About

Wayne Curtis is a Professor of Chemical Engineering at Penn State University. His research areas include Biotechnology and Synthetic Biology, Energy and Environment, with specific interests in bioprocess design and optimization. His work focuses on chemical production and protein expression from plant tissue cultures, bioreactor design for non-traditional fermentation, and plant genetic engineering. Professor Curtis has contributed to advancing understanding in these fields through extensive research and publication, emphasizing the development of biotechnological solutions for energy, environmental challenges, and agricultural applications.

Research topics

• Biology
• Biochemistry
• Botany
• Computational biology
• Cell biology
• Economics
• Bioinformatics
• Process engineering
• Medicine
• Engineering
• Chemical engineering
• Zoology
• Philosophy
• Biochemical engineering
• Biotechnology
• Linguistics
• Materials science

Selected publications

• Expression of a multigene mushroom luciferin biosynthesis pathway as a pseudo-polycistron in plants

  Scientific Reports · 2025-07-14

  articleOpen accessSenior author

  Mushroom bioluminescence is based on a luciferin/luciferase cycle that includes four catalytic enzymes and a post-translational modifier phosphopantetheinyl-transferase (NpgA). The luciferin cycle includes conversion of the plant cell wall precursor caffeic acid to the mushroom luciferin (3-hydroxyhispidin) substrate-suggesting a logical system for development of in vivo luciferin production rather than addition of exogenous luciferin substrate. In planta luciferin biosynthesis is demonstrated from a polycistronic concatenation of the luciferin pathway genes with intervening self-cleaving intein-F2A peptides. Bioluminescence was greater with NpgA transiently expressed separately from the luciferin biosynthesis (LBS) polycistron in N. benthamiana but was not detectable in tomato even with all genes on separate promoters. Separation of the bioluminescence reporter and luciferin substrate pathway facilitated studies of mushroom luciferase that reveal instability for the luciferin substrate. Agrobacterium expressing the luciferase is shown to be an effective quantitative biosensor for both the presence of luciferin as well as plant tissue quenching of bioluminescence during tissue disruption. Large plant species-dependent differences in bioluminescence assay quenching are observed, with tomato displaying instantaneous suppression comparable to wild-type negative controls. Although bioluminescence is observed using transient luciferin/luciferase co-expression in tobacco (N. benthamiana), luciferin could not be isolated for use in exogenous assay. The challenge of using the mushroom luciferin biosynthesis pathway in transgenic plants as a complementation reporter is discussed in the context of our inability to detect luciferin in tomato transgenic lines after homozygous segregation using digital PCR. The utilization of in vivo mushroom luciferin biosynthesis is anticipated to be increasingly effective in the future based on ongoing gene improvements in pathway biosynthesis subject to the constraint of substrate instability.

  PublisherOA PDFDOI

• A geminivirus attenuation vector for crop protection using episomal plant gene therapy

  Scientific Reports · 2025-07-11 · 2 citations

  articleOpen accessSenior author

  Although plant viruses inflict billions of dollars in global crop yield loss, they also encode functions that can be used for crop protection. A viral vector attenuation strategy is developed that enables modulation of a 'gene therapy' viral vector designed for protective gene delivery. This attenuation vector targets its homologous native viral counterpart, where the A-component of the bipartite tomato mottle virus (ToMoV) viral vector delivers siRNA constructs targeting native viral sequences for which its own genome has been synthetically modified to avoid silencing. A target coat protein replacement viral vector was engineered with a Nano-luciferase reporter gene to quantify effectiveness based on bioluminescence. To silence the target virus, siRNA constructs were designed against the transactivating protein (TrAP) which is responsible for activating the promoter driving the native coat protein transcript. This siRNA was placed in the attenuation vector designed to avoid self-targeting by modifying its own TrAP sequence. Viral infections were initiated in tobacco using Agrobacterium DNA delivery. Measurements at 3, 6, and 9 days post infiltration revealed a significantly reduced luminescence in attenuation treatment demonstrating suppression of the target virus transgene expression. This work sets the stage for a breadth of virus attenuation studies that can be rapidly applied to diverse crop threats.

