As shown in Figure 4, the Cinoxacin expression levels of seven miRNAs were altered in the transgenic plants overexpressing GRF1 or GRF3. It is unlikely that GRF1 and GRF3 directly impact the expression of these miRNAs. Most likely, the expression of these miRNAs are altered as a results of positive or negative feedback regulation loops between these miRNAs and their STF-118804 targets that are regulated by GRF1 and/or GRF3. This assigns new and unexpected roles for these transcription factors in regulating the crosstalk between miRNA signaling networks. Our finding that GRF1 and GRF3 regulate the expression of all targets of miR169 from which 3 are co-regulated by both GRF1 and GRF3 suggests that the cross regulation is organized in a coordinated manner. Thus, GRF1/3 may fine tune the expression levels of co-regulated genes and members of multigene families with concomitant biological functions. Consistent with this hypothesis, several genes involved in flowering control and negatively regulated by miR169 or miR172 were identified as putative targets of GRF1/3. Similarly, genes involved in auxin signaling such as auxin response factors, NAC domain-containing proteins, and auxin signaling F box protein1, which are negatively regulated by miR167, miR164 and miR393, respectively, are also regulated by GRF1 or GRF3. It is of interest to find that GRF1 and 3 regulate the expression of their putative targets in a tissue-specific manner. Identifying a subset of putative targets of GRF1/3 that are specifically expressed in roots is consistent with the abundant expression of GRF1/3 in various root-tissue types and that overexpression of GRF1 or GRF3 impacts root growth and development. Also, several recent reports support a role of GRF family members in floral organ development. Our identification of several seed-specific genes as putative targets of GRF1/3 in the current study could illuminate the molecular events controlled by GRFs and required for precise floral organ initiation and development. In conclusion, our data provide new insights into the molecular events by which GRF1/3 directly or indirectly regulate a variety of biological processes to formulate a decisive coordination between plant growth and defense responses.