Department of Entomology | Plant-Insect Interactions Lab

aphids on a leaf

Sajjan Grover

 

Welcome to the Molecular Plant-Insect Interactions Laboratory at the University of Nebraska-Lincoln.

 

Our research focus is on identifying the key components/genes/signaling mechanisms that are involved in modulating plant defenses upon insect herbivory and to understand the mechanisms by which insect salivary proteins/effectors alter the plant defense responses.

 

 

Research
  1. Sorghum defense responses to phloem-feeding aphids. Sorghum, one of the world’s most important monocot crops grown for food, feed, and fuel, suffers severe yield losses due to attack by phloem-feeding insects, including aphids. This project will fill an important gap in current research by utilizing genomic resources to gain insight into the underlying genetic networks and phenotypic traits that contribute to sorghum resistance to aphids. To investigate this, we are utilizing the natural variation in a panel of sorghum inbred lines to elucidate the novel sources of sorghum resistance to sugarcane aphids (SCA). We are using a combination of molecular, biochemical, and electrophysiological approaches to enable better understanding of the genetic basis of sorghum resistance to aphids. The results from this project will provide improved insight as to how endogenous defenses and manipulation of defense signaling networks contribute to the development of more efficient and durable insect pest-resistant varieties of sorghum. This project is recently funded for more than $1.5 Million by the National Science Foundation Faculty Early Career Development Program (CAREER) Program.

    NSF logoOverview of global changes in differentially expressed genes across days for the sugarcane infested resistant (RTx2783) or susceptible (BCK60) sorghum line

     

  2. Long-distance defense signaling in maize-insect interactions. We have identified that the aboveground feeding by aphids on maize rapidly sends a yet unidentified signal(s) to the roots that trigger belowground accumulation of the transcripts encoding insecticidal Maize Insect Resistance-Cysteine Protease (Mir1-CP), signifying a potential role of aboveground to belowground communication in maize defense against the phloem-feeding insects. Recently, we have also discovered that OPDA, an intermediate in the jasmonic acid biosynthesis pathway, can contribute to plant defense against insect pests by enhancing callose accumulation. Callose deposition is one of the defense mechanisms utilized by plants that contribute to sieve element occlusion and thus control infestation by phloem sap-feeding aphids. This study provided some interesting leads on how plant signaling mechanisms may limit insect performance by enhancing callose accumulation, thus providing an early line of defense against the insect.

    Model illustrating intraplant signaling in maize after corn leaf aphid infestation.
  3. Herbivore-Associated Molecular Patterns (HAMPs) in altering plant defenses. Plants have evolved complex defense mechanisms to overcome different stresses, including both biotic and abiotic stresses. At the same time, insects produce a suite of Herbivore-Associated Molecular Patterns (HAMPs) present in the insect oral secretions (regurgitant), saliva, and/or frass may either amplify/suppress the induced plant defenses. We are currently employing proteomic techniques to identify the protein components of caterpillar saliva and frass that modulate plant defenses in sorghum.

    image overview of plant defense responses to HAMPs
  4. Electrical Penetration Graph (EPG) as a tool to study plant-insect interactions. EPG technique is a potent technique to investigate the specifics of plant resistance to piercing/sucking insects. Monitoring this probing behavior is critical in understanding the localization of plant defenses and to determine how plants engage their defense components to restrict aphid feeding. Louis lab has a direct current (DC)-EPG system, which measures the electrical resistance fluctuations produced by the penetrating insect as well as the electromotive force (EMF) signal components that are generated as a result of the aphid feeding. This responsiveness to EMF components is utilized to differentiate between intracellular and intercellular stylet tip positions. When the aphid stylet is inserted intercellularly, the voltage is positive and when inserted intracellularly, the voltage is negative, resulting in potential drops in the signal which is correlated with the physiological condition and defense status of the host.

    Electrical penetration graph (EPG) setup used for characterizing the feeding behavior of aphids on its host plant.

