Cleaning the Cellular Factory-Deletion of McrA in NSAR1 and the Generation of a Novel Kojic Acid Deficient Strain for Cleaner Heterologous Production of Secondary Metabolites.

The use of filamentous fungi as cellular factories, where natural product pathways can be refactored and expressed in a host strain, continues to aid the field of natural product discovery. Much work has been done to develop host strains which are genetically tractable, and for which there are multiple selectable markers and controllable expression systems. To fully exploit these strains, it is beneficial to understand their natural metabolic capabilities, as such knowledge can rule out host metabolites from analysis of transgenic lines and highlight any potential interplay between endogenous and exogenous pathways.

Heterologous expression and transcript analysis of gibberellin biosynthetic genes of grasses reveals novel functionality in the GA3ox family.

Background: The gibberellin (GA) pathway plays a central role in the regulation of plant development, with the 2-oxoglutarate-dependent dioxygenases (2-ODDs: GA20ox, GA3ox, GA2ox) that catalyse the later steps in the biosynthetic pathway of particularly importance in regulating bioactive GA levels. Although GA has important impacts on crop yield and quality, our understanding of the regulation of GA biosynthesis during wheat and barley development remains limited. In this study we identified or assembled genes encoding the GA 2-ODDs of wheat, barley and Brachypodium distachyon and characterised the wheat genes by heterologous expression and transcript analysis.

Expression profiling of potato germplasm differentiated in quality traits leads to the identification of candidate flavour and texture genes.

Quality traits such as flavour and texture are assuming a greater importance in crop breeding programmes. This study takes advantage of potato germplasm differentiated in tuber flavour and texture traits. A recently developed 44,000-element potato microarray was used to identify tuber gene expression profiles that correspond to differences in tuber flavour and texture as well as carotenoid content and dormancy characteristics.

Aphid alarm pheromone produced by transgenic plants affects aphid and parasitoid behavior.

The alarm pheromone for many species of aphids, which causes dispersion in response to attack by predators or parasitoids, consists of the sesquiterpene (E)-beta-farnesene (Ebetaf). We used high levels of expression in Arabidopsis thaliana plants of an Ebetaf synthase gene cloned from Mentha x piperita to cause emission of pure Ebetaf. These plants elicited potent effects on behavior of the aphid Myzus persicae (alarm and repellent responses) and its parasitoid Diaeretiella rapae (an arrestant response).

Nitrate assimilation in the forage legume Lotus japonicus L.

Nitrate assimilation in the model legume, Lotus japonicus, has been investigated using a variety of approaches. A gene encoding a nitrate-inducible nitrate reductase (NR) has been cloned and appears to be the only NR gene present in the genome. Most of the nitrate reductase activity (NRA) is found in the roots and the plant assimilates the bulk of its nitrogen in that tissue.

Cloning and functional characterisation of a cis-muuroladiene synthase from black peppermint (Menthaxpiperita) and direct evidence for a chemotype unable to synthesise farnesene.

Using oligonucleotide primers designed to the known gene sequence of an (E)-beta-farnesene (EbetaF) synthase, two cDNA sequences (MxpSS1 and MxpSS2) were cloned from a black peppermint (Menthaxpiperita) plant. MxpSS1 encoded a protein with 96% overall amino acid sequence identity with the EbetaF synthase. Recombinant MxpSS1 produced in Escherichia coli, after removal of an N-terminal thioredoxin fusion, had a K(m) for FPP of 1.

Phylogeny and expression of paralogous and orthologous sulphate transporter genes in diploid and hexaploid wheats.

Twelve genes encoding two closely related subtypes (ST1.1a and ST1.1b) of a sulphate transporter have been identified in the diploid wheats Aegilops tauschii, Triticum urartu, and Aegilops speltoides, as well as the hexaploid Triticum aestivum.