  PublisherOA PDFDOI

• Publisher Correction: Enabling biocontained plant virus transmission studies through establishment of an axenic whitefly (Bemisia tabaci) colony on plant tissue culture

  Scientific Reports · 2024-12-03

  erratumOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Enabling biocontained plant virus transmission studies through establishment of an axenic whitefly (Bemisia tabaci) colony on plant tissue culture

  Scientific Reports · 2024-11-15 · 4 citations

  articleOpen accessSenior author

  Whiteflies (Bemisia tabaci) and the diseases they transmit are a major detriment to crop yields and a significant contributor to world hunger. The highly evolved interactions of host plant, phloem-feeding insect vector with endosymbionts and persistently transmitted virus represent a tremendous challenge for interdisciplinary study. Presented here is the establishment of a colony of axenic whiteflies on tissue-cultured plants. Efficient colony establishment was achieved by a surface sterilization of eggs laid on axenic phototrophically tissue-cultured plants. The transfer of emerging whiteflies through coupled tissue culture vessels to new axenic plants facilitates robust subculturing and produces hundreds of whitefly adults per month. Whitefly proliferation on more than two dozen plant species is shown as well as in vitro testing of whitefly preference for different plants. This novel multi-organism system provides the high-level of biocontainment required by Federal permitting to conduct virus transmission experiments. Axenic whitefly adults were able to acquire and transmit a begomovirus into tissue-cultured plants, indicating that culturable gut microorganisms are not required for virus transmission. The approach described enables a wide range of hypotheses regarding whitefly phytopathology without the expense, facilities, and contamination ambiguity associated with current approaches.

  PublisherOA PDFDOI

• Transgenic tomato strategies targeting whitefly eggs from apoplastic or ovary-directed proteins

  BMC Plant Biology · 2024-12-26

  articleOpen accessSenior author

  BACKGROUND: Transgenic plants expressing proteins that target the eggs of the ubiquitous plant pest Bemisia tabaci (whitefly) could be an effective insecticide strategy. Two approaches for protein delivery are assessed using the mCherry reporter gene in transgenic tomato plants, while accommodating autofluorescence in both the plant, phloem-feeding whitefly and pedicle-attached eggs. RESULTS: Both transgenic strategies were segregated to homozygous genotype using digital PCR. The first strategy uses a glycotransferase secretion signal peptide. Despite bright apoplastic accumulation, mCherry is not evident in the eggs. The second strategy targets in vivo whitefly eggs, where the mCherry transgene was fused to a protein transduction domain (PTD) to facilitate uptake into the whitefly hemolymph as well as a synthetic vitellogenin ovary-targeting sequence. Phloem-specific expression of the mCherry fusion is achieved from a Commelina viral promoter. Accumulation was not sufficient to be observed in females feeding on these ovary-targeting plants nor in their eggs subsequently laid on non-transgenic plants. Egg protection may be mediated by protease activity which is observed in macerated eggs. CONCLUSIONS: mCherry proved an effective reporter for the desired tissue-specific expression in tomato, but insufficiently sensitive to allow for localization in feeding whiteflies or their eggs. Segregated homozygous transgenic tomato lines were important for drawing these conclusions. The implications of these observations to possible pest-control strategies including preliminary expression of analogous chitinase constructs are discussed.

  PublisherOA PDFDOI

• Transgenic Tomato Strategies Targeting Whitefly Eggs from Apoplastic or Ovary-Directed Proteins

  Research Square · 2024-08-01

  preprintOpen accessSenior author
  PublisherOA PDFDOI

• Enabling biocontained plant virus transmission studies through establishment of an axenic whitefly (Bemisia tabaci) colony on plant tissue culture

  Research Square · 2024-03-04

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Editorial Expression of Concern: Inducible somatic embryogenesis in Theobroma cacao achieved using the DEX-activatable transcription factor-glucocorticoid receptor fusion

  Biotechnology Letters · 2023-08-01

  articleOpen accessSenior author

  The Editor-in-Chief is issuing an editorial expression of concern for this article.Concerns were raised regarding the methodology of this study including: inconsistencies between the methods and figures legends regarding the application of PGRs, three RNA extractions for the replicates from the same tissue rather than three extractions for different replicate cultures, and a lack of samples in Fig. 4 that would show that the embryogenesis would also not happen in non-transgenic explants.

