The Jander Lab uses genetic and biochemical approaches to study plant-insect interactions and plant amino acid metabolism. We employ the small crucifer Arabidopsis thaliana (Arabidopsis) as a model system for most of our research.
Myzus persicae (green peach aphids) feeding on an Arabidopsis flower stalk.
The phloem-specific feeding style of aphids poses unique challenges, both to the host plants, which must mount defense responses against herbivores that do little overt damage, and to the aphids, which must adapt to a nutritionally imbalanced and potentially toxic food source. Myzus persicae (green peach aphids) are important agricultural pests and also feed readily from Arabidopsis. We are studying plant recognition of M. persicae salivary components, Arabidopsis gene expression changes induced during aphid feeding, and plant secondary metabolites that contribute to aphid defense. On the aphid side of the interaction, our goals are to identify M. persicae enzymes that detoxify plant metabolites, as well as aphid gene expression changes that are induced in response to plant defenses.
Plant amino acid metabolism
Unlike plants, which can synthesize the complete repertoire of protein amino acids, humans and other animals must obtain certain essential amino acids in their diets. However, despite the nutritional importance of plant-derived amino acids, many aspects of plant amino acid metabolism remain uninvestigated. Recent research in the lab has been focused on studying the function two plant enzymes, threonine aldolase and homocysteine methyltransferase, which were discovered in a mutant screen for Arabidopsis lines with altered seed amino acid content. Whereas threonine aldolase mutations increase seed threonine levels, homocysteine methyltransferase mutations increase seed methionine accumulation. Manipulation of these two enzymes could be used to improve the nutritional value of crop plants in which threonine and/or methionine are limiting for mammalian diets.
Huang, T., Rehak, L. and Jander, G. 2012. meta-Tyrosine in Festuca rubra ssp. commutata (Chewings fescue) is synthesized by hydroxylation of phenylalanine. Phytochemistry 75: 60-66
Jander, G. 2012. Timely plant defenses protect against caterpillar herbivory. Proc Natl Acad Sci U S A 109: 4343-4344
Meihls, L.N., Kaur, H. and Jander, G. 2012. Natural variation in maize defense against insect herbivores. Cold Spring Harbor symposia on quantitative biology 0:
Moldrup, M.E., Geu-Flores, F., de Vos, M., Olsen, C.E., Sun, J., Jander, G. and Halkier, B.A. 2012. Engineering of benzylglucosinolate in tobacco provides proof-of-concept for dead-end trap crops genetically modified to attract Plutella xylostella (diamondback moth). Plant Biotechnology Journal 10: 435-442
Rasmann, S., De Vos, M., Casteel, C.L., Tian, D.L., Halitschke, R., Sun, J.Y., Agrawal, A.A., Felton, G.W. and Jander, G. 2012. Herbivory in the previous generation primes plants for enhanced insect resistance. Plant Physiology 158: 854-863
Rasmann, S., De Vos, M. and Jander, G. 2012. Ecological role of transgenerational resistance against biotic threats. Plant signaling & behavior 7: 447-449
Silva, A.X., Jander, G., Samaniego, H., Ramsey, J.S. and Figueroa, C.C. 2012. Insecticide resistance mechanisms in the green peach aphid Myzus persicae (Hemiptera: Aphididae) I: a transcriptomic survey. PLoS One 7: e36366
Huang, T., Jander, G. and de Vos, M. 2011. Non-protein amino acids in plant defense against insect herbivores: representative cases and opportunities for further functional analysis. Phytochemistry 72: 1531-1537
