Location: Forage Seed and Cereal Research UnitTitle: Green leaf volatiles prime for wound response in grasses
|KRONMILLER, BRENT - Oregon State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/3/2019
Publication Date: N/A
Technical Abstract: Forage and turf grasses are routinely cut and grazed upon throughout their lifecycle. When grasses are cut or damaged, they rapidly release a volatile chemical cocktail called green leaf volatiles (GLV). Previously we have shown that mechanical wounding or exposure to GLV released from cut grass, activated a Lt 46 kDa mitogen-activated protein kinase (MAPK) within 3 minutes and a 44 kDa MAPK within 15-20 minutes in the model grass species Lolium temulentum L. (Lt). Currently very little is known concerning the perception, signaling or molecular responses associated with wound stress in grasses. Since GLV are released during wounding, we investigated what genes and signaling pathways are induced in undamaged plants exposed to GLV. RNA-Seq generated transcriptome of Lolium plants exposed to GLV identified 4308 up- and 2794 down-regulated distinct differentially expressed sequences (DES). Gene Ontology analysis revealed a strong emphasis on signaling, response to stimulus and stress related categories. Transcription factors and kinases comprise over 13% of the total DES found in the up-regulated dataset. The analysis showed a strong response within the first hour of GLV exposure, with over 60% of the up-regulated DES being induced. Specifically, sequences annotated for enzymes involved in the biosynthesis of jasmonic acid and other plant hormones, MAPKs and WRKY transcription factors were identified. Interestingly, eleven DES for ferric reductase oxidase, an enzyme involve in iron uptake and transport, were exclusively found in the down-regulated dataset. Twelve DES of interest were selected for qRT-PCR analysis; all displayed rapid induction one hour after GLV exposure and were also strongly induced by mechanical wounding. The information gained from the analysis and previous studies suggests that GLV released from cut grasses transiently primes an undamaged plant’s wound stress pathways for potential oncoming damage, and may have a dual role for inter- as well as intra-plant signaling.