FINAL REPORT Submitted to the Office of the Science Advisor U.S. Agency for International Development ROLE OF HYDROXMUIC ACIDS IN CEREAL-APHID INTERACTIONS Principal Investigator : Hermann M. Niemeyer Granted Institution Facultad de Ciencias Universidad de Chile Project Number 7.012 Grant Number DPE-5542-G-SS-8077-00 Project duration September 1988 to August 1991 2 Table of contents Executive Summary 3 Research Objectives 4 Impact and Relevance of the Project 5 Project Activities/Outputs 6 Publications 6 International meetings 7 National meetings 9 Visitors to the laboratory 10 Latin American fellows trained in the laboratory 11 Chilean students trained in the laboratory 11 Project Productivity 12 Future work 13 3 zxeutive suMaMy Aphids are a major group of insect pests causing severe losses eiher through direct feeding damage or as a result of transmitting plant viruses. One important management strategy to reduce their impact is to select and breed for resistant plants. At present, this is a long and difficult procedure; however, new technologies in molecular biology hold great promise and will change the way selection procedures are conducted. To take full advantage of these technologies, research on mechanisms of resistance is required and the relationships between gene products, insect fitness and crop damage need to be clearly understood. This project has examined the role of a group of secondary chemicals in wheat (hydroxamic acids - Hx) as aphid resistant factors in the plant. Specific objectives have been to evaluate antixenosis of Hx towards aphids; to determine the effect of Hx on transmission of barley yellow dwarf virus by aphids, to study the effects of Hx on aphid parasitoids and predators, to describe ways of increasing Hx concentrations in wheat, and to explore mechanisims of toxicity o± Hx. We have shown that Hx are feeding deterrents towards aphids; that virus transmission by aphids is decreased by Hx in the plant; that high levels of Hx in wheat plants have a favorable effect on a main aphid predator; that germplasm leading to high Hx levels in the plant exists among close relatives of wheat; and that the toxicity of Hx may be due to the inhibition of key metabolic enzymes. The results of this project have given rise to 22 publications in international journals, and have been presented at 10 international meetings. As a result of this project, 15 graduate and undergraduate students have been trained, and the laboratory is conditioned to carry cut in a modern way research in a wide range of topics related to Entomology, Biochemistry and Chemistry, and thus to approach agricultural problems in a multidisciplinary way. 4 Research objectives Two main components of integrated pest management are host lant resistance and biological control. However, the increase of atural resistance of crops to pests, for example through an ncrease in the concentration of plant secondary metabolites hich may act as defensive compounds, is not devoid of risks due o possible effects at other levels in the food chain. dditionally, the efficient manipulation of the concentration oZ secondary metabolite rests on knowledge of its mechanism of ction. In this project, the role of h~droxamic acids in the efense of wheat against aphids was examined, their effect on opulations of an important aphid predator determined and their hemical mechanism of toxicity explored. Research efforts on wheat resistance to barley yellow dwarf irus are mainly directed towards finding specific resistance in he infected plant. In this project emphasis was shifted to the ontrol of virus transmission -.hrough the antibiotic and ntixenotic effects of hydroxamic acids on the virus vector. Breeding programs for resistance are normally based on time­ onsuming and costly infestation ratings. In this project, vidence was sought for the use of hydroxamic acids as markers or aphid resistance in