Project description:Comparison of gene expression between cna-2 phb-13 phv-11, cna-2 phb-13 phv-11 rev-6, and wild type (Col er-2) in 0.5 mm root tips of Arabidopsis.
Project description:Total mRNA was extracted from the root tips (2-3 mm from the root apex) of wild-type plants (Col-0 accession) and med16-2 mutants grown under low and high phosphate conditions 4 days after germination, using and sequenced by RNA-seq methodology.
Project description:Total mRNA was extracted from the root tips (10 mm from the root apex) of wild-type plants (Col-0 accession) and stop1 mutants grown 5 days after germination under optimum conditions and then transferred for 16 hours to low phosphate(Pi), low pH, Al and Fe excess mediums.
Project description:Our objective is to study root stem cell niche. We isolated total RNA from the roots tips of 5-day-old Col-0,arf2-7 and stop1 seedlings. New genes after responding to NAA treatment, during the root development, are discovered.
Project description:Phosphate limitation constrains plant development in natural and agricultural systems. Under phosphate-limiting conditions plants activate genetic, biochemical and morphological modifications to cope with phosphate starvation. One of the morphological modifications that plants induce under phosphate limitation is the arrest of primary root growth and it is induced by the root tip contact with low phosphate media. The sensitive to proton rhizotoxicity (stop1) and aluminium activate malate transporter 1 (almt1) mutants of Arabidopsis thaliana continue primary root growth under in vitro Pi-limiting conditions, thus, to get insight into the molecular components that control primary root growth inhibition under low phosphate conditions we extracted and sequenced mRNA from the root tips (2-3 mm from the root apex) of wild-type plants (Col-0 accession) and low-phosphate-insensitive mutants almt1 and stop1 grown under low and high phosphate conditions 5 days after germination using an RNA-seq methodology.
Project description:We report the discovery of a root growth program in Arabidopsis that is independent of a functional quiescent center (QC). In this regulatory program, PHABULOSA (PHB), posttranscriptionally regulated by SHR and SCR, plays a central role. In phb shr and phb scr mutants, root meristem/growth activity recovers significantly. Interestingly, this recovery does not accompany the resurgence of QC cells. PHB regulates apical root growth in stele cells of the root meristem, located proximal to the QC. Our genome-wide investigation suggests that PHB exerts its influence on root growth by regulating auxin-cytokinin homeostasis. Apical root growth was restored when cytokinin levels were genetically reduced in the shr mutant. Conversely, when miRNA-resistant PHB was expressed in the root stele cells, apical root growth and meristem functions were significantly inhibited without blocking the QC identity. Taken together, our investigation reveals two mechanisms through which SHR regulates root growth and stem cell activities: one is to specify and maintain the QC and the other is to regulate the proximal meristem activity through PHB and cytokinin. In this regulation, QC seems to be more involved in maintaining the “growth signal” and thus ensure the indeterminate root growth.
Project description:The class III HD-ZIP transcription factors regulate vascular patterning in Arabidopsis thaliana roots. In this expression study we compare the expression profile of the cna-2 phb-13 phv-11 and cna-2 phb-13 phv-11 rev-6 mutants to their wild type. The results are presented in PHABULOSA mediates an auxin signaling loop to regulate vascular patterning in Arabidopsis by Christina Joy Müller, Ana Elisa Valdés, Guodong Wang, Prashanth Ramachandran, Lisa Beste, Daniel Uddenberg, and Annelie Carlsbecker, accepted for publication in Plant Physiology Nov. 2015. Plant vascular tissues, xylem and phloem, differentiate in distinct patterns from procambial cells as an integral transport system for water, sugars and signaling molecules. Procambium formation is promoted by high auxin levels activating class III homeodomain leucine zipper (HD-ZIP III) transcription factors (TFs). In the root of Arabidopsis thaliana, HD-ZIP III TFs dose-dependently govern the patterning of the xylem axis, with higher levels promoting metaxylem cell identity in the central axis and lower levels protoxylem at its flanks. It is, however, unclear by what mechanisms the HD-ZIP III TFs control xylem axis patterning. Here we present data suggesting that an important mechanism is their ability to moderate auxin response. We found that changes in HD-ZIP III TF levels affect the expression of genes encoding core auxin response molecules. We show that one of the HD-ZIP III TFs, PHABULOSA, directly binds the promoter of both MONOPTEROS/AUXIN RESPONSE FACTOR5 (MP/ARF5), a key factor in vascular formation, and IAA20, encoding an AUX/IAA protein which is stable in the presence of auxin and able to interact with and repress MP activity. The double mutant of IAA20 and its closest homologue IAA30 forms ectopic protoxylem, while overexpression of IAA30 causes discontinuous protoxylem and occasional ectopic metaxylem, similar to a weak loss-of-function mp-mutant. Our results provide evidence that HD-ZIP III TFs directly affect auxin response and mediate a feed forward loop formed by MP and IAA20 that may focus and stabilize auxin response during vascular patterning and differentiation of xylem cell types.