Jander , G. and Clay, N. 2011. New synthesis--plant defense signaling: new opportunities for studying chemical diversity. J Chem Ecol 37: 429
Adio, A.M., Casteel, C.L., De Vos, M., Kim, J.H., Joshi, V., Li, B., Juery, C., Daron, J., Kliebenstein, D.J. and Jander, G. 2011. Biosynthesis and defensive function of Ndelta-acetylornithine, a jasmonate-induced Arabidopsis metabolite. Plant Cell 23: 3303-3318
Muller, R., de Vos, M., Sun, J.Y., Sonderby, I.E., Halkier, B.A., Wittstock, U. and Jander, G. 2010. Differential effects of indole and aliphatic glucosinolates on lepidopteran herbivores. Journal of Chemical Ecology 36: 905-913
Louis, J., Lorenc-Kukula, K., Singh, V., Reese, J., Jander, G. and Shah, J. 2010. Antibiosis against the green peach aphid requires the Arabidopsis thaliana MYZUS PERSICAE-INDUCED LIPASE1 gene. Plant Journal 64: 800-811
Joshi, V., Joung, J.G., Fei, Z. and Jander, G. 2010. Interdependence of threonine, methionine and isoleucine metabolism in plants: accumulation and transcriptional regulation under abiotic stress. Amino Acids 39: 933-947
Huang, T., Tohge, T., Lytovchenko, A., Fernie, A.R. and Jander, G. 2010. Pleiotropic physiological consequences of feedback-insensitive phenylalanine biosynthesis in Arabidopsis thaliana. Plant Journal 63: 823-835
Jander, G. and Joshi, V. 2010. Recent progress in deciphering the biosynthesis of aspartate-derived amino acids in plants. Mol Plant 3: 54-65
de Vos, M. and Jander, G. 2010. Volatile communication in plant-aphid interactions. Opinion in Plant Biology 13: 366-371
de Vos, M., Cheng, W.Y., Summers, H.E., Raguso, R.A. and Jander, G. 2010. Alarm pheromone habituation in Myzus persicae has fitness consequences and causes extensive gene expression changes. Proc Natl Acad Sci U S A 107: 14673-14678
Ramsey, J.S., MacDonald, S.J., Jander, G., Nakabachi, A., Thomas, G.H. and Douglas, A.E. 2010. Genomic evidence for complementary purine metabolism in the pea aphid, Acyrthosiphon pisum, and its symbiotic bacterium Buchnera aphidicola. Insect Mol Biol 19: Suppl 2, 241-248
Ramsey, J.S., Rider, D.S., Walsh, T.K., De Vos, M., Gordon, K.H., Ponnala, L., Macmil, S.L., Roe, B.A. and Jander, G. 2010. Comparative analysis of detoxification enzymes in Acyrthosiphon pisum and Myzus persicae. Insect Mol Biol 19: Suppl 2, 155-164
Sun, J.Y., Sonderby, I.E., Halkier, B.A., Jander, G. and de Vos, M. 2010. Non-volatile intact indole glucosinolates are host recognition cues for ovipositing Plutella xylostella. J Chem Ecol 0:
Whiteman, N.K. and Jander, G. 2010. Genome-enabled research on the ecology of plant-insect interactions. Plant Physiology 154: 475-478
Wilson, A.C.C., Ashton, P.D., Calevro, F., Charles, H., Colella, S., Febvay, G., Jander, G., Kushlan, P.F., Macdonald, S.J., Schwartz, J.F., Thomas, G.H. and Douglas, A.E. 2010. Genomic insight into the amino acid relations of the pea aphid, Acyrthosiphon pisum, with its symbiotic bacterium Buchnera aphidicola. Insect Molecular Biology 19: 249-258
Clay, N.K., Adio, A.M., Denoux, C., Jander, G. and Ausubel, F.M. 2009. Glucosinolate metabolites required for an Arabidopsis innate immune response. Science 323: 95-101
Joshi, V. and Jander, G. 2009. Arabidopsis methionine gamma-lyase is regulated according to isoleucine biosynthesis needs but plays a subordinate role to threonine deaminase. Physiology 151: 367-378
de Vos, M. and Jander, G. 2009. Myzus persicae (green peach aphid) salivary components induce defence responses in Arabidopsis thaliana. Plant Cell and Environment 32: 1548-1560
Agerbirk, N., de Vos, M., Kim, J.H. and Jander, G. 2009. Indole glucosinolate breakdown and its biological effects. Phytochem Rev 8: 101-120
