Abstract
NIP5;1 encodes s a boron (B) channel required for normal plant growth under low B conditions and its transcript accumulation is upregulated under low B conditions. At the annual meeting last year, we reported that at least +182-+200 region of 5'untranlated region (5'UTR) is important for NIP5;1 transcript accumulation in response to low B.
To elucidate mechanisms of NIP5;1 regulation in response to B, the half-life of NIP5;1 mRNA was estimated by determining time course of mRNA decay after exposure to an RNA synthesis inhibitor under the high and low B conditions. We established constructs carrying either intact 5'UTR or 5'UTR without the sequence from +182 to +200 between the GUS reporter gene and the cauliflower mosaic virus 35S RNA promoter. In transgenic plants carrying the intact 5'UTR, the GUS mRNA level under the high B condition more rapidly decreased compared to the low B condition. In transgenic plants carrying the 5'UTR without +182-+200 construct, GUS mRNA level was not significantly different between B treatments. These results indicated that the sequence from +182 to +200 is required for B-dependent mRNA degradation.
