This study investigated the effects of explant type, plant growth regulator concentration, callis status, medium conversion time, and medium tilt on the growth of rose somatic embryos. The results showed that Rosa chinensis cv. ‘Parson’s Pink China’ leaves could induce normal embryogenic calli but petioles could not. When the 2,4-dichlorophenoxyacetic acid concentration was 3.0 mg/L, the callis induction rate was the highest in the embryo proliferation medium (EP medium) supplemented with 0.5mg/L kinetin, and white and reddish-brown translucent calli were the main type of embryogenic calli induced. As the culture time in EP medium was extended, the relative induction rate for secondary embryos and multicotyledon secondary embryos gradually increased when transferred to embryo maturation medium (EM medium), but the induction rate for somatic embryos decreased. Placing the EM medium at an angle of 45° made the somatic embryos germinate faster and the germination rate was also higher. The germination buds produced by the somatic embryos with two cotyledons showed the fastest germination and greatest survival rates. The results of this experiment will help improve somatic embryo regeneration rates and explore new ways of regeneration, and lays the foundation for further optimization of the somatic embryo genetic transformation system.
SummaryTo study the function of a miRNA, it is necessary to identify its target genes. The most common methods to reveal miRNA target genes rely on ectopically expressed tagged Ago2 and nonphysiological overexpression or inhibition of the miRNA of interest. To uncover the natural association between miRNAs and their target genes, we isolated endogenous Ago2 protein followed by a selective strategy, which only amplified target genes of the selected miRNA from the purified RNA-induced silencing complex by miRNA specific primers. This enabled us to identify the mRNAs regulated by miRNAs of interest. Our data demonstrated that this strategy is effective and highly credible. Moreover, our results showed the evidence of efficient miRNA target sites in 5 0 untranslated regions and open reading frames of target mRNAs.
IUBMBIUBMB Life, 62(10): 752-756, 2010
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