Staff Profile

Career Summary

Qualifications

• PhD, University of Adelaide
• Bachelor of Science, University of Adelaide

Research

Research keywords

• Inductive signals, signalling cascades
• Nutrient transport in plants
• Plant cell development
• Plant cell trans-differentiation
• Plant cell walls
• Plant transfer cells
• Regulatory gene networks
• Resource allocation in plants

Research expertise

Transfer cells have a primitive origin being found in all plant taxa. This suggests that they play a fundamental role in plant development. The hallmark of transfer cells (TCs) is their invaginated ingrowth wall that, through an ensheathing plasma membrane enriched in nutrient transporters, confers an enhanced capacity for nutrient exchange across cell membranes. Thus, it is not surprising that transfer cells differentiate at bottlenecks for nutrient exchange within plants.

I have led, collaboratively with John Patrick, transfer cell biology research at Newcastle since 1983. We are world leaders in this field as evidenced by invited reviews in 2003 and 2008 (for details see F14.4). In 1997, I developed a TC induction system using Faba bean cotyledons (Offler et al 1997). This experimentally-powerful system (Offler et al 1997; Farley et al 2000, Wardini et al 2007b) combined with visualization technologies using SEM/FESEM and confocal microscopy (Talbot et al 2001, 2007a, 2007b) has, and continues to, underpin our TC research. In collaboration with David McCurdy (since 1997), we have made significant contributions to current knowledge of TC ingrowth walls that are comprised of a uniform wall from which wall ingrowths arise at loci and project into the cytosol. This structural unit is repeated to build the multi-layered fenestrated network that characterizes ingrowth wall architecture and acts as a scaffold to support an amplified plasma membrane surface area. We have contributed to understanding the pattern of assembly (Talbot et al 2001, 2002, 2007a) and composition (Vaughn et al 2007) of wall ingrowths and established the timing of trans-differentiation of Faba bean cotyledon epidermal cells to a TC morphology (Wardini et al 2007b) and function (Farley et al 2000, Wardini et al 2007a).

In 2007, a method for peeling the adaxial epidermal cells of cotyledons was perfected. This allowed a global gene expression analysis (Dibley et al 2009) to identify genes exhibiting changed expression exclusively in cells induced to trans-differentiate to a TC morphology. Concurrently, a project led by JW Patrick, used a targeted approach to identify inductive signals. We now have strong evidence for an auxin initiated, ethylene-reactive oxygen species-calcium channel signalling network responsible for inducing polarized deposition of the ingrowth wall (Zhou et al 2010 - ethylene; Andriunas et al 2011- ROS.; Zhang et al in prep - calcium.). The ROS signal deposition of the uniform wall against the outer periclinal wall of induced cells, while Ca2+ plumes are required to initiate wall ingrowth loci. John Patrick and I are continuing to investigate regulation of the mechanistic processes underpinning deposition of the ingrowth wall of Faba bean cotyledon transfer cells supported by ARCDP funding.

Measures of my contribution to our research outcomes in TC biology are my invited review Ann Rev Plant Biol - Offler et al (2003) that focused attention on TCs and their significance in seed growth (and see Rosche et al 2002, Pugh et al 2010) and my leadership, often with John Patrick, of a strong team researching TC biology over 28 years.

In the broader context of regulation of resource transport and allocation in plants, John Patrick and I have made significant contributions. By integrating structural and physiological studies we pinpointed the cellular location of regulatory transport processes using developing seeds and fruits (Offler and Patrick 1984, 1993; Harrington et al 1997). This approach allowed directed molecular analysis, resulting in cloning of key regulatory genes (Tegeder et al 2000) and novel sucrose effluxers (Zhou et al 2007a). My major contribution was rigorous quantitative analysis of cell parameters that highlighted cells involved in membrane transport including transfer cells.

Languages

• English

Fields of Research

Memberships

Committee/Associations (relevant to research).

• Editor - Phytogen- Newsletter of Australian Society of Plant Scientists

Editorial Board.

• Member - Australian Journal of Plant Physiology (renamed Functional Plant Biology)

Appointments

Invitations

Administrative

Administrative expertise

Administrative Roles:

Head, School of Environmental and Life Sciences, Faculty of Science & IT (September 2003 – July 2007)

Assistant Dean Curriculum Teaching & Learning, Faculty of Science & IT (January 2002- September 2003)

Faculty of Science & IT Teaching and Learning, Academic Champion (2011- )

University Governance:

Member of Academic Senate (1989 – 1991)

Member of University Promotions Sub-Committee B (1996)

Member of the University Promotions Committee (2004 -2006)

Chair Curriculum Review Committee, Discipline of Biological Sciences (2001 - 2002) and School of Environmental & Life Sciences (2002 - September 2003)

Academic Head University Electron Microscope Unit (jointly with Assoc/Prof John Heath – Faculty of Medicine & Health Sciences) (1991 – 1997)

Chair Advisory Committee for Electron Microscope/X-Ray Unit, The University of Newcastle and the Electron Microscope/X-Ray Unit User's Forum (1998 - 2002)

Chair Faculty of Science and Mathematics Women in Science Committee (1995 - 2001)

Senate Working Party for Women in Non-Traditional Areas of Study (1999)

Working Party on Women in Non Traditional Areas of Study (2000)

Chair Management Committee, the Don McNair Herbarium, The University of Newcastle (2008 - ).

Teaching

Teaching keywords

• Molecular regulation of plant development
• Plant cell development
• Plant development and physiology

Teaching expertise

Undergraduate Teaching:

Since becoming a Conjoint Professor in 2007, somewhat regrettably, I have reduced my undergraduate teaching until currently I no longer participate in delivery of the undergraduate programme. However, in my role as Academic Champion for the Faculty of Science & IT I have an opportunity to share my teaching experience with academics from a wide range of disciplines ranging across communication, design, natural history illustration and IT through psychology to mathematics, physics, chemistry and the earth, environmental and biological sciences.

My principal goals in undergraduate teaching were to awaken students to the excitement of discovery and to train them in skills required to pursue this process. Such skills are a capacity to question, to develop a logical argument, to plan and undertake experiments, to critically analyse information, to integrate ideas, to think laterally and to communicate in both verbal and written forms. A further goal was to establish for them the importance of organisational skills, responsibility, cooperation, sharing and a positive approach. My teaching philosophy was based on the premise that imparting the conceptual framework of the topic is of paramount importance. This framework then provides a means of ordering the ever increasing body of information that students need to assimilate to adequately prepare for the demands of their potential employers or their ongoing education. The integrative nature of processes governing plant growth and productivity was a key platform of my teaching. As a teacher, my goal was to encourage, support and assist students to learn, to discover their own strengths and weaknesses and to develop confidence in their own ability. I operated from a base of respecting students as individuals and working towards avoiding discouraging or intimidating them.

During my undergraduate teaching career I have taught the plant science component of Biology 1000, titled Plant Diversity and Processes; a Biology 2000 course on Plant Cell Development co-taught with John Patrick and David McCurdy and two Biology 3000 level courses – Whole Plant Development (1985 – 1997) and Plant Development and Physiology, the latter designed and co-taught with John Patrick (1998 – 2008). The focus of this latter course was development of a plant and adaptability of developmental processes to accommodate changing environmental conditions explored from the whole plant to molecular responses.

Research Training:

During my career I have been actively involved in research training. I have supervised or co-supervised 16 PhD, 3 Master of Science and 18 Bachelor of Science or Bachelor of Biotechnology Honours students to completion as well as co-supervised 4 post-doctoral research associates. Currently, I am co-supervising one postdoctoral research associate and 3 PhD students.