The utilization of @entity6619 by diatoms has both global and small-scale implications, from oceanic primary productivity to nanotechnological applications of their @entity3440 cell walls. The sensing and transport of @entity4081 are key aspects of understanding diatom @entity6619 utilization. At low @entity4081 concentrations (<30  M), transport mainly occurs through @entity4081 transport proteins (SITs), and at higher concentrations it occurs through diffusion. Previous analyses of the SITs were done either in heterologous systems or without a distinction between individual SITs. In the present study, we examined individual SITs in @entity30860 in terms of transcript and protein abundance in response to different @entity4081 regimes and examined knockdown lines to evaluate the role of the SITs in transport, @entity3440 incorporation, and lipid accumulation resulting from @entity6619 starvation. SIT1 and SIT2 were localized in the plasma membrane, and protein levels were generally inversely correlated with cellular @entity6619 needs, with a distinct response being found when the two SITs were compared. We developed highly effective approaches for RNA interference and antisense knockdowns, the first such approaches developed for a centric diatom. SIT knockdown differentially affected the uptake of @entity6619 and the incorporation of @entity4081 and resulted in the induction of lipid accumulation under @entity6619 starvation conditions far earlier than in the wild-type cells, suggesting that the cells were artificially sensing @entity6619 limitation. The data suggest that the transport role of the SITs is relatively minor under conditions with sufficient @entity4081 . Their primary role is to sense @entity4081 levels to evaluate whether the cell can proceed with its cell wall formation and division processes.

Evidence for a regulatory role of diatom @entity6619 transporters in cellular XXXX responses.

@entity4081 :: ('MESH:D012824', 'Chemical') :: ['silicic acid'] @entity30860 :: ('35128', 'Species') :: ['Thalassiosira pseudonana'] @entity6619 :: ('MESH:D012825', 'Chemical') :: ['silicon'] @entity3440 :: ('MESH:D012822', 'Chemical') :: ['silica']
@entity6619 :: (MESH:D012825,Chemical) :: ['silicon']