 

 

Publications

Click here to see full publication list and citations at Google Scholar.

1Post-doctoral Research Associate in Louis Laboratory, 2Graduate Student in Louis Laboratory, 3Undergraduate student advised by Dr. Louis, *Co-first authors, #Corresponding author

2016 - present
  1. Basu S1, Pereira A, Pinheiro DH, Wang H, Valencia-Jiménez A, Siegfried BD, Louis J, Zhou X and Vélez AM.(2019) Evaluation of reference genes for real-time quantitative PCR analysis in southern corn rootworm, Diabrotica undecimpunctata howardi (Barber). Scientific Reports, 9: 10703.
  2. Palmer NA, Basu S1, Heng-Moss TM, Bradshaw JD, Sarath G# and Louis J#(2019). Fall armyworm (Spodoptera frugiperda Smith) feeding elicits differential defense responses in upland and lowland switchgrass. PLoS One, 14(6): e0218352.
  3. Varsani S2, Grover S2, Zhou S, Koch KG, Huang PC, Kolomiets M, Williams WP, Heng-Moss T, Sarath G, Luthe DS, Jander G and Louis J# (2019). 12-Oxo-phytodienoic acid acts as a regulator of maize defense against corn leaf aphid. Plant Physiology, 179: 1402-1415.
  4. Tetreault HM, Grover S2, Scully ED, Gries T, Palmer N, Sarath G, Louis J and Sattler SE (2019). Global responses of resistant and susceptible sorghum (Sorghum bicolor) to sugarcane aphid (Melanaphis sacchari). Frontiers in Plant Science, 10: 145.
  5. Nalam VJ, Louis J and Shah J (2019). Plant defense against aphids, the pest extraordinaire. Plant Science, 279: 96-107.
  6. Grover S2, Wojahn B3, Varsani S2, Sattler SE and Louis J# (2019). Resistance to greenbugs in the sorghum nested association mapping population. Arthropod-Plant Interactions, 13: 261-269.
  7. Chapman K2, Marchi-Werle L, Hunt TE, Heng-Moss T and Louis J# (2018). Abscisic and jasmonic acids contribute to soybean tolerance to the soybean aphid (Aphis glycines Matsumura). Scientific Reports, 8: 1514.
  8. Koch KG, Donze-Reiner T, Baird LM, Louis J, Amundsen K, Sarath G, Bradshaw JD and Heng-Moss T (2018). Evaluation of greenbug and yellow sugarcane aphid feeding behavior on resistant and susceptible switchgrass cultivars. BioEnergy Research, 8: 165-174.
  9. Nalam VJ, Louis J, Patel M and Shah J (2018). Arabidopsis-Green Peach Aphid interaction: rearing the insect, no-choice and fecundity assays, and electrical penetration graph technique to study insect feeding behavior. Bio-protocol, 8(15): e2950.
  10. Basu S1, Varsani S2 and Louis J# (2018). Altering plant defenses: Herbivore-associated molecular patterns and effector arsenal of chewing herbivores. Molecular Plant-Microbe Interactions, 31(1): 13-21.
  11. Mondal H, Louis J, Archer L, Patel M, Nalam VJ, Sarowar S, Sivapalan V, Root DD and Shah J (2018). Arabidopsis ACTIN-DEPOLYMERIZING FACTOR3 is required for controlling aphid feeding from the phloem. Plant Physiology, 176: 879-890.
  12. Koch K, Chapman K2, Louis J, Heng-Moss T and Sarath, G (2016). Plant tolerance: A unique approach to control hemipteran pests. Frontiers in Plant Science, 7:1363.
  13. Ray S, Basu S1, Rivera-Vega L, Acevedo FE, Louis J, Felton GW and Luthe DS (2016). Lessons from the far end: caterpillar frass-induced defenses in maize, rice, cabbage and tomato. Journal of Chemical Ecology, 42:1130–1141.
  14. Varsani S2, Basu S1, Williams WP, Felton GW, Luthe DS and Louis J# (2016). Intraplant communication in maize contributes to defense against insects. Plant Signaling & Behavior, 11, e1212800.

