Mycorrhiza-Induced Resistance in Potato Involves Priming of Defense Responses Against Cabbage Looper (Noctuidae: Lepidoptera)

Andrew P Schoenherr; Eric Rizzo; Natasha Jackson; Patricia Manosalva; S Karen Gomez

doi:10.1093/ee/nvy195

Mycorrhiza-Induced Resistance in Potato Involves Priming of Defense Responses Against Cabbage Looper (Noctuidae: Lepidoptera)

Environ Entomol. 2019 Apr 3;48(2):370-381. doi: 10.1093/ee/nvy195.

Authors

Andrew P Schoenherr¹, Eric Rizzo¹, Natasha Jackson², Patricia Manosalva², S Karen Gomez¹

Affiliations

¹ School of Biological Sciences, University of Northern Colorado, Greeley, CO.
² Microbiology and Plant Pathology Department, University of California, Riverside, University Avenue, Riverside, CA.

PMID: 30715218
DOI: 10.1093/ee/nvy195

Abstract

Most plants form mutualistic associations with arbuscular mycorrhizal (AM) fungi that are ubiquitous in soils. Through this symbiosis, plants can withstand abiotic and biotic stresses. The underlying molecular mechanisms involved in mediating mycorrhiza-induced resistance against insects needs further research, and this is particularly true for potato (Solanum tuberosum L. (Solanales: Solanaceae)), which is the fourth most important crop worldwide. In this study, the tripartite interaction between potato, the AM fungus Rhizophagus irregularis (Glomerales: Glomeraceae), and cabbage looper (Trichoplusia ni Hübner) (Lepidoptera: Noctuidae) was examined to determine whether potato exhibits mycorrhiza-induced resistance against this insect. Plant growth, insect fitness, AM fungal colonization of roots, and transcript levels of defense-related genes were measured in shoots and roots after 5 and 8 d of herbivory on mycorrhizal and nonmycorrhizal plants. AM fungal colonization of roots did not have an effect on potato growth, but root colonization levels increased by herbivory. Larval weight gain was reduced after 8 d of feeding on mycorrhizal plants compared with nonmycorrhizal plants. Systemic upregulation of Allene Oxide Synthase 1 (AOS1), 12-Oxo-Phytodienoate Reductase 3 (OPR3) (jasmonic acid pathway), Protease Inhibitor Type I (PI-I) (anti-herbivore defense), and Phenylalanine Ammonia Lyase (PAL) transcripts (phenylpropanoid pathway) was found during the tripartite interaction. Together, these findings suggest that potato may exhibit mycorrhiza-induced resistance to cabbage looper by priming anti-herbivore defenses aboveground. This study illustrates how mycorrhizal potato responds to herbivory by a generalist-chewing insect and serves as the basis for future studies involving tripartite interactions with other pests.

Keywords: host plant resistance; molecular biology; mycology; plant–insect interaction; potato.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Biomass
Body Weight
Herbivory*
Larva
Moths*
Mycorrhizae / physiology*
Plant Roots / metabolism
Plant Shoots / metabolism
Solanum tuberosum / microbiology
Solanum tuberosum / physiology*
Symbiosis