The manipulation of apoptosis-related genes to generate resistance to Fusarium wilt and water stress in banana

Bananas are susceptible to a diverse range of biotic and abiotic stresses, many of which cause serious production constraints worldwide. One of the most destructive banana diseases is Fusarium wilt caused by the soil-borne fungus, Fusarium oxysporum f. sp. cubense (Foc). No effective control strategy currently exists for this disease which threatens global banana production. Although disease resistance exists in some wild bananas, attempts to introduce resistance into commercially acceptable bananas by conventional breeding have been hampered by low fertility, long generation times and association of poor agronomical traits with resistance genes. With the advent of reliable banana transformation protocols, molecular breeding is now regarded as a viable alternative strategy to generate disease-resistant banana plants. Recently, a novel strategy involving the expression of anti-apoptosis genes in plants was shown to result in resistance against several necrotrophic fungi. Further, the transgenic plants showed increased resistance to a range of abiotic stresses. In this thesis, the use of anti-apoptosis genes to generate transgenic banana plants with resistance to Fusarium wilt was investigated. Since water stress is an important abiotic constraint to banana production, the resistance of the transgenic plants to water stress was also examined. Embryogenic cell suspensions (ECS) of two commercially important banana cultivars, Grand Naine (GN) and Lady Finger (LF), were transformed using Agrobacterium with the anti-apoptosis genes, Bcl-xL, Bcl-xL G138A, Ced-9 and Bcl- 2 3’ UTR. An interesting, and potentially important, outcome was that the use of anti-apoptosis genes resulted in up to a 50-fold increase in Agrobacterium-mediated transformation efficiency of both LF and GN cells over vector controls. Regenerated plants were subjected to a complete molecular characterisation in order to detect the presence of the transgene (PCR), transcript (RT-PCR) and gene product (Western blot) and to determine the gene copy number (Southern blot). A total of 36 independently-transformed GN lines (8 x Bcl-xL, 5 x Bcl-xL G138A, 15 x Ced-9 and 8 x Bcl-2 3’ UTR) and 41 independently-transformed LF lines (8 x Bcl-xL, 7 x BclxL G138A, 13 x Ced-9 and 13 x Bcl-2 3’ UTR) were identified. The 41 transgenic LF lines were multiplied and clones from each line were acclimatised and grown under glasshouse conditions for 8 weeks to allow monitoring for phenotypic abnormalities. Plants derived from 3 x Bcl-xL, 2 x Ced-9 and 5 x Bcl-2 3’ UTR lines displayed a variety of aberrant phenotypes. However, all but one of these abnormalities were off-types commonly observed in tissue-cultured, non-transgenic banana plants and were therefore unlikely to be transgene-related. Prior to determining the resistance of the transgenic plants to Foc race 1, the apoptotic effects of the fungus on both wild-type and Bcl-2 3’ UTR-transgenic LF banana cells were investigated using rapid in vitro root assays. The results from these assays showed that apoptotic-like cell death was elicited in wild-type banana root cells as early as 6 hours post-exposure to fungal spores. In contrast, these effects were attenuated in the root cells of Bcl-2 3’ UTR-transgenic lines that were exposed to fungal spores. Thirty eight of the 41 transgenic LF lines were subsequently assessed