wheat and for the existance of suitable arental germplasm for breeding. Several organizationb have been involved in providing upport complementary to that granted by US-AID. The nternational Program in the Chemical Sciences at the University f Uppsala, Sweden (IPICS) has provided research funds and funds o launch a training program in Ecological Chemistry in Latin merica. The International Foundation for Science (IFS) has rovided research grants to staff members and graduate students n the laboratory. The British Council (BC) has provided funds or visits by Chilean scientists to the UK and by British cientists to Chile. 5 Impact and Relevance of the Project During the past few years there has been a continued decrease in the relative importance of aphids among the factors decreasing wheat yield in Chile. Wheat breeders in Chile, although supportive of our work, have not become directly involved in it. However, since little is known about factors other than biological control affecting aphid populations in Chile, the work is seen as an important contribution towards understanding aphid-cereal interactions and thus towards being prepared for undesirable aphid population explosions. The appearance of the Russian Wheat Aphid in Chile has produced much local interest in our project. Additionally, our work has called the attention of agronomists who realize the potential of examining other insect-plant interactions from a multidisciplinary viewpoint. The present AID project has permitted the development of a laboratory with reasoneble infrastructure, with capacity to work in a wide range of scientific disciplines, and very attractive to Ph.D. candidates with varying academic backgrounds. The impact in other parts of the world has been considerable. Laboratories in England (University of Southampton, Rothamsted Experimental Station) and in Sweden (Swedish University of Agricultural Sciences), as well as breeding compati-es (Svalbv AB in Sweden) have began projects, mostly in conjunction with our research group, to investigate further the potential of hydroxamic acids as resistance factors in wheat. Our laboratory has received the visits of numerous scientists for periods ranging from days to months. Additionally, mainly with the support of IPICS, the research philosophy of our laboratory is being disseminated towards Latin America through a training program in Ecological Chemistry. Our laboratory has received the visits of several trainees from Latin America. 6 Project Activities/OutputS The productivity of our laboratory may be judged by the publications in scientific journals or monographies, the presentation of papers at international and national meetings, by the visitors the laboratory has received, by the Latin American fellows that have received training in it and by the Chilean students and technicians trained in it. Publicatin 1. Pdrez, F.J. and Niemeyer, H.M. (1989) Reaction of DIMBOA, a Resistance Factor From Cereals, with Papain.Phytochenistry 2&: 1597-1600. 2. Niemeyer, H.M. (1990) The Role of Secondary Plant Compounds in Aphid-Host Interactions, in Aphid-Plant Genotype Interactions, Campbell, R.K. and Eikenbary, R.D., eds., pp. 187-205. 3. Thackray, D.J., Wratten, S.D., Edwards, P.J. and Niemeyer, H.M. (1990) Resistance to the Aphids Sitobion avenae and Rhopalosiphum padi in Gramineae in Relation to Hydroxamic Acid Levels. Annals of Applied Biology l: 573-582. 4. P~rez, F.J (1990) Allelopathic effect of hydroxamic acids from cereals on Avena sativa and A. fatua. Phytocheaistry 22t 773-776. 5. Cuevas, L., Niemeyer, H.M. and Pdrez, F.J. (1990) Reaction of DIMBOA, a Resistance Factor From Cereals, with a- Chymotrypsin. Phytichenistry 29: 1429-1432. 6. PLrez, F.J. and Ormefio-Ndfiez, J. (1990) Root exudates of wild oats (Arena fatua L.): allelopathic affect on Spring wheat (Triticum aestivum L.). Phytocheuistry U0: 2199-2202. 