Overexpression Microrna167 Transgenic Plant Research

The plant hormone auxin plays a critical role in the regulation of plant growth and development. Many advances have been made in understanding of auxin signal-response pathways in recent years, mainly by characterizations of auxin response mutants in Arabidopsis. In addition, small RNAs have been widely considered to be the endogenous signals directing many physiological processes to respond to the endogenous and environmental signals. However, the cross talk between plant RNA signals and hormone signals are not clear. Here we report that microRNA167, for which the sequence matches those of ARF6 (AUXIN RESPONSE FACTOR 6) and ARF8, can cause transcript degradation of ARF8 and may result in translational repression of ARF6 mRNAs. Transgenic lines carrying a 35S::MICRORNA167b fusion results in plants with aberrant morphology for all four whorls of floral organs, and the male fertility was dramatically reduced. Detailed phenotypic analysis revealed that anthers in the transgenic plants failed to open properly and filaments become rather short, which may be the main reasons for the poor fertility of the 35S::MICRORNA167b transgenic plants. In addition, 35S::MICRORNA167b plants also showed a long hypocotyl, mimicking the phenotypes of the arf8 mutant. Together, our results provide an important linker between RNA and auxin signal pathways, and reveal functions for the ARF6 and ARF8 genes in plant development. The Arabidopsis ASYMMETRIC LEAVES2 (AS2) gene is required for the establishment of leaf adaxial-abaxial polarity and the repression of the class I KNOX genes in leaves. The predicted AS2 protein shares high levels of sequence similarity to those of additional 41 predicted proteins in a gene family, but AS2 is the only one with the known functions in plant lateral organ morphogenesis. The members of this family except AS2 have been named ASLs (AS2-like genes). We characterized ASL10 and ASL11 using the reverse genetic approach. We found that overexpression of ASL10 and ASL11 resulted in several similar phentypes, showing small stature, compact inflorescence, short flower organs, and sterile flowers. These results provide useful information towards the understanding of ASL10 and ASL11 functions.