Interestingly, the repression of Pi starvation genes Volasertib order was shown to be specific for As, whereas the As induced genes Inhibitors,Modulators,Libraries were also Inhibitors,Modulators,Libraries induced by As. A model resulted that suggests arsenic acts via two separate signaling pathways. Because of the chemical similarity of As and Pi, As fools the Pi sensor, thus initiating the repression of the Pi starvation response. Although our microarray experiments did not detect dif ferential expression of any high affinity Pi transporter, which may be due to differences in experimental approach, Catarecha et al. illustrated the high sensi tivity of the Pi transporter, PHT1. 1, to As and sug gested that plants have evolved an As sensing system whereby As and Pi signaling pathways oppose each other to protect the plant from arsenic toxicity.

Based on our results, it is conceivable that the P type cyclin and ATPK19 may be involved in As sensing, but further study is required to confirm this finding. Our comparison of As repressed Inhibitors,Modulators,Libraries genes that have also been shown to be induced by Pi deprivation elucidate some promising candidates for future studies. For exam ple, we are particularly interested in genes with unknown function that are strongly induced in both roots and leaves by Pi starvation. Both at1g73010 and at1g17710 are described as phos phoric monoester hydrolases, but to our knowledge, these have not been studied in this regard. Most recently, a study described gene networks for the Arabidopsis tran scriptome based on the graphical Gaussian model of glo bal scale transcriptional studies.

In a constructed subnetwork of genes involved in phosphate starvation, SRG3, at1g73010, at3g17790, at2g11810, and at5g20790 were all closely linked, suggesting Inhibitors,Modulators,Libraries their critical roles in phosphate metabolism in Arabidopsis. Based on their strong induction in response to Pi starvation, it is reasonable to conceive Inhibitors,Modulators,Libraries that at1g73010 and at1g17710 have evolved as Pi scavengers for increasing Pi availability. We have confirmed the downregulation of these genes in response to As at both 3 and 10 day time points. In this study, at2g04460 transcript levels were strongly repressed at 3 and 10 day time points, whereas at5g20790 was repressed at day 3 and day 10. Interestingly, at2g04460 encodes for a putative retroelement pol polyprotein that has been reported as highly expressed in salt overly sensi tive Arabidopsis mutants.

Because the function of these two Pi starvation induced genes is unknown, these putative gene candidates may provide opportunities GW786034 for gaining insight into As Pi dynamics in Arabidopsis thaliana. The data presented here have led to the development of new hypotheses for future research. The potential antago nistic effects of various arsenate and Pi concentrations on the expression of the aforementioned genes in Arabidop sis are poorly understood.