    2011 - 2015
  15. Louis J#, Basu S1, Varsani S2, Castano-Duque L, Jiang V3, Williams WP, Felton GW and Luthe DS. (2015). Ethylene contributes to maize insect resistance1-mediated maize defense against the phloem sap-sucking corn leaf aphid. Plant Physiology, 169: 313-324.
  16. Louis J# and Shah J (2015). Plant defence against aphids: the PAD4 signalling nexus. Journal of Experimental Botany, 66 (2): 449-454.
  17. Louis J#, Peiffer M, Ray S, Luthe DS and Felton GW (2013). Host-specific salivary elicitor(s) of European Corn Borer (Ostrinia nubilalis) induce defenses in tomato and maize. New Phytologist, 199: 63-73.
  18. Louis J and Shah J (2013). Arabidopsis thaliana - Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids. Frontiers in Plant Science, 4: 213.
  19. Louis J#, Luthe DS and Felton GW (2013). Salivary signals of European corn borer induce indirect defenses in tomato. Plant Signaling & Behavior, 10.4161/psb.27318.
  20. Cao T, Lahiri I, Singh V, Louis J, Shah J and Ayre BG (2013). Metabolic engineering of raffinose-family oligosaccharides in the phloem reveals alterations in carbon partitioning and enhances resistance to green peach aphid. Frontiers in Plant Science, 4: 263.
  21. Louis J, Gobbato E, Mondal HA, Feys BJ, Parker JE and Shah J (2012). Discrimination of Arabidopsis PAD4 activities in defense against green peach aphid and pathogens. Plant Physiology, 158: 1860-1872. (Featured Cover article, April 2012).
  22. Louis J*, Mondal HA* and Shah J (2012). Green peach aphid infestation induces Arabidopsis PHYTOALEXIN DEFICIENT4 expression at site of stylet penetration. Plant Signaling & Behavior, 7: 11, 1431-1433. *Co-first authors.
  23. Singh V, Louis J, Ayre B, Reese JC and Shah J (2011). TREHALOSE PHOSPHATE SYNTHASE11-dependent trehalose metabolism promotes Arabidopsis thaliana defense against the phloem-feeding insect, Myzus persicae. Plant Journal, 67 (1): 94-104.
  24. Zhu L, Reese JC, Louis J, Campbell L and Chen MS (2011). Electrical penetration graph (EPG) analysis of the feeding behavior of soybean aphids on soybean cultivars with antibiosis. Journal of Economic Entomology, 104 (6): 2068-2072.

    2006 - 2010
  25. Louis J, Kukula K-L, Singh V, Reese JC, Jander G and Shah J (2010). Antibiosis against the green peach aphid requires the Arabidopsis thaliana MYZUS PERSICAE-INDUCED LIPASE1 gene. Plant Journal, 64 (5): 800-811.
  26. Pallipparambil GR, Reese JC, Avila CA, Louis J and Goggin FL (2010). Mi-mediated aphid resistance in tomato: tissue localization and impact on the feeding behavior of two potato aphid isolates with differing levels of virulence. Entomologia Experimentalis et Applicata, 135: 295-307.
  27. Louis J, Leung Q, Pegadaraju V, Reese JC and Shah J (2010). PAD4-dependent antibiosis contributes to the ssi2-conferred hyper-resistance to the green peach aphid. Molecular Plant-Microbe Interactions, 23 (5): 618-627.
  28. Mutti NS, Louis J, Pappan LK, Pappan K, Begum K, Chen MS, Park Y, Dittmer N, Marshall J, Reese JC and Reeck GR (2008). A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant. Proceedings of the National Academy of Sciences USA, 105 (29): 9965-9969.
  29. Pegadaraju V*, Louis J*, Singh V, Reese JC, Bautor J, Feys BJ, Cook G, Parker JE and Shah J (2007). Phloem-based resistance to green peach aphid is controlled by Arabidopsis PHYTOALEXIN DEFICIENT4 without its signaling partner ENHANCED DISEASE SUSCEPTIBILITY1. Plant Journal, 52 (2): 332-341.
  30. Diaz-Montano J, Reese JC, Louis J, Campbell L and Schapaugh WT (2007). Feeding behavior by the soybean aphid (Hemiptera: Aphididae) on resistant and susceptible soybean genotypes. Journal of Economic Entomology, 100 (3): 984-989.
  31. Voothuluru P, Meng J, Khajuria C, Louis J, Zhu L, Starkey S, Wilde GE, Baker CA and Smith CM (2006). Categories and inheritance of resistance to Russian wheat aphid (Homoptera: Aphididae) biotype 2 in a selection from wheat cereal introduction 2401. Journal of Economic Entomology, 99 (5): 1854-1861.

