Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Khalil, Hala [1], Wang, Xiben [2], Linning, Rob [1], Joly, David [3], Cram, Dustin [4], Thiessen, Nina [5], Taylor, Greg [5], McCallum, Brent [2], Saville, Barry [6], Bakkeren, Guus [1].

Comparative analysis of transcriptome profiles during infection of near-isogenic susceptible or resistant wheat lines by various Puccinia triticina races; time courses reveal race-specific pathogenicity factors and corresponding host.

The degree of pathogen-host intrinsic compatibility is genetically controlled by both organisms. Recently, high-throughput sequencing approaches have expanded our view to another level of understanding the response of plant to fungus invasion and vice versa. Here we compared the global gene expression dynamics and transcriptional consequences of both wheat leaf rust fungus P. triticina (Pt) and wheat T. aestivum (Ta) host genes during four genetically defined interactions. Four Pt races, BBBD (representing the race 1 reference genome sequence), MBDS, SBDG and FBDJ, were inoculated on Thatcher, the highly susceptible wheat cultivar, and two near-isogenic lines (NILs) carrying the wheat leaf rust resistance genes Lr2a and Lr3. These combinations represent various infection types (ITs) from highly susceptible (IT3 or 4), intermediate resistant (IT2), to highly resistant (IT1) triggering necrosis, that were sampled over a two-week period. Transcript profiles were generated from interactive cDNA libraries by illumina RNA sequencing technology and a workflow was developed to analyze comprehensively global relative expression levels of both Pt and Ta genes by mapping transcripts to the Pt race 1 reference genome and to the draft Ta genome from the International Wheat Genome Sequencing Consortium. Comparing expression profiles during various interactions (pathogen x host x time) identified candidate fungal and host genes that may be responsible for virulence and defense, respectively. The expression profiles of a specific fungal subset of 711 in planta-expressed Candidate Secreted Effector Protein (CSEP) genes sampled throughout all (pathogen x host x time) interactions, revealed consecutive waves of their expression during infection. A comparison between compatible and incompatible interactions revealed NIL-specific genes exclusively expressed during incompatibility and these could be responsible for the defense in wheat to cope with the rust fungus. These results shed light on the molecular basis of the behaviour of rust races and host responses during infection and will identify pathogen genes crucial for virulence and host defense genes that all can be used for targeted crop protection.

1 - Agriculture & Agri-Food Canada, Pacific Agri-food Research Center, Summerland, BC, Canada
2 - Cereal Research Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, R6M 1Y5, Canada
3 - Moncton University, Department of Biology, Moncton, NB, Canada
4 - Plant Biotechnology Institute, National Research Council of Canada, Saskatoon, SK, Canada
5 - Genome Science Centre, Vancouver, BC, Canada
6 - Trent University, Peterborough, ON, Canada

Keywords:
Transcriptome profiles
Pathogenicity
leaf rust
High-throughput Sequencing
Illumina RNA sequencing
CSEPs.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PPA018
Abstract ID:460
Candidate for Awards:None