Short tandem target mimic rice lines uncover functions of miRNAs in regulating important agronomic traits

Abstract

Improvements in plant agricultural productivity are urgently needed to reduce the dependency on limited natural resources and produce enough food for a growing world population. Human intervention over thousands of years has improved the yield of important crops; however, it is increasingly difficult to find new targets for genetic improvement. MicroRNAs (miRNAs) are promising targets for crop improvement, but their inactivation is technically challenging and has hampered functional analyses. We have produced a large collection of transgenic short tandem target mimic (STTM) lines silencing 35 miRNA families in rice as a resource for functional studies and crop improvement. Visual assessment of field-grown miRNA-silenced lines uncovered alterations in many valuable agronomic traits, including plant height, tiller number, and grain number, that remained stable for up to five generations. We show that manipulation of miR398 can increase panicle length, grain number, and grain size in rice. In addition, we discovered additional agronomic functions for several known miRNAs, including miR172 and miR156. Our collection of STTM lines thus represents a valuable resource for functional analysis of rice miRNAs, as well as for agronomic improvement that can be readily transferred to other important food crops.small RNA | microRNA | silencing | yield | crop

A putative AGO protein, OsAGO17, positively regulates grain size and grain weight through OsmiR397b in rice

“…The expression levels of some miRNAs were changed in the OsAGO17 transgenic plants, such as OsmiR156j, OsmiR396c, OsmiR398b and OsmiR408, all of which have been reported to regulate seed development in rice (Jiao et al ., ; Zhang et al ., ,b), so there may be a complex regulatory network associated with OsAGO17. In addition, OsmiR397, OsmiR398 and OsmiR408 also play an important role in abiotic and biotic stress responses (Jia et al ., ; Lu et al ., ; Pan et al ., ).…”

“…Meanwhile, OsLAC can affect the sensitivity of BR (Zhang et al ., ). OsmiR398 promotes rice yield by increasing the grain number per panicle, grain size and grain weight (Zhang et al ., ,). OsmiR408 increases panicle branching and grain number to promote rice yield and targets the uclacyanin gene OsUCL18 (Zhang et al ., ,).…”

“…OsmiR398 promotes rice yield by increasing the grain number per panicle, grain size and grain weight (Zhang et al ., ,). OsmiR408 increases panicle branching and grain number to promote rice yield and targets the uclacyanin gene OsUCL18 (Zhang et al ., ,). AGOs are essential for miRNA‐mediated regulation of target gene expression, but it remains unclear which AGO affects these yield‐related characteristics via accumulation of sRNA.…”

Genome‐wide analysis of coding and non‐coding RNA reveals a conserved miR164‐NAC regulatory pathway for fruit ripening

“…Ade-MIR164b and STTM164 (short tandem target mimic, a method for destruction of endogenous miRNAs, Zhang et al, 2017) were constructed into SK. Ade-MIR164b and STTM164 (short tandem target mimic, a method for destruction of endogenous miRNAs, Zhang et al, 2017) were constructed into SK.…”

MicroRNAs and new biotechnological tools for its modulation and improving stress tolerance in plants

“…Then, these 21-nt amiRNAs are methylated by HEN1, which subsequently undergoes nucleus-cytoplasm transport by HST to P-bodies and becomes integrated into the RISC, where it will act in a manner similar to canonical miRNAs on PTGS. (b) Target mimicry strategy to deplete specific miRNAs (Peng et al, 2018;Zhang et al, 2017). The constitutive or transient expression of the target mimic gene driven by a specific promoter is transcribed by RNA polymerase II in the nucleus.…”