Book Chapters/Proceedings

  1. Felton GW, Chung SC, Estrada-Hernańdez MG, Louis J, Peiffer M and Tian D (2014). Herbivore oral secretions are the first line of protection against plant induced defenses. Annual Plant Reviews, 47: 37-76.
  2. Luthe DS, Louis J, Jin S and Castano-Duque L (2013). Expression of the defense gene mir1 depends on herbivore feeding guild and maize genotype. In “Proceedings of the IOBC/WPRS Working Group - Induced resistance in plants against insects and diseases”, Vol 89: 323-327. M Bardin, B Mauch-Mani, S Mazzotta, P Nicot, C Pieterse, J-L Poessel, M Ponchet and A Schmitt, eds. OIBC/OILB, Avignon, France.
  3. Louis J#, Singh V and Shah J (2012). Arabidopsis thaliana – aphid interaction. The Arabidopsis Book, 10: e0159.
  4. Parker JE, Rietz S, Wirthmüller L, Bartsch M, Bautor J, Pegadaraju V, Louis J, Singh V, Reese J and Shah J (2008). Processes in plant resistance to invasive pathogens and probing insects. In “Biology of Plant-Microbe Interactions”, Vol 6. M. Lorito, S. L. Woo, and F. Scala, eds. IS- MPMI, St Paul, MN.

 

 

Members
Joe Louis image Dr. Joe Louis, Associate Professor joelouis@unl.edu
Prince Zogli image Dr. Prince Zogli, Postdoctoral Research Associate pzogli2@unl.edu
Lise Pingault image Dr. Lise Pingault, Postdoctoral Research Associate lise.pingault@unl.edu
Kait Chapman image Kait Chapman, PhD Student karmit.chapman@gmail.com
Sajjan Grover image Sajjan Grover, PhD Student sajjan.grover@huskers.unl.edu
Karen Da Silva image Karen Da Silva, PhD Student (co-advised with Sydney Everhart, Plant Pathology) kfdsilva@huskers.unl.edu
Mariana Sanchez image Mariana Sanchez, MS Student (co-advised with Ana Velez) mariana.sanchez@huskers.unl.edu
Earl Agpawa image Earl Agpawa, UNL Agricultural Research Division Undergraduate Student Research Program eagpawa@huskers.unl.edu
Ben Bradley image Ben Bradley, Lab Research Assistant, Undergraduate Student benbradley123456@gmail.com

Undergraduate students from University of Texas Rio Grande Valley (UTRGV) as part of NSF Summer Research Experience for Undergraduates (REU) Program
Adryenna Perez image Adryenna Perez, Summer 2019 Juan Raya image Juan Raya, Summer 2019

Lab Alumni
Saumik Basu image Saumik Basu, Postdoctoral Research Associate (2014 – 2017)
Suresh Varsani image Suresh Varsani, Ph.D (2014 – 2018)