Lee, M.S., Huang, T.F., Toro-Ramos, T., Fraga, M., Last, R.L. and Jander, G. 2008. Reduced activity of Arabidopsis thaliana HMT2, a methionine biosynthetic enzyme, increases seed methionine content. Plant Journal 54: 310-320
Howe, G.A. and Jander, G. 2008. Plant immunity to insect herbivores. Annual Review of Plant Biology 59: 41-66
de Vos, M. and Jander, G. 2008. Choice and no-choice assays for testing the resistance of A. thaliana to chewing insects. J Vis Exp 0:
de Vos, M., Kriksunov, K.L. and Jander, G. 2008. Indole-3-acetonitrile production from indole glucosinolates deters oviposition by Pieris rapae. Plant Physiology 146: 916-926
C. Bertin, L. A. Weston, T. Huang, G. Jander, T. Owens, J. Meinwald, and F. C. Schroeder. 2007. Grass roots chemistry: meta-tyrosine, an herbicidal non-protein amino acid. Proc Natl Acad Sci USA 43: 16964-16969
J. S. Ramsey, A. C. C. Wilson., M. de Vos, Q. Sun, C. Tamborindeguy, A. Winfield, G. Malloch, D. M. Smith, B. Fenton, S. M. Gray, and G. Jander. 2007. Genomic resources for Myzus persicae: EST sequencing, SNP identification, and microarray design. BMC Genomics 8: 423
M. de Vos, J. H. Kim, and G. Jander. 2007. Biochemistry and molecular biology of Arabidopsis-aphid interactions. BioEssays 29: 871-883
G. Jander, and C. Barth. 2007. Tandem gene arrays: a challenge for functional genomics. Trends in Plant Science 12: 203-210
Barth, C., G. Jander. 2006. Arabidopsis Myrosinases TGG1 and TGG2 have Redundant Function in Glucosinolate Breakdown and Insect Defense. Plant J 46: 549-562
G. Jander, . 2006. Gene Identification and Cloning by Molecular Marker Mapping. Methods in Molecular Biology 323: 115-126
Bush J, Jander G, Ausubel FM. 2006. Prevention and control of pests and diseases. . Methods Mol Biol 323: 13-25
G. Jander, J. Cui, B. Nhan, N.E. Pierce, and F. M. Ausubel. 2001. The TASTY locus on chromosome 1 of Arabidopsis affects feeding of the insect herbivore Trichoplusia ni. Plant Physiology 126: 890-898
Rasmann, S., De Vos, M. and Jander, G. 0. Ecological role of transgenerational resistance against biotic threats. Plant signaling & behavior 7: 447-449
How do plants ward-off insects?
feature released -2008
Understanding how plants protect themselves from insects could lead to the development of crop plants such as canola or cabbage that produce naturally-occurring insect deterrents. Such an advance could significantly reduce the amount of man-made, chemical insecticides released into the environment.
Georg Jander is studying a mechanism by which Arabidopsis plants fend off attacking caterpillars. It involves chemicals produced by the plant – called glucosinolates – which actually attract certain insects, but when these chemicals are broken down by enzymes in the plant or in the insect gut, smaller molecules are released that are natural insect repellents.
It’s known that white cabbage butterflies avoid laying eggs on glucosinolate-producing plants where caterpillars are already feeding. Although earlier work at BTI proved that intact glucosinolates attract egg-laying cabbage butterflies, Jander theorized that a glucosinolate breakdown product was acting as the deterrent. The molecule, called indole-3-acetonitrile, is produced when an enzyme in the caterpillar’s gut reacts with indole glucosinolates in the plant tissue to reduce their toxicity. When the caterpillar regurgitates on the plant, the molecule is left behind. Jander theorized that this molecule signals cabbage butterflies that caterpillars are present,which deters them from laying eggs.