for resistance to Foc race 1 in small-plant glasshouse bioassays. To overcome inconsistencies in rating the internal (vascular discolouration) disease symptoms, a MatLab-based computer program was developed to accurately and reliably assess the level of vascular discolouration in banana corms. Of the transgenic LF banana lines challenged with Foc race 1, 2 x Bcl-xL, 3 x Ced-9, 2 x Bcl-2 3’ UTR and 1 x Bcl-xL G138A-transgenic line were found to show significantly less external and internal symptoms than wild-type LF banana plants used as susceptible controls at 12 weeks post-inoculation. Of these lines, Bcl-2 3’ UTR-transgenic line #6 appeared most resistant, displaying very mild symptoms similar to the wild-type Cavendish banana plants that were included as resistant controls. This line remained resistant for up to 23 weeks post-inoculation. Since anti-apoptosis genes have been shown to confer resistance to various abiotic stresses in other crops, the ability of these genes to confer resistance against water stress in banana was also investigated. Clonal plants derived from each of the 38 transgenic LF banana plants were subjected to water stress for a total of 32 days. Several different lines of transgenic plants transformed with either Bcl-xL, Bcl-xL G138A, Ced-9 or Bcl-2 3’ UTR showed a delay in visual water stress symptoms compared with the wild-type control plants. These plants all began producing new growth from the pseudostem following daily rewatering for one month. In an attempt to determine whether the protective effect of anti-apoptosis genes in transgenic banana plants was linked with reactive oxygen species (ROS)-associated programmed cell death (PCD), the effect of the chloroplast-targeting, ROS-inducing herbicide, Paraquat, on wild-type and transgenic LF was investigated. When leaf discs from wild-type LF banana plants were exposed to 10 ìM Paraquat, complete decolourisation occurred after 48 hours which was confirmed to be associated with cell death and ROS production by trypan blue and 3,3-diaminobenzidine (DAB) staining, respectively. When leaf discs from the transgenic lines were exposed to Paraquat, those derived from some lines showed a delay in decolourisation, suggesting only a weak protective effect from the transgenes. Finally, the protective effect of anti-apoptosis genes against juglone, a ROS-inducing phytotoxin produced by the causal agent of black Sigatoka, Mycosphaerella fijiensis, was investigated. When leaf discs from wild-type LF banana plants were exposed to 25 ppm juglone, complete decolourisation occurred after 48 hours which was again confirmed to be associated with cell death and ROS production by trypan blue and DAB staining, respectively. Further, TdT-mediated dUTP nick-end labelling (TUNEL) assays on these discs suggested that the cell death was apoptotic. When leaf discs from the transgenic lines were exposed to juglone, discs from some lines showed a clear delay in decolourisation, suggesting a protective effect. Whether these plants are resistant to black Sigatoka is unknown and will require future glasshouse and field trials. The work presented in this thesis provides the first report of the use of anti-apoptosis genes as a strategy to confer resistance to Fusarium wilt and water stress in a nongraminaceous monocot, banana. Such a strategy may be exploited to generate resistance to necrotrophic pathogens and abiotic stresses in other economically important crop plants.

