RESUMEN
Aluminum (Al) toxicity significantly restricts crop production on acidic soils. Although rice is highly resistant to Al stress, the underlying resistant mechanisms are not fully understood. Here, we characterized the function of OsNIP1;2, a plasma membrane-localized nodulin 26-like intrinsic protein (NIP) in rice. Aluminum stress specifically and quickly induced OsNIP1;2 expression in the root. Functional mutations of OsNIP1;2 in two independent rice lines led to significantly enhanced sensitivity to Al but not other metals. Moreover, the Osnip1;2 mutants had considerably more Al accumulated in the root cell wall but less in the cytosol than the wild-type rice. In addition, compared with the wild-type rice plants, the Osnip1;2 mutants contained more Al in the root but less in the shoot. When expressed in yeast, OsNIP1;2 led to enhanced Al accumulation in the cells and enhanced sensitivity to Al stress, suggesting that OsNIP1;2 facilitated Al uptake in yeast. These results suggest that OsNIP1;2 confers internal Al detoxification via taking out the root cell wall's Al, sequestering it to the root cell's vacuole, and re-distributing it to the above-ground tissues.
RESUMEN
WD40 repeat proteins, the homologs of yeast MSI1, are conserved in plants, participating in protein complexes and playing fundamental functions in plant development. Although several MSI1-like proteins have been cloned and characterized in plants, the roles of MSI1-like proteins in the biennial ornamental plant, Dendrobium nobile Lindl, are still unclear. Here, we report the cloning of the DnMSI1 gene from Dendrobium nobile Lindl with RACE technology. We found that DnMSI1 expression was induced by GA3 and TDZ but inhibited by ABA, PP333, and drought and salt stress. Furthermore, DnMSI1 over-expression in Arabidopsis resulted in decreased tolerance to NaCl stress. These results suggest that DnMSI1 plays negative regulation roles in regulating salinity-stress resistance in Dendrobium nobile Lindl.