Skip to main content
ARS Home » Midwest Area » West Lafayette, Indiana » Crop Production and Pest Control Research » Research » Publications at this Location » Publication #205055
Title: Expression analysis of defense-related genes in wheat in response to infection by Fusarium graminearum

Author
item KONG, LINGRANG - PURDUE UNIV.
item OHM, HERBERT - PURDUE UNIV.
item Anderson, Joseph

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2007
Publication Date: 11/1/2007
Citation: Kong, L., Ohm, H.W., Anderson, J.M. 2007. Expression analysis of defense-related genes in wheat in response to infection by Fusarium graminearum. Genome. 50:1038-1048.

Interpretive Summary: The fungal pathogen Fusarium graminearum, which causes Fusarium head blight (FHB), continues to pose a serious threat to wheat production worldwide by lowering grain yield, and reducing grain quality due to the production of a mycotoxin. Wheat responds to F. graminearum infection by inducing various defense responses. To determine the genetic basis for this response this study extended previous research by identifying, isolating and characterizing wheat genes whose pattern of expression changed after infection by F. graminearum. The induction and suppression of 51 genes were examined in detail in two resistant genotypes compared with a susceptible genotype to begin identifying their role in the resistance response to F. graminearum. The temporal expression for some of these sequences that encode resistance proteins or defense-related proteins showed FHB induction, suggesting that these genes may play a role in protection against toxic compounds in plant - fungal interactions. On the basis of the comprehensive expression profiling of these various genes we hypothesized that the plant - pathogen interactions may be highly integrated into a network of diverse biosynthetic pathways. The identification of cellular processes that are involved in resistance to FHB will provide Plant Pathologists and other scientists information that they can use to develop durable and effective resistance to FHB.

Technical Abstract: Fusarium head blight (FHB), caused by the fungus Fusarium species, is a worldwide disease of wheat (Triticum aestivum L.). The Chinese cultivar, Ning7840, is one of few wheat cultivars with resistance to FHB. GeneCalling, an open-architecture, mRNA-profiling technology, was used to identify differentially expressed genes induced or suppressed in spikes after infection by Fusarium graminearum in wheat line Ning7840. One hundred twenty five individual cDNA fragments representing different transcripts differentially expressed in wheat spikes were identified. Based on BLASTN and BLASTX analyses putative functions were assigned to some of the unigenes: 28 were assigned function in primary metabolism and photosynthesis, 7 were involved in defense response, 14 in gene expression and regulation, 24 encoded proteins associated with structure and protein synthesis, 42 did not have any homology to the sequences in the database, and 3 genes showed similarities to the cloned multidrug resistance or disease resistance proteins. Of particular interest in this study were genes associated with resistance and defense genes to pathogen infection. Real-time quantitative reverse-transcriptase PCR indicated that of 51 genes tested, 19 genes showed 2-fold or greater induction or suppression in the FHB resistant wheat cultivar Ning7840 in contrast to the water treated control. The remaining 32 genes were not significantly induced or suppressed in Ning7840 compared to the control. Subsequently, these 19 induced or suppressed genes were examined in the wheat line KS24-1 containing FHB resistance derived from Lophopyrum elongatum and Len a FHB susceptible wheat cultivar. The temporal expression for some of these sequences encoding resistance proteins or defense-related proteins showed FHB induction, suggesting that these genes may play a role in protection against toxic compounds in plant - fungal interactions. On the basis of comprehensive expression profiling of various biotic or abiotic response genes revealed by real-time PCR in this study and other supporting data, we hypothesized that the plant - pathogen interactions may be highly integrated into a network of diverse biosynthetic pathways.