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Brisbane, Australia

Xue G.-P.,CSIRO | Way H.M.,CSIRO | Richardson T.,CSIRO | Drenth J.,CSIRO | And 2 more authors.
Molecular Plant

NAC proteins are plant-specific transcription factors and enriched with members involved in plant response to drought stress. In this study, we analyzed the expression profiles of TaNAC69 in bread wheat using Affymetrix Wheat Genome Array datasets and quantitative RT-PCR. TaNAC69 expression was positively associated with wheat responses to both abiotic and biotic stresses and was closely correlated with a number of stress up-regulated genes. The functional analyses of TaNAC69 in transgenic wheat showed that TaNAC69 driven by a barley drought-inducible HvDhn4s promoter led to marked drought-inducible overexpression of TaNAC69 in the leaves and roots of transgenic lines. The HvDhn4s:TaNAC69 transgenic lines produced more shoot biomass under combined mild salt stress and water-limitation conditions, had longer root and more root biomass under polyethylene glycol-induced dehydration. Analysis of transgenic lines with constitutive overexpression of TaNAC69 showed the enhanced expression levels of several stress up-regulated genes. DNA-binding assays revealed that TaNAC69 and its rice homolog (ONAC131) were capable of binding to the promoter elements of three rice genes (chitinase, ZIM, and glyoxalase I) and an Arabidopsis glyoxalase I family gene, which are homologs of TaNAC69 up-regulated stress genes. These data suggest that TaNAC69 is involved in regulating stress up-regulated genes and wheat adaptation to drought stress. © 2011 The Author. Source

The greyback canegrub, Dermolepida albohirtum, is a major sugarcane pest that occurs between Mossman to Sarina in Queensland, Australia. Over a period of more than 100years, BSES Limited has conducted extensive field and laboratory studies on this pest species and information is available in several reports, articles and scientific papers. This document summarises much of the published work on D. albohirtum as well as anecdotal observations on its biology, ecology and management. D. albohirtum has an annual life cycle, and adult beetles usually lay eggs in cane crops around December-January, by which time the crop has become well advanced making pesticide application difficult. Hence, fields that require chemical treatment need to be carefully selected prior to beetle flights and egg laying. To assist in field selection, a prediction system is currently being developed to ensure that chemicals are strategically applied in areas likely to receive grub damage. Knowledge of the life cycle and population dynamics of this pest is essential in developing robust forecast systems. This document is designed to serve as a comprehensive reference for both researchers and cane growers seeking detailed information on the biology, ecology and management of this pest species. © 2010 The Author; Journal compilation © 2010 Australian Entomological Society. Source

Brackin R.,University of Queensland | Robinson N.,University of Queensland | Lakshmanan P.,BSES Ltd | Schmidt S.,University of Queensland
Soil Biology and Biochemistry

Soil microbial communities and their activities are altered by land use change; however impacts and extent of these alterations are often unclear. We investigated the functional responses of soil microbes in agricultural soil under sugarcane and corresponding native soil under Eucalyptus forest to additions of contrasting plant litter derived from soybean, sugarcane and Eucalyptus in a microcosm system, using a suite of complimentary techniques including enzyme assays and community level physiological profiles (CLPP). Initially agricultural soil had 50% less microbial biomass and lower enzyme activities than forest soil, but significantly higher nitrification rates. In response to litter addition, microbial biomass increased up to 11-fold in agricultural soil, but only 1.8-fold in forest soil, suggesting a prevalence of rapidly proliferating 'r' and slower growing 'K' strategists in the respective soils. Litter-driven change in microbial biomass and activities were short lived, largely returning to pre-litter addition levels by day 150. Decomposition rates of sugarcane and soybean litter as estimated via CO2 production were lower in agricultural than in forest soil, but decomposition of more recalcitrant Eucalyptus litter was similar in both soils, contradicting the notion that microbial communities specialise in decomposing litter of the dominant local plant species. Enzyme activities and community level physiological profiles (CLPP) were closely correlated to microbial biomass and overall CO2 production in the agricultural soil but not the forest soil, suggesting contrasting relationships between microbial population dynamics and activity in the two soils. Activities of enzymes that break down complex biopolymers, such as protease, cellulase and phenol oxidase were similar or higher in the agricultural soil, which suggests that the production of extracellular biopolymer-degrading enzymes was not a factor limiting litter decomposition. Enzyme and CLPP analyses produced contrasting profiles of microbial activity in the two soils; however the combination of both analyses offers additional insights into the changes in microbial function and community dynamics that occur after conversion of forest to agricultural land. © 2012 Elsevier Ltd. Source

Canegrubs, larvae of a complex of endemic melolonthine scarabs, are the key pests in Australian sugarcane. In the early 1990s, following the withdrawal of organochlorines, the Australian sugarcane industry faced a crisis with increasing canegrub damage. A comprehensive integrated pest management strategy was developed on the basis of research on a wide range of topics such as basic taxonomy, species identification, ecology and biology of the different species within the sugarcane system, development of new insecticides and new formulations of insecticides, potential development of genetically modified pest-resistant canes, and methods for predicting risk of infestations. The value of the research depended on a wide-ranging extension program that saw broadscale adoption of the new strategies. However, the cropping system is not static, and recent changes have the potential to alter plant architecture and phenology and therefore could affect canegrub biology, canegrub feeding, the impact of natural controls on canegrubs, and the accessibility to soil for sampling and insecticide application. Growers also demand cheaper, easier-to-use options. © 2010 by Annual Reviews All rights reserved. Source

Haynes R.J.,University of Queensland | Belyaeva O.N.,University of Queensland | Kingston G.,BSES Ltd
Journal of Plant Nutrition and Soil Science

Six inorganic industrial-waste materials (coal fly ash, bauxite-processing mud, steel slag, two samples of air-cooled blast furnace [BF] slag, and one sample of water-cooled BF slag), along with wollastonite, were evaluated as fertilizer-Si sources. Evaluation was carried out by analyzing total and extractable Si fractions in the materials, by incubating them at two rates with a Si-deficient soil and measuring potentially available extractable Si and by measuring yield and Si uptake by two successive rice crops grown in the fertilized soils. Of the waste materials used, fly ash had the highest total Si content (29%) but a negligible quantity was present in extractable forms. Steel slag and bauxite-processing mud had only 5%-7% Si content while BF slags contained 14%-18% Si. All materials, other than fly ash, increased the amount of extractable Si present in the soil. Additions of steel slag and bauxite-processing mud caused greater increases in Si extractability than the air-cooled BF slags while water-cooled BF slag-treated soils contained notably high acid-extractable Si. Because of the alkaline nature of the materials, and their reaction products, there was a positive relationship between extractable soil Si and soil pH. However, an equilibration experiment using NaSiO3 as the Si source confirmed that Si solubility in the soil decreased with increasing pH. Dry-matter yields of rice, at the lower rate of Si addition, were increased by all treatments other than fly ash. The higher rates of steel slag and bauxite-processing mud caused yield depressions. Total Si uptake by rice was increased by all treatments, other than fly ash, and was greater at the higher rate of Si addition. It was concluded that the BF slags are the most effective waste materials as fertilizer-Si sources and that, in slag-amended soils, CaCl2 and NH4 acetate are the most reliable soil-test extractants. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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