Seed treatment with prodigiosin controls damping-off of cucumber caused by Pythium ultimum

Authors: Roberts, Daniel; Selmer, Kaitlyn; LUPITSKYY, ROBERT - Tic Gums, Inc; Rice, Clifford; Buyer, Jeffrey; Maul, Jude; Lakshman, Dilip; DE SOUZA, JORGE - Federal University Of Lavras

Submitted to: Applied Microbiology and Biotechnology Express (AMB Express)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/14/2020
Publication Date: 1/6/2021
Citation: Roberts, D.P., Selmer, K.J., Lupitskyy, R., Rice, C., Buyer, J.S., Maul, J.E., Lakshman, D.K., De Souza, J. 2021. Seed treatment with prodigiosin controls damping-off of cucumber caused by Pythium ultimum. Applied Microbiology and Biotechnology Express (AMB Express). 11:10. https://doi.org/10.1186/s13568-020-01169-2.
DOI: https://doi.org/10.1186/s13568-020-01169-2

Interpretive Summary: Oomycete soilborne plant pathogens such as Pythium ultimum cause severe economic losses to a wide range of agriculturally important crops. Additional control measures need to be developed for these pathogens as existing measures are sometimes ineffective. For example, cultural methods such as crop rotation can be problematic due to the long-term persistence in soil and wide host range of P. ultimum. Seed treatment with pesticides can be very effective for managing diseases caused by this pathogen, but there are concerns regarding the development of resistance in pathogen populations. We show here that purified prodigiosin from the bacterium, Serratia marcescens can control disease caused by Pythium ultimum when applied as a seed treatment. This work will be useful to scientists as it identifies prodigiosin as a promising compound for development, for control of diseases caused by this important group of plant pathogens.

Technical Abstract: Ethanol extract of cell mass of Serratia marcescens strain N4-5, when applied as a treatment to cucumber seed, has been shown to provide control of the oomycete soil-borne plant pathogen, Pythium ultimum equivalent to that provided by a seed-treatment chemical pesticide in some soils. Two dominant compounds in this extract, prodigiosin and the serratamolide serrawetin W1, were identified based on mass and collision induced dissociation mass fragmentation spectra. An additional four compounds with M+H+ masses (487, 541, 543, and 571) consistent with serratomolides reported in the literature were also detected. Several other compounds with M+H+ masses of 488, 536, 684, 834, 906, and 908 m/z were detected in this ethanol extract inconsistently over multiple LC/MS-MS runs. A purified preparation of prodigiosin provided control of damping-off of cucumber caused by P. ultimum when applied as a seed treatment while ethanol extract of cell mass of strain Tn246, a transposon-mutant-derivative of strain N4-5, did not. Strain Tn246 contained a mini-Tn5 Km insertion in a prodigiosin biosynthetic gene and was deficient in production of prodigiosin. All other compounds detected in N4-5 extract were detected in the Tn246 extract. This is the first report demonstrating that prodigiosin can control a plant disease. Other compounds in ethanol extract of strain N4-5 may contribute to disease control.