MicroRNAs associated with AGL6 and IAA9 function in tomato fruit set

Area of Science:

• Plant biology
• Molecular genetics
• Reproductive biology

Background:

• Fruit set in tomatoes is regulated by downregulating ovary growth repressors like Auxin/indole-3-acetic acid 9 (IAA9) and Agamous-like 6 (AGL6).
• Previous research established methods to silence IAA9 and AGL6 in tomato ovaries using exogenous dsRNAs and confirmed siRNA presence.

Purpose of the Study:

• To identify microRNAs (miRNAs) that are differentially expressed in tomato ovaries following the silencing of IAA9 and AGL6.
• To leverage existing small RNA libraries from silenced ovaries for miRNA discovery.

Main Methods:

• RNA sequencing of small RNA libraries from IAA9- and AGL6-silenced tomato ovaries.
• Comparison of miRNA expression profiles against unpollinated control ovaries.
• Validation of specific miRNA expression using stem-loop qRT-PCR.

Main Results:

• Identification of 125 known and 509 novel miRNAs (mature sequences) and 104 known and 516 novel miRNAs (hairpin sequences).
• Differential expression of 7 known miRNAs in IAA9-silenced ovaries and 45 in AGL6-silenced ovaries compared to controls.
• Discovery of 6 common differentially expressed miRNAs between both silencing experiments, including miR393 and miR482e-5p.

Conclusions:

• The study identified a pool of regulatory small RNAs, specifically miRNAs, implicated in tomato fruit initiation.
• The identified miRNAs, particularly those common to both silencing experiments, are potential key players in regulating tomato fruit set.