About

Kathie Therese Hodge is an Associate Professor in the School of Integrative Plant Science, specializing in the classification, evolution, and characterization of fungi, particularly those that cause diseases of plants and insects. She is a mycologist focused on fungal biodiversity, especially of species that are pathogens of insects and molds that spoil foods. Her research employs molecular and morphological approaches to discover relationships among fungi, develop classification systems, and understand factors driving their evolution. She directs the Cornell Plant Pathology Herbarium, a world-class collection documenting fungal biodiversity and plant disease organisms, which holds over 300,000 specimens and more than 60,000 images. Hodge's work includes describing new species and genera, investigating fungal ecology, and understanding their roles in the environment. Notable research includes characterizing Paecilomyces niveus, a mycotoxin-producing mold causing apple rot, and exploring its implications for food safety. She also collaborates on innovative projects such as harnessing electrical signals from fungal mycelia to control biohybrid robots. Her outreach efforts aim to demystify fungi, promote public appreciation, and provide consultations on fungal identification and safety. Hodge has received multiple awards for her teaching, mentoring, and research, and she actively teaches courses at both undergraduate and graduate levels, fostering critical thinking and public understanding of fungi and their roles in health, food security, and the environment.

Research topics

• Botany
• Biology
• Microbiology
• Evolutionary biology
• Genetics
• Zoology
• Horticulture

Selected publications

• Sensorimotor control of robots mediated by electrophysiological measurements of fungal mycelia

  Science Robotics · 2024-08-28 · 26 citations

  article

  Living tissues are still far from being used as practical components in biohybrid robots because of limitations in life span, sensitivity to environmental factors, and stringent culture procedures. Here, we introduce fungal mycelia as an easy-to-use and robust living component in biohybrid robots. We constructed two biohybrid robots that use the electrophysiological activity of living mycelia to control their artificial actuators. The mycelia sense their environment and issue action potential-like spiking voltages as control signals to the motors and valves of the robots that we designed and built. The paper highlights two key innovations: first, a vibration- and electromagnetic interference-shielded mycelium electrical interface that allows for stable, long-term electrophysiological bioelectric recordings during untethered, mobile operation; second, a control architecture for robots inspired by neural central pattern generators, incorporating rhythmic patterns of positive and negative spikes from the living mycelia. We used these signals to control a walking soft robot as well as a wheeled hard one. We also demonstrated the use of mycelia to respond to environmental cues by using ultraviolet light stimulation to augment the robots' gaits.

  PublisherDOI

• Patulin contamination of hard apple cider by Paecilomyces niveus and other postharvest apple pathogens: Assessing risk factors

  International Journal of Food Microbiology · 2024-01-05 · 6 citations

  articleSenior author
  PublisherDOI

• A quantitative PCR assay for detection of the mycotoxigenic plant pathogen and food spoiling mold <i>Paecilomyces niveus</i> in fruit, food, and soil

  bioRxiv (Cold Spring Harbor Laboratory) · 2023-02-18 · 1 citations

  preprintOpen accessSenior author

  Abstract The postharvest fruit pathogen Paecilomyces niveus produces ascospores that can survive some pasteurization temperatures, spoil fruit products, and contaminate them with patulin, an FDA-regulated mycotoxin. Preventing P. niveus from entering food systems requires a robust detection method to effectively determine sources of P. niveus spoilage and disease inoculum. We designed a new robust and culture-independent detection method using species-specific primers (PnPATf/r) based on the patK gene, encoding a 6-methylsalicylic acid synthase, in P. niveus , for use in a rapid qPCR assay. Primer specificity was validated using 24 different P. niveus isolates and 16 other important food spoilage and fruit pathogenic fungi. The threshold for detection of qPCR was 18 genome equivalents. To further validate our new detection method, we demonstrate its use in detecting P. niveus in infected fruits, infested soils and ciders, and in fruit arising from apple blossoms sprayed with a P. niveus spore suspension. Results from this study may help fruit producers address spoilage and patulin contamination by this food spoiling fungus. Highlights New primers specific to Paecilomyces niveus (PnPATf/r) were developed based on the patK gene A qPCR assay to detect P. niveus was validated, and shown to be able to detect quantities of P. niveus DNA as low as 18 genome equivalents The new qPCR assay was used to investigate the ability of P. niveus ascospores to infect strawberry fruits and enter apple fruits through apple blossom infestation