Decentred optical axes and aberrations along principal visual field meridians

Suggestions that peripheral imagery may affect the development of refractive error have led to interest in the variation in refraction and aberration across the visual field. It is shown that, if the optical system of the eye is rotationally symmetric about an optical axis which does not coincide with the visual axis, measurements of refraction and aberration made along the horizontal and vertical meridians of the visual field will show asymmetry about the visual axis. The departures from symmetry are modelled for second-order aberrations, refractive components and third-order coma. These theoretical results are compared with practical measurements from the literature. The experimental data support the concept that departures from symmetry about the visual axis in the measurements of crossed-cylinder astigmatism J45 and J180 are largely explicable in terms of a decentred optical axis. Measurements of the mean sphere M suggest, however, that the retinal curvature must differ in the horizontal and vertical meridians.

Printmaking as an expanding field in contemporary art practice : a case study of Japan, Australia and Thailand

This thesis proposes that contemporary printmaking, at its most significant, marks the present through reconstructing pasts and anticipating futures. It argues this through examples in the field, occurring in contexts beyond the Euramerican (Europe and North America). The arguments revolve around how the practice of a number of significant artists in Japan, Australia and Thailand has generated conceptual and formal innovations in printmaking that transcend local histories and conventions, whilst paradoxically, also building upon them and creating new meanings. The arguments do not portray the relations between contemporary and traditional art as necessarily antagonistic but rather, as productively dialectical. Furthermore, the case studies demonstrate that, in the 1980s and 1990s particularly, the studio practice of these printmakers was informed by other visual arts disciplines and reflected postmodern concerns. Departures from convention witnessed in these countries within the Asia-Pacific region shifted the field of the print into a heterogeneous and hybrid realm. The practitioners concerned (especially in Thailand) produced work that was more readily equated with performance and installation art than with printmaking per se. In Japan, the incursion of photography interrupted the decorative cast of printmaking and delivered it from a straightforward, craft-based aesthetic. In Australia, fixed notions of national identity were challenged by print practitioners through deliberate cultural rapprochements and technical contradictions (speaking across old and new languages).However time-honoured print methods were not jettisoned by any case study artists. Their re-alignment of the fundamental attributes of printmaking, in line with materialist formalism, is a core consideration of my arguments. The artists selected for in-depth analysis from these three countries are all innovators whose geographical circumstances and creative praxis drew on local traditions whilst absorbing international trends. In their radical revisionism, they acknowledged the specificity of history and place, conditions of contingency and forces of globalisation. The transformational nature of their work during the late twentieth century connects it to the postmodern ethos and to a broader artistic and cultural nexus than has hitherto been recognised in literature on the print. Emerging from former guild-based practices, they ambitiously conceived their work to be part of a continually evolving visual arts vocabulary. I argue in this thesis that artists from the Asia-Pacific region have historically broken with the hermetic and Euramerican focus that has generally characterised the field. Inadequate documentation and access to print activity outside the dominant centres of critical discourse imply that readings of postmodernism have been too limited in their scope of inquiry. Other locations offer complexities of artistic practice where re-alignments of customary boundaries are often the norm. By addressing innovative activity in Japan, Australia and Thailand, this thesis exposes the need for a more inclusive theoretical framework and wider global reach than currently exists for ‘printmaking’.

Field instrumentation of a water reticulation pipe buried in reactive soil

The loss of valuable water resources due to pipe failure has become a major problem in Australia, especially in areas under high level of water restrictions. Generally pipe failure occurs due to a combination of physical and environmental factors. Stresses induced by shrinking and swelling of reactive soils are one of the major factors affecting the performance of buried pipes. This paper presents the details of a field instrumentation undertaken to monitor the performance of an in-service water reticulation pipe buried in a reactive soil and subjected to seasonal climatic changes.

Damage assessment of 3D reinforced concrete frame under external explosion loading

Multi-storey buildings are highly vulnerable to terrorist bombing attacks in various parts of the world. Large numbers of casualties and extensive property damage result not only from blast overpressure, but also from the failing of structural components. Understanding the blast response and damage consequences of reinforced concrete (RC) building frames is therefore important when assessing multi-storey buildings designed to resist normal gravity loads. However, limited research has been conducted to identify the blast response and damage of RC frames in order to assess the vulnerability of entire buildings. This paper discusses the blast response and evaluation of damage of three-dimension (3D) RC rigid frame under potential blast loads scenarios. The explicit finite element modelling and analysis under time history blast pressure loads were carried out by LS DYNA code. Complete 3D RC frame was developed with relevant reinforcement details and material models with strain rate effect. Idealised triangular blast pressures calculated from standard manuals are applied on the front face of the model in the present investigation. The analysis results show the blast response, as displacements and material yielding of the structural elements in the RC frame. The level of damage is evaluated and classified according to the selected load case scenarios. Residual load carrying capacities are evaluated and level of damage was presented by the defined damage indices. This information is necessary to determine the vulnerability of existing multi-storey buildings with RC frames and to identify the level of damage under typical external explosion environments. It also provides basic guidance to the design of new buildings to resist blast loads.

Thermal requirements, field mortality and population phenology modelling of Paropsis atomaria Olivier, an emergent pest in subtropical hardwood plantations

