‘In GRAINS’ Investing in Young Scientists, is a publication of the Grains Research and Development Corporation (GRDC). The publication not only illustrates the type of projects undertaken by students supported by the GRDC but also shows the skills they developed and the value they gained from their links to an industry body. It also demonstrates the breadth of scientific knowledge these students add to the grains industry via peer reviewed journal articles and conference papers.
The publication included an article featuring Dr Michael Dow, a Patent Technical Specialist with Madderns, and has been reproduced with the permission of the GRDC below. A link to the full publication is available at www.grdc.com.au/InvestingInYoungScientists.
Identification of key components in salinity tolerance regulation
Salinity is a major abiotic stress of crop plants worldwide. In Australia it is a significant factor impeding crop production in dryland environments. It has been estimated that up to 80% of Australia’s cereal production areas are at risk of developing problems related to salinity and the losses are estimated to be in the hundreds of millions of dollars each year. A genetic solution to salinity stress for cereals would therefore be of great economic advantage to the Australian grains industry.
By taking a genetic approach to unravelling the controls for salinity tolerance, Michael Dow has shown links between salt tolerance and other plant stress responses. His PhD was supported by a Grains Industry Research Scholarship from the GRDC.
Methods of selecting for salinity tolerance in plants
An excessive level of the salt sodium chloride is the common cause of salinity stress, which affects plants in two ways. Firstly, the salt increases the osmotic pressure of the soil water that in turn reduces the amount of water available to the plant, an effect similar to drought. Secondly, if the salt enters the plant it can gradually accumulate to toxic levels in the cells. Both of these effects compromise plant growth and development resulting in lower yield.
Salt tolerant plants are able to survive in saline soils by virtue of an array of channels and pumps that minimise sodium entry into roots. They also control the accumulation of sodium in the vacuole of the cells of both the plant’s roots and shoots.
Traditional methods of screening crops for tolerance to salinity have involved growing plants in saline environments. There has been limited success using this simple selection method as research has consistently shown salt resistance is a complex character controlled by a number of genes or groups of genes and involves a number of component traits which are likely to be quantitative in nature. New methods of developing salt tolerant plants using reverse genetic techniques are being explored and it is one such method that Michael Dow investigated during his PhD at the University of Adelaide.
A reverse genetic approach using a model plant species
Michael used the model cereal plant rice, which has had its genome completely sequenced, as a platform to investigate the molecular basis of salinity tolerance. He focused on transcription factors which are molecules involved in regulating gene expression. They are usually proteins, although they can also consist of short, non-coding RNA. Transcription factors are also usually found working in groups or complexes, forming multiple interactions that allow for varying degrees of control over rates of transcription, which is the first step in gene expression.
Michael generated transgenic rice plants with altered expression of six transcription factors. Previous research had found all six factors alter levels of transcription in salt tolerant plants but not in salt sensitive plants. Altering the expression level of each transcription factor individually allowed the effect of each transcription factor on plant salt tolerance to be assessed.
The altered expression of five of the transcription factors affected the tolerance of the plants to salinity. This was shown by changes in sodium and potassium accumulation and plant dry weight. These five transcription factors were significant similarity to other previously known stress responsive genes, suggesting their involvement in other plant stress responses. Additionally, one transcription factor that Michael identified also affected drought tolerance; these plants had a ‘stay-green’ character under drought stress.
Further experiments are underway at the University of Adelaide to determine the precise role of these transcription factors in plant responses to salt stress.
Where am I now?
Michael is currently working as a Patent Technical Specialist in the Life Sciences area with the patent and trade marks attorney firm Madderns, based in Adelaide. It is a role that he very much enjoys and it draws heavily on his technical skills, and his problem solving and critical thinking skills that he developed during his PhD.
“Research work has a level of repetition that can be tedious and frustrating, it is not for everyone,” says Michael.
“In my current job I juggle several projects at once and each day I have a sense of resolution and success. It is a very dynamic environment to work in and probably more suitable for me than a research career.”
Michael faced a number of challenges during his PhD including a number of delays in propagating plants. He took on postgraduate work in the USA while writing up his thesis and it took him five years to complete his PhD.
“Be aware of what you are taking on when you apply for a PhD,” advises Michael.
“I recommend students thoroughly understand what is involved; the University’s graduate centre is a good place to start such an investigation.”
Michael enjoyed working in a multicultural environment at the Australian Centre for Plant Functional Genomics at the University of Adelaide and also in his post doctoral role in the USA.
“This experience developed my skills in working with people with different expectations, which is very relevant in my current role.”
In his postdoctoral role at Oregon State University Michael juggled several jobs, which included laboratory based work, directing a field trial on poplar trees and as Executive Director of an Outreach Biotechnology Program which worked with high schools. This variety of projects honed his skills in multi-tasking which he continues to use in his work with Madderns.