  PublisherOA PDFDOI

• Enabling biocontained plant virus transmission studies through establishment of axenic whitefly (Bemisia tabaci) colony on plant tissue culture

  Research Square · 2023-10-27 · 2 citations

  preprintOpen accessSenior authorCorresponding

  Abstract A colony of axenic ‘sweet potato’ whiteflies (i.e., free from culturable microorganisms) was established on tissue-cultured plants and was used to demonstrate in vitro begomovirus transmission. A co-culture system based on non-viral host cabbage ( Brassica oleracea ) provides for efficient maintenance of a whitefly ( Bemisia tabaci ) colony. The recovery of emerging whiteflies through coupled tissue culture vessels to new axenic plants allows robust subculturing and facilitates the production of hundreds of whitefly adults per month in a 1.1 L tissue culture vessel. This novel ‘communal axenic’ plant-insect-virus (aP-I-V) protocol provides high-level biocontainment to allow for work with genetically modified viruses. Versatility is illustrated by achieving whitefly proliferation on more than a dozen plant species as well as methods for in vitro testing of whitefly preference for different plants – although there were large differences in whitefly accumulation and ease of host use. Although initial colony establishment was achieved with surface sterilization of detached whitefly eggs on vegetatively propagated sweet potato ( Ipomoea batatas ), a much more reliable approach is described based on non-axenic whitefly egg-lay onto axenic phototrophically tissue-cultured plants, followed by surface sterilization of the pedicel-attached eggs. Axenic whitefly adults were able to acquire and transmit tomato mottle virus (ToMoV) (Genus: begomovirus ) from Nicotiana benthamiana tissue cultured material. This indicated the absence of a role for culturable gut microorganisms in the transmission of this begomovirus. Acquisition occurred from tissue-cultured plants initially inoculated with ToMoV via Agrobacterium infective clones as well as from a gamma irradiated sachet of parafilm. An autoclavable membrane device was developed to facilitate a simpler approach to undertake virus transmission in biocontained, axenic plant tissue culture. The methodology described here could be used to address a wide range of questions regarding whitefly feeding on plants as well as their transmission of viruses without the expense, facilities, and contamination risks associated with standard approaches.

  PublisherOA PDFDOI

• In planta Female Flower Agroinfiltration Alters the Cannabinoid Composition in Industrial Hemp (Cannabis sativa L.)

  Frontiers in Plant Science · 2022-07-21 · 13 citations

  articleOpen access

  Industrial hemp is a diploid (2n = 20), dioecious plant, and an essential source of various phytochemical productions. More than 540 phytochemicals have been described, some of which proved helpful in the remedial treatment of human diseases. Therefore, further study of hemp phytochemicals in medicine is highly anticipated. Previously, we developed the vacuum agroinfiltration method, which allows the transient gene expression in hemp tissues including female flowers, where cannabinoids are produced and accumulated. In this study, we attempted to alter the composition of total CBD and THC. The RT-PCR and sanger sequence identified eleven copies of the CBDAS gene, two copies of the THCAS gene, and one CBCAS gene. Binary vectors were constructed to overexpress the CBDAS gene and silence the THCAS gene via RNA interference. The Transcript level of the CBDAS gene was increased by more than 10 times than the plants used as a control, which led to a 54% higher total CBD content. The silencing of the THCAS gene led to downregulation of the THCAS gene, with an 80% reduction in transcript levels, and total THC content was reduced to 43% compared with mock plant. These results suggest that hemp vacuum infiltration is highly effective for metabolic engineering of cannabinoids in hemp.

  PublisherOA PDFDOI

Recent grants

• Low-cost Plant Propagation Bioreactor Development using Cacao

  NSF · $517k · 2010–2015

• Development of a Sustainable Production Platform for Renewable Petroleum Based Oils in Algae

  NSF · $358k · 2008–2012

• BREAD ABRDC: Advanced Technologies to Get Improved Yams in Farmers Hands

  NSF · $648k · 2016–2024

Frequent coauthors

• Steven J. Holmes

  National Institute of Water and Atmospheric Research

  34 shared

• Mary Guthrie

  32 shared

• Hugh B. Wilder

  25 shared

• Charles Zeleny

  25 shared

• W. B. Castle

  25 shared

• C Herrick

  25 shared

• M. F. Guyer

  25 shared

• H. B. Ward

  25 shared

Education

• PhD, Chemical Engineering

  Purdue University

  1989

Awards & honors

• Outstanding Engineering Alumni Award
• Early Career Alumni Recognition Award
• Alumni Achievement Award
• Alumni Fellow Award