Research

Common ragweed has rapidly evolved resistance to ALS-inhibiting herbicides. Waterhemp: Illinois' worst weed. Although it looks like waterhemp, this plant is actually a smooth pigweeed by waterhemp hybrid. Common cocklebur growing in a cornfield. Jianyang Liu Kate Thinglum Michael Bell Sukhvinder Singh Stephanie Rousonelos

A common theme among most of the research projects in my laboratory is variability within weed species. Another uniting feature of my research projects is that nearly all utilize molecular techniques.

Many species owe their success as weeds to their underlying genetic diversity and, consequently, to their ability to adapt to a variety of cropping practices. Probably the best example of weed adaptation to a particular cropping practice is the development of herbicide resistance. For this reason, several past and current projects in my lab focus on the evolution of herbicide resistance. For example, we have characterized several weed populations with resistance to herbicides that inhibit acetolactate synthase (ALS), and identified the underlying mutations in the ALS gene that are responsible for resistance.

More recently, we have been investigating resistance to herbicides that inhibit protoporphyrinogen oxidase (PPO). Waterhemp was the first weed in the world to evolve resistance to this group of herbicides. We determined that an amino acid deletion (rather than a substitution) in a waterhemp PPO gene conferred the resistance. Moreover, this mutation was in a gene that encodes both chloroplast and mitochondria PPOs.

Current efforts in my lab include investigations of glyphosate resistance in waterhemp. In this case, resistance is less "black-and-white" compared to other herbicide resistances, i.e., the level of resistance is not as high and it may be controlled by more than one gene.

Waterhemp is by no means the only weedy Amaranthus (pigweed) species that is commonly found in Illinois. In fact, eight pigweed species (or nine if you distinguish the two waterhemp species) are commonly encountered in our state. Because these species are closely related, they may occasionally hybridize. We are interested in determining if gene exchange among the pigweeds contributes significantly to their weediness. For example, can herbicide resistance move from one pigweed species to another? We are now using various cytogenetic approaches to address questions related to chromosome pairing, gene exchange, and ploidy in the hybrids and backcross progeny. One of the things we have learned is that, although hybrids form relatively easily, genomic incompatibilities may limit subsequent gene introgression.

Herbicide resistance is not the only consequence of genetic variability within weed species. We investigated variability for other traits in common cocklebur. This species is a very widespread and competitive weed, and has a complex taxonomic history. We used molecular fingerprinting to better understand genetic relationships among U.S. cocklebur accessions. These accessions were separated by our molecular markers into two main groups, which followed a north-south distribution. We also determined that different cocklebur accessions varied in their competitive abilibies when grown with soybean.

Modern investigations of weeds are limited by the fact that we do not yet have genomic resources for most of these species. In the next few years, we hope to develop such resources. Such resources will help to elucidate the fascinating ways weeds thwart our attempts to control them, and their unique characteristics that make them weeds!

 

 

Who is actually doing the work?

Jianyang Liu (Post-doc) - Evolutionary history of resistance to Protox-inhibiting herbicides in waterhemp.

Chance Riggins (Post-doc) - Waterhemp genomics.

Kate Thinglum (M.S. student) - Evolutionary history of resistance to Protox-inhibiting herbicides in waterhemp.

Michael Bell (M.S. student) - Glyphosate resistance in waterhemp.

Sukhvinder Singh (Ph.D. student) - IPM of the weedy Chenopodium (lambsquarters) complex.

Stephanie Rousonelos (M.S. student) - Resistance to Protox-inhibiting herbicides in common ragweed.

 

Teaching

CPSC 226 - Introduction to Weed Science

This course, which I teach every fall semester, covers fundamentals of weed biology, ecology, and management. Emphasis is placed on principles that are relevant to both crop and non-crop ecosystems.

