Biochemical genetics of glucosinolate modification in Arabidopsis and Brassica

Fine mapping of the glucosinolate biosynthesis gene OHP, which regulates the conversion of 3-methylsulphinylpropyl to 3-hydroxypropyl glucosinolate, in an Arabidopsis thaliana Columbia × Landsberg erecta RI line population positioned the gene within 54 kb of DNA on chromosome IV. Sequence data identified a family of genes encoding 2-oxoglutarate-dependent dioxygenases in this region. A probe based on these genes co-segregated with ALK in Brassica oleracea,a gene regulating the synthesis of alkenyl glucosinolates. The reactions catalysed by the OHP and ALK enzymes utilise similar substrates and may have a common mechanism. Thus, these dioxygenases are prime candidates for controlling the side chain modification of glucosinolates. Received: 12 May 2000 / Accepted: 29 May 2000     

N-terminal domain antigenic mapping reveals a site of vulnerability for SARS-CoV-2

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Spectrophotometric assay and electrophoretic detection of trans-feruloyl esterase activity.

Wheat bran cell walls were subjected to mild acid hydrolysis and the major phenolic product was purified and identified as 5-O-(trans-feruloyl)-arabinofuranose. Sensitive continuous and stopped, microtiter plate-based spectrophotometric assays for trans-feruloyl esterase activity were developed using this compound as substrate. Procedures were also developed for the detection of trans-feruloyl esterase activities on gels following electrophoresis using this compound. These procedures are applicable to other natural feruloyl esters derived from plant cell walls by enzymatic hydrolysis. The extracellular trans-feruloyl esterases of Aspergillus niger 814 grown on 1% wheat bran were fractionated by anion-exchange chromatography and isoelectric focusing. These studies indicate that there are multiple forms of trans-feruloyl esterase but that most activity is associated with a major isozyme with a pI of 3.2.     

Global spread of helminth parasites at the human–domestic animal–wildlife interface

Changes in species distributions open novel parasite transmission routes at the human–wildlife interface, yet the strength of biotic and biogeographical factors that prevent or facilitate parasite host shifting are not well understood. We investigated global patterns of helminth parasite (Nematoda, Cestoda, Trematoda) sharing between mammalian wildlife species and domestic mammal hosts (including humans) using >24,000 unique country‐level records of host–parasite associations. We used hierarchical modelling and species trait data to determine possible drivers of the level of parasite sharing between wildlife species and either humans or domestic animal hosts. We found the diet of wildlife species to be a strong predictor of levels of helminth parasite sharing with humans and domestic animals, followed by a moderate effect of zoogeographical region and minor effects of species’ habitat and climatic niches. Combining model predictions with the distribution and ecological profile data of wildlife species, we projected global risk maps that uncovered strikingly similar patterns of wildlife parasite sharing across geographical areas for the different domestic host species (including humans). These similarities are largely explained by the fact that widespread parasites are commonly recorded infecting several domestic species. If the dietary profile and position in the trophic chain of a wildlife species largely drives its level of helminth parasite sharing with humans/domestic animals, future range shifts of host species that result in novel trophic interactions may likely increase parasite host shifting and have important ramifications for human and animal health.     

Mapping quantitative trait loci controlling agronomic traits in the spring wheat cross RL4452x'AC Domain'.

Relatively little is known about the genetic control of agronomic traits in common wheat (Triticum aestivum L.) compared with traits that follow Mendelian segregation patterns. A doubled-haploid population was generated from the cross RL4452x'AC Domain' to study the inheritance of the agronomic traits: plant height, time to maturity, lodging, grain yield, test weight, and 1000-grain weight. This cross includes the genetics of 2 western Canadian wheat marketing classes. Composite interval mapping was conducted with a microsatellite linkage map, incorporating 369 loci, and phenotypic data from multiple Manitoba environments. The plant height quantitative trait loci (QTLs), QHt.crc-4B and QHt.crc-4D, mapped to the expected locations of Rht-B1 and Rht-D1. These QTLs were responsible for most of the variation in plant height and were associated with other agronomic traits. An additional 25 agronomic QTLs were detected in the RL4452x'AC Domain' population beyond those associated with QHt.crc-4B and QHt.crc-4D. 'AC Domain' contributed 4 alleles for early maturity, including a major time to maturity QTL on 7D. RL4452 contributed 2 major alleles for increased grain yield at QYld.crc-2B and QYld.crc-4A, which are potential targets for marker-assisted selection. A key test weight QTL was detected on 3B and prominent 1000-grain weight QTLs were identified on 3D and 4A.