  PublisherOA PDFDOI

• Patulin contamination of hard apple cider by Paecilomyces niveus and other postharvest apple pathogens: assessing risk factors

  bioRxiv (Cold Spring Harbor Laboratory) · 2023-01-17

  preprintOpen accessSenior author

  Abstract Hard apple cider is considered to be a low-risk product for food spoilage and mycotoxin contamination due to its alcoholic nature and associated food sanitation measures. However, the thermotolerant mycotoxin-producing fungus Paecilomyces niveus may pose a significant threat to hard cider producers. Pa. niveus is known to infect apples ( Malus x domestica ), and previous research indicates that it can survive thermal processing and contaminate finished apple juice with the mycotoxin patulin. To determine if hard apple cider is susceptible to a similar spoilage phenomenon, cider apples were infected with Pa. niveus or one of three patulin-producing Penicillium species and the infected fruits underwent benchtop fermentation. Cider was made with lab inoculated Dabinett and Medaille d’Or apple cultivars, and patulin was quantified before and after fermentation. Results show that all four fungi can infect cider apples and produce patulin, some of which is lost during fermentation. Only Pa. niveus was able to actively grow throughout the fermentation process. To determine if apple cider can be treated to hinder Pa. niveus growth, selected industry-grade sanitation measures were tested, including chemical preservatives and pasteurization. High concentrations of preservatives inhibited Pa. niveus growth, but apple cider flash pasteurization was not found to significantly impact spore germination. This study confirms that hard apple cider is susceptible to fungal-mediated spoilage and patulin contamination. Pa. niveus should be of great concern to hard apple cider producers due to its demonstrated thermotolerance, survival in fermentative environments, and resistance to sanitation measures. Highlights Apple fruits of traditional cider cultivars Dabinett and Medaille d’Or were found to be susceptible to infection by three patulin-producing Penicillium spp. and Paecilomyces niveus Pa. niveus can grow in finished fermented hard cider at 5.22% ethanol Patulin levels in cider were reduced by fermentation but still exceeded 50 µg/kg, a maximum limit set by various regulatory agencies Pa. niveus was observed to be able to grow in low concentrations of three preservatives: potassium sorbate, sulfur dioxide, and sodium benzoate

  PublisherOA PDFDOI

• The Early Terrestrial Fungal Lineage of Conidiobolus—Transition from Saprotroph to Parasitic Lifestyle

  Journal of Fungi · 2022 · 23 citations

  • Biology
  • Zoology
  • Evolutionary biology

  group and Ancestral State Reconstruction suggests that the evolution of ballistic conidia preceded the evolution of the parasitic lifestyle.

  PublisherOA PDFDOI

• Susceptibility of rosaceous fruits and apple cultivars to postharvest rot by Paecilomyces niveus

  bioRxiv (Cold Spring Harbor Laboratory) · 2021-04-03

  preprintOpen accessSenior author

  Abstract Paecilomyces rot of apples is a postharvest disease caused by Paecilomyces niveus , a problematic spoiling agent of fruit juices and derivatives. The fungus produces ascospores that can survive food processing and germinate in finished fruit products. Processing apple fruits infected with Paecilomyces rot can lead to P. niveus contaminated juices. Because the fungus produces the mycotoxin patulin, juice spoilage by P. niveus is an important health hazard. Little is known about the disease biology and control mechanisms of this recently described postharvest disease. Following Koch’s postulates, we determined that a range of previously untested rosaceous fruits and popular apple cultivars are susceptible to Paecilomyces rot infection. We also observed that two closely related food spoiling fungi, Paecilomyces fulvus and Paecilomyces variotti , were unable to infect, cause symptoms in, or reproduce in wounded fruits. Our results highlight the unique abilities of Paecilomyces niveus to infect a variety of fruits, produce patulin, and form highly-resistant spores capable of spoiling normally shelf-stable products.

  PublisherOA PDFDOI

• <i>Paecilomyces niveus</i> as a Wound-Infecting Pathogen of Citrus: Oranges and Clementines

  Plant Health Progress · 2020 · 5 citations

  Senior authorCorresponding
  • Biology
  • Horticulture
  • Botany

  Paecilomyces niveus is a heat-resistant mold that can spoil fruit products including orange juice, potentially introducing the regulated mycotoxin patulin. The authors hypothesize this fungus may enter orange juice through infected fruits. This study confirms P. niveus can be a wound-infecting pathogen of both oranges and clementines.

