Comparative Transcriptome Analysis of Wheat Lines in the Field Reveals Multiple Essential Biochemical Pathways
Manuel Poretti1,2, Alexandros G Sotiropoulos1, Johannes Graf1
1Department of Plant and Microbial Biology, University of Zürich, Zurich, Switzerland.
Frontiers in Plant Science
|October 18, 2021
Summary
Powdery mildew and leaf rust severely impact wheat yield. This study reveals pathogens suppress key wheat defense pathways, including programmed cell death, to evade resistance and reduce crop output.
Area of Science:
- Plant Pathology
- Molecular Biology
- Genetics
Background:
- Cereal crops like wheat face significant yield losses annually due to fungal pathogens such as powdery mildew and rust.
- Understanding the molecular interactions between wheat and these pathogens is crucial for developing effective disease resistance strategies.
- Existing wheat resistance genes offer control, but the underlying mechanisms of pathogen interaction remain largely unknown.
Purpose of the Study:
- To compare the transcriptomic profiles of susceptible and resistant wheat lines upon infection with powdery mildew and leaf rust.
- To identify specific genes and biochemical pathways targeted by these fungal pathogens.
- To elucidate the molecular strategies employed by pathogens to overcome wheat's defense mechanisms.
Main Methods:
- RNA sequencing (RNA-Seq) was employed to analyze gene expression in susceptible and resistant wheat lines under both control and infected conditions.
- Comparative transcriptomic analysis was performed, particularly between near-isogenic lines Thatcher and Thatcher-Lr34.
- Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was utilized to identify suppressed biological processes.
Main Results:
- Infection led to the differential expression of thousands of genes in both susceptible and resistant wheat lines.
- Susceptible lines generally exhibited downregulation of numerous genes following mixed infection.
- Specifically, 753 genes were uniquely downregulated in the susceptible Thatcher line compared to Thatcher-Lr34 upon infection.
- KEGG analysis identified the suppression of six key pathways: nuclear transport, alternative splicing, DNA damage response, ubiquitin-mediated proteolysis, phosphoinositol signaling, and photosynthesis.
Conclusions:
- Powdery mildew and leaf rust pathogens appear to evade wheat defenses by suppressing programmed cell death (PCD) and cellular damage responses.
- Pathogens likely target critical "master regulator" genes within these suppressed pathways.
- Identifying these targeted wheat genes offers potential for novel breeding strategies to enhance wheat disease resistance.
