Project description:We have undertaken a detailed study to identify mechanisms regulating expression of NCRs. We used a custom Affymetrix oligonucleotide microarray to examine the expression changes of 566 NCRs in different stages of nodule development. Additionally, rhizobial mutants were used to understand the importance of the rhizobial components in induction of NCRs. Early NCRs were detected during the initial infection of rhizobia in nodules and continue to be expressed into the late stages of nodule development. Late NCRs were induced concomittant with bacteroid development in the nodules. The induction of these groups of genes was correlated with the number and morphology of rhizobia in the nodule. We used a custom Affymetrix chip containing 684 probe sequences of Medicago DEFLs to explore the expression patterns of NCRs in nodules inoculated with Sinorhizobium meliloti 1021(Sm1021) at marked developmental stages and nodules inoculated with various mutants derived from Sm1021 totalling 14 different treatments. Each treatment was supported by three biological replicates giving a grand total of 42 samples.
Project description:In order to better understand the commonalities and differences in lateral root and nodule development, we compared their organogenesis and correlated this with changes in gene expression. To initiate lateral roots in Medicago truncatula we turned 2-day-old seedlings 135°, before returning them to their original axis of growth, while for nodule initiation we applied droplets of Sinorhizobium meliloti on the susceptibility zone of the root.
Project description:We have undertaken a detailed study to identify mechanisms regulating expression of NCRs. We used a custom Affymetrix oligonucleotide microarray to examine the expression changes of 566 NCRs in different stages of nodule development. Additionally, rhizobial mutants were used to understand the importance of the rhizobial components in induction of NCRs. Early NCRs were detected during the initial infection of rhizobia in nodules and continue to be expressed into the late stages of nodule development. Late NCRs were induced concomittant with bacteroid development in the nodules. The induction of these groups of genes was correlated with the number and morphology of rhizobia in the nodule.
Project description:Medicago truncatula engages in root nodule symbiosis by developing a de novo plant organ (known as nodule) in its roots in response to the infection by rhizobia. These nodules are de novo plant organs that provide an optimal environment for the rhizobia to fix nitrogen in exchange for photosynthates. The establishment of root nodule symbioses (RNS) requires the coordination of two distinct processes: bacterial infection and nodule organogenesis. In this study we used single-cell RNA-seq to investigate the first hours of the establishment of the root nodule symbiosis aiming to identify the transcriptional mechanisms governing this process.
Project description:Current prostate cancer prognostic models are based on pre-treatment prostate-specific antigen (PSA) levels, biopsy Gleason score, and clinical staging but in practice are inadequate to accurately predict clinical disease progression. Hence, we sought to develop a molecular panel for prostate cancer progression by reasoning that molecular profiles might further improve current clinical models. We analyzed a Swedish Watchful Waiting cohort (1977–1999) with up to 30 years of clinical follow up using a novel method for gene expression profiling. This cDNA-mediated annealing, selection, ligation, and extension (DASL) method enabled the use of formalin-fixed paraffin-embedded transurethral resection of prostate (TURP) samples taken at the time of the initial diagnosis. We determined the expression profiles of 6100 genes for 281 men divided in two extreme groups: men who died of prostate cancer or developed metastases and men who survived more than 10 years without metastases (lethals and indolents, respectively). Several models using clinical and molecular features were evaluated for their ability to distinguish lethal from indolent cases. Surprisingly, none of the predictive models using molecular profiles significantly improved over models using clinical variables only. We reasoned that tumor sampling might preclude the identification of the dominant metastatic nodule. Additional computational analysis confirmed that molecular heterogeneity within both the lethal and indolent classes is widespread in prostate cancer as compared to other types of tumors. Thus the determination of the molecularly dominant tumor nodule may be limited by sampling at time of initial diagnosis, may not be present at time of initial diagnosis, or may occur as the disease progresses preventing the development of molecular biomarkers for prostate cancer progression.