Project description:RNA-directed DNA methylation (RdDM) in plants is a well-characterized example of RNA interference-related transcriptional gene silencing. To determine the relationships between RdDM and heterochromatin in the repeat-rich maize (Zea mays) genome, we performed whole-genome analyses of several heterochromatic features: dimethylation of lysine 9 and lysine 27 (H3K9me2 and H3K27me2), chromatin accessibility, DNA methylation, and small RNAs; we also analyzed two mutants that affect these processes, mediator of paramutation1 and zea methyltransferase2.
Project description:The differentiation of specialized feeding sites in Zea mays root cells in response to nematode infestation involves substantial cellular reprogramming of host cells that is not well characterized at the molecular level. Expression data was generated from Zea mays root cells undergoing giant cell formation due to nematode infestation and from non-infested control root cells. Cells were laser captured 14 and 21 days after infestation. Overall design: Each time point (14 day and 21 day) consisted of three biological replicates per treatment (control root cells or giant cells). Control cells were captured from an area ~13,000,000 um2 in size and giant cells were captured from an area ~5,000,000 um2 in size. RNA samples were isolated using the PicoPure RNA Isolation Kit (Arcturus, Mountain View, USA). RNA amplifications were carried out with the NuGEN WT-Ovation Pico kit.
Project description:Papain-like cysteine proteases (PLCPs) play important roles in plant defense mechanisms. Previous work identified a set of five apoplastic PLCPs (CP1A, CP1B, CP2, XCP2 and CatB) which are crucial for the orchestration of SA-dependent defense signaling and vice versa in maize (Zea mays). One central question from these findings is which mechanism is triggered by apoplastic PLCPs to induce SA-dependent defenses. By a mass spectrometry approach we discovered a novel peptide (Zip1 = Zea mays immune signaling peptide) to be enriched in apoplastic fluid upon SA treatment. Zip1 induces PR-gene expression when applied to naїve maize leaves. Moreover, it activates apoplastic PLCPs similar as SA does, suggesting Zip1 to play an important role in SA-mediated defense signaling. In vitro studies using recombinant protein showed that CP1A and CP2, but not XCP2 and CatB, release Zip1 from its pro-peptide (PROZIP1) in vitro. Strikingly, metabolite analysis showed direct induction of SA de novo synthesis by Zip1 in maize leaves. In line with this, RNA sequencing revealed that Zip1-mediated changes in maize gene expression largely resemble SA-induced responses. Consequently, Zip1 increases maize susceptibility to the necrotrophic fungal pathogen Botrytis cinerea. In summary, this study identifies the PLCP-released peptide signal Zip1, which triggers SA signaling in maize.
Project description:In this study we perform a transcriptomics analysis of two maize (Zea mays) organs, roots and leaves, from plants grown in the presence of a sufficient (1000 uM) or limiting (10 uM) concentration of soil phosphate. Overall design: Duplicate root and leaf mRNA profiles for plants grown in the presence of 1000 uM or 10 uM soil phosphate.
Project description:We applied a custom 2k micro-array with 2232 oligonucleotide sequences (50-70 nt) to a factorial with 13 parental inbred lines (4 Dent, 9 Flint) of European maize (Zea mays L.). The selection of oligonucleotides was based on 47k-array expression data from a 14x7 factorial with 98 hybrids (GSE17754). The main fraction of oligonucleotides (1639) represents genes that showed differential expression between the parental genotypes in the 14x7 factorial and consistent association with HP for GY in cross validation runs to estimate prediction accuracies for this trait. In addition the array contains partial overlapping fractions of genes that correlated with HP/GY (378), HP/GDMC (200), or MPH/GY (345) and 205 representatives of the 6 most overrepresented biological processes among genes correlated with HP/GY in the 14x7 factorial. Overall design: Four seedlings of each maize inbred line (9 Flint lines: F005, F012, F013, F023, F030, F034, L005, L007, L012; 4 Dent lines: P006, P033, S002, S028) as well as of two control lines (F043, S067) were grown for 7 days under controlled conditions (25 °C 16 h day, 21 °C 8 h night, 70 per cent air humidity) with randomized plate positions. The whole 7-day-old-seedlings were sampled and frozen in liquid nitrogen. The biological replicates were pooled and homogenized prior to RNA extraction.