After completing this course, students should:

• appreciate weeds from a plant science perspective
• be able to identify important plant families and weed species
• understand basic weed control strategies
• be versed with the chemistry, physiology, and use of herbicides
• be familiar with weed management strategies used in diverse crop/non-crop systems

 

CPSC 428 - Weed Science Practicum

This course, taught during spring semesters, is designed to train students for the North Central Weed Science Society's annual contest. It also provides intensive, hands-on training for students planning internships or careers in weed science or applied crop production. Topics covered include:

• weed and weed seed identification
• sprayer calibration
• herbicide symptomatology
• field diagnostics/problem solving

 

 

Publications

Review articles/book chapters

• Stewart, C. N., Jr., Y. Peng, L. G. Abercrombie, M. D. Halfhill, M. R. Rao, P. Ranjan,  J Hu, R. D. Sammons, G. R. Heck, P. J. Tranel, and J. S. Yuan. 2010. Genomics of glyphosate resistance. Pp xxx in V. Nandula (ed.) Glyphosate Resistance in Weeds. Blackwell Publishing, Ames, In press.
• Stewart, C. N., Jr., P. J. Tranel, D. P. Horvath, J. V. Anderson, L. H. Rieseberg, J. H. Westwood, C. A. Mallory-Smith, M. L. Zapiola, and K. M. Dlugosch. 2009. Evolution of weediness and invasiveness:  charting the course for weed genomics. Weed Sci. In press.
• Tranel, P. J. and F. Trucco. 2009. The Amaranthus complex: a model for weed genomics. Pp. xxx In C. N. Stewart Jr. (ed.) Weedy and Invasive Plant Genomics. Blackwell Publishing, Ames, In press.
• Hu, J., P. J. Tranel, C. N. Stewart Jr., and J. S. Yuan. 2009. Molecular and genomic mechanisms of non-target site herbicide resistance. Pp xxx in C. N. Stewart Jr. (ed.) Weedy and Invasive Plant Genomics. Blackwell Publishing, Ames, In press.
• Tranel, P. J. and D. P. Horvath. 2009. Molecular biology and genomics: new tools for weed science. Bioscience 59:207-215.
• Lee, R. M. and P. J. Tranel. 2008. Utilization of DNA microarrays in weed science research. Weed Sci. 56:283-289.
• Yuan, J. S., P. J. Tranel, and C. N. Stewart Jr. 2007. Non-target-site herbicide resistance: a family business. Trends Plant Sci. 12:6-13.
• Tranel, P. J. and F. Trucco. 2004. Molecular biology applied to weed science. Pages 745-747 In R. M. Goodman (ed.) Encyclopedia of Plant and Crop Science. Dekker, New York.
• Tranel, P. J. 2002.Weeds and weed control strategies, Chapter 17. Pp. 446-471 in M.J. Chrispeels and D. E. Sadava (eds.) Plants, Genes, and Crop Biotechnology, 2nd Edition. Jones and Bartlett Publishers, Boston.
• Tranel, P. J. and T. R. Wright. 2002. Resistance of weeds to ALS-inhibiting herbicides: What have we learned? Weed Sci. 50:700-712.

