ABS18239

Hunting for Orphans genes involved in wheat defence against Septoria tritici blotch & Fusarium head blight disease


  • Oral Presentation
  • Plant Genetics and Evolution
  • 13 Jun 2018 09:00
  • FS-G01, UCD Agriculture and food science Centre
  • View all IPSAM abstracts

Sobia Ajaz*
School of Biology and Environmental science and UCD Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.

CiarĂ¡n Brennan
School of Biology and Environmental science and UCD Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.

Harriet R. Benbow
School of Biology and Environmental science and UCD Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.

Fiona M. Doohan
School of Biology and Environmental science and UCD Earth Institute, College of Science, University College Dublin, Belfield, Dublin 4, Ireland.

*Presenting Author


Bread wheat (Triticum aestivum L.) is the second largest edible cereal crop globally but production is constrained by several fungal pathogens, such as Fusarium graminearum and Zymoseptoria tritici, the causative agents of Fusarium head blight (FHB) and Septoria tritici blotch (STB). Pathogenic stress leads to species-specific adaptation and the emergence of orphan genes in the host. The focus of this study is the identification and characterisation of genes that have specifically evolved for defence and/or disease mitigation in wheat in response to these fungal infections. A novel pipeline has been developed for the mining of wheat genes that are taxonomically restricted at four levels (Family, Tribe, Genus, Species). This pipeline is now being used to identify wheat-specific genes involved in defence against STB and Pooideae specific genes involved in defence against FHB disease. This involves a deductive process of differential expression analysis, iterative homology searches, motif detection, domain archiving and functional profiling. The pipeline was used to mine STB responsive orphan genes from a microarray analysis of susceptible (Gallant) and resistant (Stigg) wheat genotypes in mock and STB scenarios at different post-inoculation time points (4, 8, 12 days). Three candidate genes were functionally characterised using virus-induced gene silencing (VIGS), confirming that these three taxonomically-restricted genes are involved in the wheat-STB interaction. For FHB, the mining of next generation sequencing (NGS) RNAseq data (Gou et al., 2016; Schweiger et al., 2016) was completed, to identify wheat-specific genes involved in defence against FHB disease. Pre-analysis of the two datasets includes de novo assembly of RNAseq reads, and identification of differentially expressed transcripts. The orphan hunting pipeline was used to assign the differentially expressed genes into the four taxonomically restricted levels. Currently, selection of good candidate orphan genes is in progress, and after selection the role of putative orphans in disease resistance will be assessed using virus induced gene silencing (VIGS) and qPCR.