Project description:When grown under phosphate (Pi) deficiency, plants adjust their developmental program and metabolic activity to cope with this nutritional stress. For Arabidopsis, the developmental responses include inhibition of primary root growth and enhanced formation of lateral roots and root hairs. Pi deficiency also inhibits photosynthesis by suppressing the expression of photosynthetic genes. Interestingly, early studies showed that photosynthetic gene expression was also suppressed in roots, a non-photosynthetic tissue. The biological relevance of this phenomenon, however, is not known. In this work, we characterized an Arabidopsis mutant, hps7, which is hypersensitive to Pi deficiency; the hypersensitivity includes an increased inhibition of root growth. HPS7 encodes a tyrosylprotein sulfotransferase (TPST). Accumulation of TPST proteins, but not mRNA, is induced by Pi deficiency. Comparative RNA-Seq analyses indicated that expression of many photosynthetic genes was activated in the roots of hps7. Under Pi deficiency, the expression of the photosynthetic genes in hps7 is further increased, which leads to the enhanced accumulation of chlorophyll, starch, and reactive oxygen species. The increased inhibition of root growth in hps7 under Pi deficiency was completely reversed by growing plants in the dark. Based on these results, we propose that suppression of photosynthetic gene expression in roots is required for sustained root growth under Pi deficiency.
Project description:To optimize access to nitrogen under limiting conditions, root systems must continuously sense and respond to local or temporal fluctuations in nitrogen availability. In Arabidopsis thaliana and several other species, external N levels that induce only mild deficiency stimulate the emergence of lateral roots and especially the elongation of primary and lateral roots. However, the identity of the genes involved in this coordination remains still largely elusive. In order to identify novel genes and mechanisms underlying nitrogen-dependent root morphological changes, we investigated time-dependent changes in the root transcriptome of Arabidopsis thaliana plants grown under sufficient nitrogen or under conditions that induced mild nitrogen deficiency.
Project description:Phosphate (Pi) deficiency alters root hair length and frequency as a means of increasing the absorptive surface area of roots. Three partly redundant single R3 MYB proteins, CAPRICE (CPC), ENHANCER OF TRY AND CPC1 (ETC1) and TRIPTYCHON (TRY), positively regulate the root hair cell fate by participating in a lateral inhibition mechanism. To identify putative targets and processes that are controlled by these three transcription factors (TFs), we conducted transcriptional profiling of roots from Arabidopsis thaliana wild-type plants, and cpc, etc1 and try mutants grown under Pi-replete and Pi-deficient conditions using RNA-seq.
Project description:Phosphate (Pi) deficiency impairs plant growth and productivity in many agricultural ecosystems, causing severe reductions in crop yield. To uncover novel aspects in acclimation to Pi starvation, we investigated the correlation between Pi deficiency-induced changes in transcriptome and proteome profiles in Arabidopsis roots.
Project description:Regulation of genes in shoots and roots and Arabidopsis in response to Zn-deficiency in wild-type and hma2 hma4 mutants plants We used microarrays to determine co-regulated genes in the roots of Zn deficient wild-type plants with hma2 hma4 plants from control conditions. These co-regulated genes are candidates for regulation by a systemic signal