Research papers

• Trucco, F., T. Tatum, A. L. Rayburn, and P. J. Tranel. 2009. Out of the swamp: Unidirectional hybridization with weedy species may explain Amaranthus tuberculatus‘ prevalence as a weed. New Phytol. In press.
• Lee, R. M., J. Thimmapuram, K. A. Thinglum, G. Gong, A. G. Hernandez, C. L. Wright, R. W. Kim, M. A. Mikel, and P. J. Tranel. 2009. Sampling the waterhemp (Amaranthus tuberculatus) genome using pyrosequencing technology. Weed Sci. 57: In press.
• Zhu, J., W. L. Patzoldt, O. Radwan, P. J. Tranel, and S. J. Clough. 2009. Effects of photosystem-II-interfering herbicides atrazine and bentazon on the soybean transcriptome. Plant Gen. 2:191-205.
• Zhu, J., W. L. Patzoldt, R. T. Shealy, L. O. Vodkin, S. J. Clough, and P. J. Tranel. 2008. Transcriptome response to glyphosate in sensitive and resistant soybean. J. Agric. Food Chem. 56:6355-6363.
• Lee, R. M., A. G. Hager, and P. J. Tranel. 2008. Prevalence of a novel resistance mechanism to PPO-inhibiting herbicides in waterhemp (Amaranthus tuberculatus). Weed Sci. 56:371-375.
• Hugie, J. A., G. A. Bollero, P. J. Tranel, and D. E. Riechers. 2008. Defining the rate requirements for synergism between mesotrione and atrazine in redroot pigweed (Amaranthus retroflexus). Weed Sci. 56:265-270.
• Brotherton, J. E., M. R. Jeschke, P. J. Tranel, and J. M. Widholm. 2007. Identification of Arabidopsis thaliana variants with differential glyphosate responses. J. Plant Physiol. 164:1337-1345.
• Volenberg, D. S., W. L. Patzoldt, A. G. Hager, and P. J. Tranel. 2007. Responses of contemporary and historical waterhemp (Amaranthus tuberculatus) accessions to glyphosate. Weed Sci. 55:327-333.
• Volenberg, D. S., P. J. Tranel, J. F. Holt, F. W. Simmons, S. C. Weller, A. Sharkhuu, and D. E. Riechers. 2007. Assessment of two biotypes of Solanum ptycanthum that differ in resistance levels to imazamox. Weed Res. 47:353-363.
• Patzoldt, W. L. and P. J. Tranel. 2007. Multiple ALS mutations confer herbicide resistance in waterhemp (Amaranthus tuberculatus). Weed Sci. 55:421-428.
• Trucco, F., D. Zheng, A. J. Woodyard, J. R. Walter, T. C. Tatum, A. L. Rayburn, and P. J. Tranel. 2007. Non-hybrid progeny from crosses of dioecious amaranths:  implications for gene flow research. Weed Sci. 55:119-122.
• Patzoldt, W. L., A. G. Hager, J. S. McCormick, and P. J. Tranel. 2006. A codon deletion confers resistance to herbicides inhibiting protoporphyrinogen oxidase. Proc. Natl. Acad. Sci. USA. 103:12329-12334. [Also see associated In This Issue (103:1211-12212) and Commentary (103:12215-122160].
• Trucco, F., T. Tatum, K. R. Robertson, A. L. Rayburn, and P. J. Tranel. 2006. Characterization of waterhemp (Amaranthus tuberculatus) x smooth pigweed (A. hybridus) F1 hybrids. Weed Technol. 20:14-22.
• Trucco, F., A. G. Hager, and P. J. Tranel. 2006. Acetolactate synthase mutation conferring imidazolinone-specific herbicide resistance in Amaranthus hybridus. J. Plant Physiol. 163:475-479.
• Tatum, T. C., R. Skirvin, P. J. Tranel, M. Norton, and A. L. Rayburn. 2005. In vitro procedure for obtaining mitotic chromosomes from weedy Amaranthus species. In Vitro Cell. Dev.-Pl. 41:844-847.
• Rayburn, A. L., R. McCloskey, T. C. Tatum, M. R. Jeschke, and P. J. Tranel. 2005. Genome size analysis of weedy Amaranthus species. Crop Sci. 45:2557-2562.
• Trucco, F., T. Tatum, A. L. Rayburn, and P. J. Tranel. 2005. Fertility, segregation at a herbicide-resistance locus, and genome structure in BC1 hybrids from two important weedy Amaranthus species. Mol. Ecol. 14:2717-2728.
• Zheng, D., W. L. Patzoldt, and P. J. Tranel. 2005. Association of the W574L ALS substitution with resistance to cloransulam and imazamox in common ragweed (Ambrosia artemisiifolia). Weed Sci. 53:424-430.
• Wassom, J. J. and P. J. Tranel. 2005. Amplified fragment length polymorphism-based genetic relationships among weedy Amaranthus species. J. Heredity. 96:410-416.
• Trucco, F., M. R. Jeschke, A. L. Rayburn, and P. J. Tranel. 2005. Promiscuity in weedy amaranths: high frequency of female tall waterhemp (Amaranthus tuberculatus) x smooth pigweed (A. hybridus) hybridization under field conditions. Weed Sci. 53:46-54.