Allison Siekman (Summer 2014)
Zhang Jing (Summer 2014; Research Exchange Student from Northwest Agriculture and Forestry University [NWAFU], China)
Shelby Patak (September 2014 – December 2014)
Anqui Li (Summer 2015; Research Exchange Student from NWAFU, China)
Mengke Yuan (Summer 2015; Research Exchange Student from NWAFU, China)
Yizi Mao (September 2015 – January 2016)
Ellis Johnson (January 2016 – May 2017) (Undergraduate Creative Activities and Research Experience [UCARE] Program, UNL)
Braden Wojahn (March 2017 – May 2018) (UCARE Program)
Luisa Valencia (August 2017 – July 2018)

 

 

Teaching

 

electron microscope aphid image
aphid on leaf
  1. Insect Control by Host Plant Resistance (ENTO 409/809): Offered every odd years of Spring semester for resident students and every even years of Summer semester as an online distance education course.

    This graduate-level course (cross-listed for seniors) is designed to understand the innate defense mechanisms used by plants to defend themselves, role of resistant (R) genes, signaling pathways and biotechnology in plant resistance to insects, and assess current research on plant resistance genes and “omic” approaches to understand the insect interactions with host plants.

     

  2. Chemical Ecology of Insect-Plant Interactions (ENTO 835): Offered every even years of Spring semester for resident students.

    This course focuses on direct and indirect plant defenses against herbivory, tritrophic interactions among plant, insect herbivores and herbivore natural enemies, biochemical mechanisms of plant defenses, insect herbivore-produced elicitors of plant defenses, and chemical ecology of insect vectors of plant diseases.

 

 

Outreach and Media

 

The Louis lab organizes and participates in various public scientific education and outreach events. These events include “BugFest”, “Fascination of Plants Day”, “Research Experience for Teachers” Program, “Visits by Scientist” program at Lincoln Public Schools, and “Research Experience for Undergraduate Students” Program.

 

earl with small girljoe's lab at outdoor festivalkait teaching
suresh with small childrenclassroom imagesajjan teaching

 

Media

University of Nebraska – Lincoln’s Institute of Agriculture and Natural Resources Vice Chancellor Mike Boehm joins Alex Voichoskie to explore research at the Louis Lab that is focused on identifying the gene or genes in sorghum that will protect the crop against damaging sugarcane aphids.

Nebraska study to help sorghum defend against sugarcane aphid – FarmProgress

Study of aphid damage in sorghum receives NSF CAREER award – Nebraska Today

Experiments underscore overlooked aspect of defending corn from pest – Nebraska Today

cover photo
   Cover story, Louis J, Gobbato E, Mondal HA, Feys BJ, Parker JE and Shah J (2012). Discrimination of Arabidopsis PAD4 activities in defense against green peach aphid and pathogens. Plant Physiology, 158: 1860-1872.

 

 

 

 

 

Lab News

Louis' photo
Joe Louis was named as the 2019 recipient of the Early Career Innovation Award from the Entomological Society of America. See news release here and here.

August 2019
Sajjan's image Karen's image
Sajjan Grover and Karen Da Silva were awarded the 2019 Widaman Distinguished Graduate Fellowship and Hardin Distinguished Graduate Fellowship, respectively, from the Institute of Agricultural and Natural Resources (IANR), UNL. Congratulations, Sajjan and Karen! A luncheon to honor all those receiving Graduate Fellowships will be held later this Fall.

Adryenna at her poster Juan at his poster
Adryenna Perez and Juan Raya presented their work at the Nebraska Summer Research Symposium (pictured with Sajjan Grover).

July 2019
Earl Agpawa imageEarl Agpawa’s research proposal was awarded a $2,500 grant from the IANR Agricultural Research Division Undergraduate Student Research Program. Congratulations, Earl!

Karen's image Karen Da Silva was named as the 2019 recipient of the I.E. Melhus Graduate Student Symposium Award from the American Phytopathological Society. Congratulations Karen!