Working with Arabidopsis plants and white cabbage butterflies, Jander’s lab proved that indole-3-acetonitrile in fact deters egg laying. They also found that some Arabidopsis plants naturally produce this molecule in the absence of caterpillar feeding. As a result, Jander believes that nitrile production by the plant is an adaptive mechanism to reduce the caterpillar population on the plant by reducing the number of eggs laid on it.
In other Arabidopsis plants, glucosinolates are converted into indole-3-carbinol when insects feed on them. This molecule reacts with other compounds in the plant to produce new molecules that are toxic to many insects, but attract egg-laying cabbage butterflies. Since indole- 3-actonitrile and indole-3-carbinol are produced from the same starting material, plants seem to face a defensive tradeoff concerning which one to produce. Jander theorizes that a plant’s habitat and the prevalent insect threat determine which molecule is produced in greater abundance.
Plants versus Aphids.
feature released -2007
Picture this: You can’t move, and small insects are eating you alive. That’s the nightmare scenario many plants cope with everyday. One way they do is with chemical weapons.
Glucosinolates, for example, sit benignly inside a cell until it’s punctured—usually by predator feeding. They then mix with certain enzymes from other cells, reacting to yield sharp-tasting, sometimes toxic compounds such as those that give mustard and horseradish their distinctive tanginess.
Because of this phenomenon, “a radish doesn’t taste like a radish until you bite into it,” explains Georg Jander. In one project, he studies interactions of green peach aphids with Arabidopsis to learn more about how plants deploy glucosinolates—and how insect pests get around them.
Aphids on Arabidopsis flower stalk.
Recently, Jander’s lab let aphids snack on a certain Arabidopsis variety and analyzed plant extracts to find which glucosinolates the plant responded with. Although this variety can make 20 different glucosinolates, they found that aphid feeding caused the plant to produce only some of these. The lab also fed aphids sugar solutions containing different glucosinolates to find which affected their reproduction. Of all the glucosinolates in the Arabidopsis strain’s arsenal, only those induced by aphid feeding had a significant negative effect on the insects.
These results seem to indicate that the plant can somehow tell aphids apart from other pests and react accordingly. Its other glucosinolates may be intended for other insects or hungry animals. Jander plans to test both these hypotheses and find out more about how plants differentiate between predators and communicate the need for defensive responses. In the future, such knowledge could help agricultural scientists make crops better equipped to ward off insect herbivores.
Good for You, Bad for Arabidopsis.
feature released -2007
For college students, tight finances often motivate a diet of ramen noodles. For farmers faced with a tough bottom line, though, skimping on livestock feed isn’t an option: while using just one crop for fodder would be cheap and simple, their animals need all of the essential amino acids to stay healthy. Since any one plant can’t provide all of the amino acids in sufficient quantities, farmers fill in the gaps with supplements, at a cost of over a billion dollars a year in the United States.
Developing crops with elevated levels of needed amino acids could cut down on those costs but to engineer fortified foods, scientists need to know more about the pathways plants use to make the compounds. (Like animals, plants need 20 amino acids to make vital proteins, but unlike animals, most plants can make them all). To better understand the pathways, and how tinkering with them might affect other processes in plants, Georg Jander’s lab is trying to make an Arabidopsis plant that contains more threonine. In Arabidopsis seeds, the enzyme threonine aldolase normally converts most threonine into another amino acid, glycine.
Jander’s lab members tried knocking out a gene for threonine aldolase, but found this killed the plant. They then tried making a plant that had no threonine aldolase but extra threonine deaminase, an enzyme that converts threonine into yet another amino acid. The doubly-mutated plant appeared healthy, indicating that excess threonine (not lack of glycine) probably killed the plants with just threonine aldolase knocked out. If the lab can find a way to make healthy, threonine-rich Arabidopsis, other researchers might be able to apply that knowledge to threonine-deficient crops such as soy and rice, making healthy eating a little bit cheaper.
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