A Conversation With... Adrienne Clarke
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A Conversatonwith.. Adrienne Clarke NeilA. Campbell Australiais home to an ex- boards its role is to set policy, to hire (and fire) the traordinarynumber of the chief executive (through the Minister), to monitor the worldleaders in botanicaland progress of the organization, and to make sure that agricultural research, and the financial reporting and the achievements of the AdrienneClarke is one of the organization are consistent with the government's Downloaded from http://online.ucpress.edu/abt/article-pdf/58/1/34/47429/4450069.pdf by guest on 24 September 2021 mostprominent of theseAus- goals. The CSIROboard is very diverse. We have a / _ tralian plant biologists. In farmerwho was an academic chemist before he went * fact, as chairman of the back to the family farm; the chief executive of a big CSIRO board, the national food company; a chief executive from a mining com- agencyfor scienceand tech- pany; someone from the banking sector; another nology, Dr. Clarkeis one of business leader who is also an engineer; someone Australia's most influential who is a union representative; an animal biologist; scientists.I traveledto Aus- and an academic physicist who is the Deputy Vice traliato interviewDr. Clarke Chancellor of Research from a university in Western in her officeat the Universityof Melbourne,where she is Australia. Professorof Botany.Professor Clarke arrived for the inter- view from a meeting with top Australiangovernment Campbell: Is your work as Chairman at CSIRO officials,so it seemedtimely for me to beginby askingher politically sensitive? aboutCSIRO and its nationalimportance. Clarke:Well, because we are a government-funded organization to a large extent-70% of our budget Campbell: What is CSIRO and what is its mission? comes from the government-and we report to the Clarke: CSIRO stands for the Commonwealth Scien- government, there is clearly a political component to tific and Industrial Research Organization. It is the my role. main government body that does research for the benefit of Australia. We do scientific research related Campbell: How do you see science fitting into the to the main economic sectors of the country, primar- country's political and economic landscape? ily mining, energy, and agriculture. We also do a lot Clarke:It is very clear to the State now that science of research on environmental problems. As our econ- and technology are driving our future. Look at min- omy is changing from the traditional base of agricul- ing, where we are very successful. It is tremendously ture and mining, manufacturing is becoming more technology-intensive. People think that it is digging important and so we are putting more emphasis into up a bucket of coal, but mining requires exploring the some aspects of manufacturing technology and infor- earth, scooping out of the mine, scheduling and mation technology. engineering the banks of the pits, moving materialon the railways, and loading of ships. Another example Campbell: What are your responsibilities as Chair- is agriculture;it is absolutely based on technology. man of the CSIRO Board? Look at wheat, for example-the breeding of wheat Clarke: As Chairman of the board my responsibility is varieties, the wheat harvest, the processing, and the to report to government on the research activities of evaluation of flour-people seem to forget that it is all the organization in relation to the governing Act of enormously technology-intensive. Parliament and a set of Ministerial guidelines. The board is drawn from the community and like most Campbell: Would you say that scientists and politi- cians approach problems differently? Clarke:Yes, I think they do. They are under different Nell A. Campbell is a VisitingScholar in the Department of PlantSciences, Universityof California,Riverside, CA 92521. pressures and are from different backgrounds. The scientists, very comfortablewith acknowledging that 34 THEAMERICAN BIOLOGY TEACHER, VOLUME 58, NO. 1, JANUARY1996 they do not know something, can say, "Well, I don't genetic locus with multiple alleles that controls self- know what the answers are," and then set about incompatibility. This gene-the S gene (for self-in- systematically acquiring the knowledge to solve the compatibility)-directs the secretion of a glycoprotein problem. On the other hand, it is often difficult for (that is a sugar joined to a protein) into the cells of the politicians to admit ignorance. They are often under pistil. This is the pistil tissue through which the enormous time pressures to come up with some pollen tubes must grow to reach the ovules and decision and they are subject to bombardment from fertilize eggs. As the pollen tubes grow on their way various interest groups that are often competing. I down to the ovary, they are bathed with the