Project description:We report on the identification of nitric-oxide regulated H3K9/14ac sites in Arabidopsis. For this purpose liquid grown Arabidopsis seedlings were treated with the natural NO-donor S-nitrosoglutathione (GSNO), GSNO in combination with the NO-scavenger cPTIO, GSH (control) or TSA (positive control). Material was crosslinked and harvested 3h and 16h after onset of the treatments. Then, quantitative analysis of the H3K9/14ac patterns across these treatment was performed using DiffBind. By comparison of the GSNO and GSNO/cPTIO treatment, NO-regulated H3K9/14ac sites were identified. These sites were then annotated to the nearest TSS. GO enrichment analysis revealed that NO affects H3K9/14ac at many stress-responsive and photosynthetic genes.
Project description:Nitric oxide regulates plant development and responses to stress. However, the mechanisms underlying its regulatory role are still poorly known, and the impact of endogenous NO on the genome-wide transcriptome of plants has not been studied. For that purpose, we compared the transcriptomes of NO-deficient nia1nia2, noa1-2 and nia1nia2noa1-2 mutant versus wild type Arabidopsis thaliana plants. A core comprising 66 NO-responsive genes with similar expression in all NO-deficient genotypes was identified. Among them, 46 were down- and 20 up-regulated in NO-deficient plants, and thus positively and negatively regulated by endogenous NO, respectively. Accordingly with changes in its transcriptome, the NO-deficient nia1nia2noa1-2 mutant accumulated anthocyanins and indolic glucosinolates, displayed abnormal iron homeostasis in shoots and roots, and also showed altered root sensitivity to hormones such as ABA, ET, CYK and IAA. Together the presented data suggest NO functions essentially as a modulator of hormone action. Compared analysis of the transcriptomes of 15-day old seedlings from 3 different nitric oxide (NO)-deficient mutant genotypes versus wild type background Col-0 (3 independent biological replicates per genotype). NO-deficient mutant seedlings in Col-0 background were the double nia1nia2 mutant in nitrate reductases (NR/NIA) 1 and 2 (abbreviated as nia); the noa1-2 mutant allele in Nitric Oxide Associated 1 (AtNOA1) (abbreviated as noa); and, the triple nia1nia2noa1-2 (abreviated as nino).
Project description:Non-symbiotic hemoglobins are ubiquitously expressed proteins known to interact with nitric oxide, an inhibitor of mitochondrial respiration and an important signalling component. We evaluated the underlying molecular mechanisms of AtHb1 (also referred as AtGLB1 or AHb1) function, its effects on stress response and the interplay with nitric oxide. For this purpose, AtHb1 was overexpressed in Arabidopsis thaliana under control of the seed-specific promoter LeB4. We performed comparative transcriptome analysis of developing siliques from wild type (WT, Col-0) and transgenic plants subjected to control and moderate hypoxic conditions. The experimental design was used to analyze the underlying molecular mechanisms of AtHb1 function and to assess differences in the hypoxic response between WT and AtHb1-overexpressing seeds/siliques.
Project description:Nano-aluminium oxide (nAl2O3) is one of the most widely used nanomaterials, but the molecular toxic mechanism of nAl2O3 on plants is still not clarified completely. In this study, we compared the toxic effects of nAl2O3 and Al3+ ion at the physiological and molecular levels. The shoot weight and root weight of Arabidopsis thaliana were decrease to 57.01% and 45.15% after the Al3+ ion exposure , while nAl2O3 increased the root weight by 48.07% and length by 38.53% at the selected concentration (98 mmol/L) for 10 d exposure. Physiological research showed that the photosystem (chlorophyll fluorescence parameters down-regulated) and antioxidant system (MDA and H2O2 content up-regulated) in A. thaliana were severely injured by the Al3+ ion. Data from transcriptome analysis clarified how nAl2O3 and Al3+ ion selectively affected root development and growth. nAl2O3 stimulated root growth directly (e.g., up-regulation of the root hair-specific gene family and root development genes, POLARIS protein), or indirectly (e.g., up-regulation of N and P absorption-related genes). Conversely, Al3+ ion disturbed ion homeostasis (up-regulated Al and Cu content) and caused severe oxidative stress, thus activating the salicylic acid (SA) signaling pathway and up-regulating nitric oxide (NO)-related genes, inducing the plant defense response. However, the overproduced SA and NO (up-regulated 2.60-fold) led to the inhibition of CAT activity (down-regulation of CAT1 and CAT2 genes) and increased the H2O2 level (up-regulated 2.84-fold). Subsequently, root development-related genes (e.g., auxin induced in root cultures 1) were down-regulated. This work gives us new insight into understanding the different molecular mechanisms of the plant response to nAl2O3 and Al3+ stresses.