Hannah Merrill and Elliot Marston

Hannah Merrill is a graduate student with Dr. Xianming Chen and Elliot Marston is a graduate student with Dr. Deven See.

“A Light in the Darkness: History, Phylogeny, Physiology, and Applications of Bioluminescent Fungi”

Elliot Marston, PhD Candidate, See Lab, Department of Plant Pathology

Abstract:

Our record of bioluminescent fungi dates back nearly two millennia, but research into bioluminescent fungi has been sparse. More than 150,000 species of fungi that have been described, but only 71 species are known to bioluminescence. Of the 71 known species of bioluminescent fungi, all are white-rot basidiomycetes and saprotrophs (with the exception of some phytopathogens) that fall into four distinct lineages within the order of Agaricales. A luciferin (heat-stable substrate) and lucerifase (enzyme) mechanism of luminescence was hypothesized but not confirmed until Airth and Foerster used Dubois’ hot-cold extract method in 1959. Failure to replicate their results led researchers to suggest non-enzymatic mechanisms until Oliveira and Stevani verified the results of Airth and Foerster in 2009. Oliveira and Stevani went on in 2012 to confirm cross-reactivity of luciferin and luciferase extracts both within the Mycenoid lineage and between all four lineages of bioluminescent fungi. Originally hypothesized to be a two-enzyme process, the mechanism behind bioluminescence in fungi involves four enzymes and begins with caffeic acid, an organic compound frequently found in many plants and an intermediate of lignin biosynthesis. The genes of the four enzymes directly involved in fungal bioluminescence have been successfully sequenced, cloned, and expressed within several organisms including yeast, tobacco, Arabidopsis, tomato, dahlia, and other ornamental plants. Current applications of fungal bioluminescence include ecological toxicity assays, as well as molecular imaging techniques. With the recent breakthrough in developing a bioluminescence gene cassette specifically for expressing bioluminescence within eukaryotes, there are many opportunities to develop in vivo bioluminescence assays for research and medical applications.

References:

1. Ke, HM and Tsai, IJ. (2022). Understanding and using fungal bioluminescence – Recent progress and future perspectives. Current Opinion in Green and Sustainable Chemistry, 33: 100570.
2. Mihael, JD. (2013). Comparative bioluminescence dynamics among multiple Armillaria gallica, A., mellea, and A. tabescens genets. Fungal Biology, 117: 202 – 210.
3. Oliveira, AG, Desjardin, DE, Perry, BA, Stevani, CV. (2012). Evidence that a single bioluminescent system is shared by all known bioluminescent fungal lines. Photochemical and Photobiological Sciences, 11: 848 – 852.
4. Stevani, CV, Oliveira, AG, Mendes, LF, Ventura, FF, Waldenmaier, HE, Carvalho, RP, and Pereira, TA. (2013). Current Status of Research on Fungal Bioluminescence: Biochemistry and Prospects for Ecotoxicological Applications. Photochemistry and Photobiology, 89: 1318 – 1326.
5. Tsarkova, AS, Kaskova, ZM, and Yampolsky, IV. (2016). A Tale of Two Luciferins: Fungal and Earthworm New Bioluminescent Systems. Accounts of Chemical Research, 49: 2372 – 2380.

More information regarding Elliot’s seminar can be found in the seminar announcement.

“Grapevine Red Blotch”
Hannah Merrill, Master’s degree candidate, Chen Lab,  Department of Plant Pathology

Abstract:
Grapevines are one of the most important and prolific crops grown commercially, with about 6.05 million tons of grapes grown annually in the United States with an average of 69 tons of grapes produced per acre, valued at 5.53 million dollars. Because grapes are such an important crop in the United States, it is important to consider all aspects of grapevine health. Recently, an emergent pathogen called Grapevine Red Blotch (GRBaV) has damaged grapevine and limited production of usable grapes on the west coast and primarily in California and Oregon. One of the primary symptoms of the virus is leafroll, which is indicative of many viruses affecting grapevines, although tests run on diseased grapevines did not yield positive results for any known virus. This led to the discovery of GRBaV and an emphasis has been placed on the study of the pathogen to limit its spread.
Research on GRBaV includes studying the genetic material and determining what causes the spread of the virus. Since being discovered, the genome of 15 isolates have been sequenced, and 2 distinct groups have been identified, although there does not appear to be a biological difference between the two groups. The virus is monopartite and contains a circular strand of ssDNA. Additionally, several studies have been done to determine the ways through which the virus is spread. It was determined through PCR techniques by multiple researchers that GRBaV is spread by an insect vector called the three-cornered alfalfa hopper, Spissistilus festinus. One group concluded that in addition to the insect vector, there is a possibility that there are host plants which do not exhibit symptoms, but rather host the virus until a vector is able to transmit the pathogen, but further research is needed to confirm this hypothesis. A $3 million USDA -NIFA grant has been issued to UC Davis, UC Berkeley, and Oregon State University to continue research on this virus, as the only known treatment for GRBaV is to remove the entire vine. The partnership between these universities will allow progress to be made quickly and ensure successful yield of healthy grapes.

References:
Bahder, B. W., Zalom, F. G., Jayanth, M., and Sudarshana, M. R. 2016. Phylogeny of Geminivirus Coat Protein Sequences and Digital PCR Aid in Identifying Spissistilus festinus as a Vector of Grapevine red blotch-associated virus. Phytopathology®. 106:1223–1230.
Flasco, M., Hoyle, V., Cieniewicz, E. J., Roy, B. G., McLane, H. L., Perry, K. L., et al. 2021. Grapevine Red Blotch Virus Is Transmitted by the Three-Cornered Alfalfa Hopper in a Circulative, Nonpropagative Mode with Unique Attributes. Phytopathology®. 111:1851–1861.
Iowa State University. 2023. Grapes. Agricultural Marketing Resource Center, Iowa State University.
Rumbaugh, A. C., Durbin-Johnson, B., Padhi, E., Lerno, L., Cauduro Girardello, R., Britton, M., et al. 2022. Investigating Grapevine Red Blotch Virus Infection in Vitis vinifera L. cv. Cabernet Sauvignon Grapes: A Multi-Omics Approach. IJMS. 23:13248.
Quinton, A. 2019. Grapevine Red Blotch Disease Threatens U.S. Grape Industry. UC Davis.
Sudarshana, M. R., Perry, K. L., and Fuchs, M. F. 2015. Grapevine Red Blotch-Associated Virus, an Emerging Threat to the Grapevine Industry. Phytopathology®. 105:1026–1032.

For more information regarding Hannah’s seminar please see the seminar announcement.