glyco- think politicians and scientists have to understand protein. We isolated the glycoprotein, cloned the each other's culture and try to come to grips with gene, and found, very interestingly, that it is a working productively together. ribonuclease (RNase). That is, it has an enzymatic function to degrade RNA. We believe that it acts as a Campbell: In addition to your position with the toxin to "self" pollen. What happens is that RNAase CSIRO, you also direct the Plant Cell Biology Re- is taken up from the female tissues into the male search Centre at the University of Melbourne. What pollen tube. If it is a self-incompatiblesituation (i.e. if are the research objectives of this group? the pollen and pistil have matching alleles for the S Downloaded from http://online.ucpress.edu/abt/article-pdf/58/1/34/47429/4450069.pdf by guest on 24 September 2021 Clarke:The Plant Cell Biology ResearchCentre is one gene) we can see that the ribosomal RNA of the of the original special research centers set up by the pollen is degraded. Pollen, unlike most other tissues Australian government. In this center we study two and cells, is apparently not able to make more ribo- related fundamental questions in biology: one ques- somal RNA. When pollen is produced, it has all the tion is how plants recognize and resist fungal infec- ribosomal RNA that it is ever going to have. Once it tion, and the other has to do with how plants fertilize is gone, the pollen can no longer produce proteins, themselves or other If plants. you look at flowers, and so growth of the pollen tube grinds to a halt. you will see that many have the female part, the The missing link in all of this, the part we don't pistil, very closely pressed to the male part, the understand yet, is the nature of the product of the S anther. If the flowers were left to their own devices, gene in pollen and what controls the the sperm in the pollen from a particularplant would specificity. How fertilize the female in that same plant. This would is it that the RNAase from the pistil tissue destroys lead to inbreeding and inbreeding depression. So, RNA in self pollen but not in non-self pollen? It is a very early in evolution plants devised a way of very hot topic, and there are many labs around the ensuring outcrossing that would make the female world working on it now. recognize and reject the male from the same plant-a mechanism of self-incompatibility.How the plant can distinguish self from non-self is a very fundamental Campbell: Earlier, you connected your research on question in plant biology. Not only does it tell us self-incompatibility in plants to the plant's defenses something about how plants achieve fertilization, it against pathogens, especially fungi. How are those also tells us more broadly about how plant cells two processes similar? recognize each other. In the animals, cells are recog- Clarke:It is always a little dangerous to draw parallels nized as being self or non-self (foreign) by the im- too finely, but there are simple parallels. If you look mune system. Humans have a circulatingblood sys- at it in the grossest sense, you can imagine that a tem with white blood cells that can recognize and fungal hypha is a bit like a pollen tube because it reject foreign material. We basically understand how grows from the tip and penetrates into the tissues of recognition of foreign materials happens in the ani- the host plant. Another parallelis that in many cases mal system, but we have very little idea at all of how the resistance of the plant to a fungus is controlledby it happens in plants. By understanding how a plant a single gene, which has some resemblance to the recognizes self and non-self pollen, we will get some genetic system I described for self-incompatibilityin insight into how plants recognize and reject other plant fertilization.Some responses of the plant to self foreign invaders such as fungi and other pathogenic pollen and fungal hyphae are similar. One common organisms. response in the arrested growth of an incompatible pollen tube involves the plant depositing a material Campbell: What is the genetic basis for self-incom- called callose. In a fungal infection, one of the things patibility? How does a plant distinguish self and the host plant often does to defend itself is to deposit non-self? callose in its walls and around the penetration site, Clarke: We don't know the full answer yet, but which helps to arrest growth of the fungus and working with plants in the tomato family (such as contain the infection. These are just some of the tomato, tobacco and potato), we found a single parallels. INTERVIEWWITH ADRIENNE CLARKE 35 Tools for learning science ... Campbell: What impact is biotechnology having on agriculture? as a way of knowing Clarke: I think biotechnology promises to change agriculture, possibly most dramaticallyin two areas.