Arabidopsis emf2 mutants bypass vegetative development and flowering upon seed germination. We introduced a broccoli BoEMF2.1 gene into emf2 mutants and obtained rescued emf2 plants that harbored 35S::BoEMF2.1. We found that BoEMF2.1 can partially rescue the phenotype of emf2 to that of WT. We used microarrays to study the global program of gene expression and to identify genes misexpressed in the Arabidopsis emf2 mutant that had been rescued by 35S::BoEMF2.1.
Molecular and functional characterization of broccoli EMBRYONIC FLOWER 2 genes.
Age, Specimen part
View SamplesPollen is the male gametophyte of land plants. Proper development and maturation of pollen is necessary for the successful reproduction of seed plants. This process involves sophisticated coordination between sporophytic and gametophytic tissues in anthers. To advance the mechanistic studies of anther development, additional players need to be discovered for a comprehensive understanding of the underlying regulatory network. Here we show that the Arabidopsis dual specificity tyrosine phophorylated and regulated kinase (DRYK), AtYAK1, is essential for development of rosette leaves and the male but not female gametophyte in Arabidopsis. Arabidopsis mutant plants carrying a mutation in AtYAK1 produce developmentally stalled microspores, likely because of the defects in the two consecutive mitosis steps in the post-meiotic maturation process of pollen. The mutation of AtYAK1 has a significant effect on gene expression programs in developing pollen. Transcritpome analysis of atyak1 revealed downstream genes in families of protein kinases, transporters and transcription factors, which potentially contribute to pollen development. This study represents the first molecular characterization of DYRK in the plant kingdom. Our results also imply that the regulation of cytokinesis by DYRKs is evolutionally conserved in fungus, fruit fly, animals and plants.
No associated publication
Age, Specimen part
View SamplesTranscriptome analysis has revealed a light-regulated WD (tryptophan and aspartate)-containing protein, LWD1. LWD1 and LWD2 share greater than 90% amino acid sequence homology. The lack of phenotype changes in the lwd1 or lwd2 single mutant implies that the proteins function redundantly. The lwd1lwd2 double mutant, however, has an early flowering phenotype under both long-day (LD) and short-day (SD) conditions. Functional complementation experiment revealed that LWDs are indeed responsible for the defect in photoperiod sensing in lwd1lwd2 double mutant plants. The expression of LWD1 exhibits a diurnal pattern and peaks before dawn. The period length of oscillator (CCA1, LHY, TOC1 and ELF4) and output (CCR2 and CAB2) genes in the lwd1lwd2 double mutant is significantly shorter than that in wild-type Arabidopsis under free running condition. Under entrainment conditions, the expression phase of oscillator (CCA1, LHY, TOC1 and ELF4) and output (GI, FKF1, CDF1, CO and FT) genes shifts ~3 hr forward in the lwd1lwd2 double mutant. Our data indicated that the early flowering phenotype in lwd1lwd2 plants is contributed by the significant phase shift of CO and, therefore, an increased expression of FT before dusk under SD conditions. Our data imply that LWD1/LWD2 proteins function in close proximity to the circadian oscillators for the regulation of photoperiod sensing.
Two new clock proteins, LWD1 and LWD2, regulate Arabidopsis photoperiodic flowering.
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View SamplesAlthough abscisic acid (ABA) and gibberellins (GAs) play pivotal roles in many physiological processes in plants, their interaction in the control of leaf growth remains elusive. In this study, genetic analyses of ABA and GA interplay in leaf growth were performed in Arabidopsis thaliana. The results indicate that for ABA and GA interaction, leaf growth of both the aba2/ga20ox1 and aba2/GA20OX1-OE plants exhibits partially additive effects but is similar to the aba2 mutant. Consistent with this result, transcriptome analysis suggests that a substantial proportion (45-65%) of the gene expression profile of aba2/ga20ox1 and aba2/GA20OX1-OE plants overlaps and shares a similar pattern to the aba2 mutant. Thus, these data support that ABA deficiency dominates leaf growth regardless of GA levels. Moreover, gene ontology (GO) analysis indicates gene enrichment in the categories of hormone response, developmental and metabolic processes, and cell wall organization in these three genotypes. Leaf developmental genes are also involved in ABA-GA interaction. Collectively, these data support that the genetic relationship of ABA and GA interaction involves multiple coordinated pathways rather than a simple linear pathway in the regulation of leaf growth.
