microRNA396 is a coordinative regulator that can be modulated to reconcile the reverse relationship between fruit size and quality in tomato

The microRNA396 (miR396) family is a group of small, non-coding RNA molecules that regulates expression of growth-regulating factors (GRFs) in plants. In this study, the researchers used short tandem target mimic (STTM) and artificial miRNA (amiRNA) techniques to either decrease or increase the expression of miR396 in tomatoes to investigate its role in regulating organ size and nutrition accumulation. Decreasing the expression of miR396 increased organ size, total soluble solids (TSS), and secondary metabolites in the fruits. The researchers also observed that increased miR396 expression reduced fruit size and weight but promoted the growth of axillary buds. These results suggest that modulating the expression of miR396 may be a way to improve the productivity and quality of tomatoes by reconciling fruit size and nutrition. Analysis of mRNA profiling in tomato fruits from mature-green and red-ripe stages in the three genotypes, STTM396, amiR396, and the wild-type, demonstrated an accountable altered expression of genes involved in photosynthetic capacity, sugar synthesis and unloading, and starch synthesis. The researchers tentatively concluded that modulating miR396 expression in tomatoes could be a useful approach for improving both productivity and quality through genetic modifications. Overall design: In this study, we used short tandem target mimic (STTM) and artificial miRNA (amiRNA) technologies to generate a set of experimental materials with up- or down-regulated miR396 expression and studied the effect of miR396 on fruit size, productivity, and quality in tomatoes.