Paropsis atomaria is a recently emerged pest of eucalypt plantations in subtropical Australia. Its broad host range of at least 20 eucalypt species and wide geographical distribution provides it the potential to become a serious forestry pest both within Australia and, if accidentally introduced, overseas. Although populations of P. atomaria are genetically similar throughout its range, population dynamics differ between regions. Here, we determine temperature-dependent developmental requirements using beetles sourced from temperate and subtropical zones by calculating lower temperature thresholds, temperature-induced mortality, and day-degree requirements. We combine these data with field mortality estimates of immature life stages to produce a cohort-based model, ParopSys, using DYMEX™ that accurately predicts the timing, duration, and relative abundance of life stages in the field and number of generations in a spring–autumn (September–May) field season. Voltinism was identified as a seasonally plastic trait dependent upon environmental conditions, with two generations observed and predicted in the Australian Capital Territory, and up to four in Queensland. Lower temperature thresholds for development ranged between 4 and 9 °C, and overall development rates did not differ according to beetle origin. Total immature development time (egg–adult) was approximately 769.2 ± S.E. 127.8 DD above a lower temperature threshold of 6.4 ± S.E. 2.6 °C. ParopSys provides a basic tool enabling forest managers to use the number of generations and seasonal fluctuations in abundance of damaging life stages to estimate the pest risk of P. atomaria prior to plantation establishment, and predict the occurrence and duration of damaging life stages in the field. Additionally, by using local climatic data the pest potential of P. atomaria can be estimated to predict the risk of it establishing if accidentally introduced overseas. Improvements to ParopSys’ capability and complexity can be made as more biological data become available.

Are the financial services external complaints resolution schemes subject to judicial review?

In Australia seven schemes (apart from the Superannuation Complaints Tribunal) provide alternative dispute resolution services for complaints brought by consumers against financial services industry members. Recently the Supreme Court of New South Wales held that the decisions of one scheme were amenable to judicial review at the suit of a financial services provider member and the Supreme Court of Victoria has since taken a similar approach. This article examines the juristic basis for such a challenge and contends that judicial review is not available, either at common law or under statutory provisions. This is particularly the case since Financial Industry Complaints Service Ltd v Deakin Financial Services Pty Ltd (2006) 157 FCR 229; 60 ACSR 372 decided that the jurisdiction of a scheme is derived from a contract made with its members. The article goes on to contend that the schemes are required to give procedural fairness and that equitable remedies are available if that duty is breached.

External auditors' reliance on internal audit : the impact of sourcing arrangements and consulting activities

This study examines the impact of internal audit outsourcing and internal audit’s involvement in consulting on external auditors’ reliance on the work of internal audit. We test whether these factors influence (i) reliance on internal audit work already undertaken and (ii) the use of internal auditors as assistants. In each case, we distinguish between control evaluation and substantive testing. We find that involvement in consulting impacts reliance on work undertaken and the use of internal auditors as assistants for control evaluation. External auditors make greater use of internal auditors as assistants for substantive testing when internal audit is provided in-house. Overall, external auditors use internal audit more for control evaluation tasks than for substantive testing.

Cross culture comparison of tax morale and tax compliance : evidence from Costa Rica and Switzerland

This paper analyzes the effects of internal and external social norms on tax morale and tax compliance behavior. Field data and data derived from laboratory experiments are used to examine tax morale and tax compliance behavior in Costa Rica and Switzerland. The results indicate that internal and external social norms have a significant effect on tax morale and tax compliance.

In Interaction

The field was the design of cross-cultural media art exhibition outcomes for the Japanese marketplace. The context was improved understandings of spatial, temporal and contextual exhibition design procedures as they ultimately impact upon the augmentation of cross-cultural understanding. The research investigated cross-cultural new media exhibition practices suited to the specific sensitivies of Japanese exhibition practices. The methodology was principally practice-led. The research drew upon seven years of prior exhibition design practices in order to generate new Japanese exhibition design methodologies. It also empowered Zaim Artpsace’s Japanese curators to later present a range of substantial new media shows. The project also succeeded in developing new cross-cultural alliances that led to significant IDA projects in Beijing, Australia and Europe in the years 2008-10. Through invitations from external curators the new versions of the exhibition work subsequently travelled to 4 other major venues including the prestigious Songzhang Art Museum, Beijing in 07/08, the Block, QUT, Brisbane and the Tokyo International Film festival. Inspiration Art Press printed a major catalogue for the event extensively featuring this exhibition. This project also led to the Sudamalis (2007) paper, ‘Building Capacity: Literacy And Creative Workforce Development Through International Digital Arts Projects’ (IDAprojects) Exhibition Programs And Partnerships’.