Cooperative Research Centre

About: Cooperative Research Centre is a based out in . It is known for research contribution in the topics: Population & Sea ice. The organization has 7633 authors who have published 8607 publications receiving 429721 citations.

Characterization of Quantitative Trait Loci Controlling Genetic Variation for Preharvest Sprouting in Synthetic Backcross-Derived Wheat Lines

Abstract: Aegilops tauschii, the wild relative of wheat, has stronger seed dormancy, a major component of preharvest sprouting resistance (PHSR), than bread wheat. A diploid Ae. tauschii accession (AUS18836) and a tetraploid (Triticum turgidum L. ssp. durum var. Altar84) wheat were used to construct a synthetic wheat (Syn37). The genetic architecture of PHS was investigated in 271 BC(1)F(7) synthetic backcross lines (SBLs) derived from Syn37/2*Janz (resistant/susceptible). The SBLs were evaluated in three environments over 2 years and PHS was assessed by way of three measures: the germination index (GI), which measures grain dormancy, the whole spike assay (SI), which takes into account all spike morphology, and counted visually sprouted seeds out of 200 (VI). Grain color was measured using both Chroma Meter- and NaOH-based approaches. QTL for PHSR and grain color were mapped and their additive and epistatic effects as well as their interactions with environment were estimated by a mixed linear-model approach. Single-locus analysis following composite interval mapping revealed four QTL for GI, two QTL for SI, and four QTL for VI on chromosomes 3DL and 4AL. The locus QPhs.dpiv-3D.1 on chromosome 3DL was tightly linked to the red grain color (RGC) at a distance of 5 cM. The other locus on chromosome 3D, "QPhs.dpiv-3D.2" was independent of RGC locus. Two-locus analysis detected nine QTL with main effects and 18 additive x additive interactions for GI, SI, and VI. Two of the nine main effects QTL and two epistatic QTL showed significant interactions with environments. Both additive and epistatic effects contributed to phenotypic variance in PHSR and the identified markers are potential candidates for marker-assisted selection of favorable alleles at multiple loci. SBLs derived from Ae. tauschii proved to be a promising tool to dissect, introgress, and pyramid different PHSR genes into adapted wheat genetic backgrounds. The enhanced expression of PHS resistance in SBLs enabled us to develop white PHS-resistant wheat germplasm from the red-grained Ae. tauschii accession.

Multiplex PCR assay for Cylindrospermopsis raciborskii and cylindrospermopsin-producing cyanobacteria.

Abstract: Water bodies are routinely monitored for the presence of potentially toxic cyanobacteria; however, the methodology for confirming toxicity is currently complex and expensive. Here we describe the application of gene-based technology to rapidly identify cylindrospermopsin-producing cyanobacteria, specifically, Cylindrospermopsis raciborskii. A multiplex polymerase chain reaction (PCR) test was developed that simultaneously identified polyketide synthase (pks) and peptide synthetase (ps) determinants associated with cylindrospermopsin production and distinguished C. raciborskii from other cylindrospermopsin-producing cyanobacteria of the species Anabaena bergii and Aphanizomenon ovalisporum, by targeting the rpoC1 gene. Twenty-one C. raciborskii, 5 A. bergii, 10 Aph. ovalisporum isolates and 3 environmental samples all yielded PCR results consistent with their toxicological status, as assessed by high-performance liquid chromatography coupled to mass spectrometry or matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, and C. raciborskii was always correctly identified. The PCR test is a rapid, reliable, and economical way of assessing the toxic potential of cyanobacterial blooms formed by these organisms.

Root Iron Plaque on Wetland Plants as a Dynamic Pool of Nutrients and Contaminants

Abstract: Loading of nutrients and contaminants is increasing in wetlands due to anthropogenic activities. The scope of this paper is to (1) provide an overview of natural, cultivated, and constructed wetlands and hydrophytes, (2) characterize root iron plaque of hydrophytes, (3) show roles played by root iron plaque as a source and sink for nutrients and contaminants for hydrophytes, (4) present toxicity tolerance mechanisms employed by hydrophytes, and (5) offer implications of the findings about iron plaque, and (6) to suggest future research. Iron plaque deposits on hydrophyte root surfaces are a result of oxidation of ferrous iron in the oxic rhizosphere under waterlogged conditions in wetlands. The iron plaques mainly consists of amorphous and crystalline iron oxyhydroxides. They, therefore, can sequester nutrients and contaminants that can bind to iron oxides. Recently advanced spectroscopic techniques, such as synchrotron radiation techniques, have been used to identify and characterize iron plaque components. Sequestration and plant uptake of these materials mainly depend on the available nutrients and contaminants, oxygen diffusion capability of hydrophyte roots, and bio-physico-chemical properties of the rhizosphere. Root iron plaque plays a vital role in controlling the sequestration of excess loads of nutrients and contaminants in wetlands.