Genetic analyses of the interaction between abscisic acid and gibberellins in the control of leaf development in Arabidopsis thaliana.
Specimen part
View SamplesAlthough the nucleolus is known to be involved in the plant stress response, the underlying mechanisms remain unclear. In the present study, we genetically isolated and characterized the Arabidopsis thaliana salt hypersensitive mutant 1 (sahy1), which exhibits slow growth, short roots, and sterility. SAHY1 encodes an unknown protein that is predominantly expressed in root tips and mature pollens. Subcellular localization further demonstrated that SAHY1 is a nucleolar protein. Ploidy analysis and detection of S-phase cell cycle progression indicated that mitosis is reduced in the root tips of sahy1 plants. Furthermore, levels of reactive oxygen species (ROS) are reduced in the mutant. In addition to exhibiting changes in venation pattern, palisade mesophyll cells, the auxin response, and fertility, the sahy1 mutant is resistant to the protein translation inhibitors, streptomycin and cycloheximide, and has altered expression profiles of ribosome-related genes, reflecting the involvement of SAHY1 in ribosome assembly. Using a combination of transcriptome and gene coexpression clustering analyses, we identified a striking functional module in which SPIRAL 1-LIKE 4 (SPL4), which encodes a microtubule-localized protein, mediates the salt response that acts by modulating dynamic microtubule instability. Supporting evidence indicates that sahy1 is resistant to a microtubule-destabilizing drug (oryzalin), that the cortical microtubule array in sahy1 exhibits changes in dynamic instability, and that the spr1/spl2/spl3/spl4 quadruple mutant is oversensitive to salt. Collectively, these data demonstrate that a novel nucleolar protein, SAHY1, plays critical roles in salt sensitivity, plant growth, and development by integrating the diverse functions of its downstream genes.
No associated publication
Specimen part
View SamplesTo understand the function of soybean endosperm
No associated publication
Specimen part
View SamplesDue to limited bio-availability of Fe, plants evolved adaptive alterations in development regulated at the transcriptional level. We investigated the early transcriptional response to Fe deficiency.
Early iron-deficiency-induced transcriptional changes in Arabidopsis roots as revealed by microarray analyses.
Specimen part
View SamplesThe environmental light plays a vital role in regulating the plant growth and development. Transcriptomic profilings were widely used to examine how light regulates the changes of mRNA populations at a genome-wide scale. However, it remains unclear if translational regulation represents a new dimension of gene expression regulation in response to the light signal. Through a transcriptomic comparison of steady-state and polysome-bound mRNAs, we revealed an increased translational efficiency in de-etiolating Arabidopsis seedlings. Over 3,500 genes are subjected to translational regulation whereas only about 770 genes have increased mRNA abundances in response to the light signal. This result suggests a stronger impact of translational control over transcriptomic changes during photomorphogenesis. Genes encoding ribosomal protein are preferentially regulated at the translational level, possibly contributing to the enhancement of translation efficiency as observed. We also uncovered mRNAs regulated at the translational level share characteristics of longer half-lives and shorter cDNA length. The presence of a cis-element, TAGGGTTT, in the 5untranslated region of a transcript renders its translational regulation by light signals. Taken together, our study revealed a previously neglected aspect of gene expression regulation during Arabidopsis photomorphogenesis. The identities and molecular signatures associated with mRNAs regulated at the translational level also offer new directions to perform mechanistic studies of light-trigged translational enhancement in Arabidopsis.
Widespread translational control contributes to the regulation of Arabidopsis photomorphogenesis.
Specimen part, Treatment, Time
View SamplesCsUBC13 was identified via proteomics from iron starvation treated Cucumber root. ubc13A is an ABRC seed stock (CS51269). CS851269 was purchased from ABRC and confirmed as homozygous Atubc13A knock-out T-DNA mutant. We generated transgenic arabidopsis with ectopic expression of CsUBC13 gene under control of the cauliflower 35S promotor. Both genotypes and Col-0 were used to investigate the transcriptional response to Iron (Fe) deficiency.
A lysine-63-linked ubiquitin chain-forming conjugase, UBC13, promotes the developmental responses to iron deficiency in Arabidopsis roots.
Specimen part
View SamplesWe have reported that JMJ17 act as a repressor to a set of genes involved in photosynthesis, tetrapyrrole biosynthesis and light response related development in the dark, while during dark to light irradiation it acts as an activator of same set of genes.
No associated publication
Specimen part, Treatment
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