Abstract Detail

Biological Control of diseases and weeds (CFBC)

Chu, Mingguang [1], Song, Tao [1], Yu, Fengqunq [1], Gossen, Bruce D. [2], Peng, Gary [3].

The effect of sethoxydim on transcriptome of green foxtail and its potential role in synergizing Pyricularia setariae for improved weed control.

The herbicide sethoxydim at sub-lethal rates enhances efficacy of Pyricularia setariae Niskada, a mycoherbicide agent, in biocontrol of green foxtail (GFT, Setaria viridis), presumably due to a predisposition of GFT by the herbicide. To understand mechanisms involved in this interaction, this study examined transcriptomic responses of GFT induced by the herbicide and/or fungal infection. A reference GFT transcriptome was constructed using de novo assembly of reads from RNA sequencing (RNA-seq) on a mixture of RNA samples isolated from untreated GFT tissues collected from germination to heading stages. In a greenhouse, two GFT populations, susceptible and resistant (G1-S and G1-R) to sethoxydim respectively, were treated at the 3-leaf stage with the herbicide at a quarter of the recommended rate, and then inoculated with a fungal suspension (2 ×10⁶ conidia/ml) 24 h later. Inoculated plants were placed in a dew chamber for 24 h to allow fungal infection. The second leaves were sampled at 48 and 96 h after inoculation and subjected to RNA-seq analysis to identify the groups of differentially expressed genes (DEGs) which were further functionally annotated according to Gene Ontology (GO) terms using the Blast2GO software. The predisposition of G1-S by the herbicide enhanced the weed control by P. setariae; the combined treatment was more effective when compared to either the herbicide or fungus applied alone. RNA-seq identified down regulation of several groups of genes in G1-S upon herbicide treatment that may be involved in host defense responses. These changes were not observed with G1-R. The suppression of gene expression may be related to increased virulence by P. setariae on herbicide-treated G1-S and to the synergism in weed control.

1 - Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
2 - Agriculture and Agri-Food Canada, Sasktoon Research Centre, 107 Science Pl., Saskatoon, SK, S7N 0X2, Canada
3 - Agriculture and Agri-Food Canada, Saskatoon Research Centre, 107 Science Place, Saskatoon, SK, S7N )X2, Canada

Keywords:
Gene ontology
Greenfoxtail
biocontrol
synergism
Transcriptome
denovo assembly.

Presentation Type: Oral Paper:Papers for Topics
Session: 75
Location: Salon 2/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 4:00 PM
Number: 75002
Abstract ID:591
Candidate for Awards:None