We welcome Drs. Lise Pingault and Prince Zogli as the postdoctoral research associates in our lab.
Lise's photoPrince's photo

June 2019
We welcome Adryenna Perez and Juan Raya to our lab from the University of Texas Rio Grande Valley (UTRGV; Kariyat Lab) as part of the NSF Summer Research Experience for Undergraduates (REU) Program.
Adryenna's photoJuan's photo

May 2019
Suresh Varsani at the Graduation Commencement.
suresh and Joe at graduation
Congratulations Dr. Varsani!
Suresh with pillowcase
Suresh Varsani receiving his insect pillow case at the Department of Entomology graduation ceremony.

April 2019
Joe Louis was promoted to Associate Professor and granted tenure at the UNL Promotion and Tenure celebration.
Joe at tenure ceremony
Pictured with UNL College of Agriculture Sciences and Natural Resources Dean Dr. Tiffany Heng-Moss and Department of Biochemistry Chair Dr. Paul Black.

March 2019
ESA award winners
Student winners at the ESA-NCB meeting held March 17-20, 2019, in Cincinnati, OH, were: Kait Chapman, 1st Place Ph.D. poster session; Mariana Sanchez, 1st Place M.S. paper session; and Sajjan Grover, 2019 Graduate Student Scholarship Award. Also pictured are Jordy Reinders (extreme left; Advised by Dr. Lance Meinke), 2nd Place Ph.D. paper session; Blessing Ademokoya (3rd from right; Advised by Drs. Tom Hunt and Bob Wright), 3rd Place Ph.D. paper session; and Lindsay Overmyer (3rd from left; Advised by Dr. Gary Hein), 3rd Place M.S. paper session.

Joe's lab at the ESA meeting
Plant-Insect Interactions Lab at the 2019 North Central Branch-Entomological Society of America annual meeting held at Cincinnati, OH.

Kait Chapman and Sajjan Grover received the North Central Branch-Entomological Society of America Student Travel Scholarships to attend the meeting. Mariana Sanchez received the Graduate Student Travel Award from UNL’s Office of Graduate Studies.

Sajjan receiving his fellowship
Sajjan receiving Wirth-McGowen Memorial Fellowship during the College of Agriculture Sciences and Natural Resources (CASNR) Awards Luncheon. Pictured with Janet Poley (Award sponsor; second from right) and Dr. Tiffany Heng-Moss (CASNR Dean; extreme left).

February 2019
Joe Louis received a five-year $1.5 million Faculty Early Career Development Program (CAREER) award from the National Science Foundation.

October 2018
Sajjan receiving his award
Sajjan Grover receiving the 2018 Hardin Distinguished Graduate Fellowship from the ARD Dean Dr. Archie Clutter.

March 2018
Joe getting his plaque
Joe Louis served as the Program Chair for the North Central Branch-Entomological Society of America annual meeting held at Madison, WI (pictured with Drs. John Ruberson and Michael Parrella)

Kait receiving award
Kait Chapman received the 2018 Graduate Student Scholarship from the North Central Branch-Entomological Society of America (pictured with Drs. John Ruberson and Michael Parrella).

Kait Chapman and Suresh Varsani received the North Central Branch-Entomological Society of America Student Travel Scholarships to attend the meeting.

January 2018
Kait receiving award
Kait received the 2018 Outstanding Research Award from Gamma Sigma Delta, UNL (pictured with ARD Dean, Dr. Archie Clutter).

 

Opportunities

No current openings.

If you are interested in applying for fellowships/grants (graduate or postdoctoral fellowships), please send me an email along with your CV and a brief description of your research interests. Below are the links to some funding sources.

USDA NIFA Fellowship Program

NSF Graduate Research Fellowship Program

NSF Postdoctoral Research Fellowships in Biology (PRFB)

 

 

Contact Us

Email: joelouis@unl.edu

Office phone: (402) 472-8098

Lab Location: 309 Entomology Hall
UNL East Campus

 

 

 

 

UNL Entomology Department Page
Entomology Hall image