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: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:12plex_medicago_2014_02 - nar nodule vs root transcriptome - which are the genes differentially expressed in alfalfa spontaneous (non rhizobium-infected) nodules vs. control roots? - biological material: aeroponically grown cuttings of a Medicago sativa (alfalfa) accession that produces empty nodules when nitrogen-starved. Samples for transcriptome comparison: isolated NAR nodules (10 days post N-starvation) vs. roots of the same plants (pools of 3 roots).
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:Root nodules of the medicago truncatula-sinorhizobium meliloti plant-bacterail symbiotic model system were hand sectioned followed by LCMS. Sections were made to separate different developmental zones along the nodules longitudinal axis.
Project description:Brassinosteroid (BR) is an essential hormone in plant growth and development. BR signaling pathway has been extensively studied, in which Brassinazole resistant 1 (BZR1) functions as a key regulator. Here, we carried out a functional study of the homolog of BZR1 in Medicago truncatula, whose expression was induced in nodules upon rhizobial inoculation. We identified a loss-of-function mutant mtbzr1-1 and generated 35S:MtBZR1 transgenic lines for further analysis at the genetic level. Both the mutant and the overexpressor lines of MtBZR1 showed no obvious phenotypic changes under normal growth condition. After rhizobial inoculation, however, the shoot and root dry mass was reduced in mtbzr1-1 compared with the wild-type, caused by partially impaired nodule development. The transcriptomic analysis identified 1,319 differentially expressed genes in mtbzr1-1 compared with wild-type, many of which are involved in nodule development and secondary metabolite biosynthesis. Our results demonstrate an essential role of MtBZR1 in nodule development in M. truncatula, shedding light on the potential role of BR in legume-rhizobium symbiosis.
Project description:The hlh-30 gene encodes a C. elegans basic-helix-loop-helix (bHLH) transcription factor; We compared RNA from wild type worms and worms mutant for the hlh-30 gene to identify putative target genes of the HLH-30 transcription factor.
Project description:The hlh-30 gene encodes a C. elegans basic-helix-loop-helix (bHLH) transcription factor; We compared RNA from wild type worms and worms mutant for the hlh-30 gene to identify putative target genes of the HLH-30 transcription factor. Experiment Overall Design: Total RNA from three biological replicates were isolated from embryos, L1 larvae, and L2 larvae from both wild type and hlh-30(tm1978) mutant worms