Browsing by Subject "xylem"

Secondary growth in plant vasculature tissues originate from meristematic tissue vascular cambium. Vascular cambium produces xylem inwards and phloem outwards in the plant root and stem. Vascular cambium regulatory mechanisms are not completely known, and while plants and especially trees are dependent on the mechanical support and transportation systems the vasculature provide, increased knowledge of the vascular cambium and especially xylem development is valuable. In this thesis, I explored Arabidopsis thaliana single-cell RNA-sequencing data from secondary growth stage via cloning transcriptional reporter lines, and later utilized the transcriptomics data to find potential xylem development regulators. By loss-of-function mutant and inducible overexpression line screening, I found two genes in a family of MYB transcription factors to be potential regulators in xylem development. Loss-of-function mutant did not show significant phenotype, but overexpression lines under constitutive 35S promoter showed extreme halt of growth, and a stain-filled vessel phenotype in a fixed and resin-embedded Arabidopsis cross-section. Under developing xylem -specific promoters, inducible overexpression lines showed the same phenotype, and while grown to the secondary growth stage, I detected some patterning defects. Thus, these results indicate, that these MYBs expressed in the xylem parenchyma in the single-cell transcriptomics data, might have a function in xylem development.