and MIR529 genes.
• MIR529 shows preferential expression in reproductive tissues, whereas MIR156 is expressed in other tissues.
• PARE analysis in maize revealed both common and specific targets for miR156 and miR529, confirming functional divergence.

Conclusions:

• miR156 and miR529 have diverged in their evolution and possess distinct regulatory functions.
• Differences in target recognition, precursor conservation, and expression patterns contribute to their specialized roles.
• The study provides a novel method for identifying these microRNA families and enhances understanding of plant gene regulation.