The RNA-binding protein Rrm4 is essential for efficient secretion of endochitinase Cts1.

Long-distance transport of mRNAs is crucial in determining spatio-temporal gene expression in eukaryotes. The RNA-binding protein Rrm4 constitutes a key component of microtubule-dependent mRNA transport in filaments of Ustilago maydis. Although a number of potential target mRNAs could be identified, cellular processes that depend on Rrm4-mediated transport remain largely unknown.

Activation of the heat shock transcription factor Hsf1 is essential for the full virulence of the fungal pathogen Candida albicans.

The evolutionarily conserved heat shock transcription factor Hsf1 plays a central role in thermal adaptation in the major fungal pathogen of humans, Candida albicans. Hsf1 becomes hyperphosphorylated in response to heat shock and activates the transcription of genes with heat shock elements (HSEs) in their promoters, these genes contributing to thermal adaptation. However, the relevance of Hsf1 activation to C.

Phosphorylation regulates polarisation of chitin synthesis in Candida albicans.

The ability to undergo polarised cell growth is fundamental to the development of almost all walled organisms. Fungi are characterised by yeasts and moulds, and both cellular forms have been studied extensively as tractable models of cell polarity. Chitin is a hallmark component of fungal cell walls.

Effector proteins of the bacterial pathogen Pseudomonas syringae alter the extracellular proteome of the host plant, Arabidopsis thaliana.

In plants, potential pathogenic bacteria do not enter the host cell. Therefore, a large portion of the molecular interaction between microbial pathogen and host occurs in the extracellular space. To investigate potential mechanisms of disease resistance and susceptibility, we analyzed changes in the extracellular proteome, or secretome, using the Arabidopsis-Pseudomonas syringae pathosystem.

Involvement of cathepsin B in the plant disease resistance hypersensitive response.

A diverse range of plant proteases are implicated in pathogen perception and in subsequent signalling and execution of disease resistance. We demonstrate, using protease inhibitors and virus-induced gene silencing (VIGS), that the plant papain cysteine protease cathepsin B is required for the disease resistance hypersensitive response (HR). VIGS of cathepsin B prevented programmed cell death (PCD) and compromised disease resistance induced by two distinct non-host bacterial pathogens.

Environmental and developmental effects on the biosynthesis of UV-B screening pigments in Scots pine (Pinus sylvestris L.) needles.

The major UV-B screening pigments of the epidermal layer of Scots pine (Pinus sylvestris) needles are flavonol 3-o-glycosides (F3Gs) esterified with hydroxycinnamic acids at positions 3" and 6". Acylation is the last step in biosynthesis and is catalysed by position-specific hydroxycinnamoyl transferases (3" and 6"HCT). The UV-B dependence of these enzyme activities was studied in primary needles of Scots pine seedlings grown under different UV-B conditions in environmentally controlled sun simulators.

Tetracycline-regulated gene expression in the pathogen Ustilago maydis.

A powerful approach to explore gene function is the use of tetracycline-regulated expression. Here, we report the establishment of this titratable gene expression system for Ustilago maydis. Obstacles of premature polyadenylation of the native tetR gene, high basal activity of the tetracycline-responsive promoter, and toxicity of the viral activation domain were overcome by designing a synthetic tetR* gene according to context-dependent codon usage, removing cryptic enhancer elements from the promoter, and using an acidic minimal activation domain, respectively.

Flavonol 3-O-glycoside hydroxycinnamoyltransferases from Scots pine (Pinus sylvestris L.).

Flavonol 3-O-glucosides esterified with ferulic or p-coumaric acid at positions 3'' and 6'' are the major UV-B screening pigments of the epidermal layer of Scots pine (Pinus sylvestris) needles. The last steps in the biosynthesis of these compounds are catalyzed by enzymes that transfer the acyl part of hydroxycinnamic acid CoA esters to flavonol 3-O-glucosides. A newly developed enzyme assay revealed three flavonol 3-O-glucoside hydroxycinnamoyltransferases (HCTs) in Scots pine needles with specificities for positions 3'', 4'' or 6''.

PKA and MAPK phosphorylation of Prf1 allows promoter discrimination in Ustilago maydis.

Mating in Ustilago maydis requires cross-talk between cAMP and mitogen-activated protein kinase (MAPK) signalling. During this process, pheromone response factor 1 (Prf1) activates transcription of a and b mating type genes by binding to pheromone response elements (PREs) located in regulatory regions of these genes. Here, we show that PREs are also necessary and sufficient to mediate cAMP-induced gene expression.