7. Givovich, A. and Niemeyer, H.M. (1991) Hydroxamic Acids Affecting Barley Yellow Dwarf Virus Transmission by the Aphid Rhopalosiphum padi. Entonologia Experimentalis et Applicata 52: 79-85. 8. Wratten, S.D., Martin, J.J., Rhind, D. and Niemeyer, H.M. (1991) Mechanisms of Resistance in Cereals to Pests. ProceedIngs of 1990 Brighton Pest Control Conference-FestA and Diseases-1990. pp. 925-934. 9. Pdrez, F.J. and Ormefio-Ndfiez, J. (1991) Difference in hydroxamic acid content in roots and root exudates of wheat (Triticum aestivum L.) and rye (Secale cereale L.): possible role in allelopathy. Journal of Chemical Ecology 1: 1037­ 1043. 7 10. Niemeyer, H.M. (1991) Secondary Plant Chemicals in Aphid- Host Interactions. Aphid-plant interactions: populations to molecu es. Peters, D.C., Webster, J.A. and Chlouber, C.S., eds., USDA/Agricultural Research Service, Oklahoma State University. pp. 101-111. 11. Copaja, S.V., Barria, B.N. and Niemeyer, H.M (1991) Hydroxamic Acid Content of Perennial Triticeae. Phytochemistry 2D: 1531-1534. 12. Copaja, S.V., Niemeyer, H.H. and Wratten, S.D. (1991) Hydroxamic Acid Levels in Chilean and British Wheat Seedlings. Annals of Applied Biology 1j&: 223-227. 13. Barria, B.N., Copaja, S.V. and Niemeyer, H.M. (1991) Occurrence of DIBOA in Wild Hordeum Species and Relation to Aphid Resistance. Phytochemistry, in press. 14. Bravo, H.R. and Niemeyer, H.M. (1991) Decomposition of 7­ Nitro-2,4-dihydroxy-1,4-benzoxazolin-3-one in Aqueous Solutions. Heterocycles, in press. 15. Quiroz, A. and Niemeyer, H.M. (1991) Reaction of 7­ Substituted-4-hydroxyl-l, 4-benzoxazin-3-ones in Strongly Acidic Media. Heterocycles, in press. 16. Njemeyer, H.M., Copaja, S.V. and Barria, B.N. (1992) Sources of Hydroxamic Acids, Secondary Metabolites in Wheat Conferring Resistance Against Aphids. Hereditas, submitted. 17. Martos, A., Givovich, A. and Niemeyer, H.M. (1992) Effect of DIMBOA, an Aphid Resistance Factor in Wheat, on the Aphid Predator Eriopis connexa Germar (Col.: Coccinellidae). Journal of Chemical Ecology, submitted. 18. Givovich, A., Morse, S., Cerda, H., Niemeyer, H.M., Wratten, S.D. and Edwards, P.J. (1992) Hydroxamic Acid Glucosides in the Honeydew of Aphids Feeding on Cereals, and Their Relation to Aphid Growth Rates. Journal of Chemical Zoology, submitted. International meetings 1. Niemeyer, H.M. and Givovich, A. (1989) The Role of Hydroxamic Acids From Wheat in Pest and disease Resistance. Seventh International Symposium on Insect-Plai.t Relationships, Budapest, Hungary. 2. Niemeyer, H.M., Pdrez, F.J., and Cuevas, L. (1989) Chemical Basis for Toxicity of Hydroxamic Acids from Cereals. 32nd IUPAC Congress, Stockholm, Sweden. 8 3. Niemeyer, H.M., Givovich, A. and Copaja, S.V. (1989) Chemical Basis of Wheat Defense Against Pests and diseases. Annual Meeting of the International Society of Chemical Ecology, Gothemburg, Sweden. 4. Pdrez, F.J. and Gonzalez, L.F. (1990) Auxin high affinity binding sites from coleoptile membranes of avena (Avena sativ L.). 7th Congress of the Federation of European Societies of Plant Physiologists. UmeA, Sweden. 5. Niemeyer, H.M. (1990) Secondary Plant Chemicals in Aphid- Host Interactions. Iriternational Symposium on Aphid-plant interactions: populations to molecules. Stillwater, Oklahoma, U.S.A.. 6. Wratten, S.D., Thackray, D.J., Niemeyer, H.M., Morse, S. and Edwards, P.J. (1990) The Role of Hydroxamic Acids in Wheat and Maize in Conferring Resistance to Aphids. International Symposium on Aphid-plant interactions: populations to molecules. Stillwater, Oklahoma, U.S.A.. 7. Wratten, S.D., Martin, J.J., Rhind, D. and Niemeyer, H.M. (1990) Mechanisms of Resistance in Cereals to Pests. Brighton Peat Control Conference, Pests and Diseases, Brighton, England. 8. Thackray, D.J., Wratten, S.D., Edwards, P.J. and Niemeyer, H.M. (1990) Hydroxamic Acids - Potential Resistance Factors in Wheat Against the Cereal Aphids Si~t navenae and Rhopalosiphum oadi. Brighton Pest Control Conference, Pests and Diseases, Brighton, England. 