• Patzoldt, W. L., P. J. Tranel, and A. G. Hager. 2005. A waterhemp (Amaranthus tuberculatus) biotype with multiple resistance across three herbicide sites of action. Weed Sci. 53:30-36.
• Trucco, F., M. R. Jeschke, A. L. Rayburn, and P. J. Tranel. 2005. Amaranthus hybridus can be pollinated frequently by A. tuberculatus under field conditions. Heredity 94:64-70.
• Maertens, K. D., C. L. Sprague, P. J. Tranel, and R. A. Hines. 2004. Amaranthus hybridus populations resistant to triazine and acetolactate synthase-inhibiting herbicides. Weed Res. 44:21-26.
• Tranel, P. J., W. Jiang, W. L. Patzoldt, and T. R. Wright. 2004. Intraspecific variability of the acetolactate synthase gene. Weed Sci. 52:236-241.
• Patzoldt, W. L., B. S. Dixon, and P. J. Tranel. 2003. Triazine resistance in Amaranthus tuberculatus (Moq) Sauer that is not site-of-action mediated. Pest Manag. Sci. 59:1134-1142.
• Wassom, J. J., A. W. Knepp, P. J. Tranel, and L. M. Wax. 2003. Variability in photosynthetic rates and accumulated biomass among greenhouse-grown common cocklebur (Xanthium strumarium) accessions. Weed Technol. 17:84-88.
• Ainsworth, E. A., P. J. Tranel, B. G. Drake, and S. P. Long. 2003. The clonal structure of Quercus geminata revealed by conserved microsatellite loci. Mol. Ecol. 12:527-532.
• Tranel, P. J., M. R. Jeschke, J. J. Wassom, D. J. Maxwell, and L. M. Wax. 2003. Variation in soybean (Glycine max (L.) Merr.) interference among common cocklebur (Xanthium strumarium L.) accessions. Crop Prot. 22:375-380.
• Jeschke, M. R., P. J. Tranel, and A. L. Rayburn. 2003. DNA content analysis of smooth pigweed (Amaranthus hybridus) and tall waterhemp (A. tuberculatus): implications for hybrid detection. Weed Sci. 51:1-3.
• Patzoldt, W. L., P. J. Tranel, and A. G. Hager. 2002. Variable herbicide responses among Illinois waterhemp (Amaranthus rudis and A. tuberculatus) populations. Crop Prot. 21:707-712.
• Patzoldt, W. L. and P. J. Tranel. 2002. Molecular analysis of cloransulam resistance in a population of giant ragweed. Weed Sci. 50:299-305.
• Tranel, P. J., J. J. Wassom, M. R. Jeschke, and A. L. Rayburn. 2002. Transmission of herbicide resistance from a monoecious to a dioecious weedy Amaranthus species. Theor. Appl. Genet. 105:674-679.
• Wassom, J. J., P. J. Tranel, and L. M. Wax. 2002. Variation among U.S. accessions of common cocklebur (Xanthium strumarium). Weed Technol. 16:171-179.
• Patzoldt, W. L., P. J. Tranel, A. L. Alexander, and P. R. Schmitzer. 2001. A common ragweed population resistant to cloransulam-methyl. Weed Sci. 49:485-490.
• Tranel, P. J. and J. J. Wassom. 2001. Genetic relationships of common cocklebur accessions from the United States. Weed Sci. 49:318-325.
• Foes, M. J., L. Liu, G. Vigue, E. W. Stoller, L. M. Wax, and P. J. Tranel. 1999. A kochia (Kochia scoparia) biotype resistant to triazine and ALS-inhibiting herbicides. Weed Sci. 47:20-27.
• Foes, M. J., L. Liu, P. J. Tranel, L. M. Wax, and E. W. Stoller. 1998. A biotype of common waterhemp (Amaranthus rudis) resistant to triazine and ALS herbicides. Weed Sci. 46:514-520.
• Tranel, P. J. and K. Keegstra. 1996. A novel, bipartite transit peptide targets OEP75 to the outer membrane of the chloroplastic envelope. Plant Cell 8:2093-2104.
• Tranel, P. J., J. Froehlich, A. Goyal, and K. Keegstra. 1995. A component of the chloroplastic protein import apparatus is targeted to the outer envelope membrane via a novel pathway. EMBO J. 14:2436-2446.
• Tranel, P. J., D. R. Gealy, and G. P. Irzyk. 1993. Physiological responses of downy brome (Bromus tectorum) roots to Pseudomonas fluorescens strain D7 phytotoxin. Weed Sci. 41:483-489.
• Tranel, P. J., D. R. Gealy, and A. C. Kennedy. 1993. Inhibition of downy brome (Bromus tectorum) root growth by a phytotoxin from Pseudomonas fluorescens strain D7. Weed Technol. 7:134-139.
• Tranel, P. J. and J. Dekker. 1992. Inheritance of clomazone tolerance in maize seedlings. Maydica 37:137-142.

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