  PublisherOA PDFDOI

• Psychoactive plant- and mushroom-associated alkaloids from two behavior modifying cicada pathogens

  Fungal ecology · 2019-06-24 · 78 citations

  articleOpen access

  Entomopathogenic fungi routinely kill their hosts before releasing infectious spores, but a few species keep insects alive while sporulating, which enhances dispersal. Transcriptomics-and metabolomicsbased studies of entomopathogens with post-mortem dissemination from their parasitized hosts have unraveled infection processes and host responses. However, the mechanisms underlying active spore transmission by Entomophthoralean fungi in living insects remain elusive. Here we report the discovery, through metabolomics, of the plant-associated amphetamine, cathinone, in four Massospora cicadinainfected periodical cicada populations, and the mushroom-associated tryptamine, psilocybin, in annual cicadas infected with Massospora platypediae or Massospora levispora, which likely represent a single fungal species. The absence of some fungal enzymes necessary for cathinone and psilocybin biosynthesis along with the inability to detect intermediate metabolites or gene orthologs are consistent with possibly novel biosynthesis pathways in Massospora. The neurogenic activities of these compounds suggest the extended phenotype of Massospora that modifies cicada behavior to maximize dissemination is chemically-induced.

  PublisherOA PDFDOI

• Evolutionary relationships among <i>Massospora</i> spp. (Entomophthorales), obligate pathogens of cicadas

  bioRxiv (Cold Spring Harbor Laboratory) · 2019-10-21 · 2 citations

  preprintOpen access

  Abstract The fungal genus Massospora (Zoopagomycota: Entomophthorales) includes more than a dozen obligate, sexually transmissible pathogenic species that infect cicadas (Hemiptera) worldwide. At least two species are known to produce psychoactive compounds during infection, which has garnered considerable interest for this enigmatic genus. As with many Entomophthorales, the evolutionary relationships and host associations of Massospora spp. are not well understood. The acquisition of M. diceroproctae from Arizona, M. tettigatis from Chile, and M. platypediae from California and Colorado provided an opportunity to conduct molecular phylogenetic analyses and morphological studies to investigate if these fungi represent a monophyletic group and delimit species boundaries. In a three-locus phylogenetic analysis including the D1–D2 domains of the nuclear 28S rRNA gene (28S), elongation factor 1 alpha-like (EFL), and beta-tubulin (BTUB), Massospora was resolved in a strongly supported monophyletic group containing four well-supported genealogically exclusive lineages, based on two of three methods of phylogenetic inference. There was incongruence among the single-gene trees: two methods of phylogenetic inference recovered trees with either the same topology as the 3-gene concatenated tree (EFL), or a basal polytomy (28S, BTUB). Massospora levispora and M. platypediae isolates formed a single lineage in all analyses and are synonymized here as M. levispora . Massospora diceroproctae was sister to M. cicadina in all three single-gene trees and on an extremely long branch relative to the other Massospora , and even the outgroup taxa, which may reflect an accelerated rate of molecular evolution and/or incomplete taxa sampling. The results of the morphological study presented here indicate that spore measurements may not be phylogenetically or diagnostically informative. Despite recent advances in understanding the ecology of Massospora , much about its host range and diversity remains unexplored. The emerging phylogenetic framework can provide a foundation for exploring co-evolutionary relationships with cicada hosts and the evolution of behavior-altering compounds.

  PublisherOA PDFDOI

• Boyce et al. 2018 Tables S1-S17.xlsx

  Figshare · 2018-01-01

  datasetOpen access

  Supplemental tables for "Discovery of psychoactive plant and mushroom alkaloids in ancient fungal cicada pathogens."

  PublisherDOI

Recent grants

• Digitization TCN: Collaborative: The Microfungi Collections Consortium: A Networked Approach to Digitizing Small Fungi with Large Impacts on the Function and Health of Ecosystems

  NSF · $200k · 2015–2019

Frequent coauthors

• Megan N. Biango‐Daniels

  Tufts University

  27 shared

• Priscila Chaverri

  Universidad de Costa Rica

  14 shared

• Tristan W. Wang

  Plant (United States)

  12 shared

• Richard A. Humber

  Robert W. Holley Center for Agriculture & Health

  12 shared

• Kerik D. Cox

  Cornell University

  10 shared

• Katrin M. Ayer

  Cornell University

  9 shared

• Joseph F. Bischoff

  Sandia National Laboratories California

  8 shared

• Ann E. Hajek

  Cornell University

  8 shared

Labs

• Organic Robotics LabPI

  The Shepherd lab at Cornell University is a recognized authority in the field of Soft Robotics.

Education

• Ph.D., Plant Pathology

  Cornell University

  1998

• M.S., Plant Pathology

  Cornell University

  1993

• B.Sc.

  University of Toronto

  1990

Awards & honors

• 2024 Schwartz Research Fund Award - Recognizing female facul…
• 2024 Donald C.. Burgett Distinguished Advisor Award - Recogn…
• 2022 Stephen H.. Weiss Junior Fellow - Honoring excellence i…
• 2013 CALS Innovative Teacher Award
• 2024 Schwartz Research Fund Award