9. Givovich, A. (1990) Hydroxamic acids affecting Barley Yellow Dwarf Virus transmission by aphids. IFS Regional Meeting on Plant Virusis, Argentina. 10. Copaja, S.V. (1990) Producci6n de Acidos hidroxdmicos en plantas de trigo. III Congreso Latinoamericano do Cromatograffa. Aguas de San PedLro, Brazil. 11. Copaja, S.V. and Barria, B.N. (1990) Acidos hidroxAmicos en la quimiotaxonomia de gramineas silvestres. XIX Congreao Latinoamericano do Qu Wica. Buenos Aires, Argentina. 12. Niemeyer, H.M., Copaja, S.V. and Barria, B.N. (1991) Perennial Triticeae as Source of Hydroxamic Acids, a Resistance Factor in Cereals. First International Triticeae Symposium, Helsingborg, Sweden. 9 National meetings 1. Givovich, A. (1989) Feeding preferences and behavior of Rhopalosiphum padi L. in wheat with different hydroxamic acid levels. IFS Workshop on Chemical Interaction Between Organisms, Santiago, Chile. 2. Copaja, S.V. and Barria, B.N. (1989) Hydroxamic acid content in perennial Triticeae. IFS Workshop on Chemical Interactions Between Organisms, Santiago, Chile. 3. Cuevas, L. (1989) Characterization of cholinesterases from Rhopalosiphum padi and their reaction with DIMBOA. Workshop on Chemical Interacticns Between Organisms, Santiago, Chile. 4. Bravo, H.R. (1989) Chemical reactivity of hydroxamic acids from cereals. IFS Workshop on Chemical Interactions Between Organisms, Santiago, Chile. 5. Pdrez, F.J. and L.F. GonzAlez (1989) Allelopathic effect of hydroxamic acids from wheat on oat Avena sativa L. and on wild oat Avena fatua L. IFS Workshop on Chemical Interactions Between Organisms, Santiago, Chile. 6. Martos, A. (1989) Effect of DIMBOA on development of 9j connexa Germar (Col.: Coccinellidae). IFS Workshop on Chemical Interactions Between Organisms, Santiago, Chile. 7. Quiroz, A. (1989) Behavior of 4-hydroxy-l,4-benzoxazin-3­ ones in strong acic media. IFS Workshop on Chemical Interactions Between Organisms. Santiago, Chile. B Copaja, S.V. and Barria, B.N. (1989) Contenido de Acidos hidrox~micos en gramineas silvestres. XVIII Jornadas Chilenas de QuiaIca, Santiago, Chile. D. Weiss, B. and Bravo, H.R. (1989) Estudio conformacional de 2,4-dihidroxi-7-metoxi-l,4-benzoxazin-3-ona (DIMBOA). XVIII Jornadas Chilenas de Quimca, Santiago, Chile. 10. Bravo, H.R. (1989) Efecto del sustituyente en la descomposici6n de dcidos hidrox~micos ciclicos de cereales. XVIII Jornadas Chilenas de QuInica, Santiago, Chile. 10 Visitors to the laboratory Prof. J. T. Arnason, University of Ottawa, Canada, August 1988 Prof. B.J.R. Philogbne, University of Ottawa, Canada, August 1988 Dr. J. Atkinson, University of Ottawa, Canada, October 1988 Prof. J. R. Cannon, University of Western Australia, Ausralia, November 1988 Prof. J. L. Auclair, University of Montreal, Canada, March-April 1989 Prof. C. A. Oehschlager, University of British Columbia, Canada, November 1989 Prof. G. D. Prestwich, State University of New York, USA, November 1989 Prof. F. A. Einhellig, University of South Dakota, USA, November 1989 Prof. K. S. Brown, Campinas State University, Brazil, November 1989 Prof. T. Norin, Royal Institute of Technology, Sweden, November 1989 Prof. J. Pettersson, Swedish University of Agricultural Sciences, Sweden, November 1989 Prof. P. Baeckstr6m, Royal Institute of Technology, Sweden, November 1989 Dr. S.D. Wratten, Southamton University, England, November 1989, September 1991 Ms. M. Friberg, Pharmacia AB, Sweden, March 1990 Dr. W. F. Tjallingii, Wageningen Agricultural University, The Netherlands, April 1990 Dr. L. Jonsson, Swedish University of Agricultural Sciences, Sweden, April 1990 Dr. F. Dajas, Instituto de Investigaciones Biol6gicas Clemente Estable, Uruguay, June 1990, July 1991 Dr. P. J. Edwards, Southampton University, England, October 1990 Prof. Michael Wink, University of Heidelberg, Germany, December 1990