|GILL, UPINDER - University Of Florida|
|LEE, SEONGHEE - University Of Florida|
|MYSORE, KIRANKUMAR - Samuel Roberts Noble Foundation, Inc|
Submitted to: Plant Signaling and Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2018
Publication Date: 12/12/2018
Citation: Gill, U.S., Lee, S., Jia, Y., Mysore, K.S. 2018. Exploring natural variation for rice sheath blight resistance in Brachypodium distachyon. Plant Signaling and Behavior. https://doi.org/10.1080/15592324.2018.1546527.
Interpretive Summary: Sheath blight caused by the soil borne fungus Rhizoctonia solani AG1-IA is one of the major diseases in rice in the world. Genetic resistance in rice against this disease has not been very successful so far. We attempted to address this issue by exploring novel sources of durable resistance in a related model species, Brachypodium distachyon. Screening of Brachypodium accessions identified few lines which showed a resistant response against the sheath blight pathogen, R. solani AG1-IA. We also quantified defense plant hormones in resistant, moderately susceptible, and susceptible Brachypodium lines and found a link between hormone concentration, especially jasmonic acid, and disease resistance. Our results provide a new foundation to explore this area for more durable resistance against sheath blight of rice.
Technical Abstract: Non-host disease resistance is considered to be more durable than gene-for-gene resistance. Therefore, the current study was designed to explore non-host disease resistance in Brachypodium accessions against sheath blight pathogen of rice, Rhizoctonia solani AG1-IA. Brachypodium is considered a model species for several cereal crops, and it has been studied extensively to identify novel sources of non-host disease resistance against cereal crop diseases. A total of 19 Brachypodium accessions were inoculated with Rhizoctonia solani AG1-IA, and different levels of resistance reactions were observed and the concentrations of jasmonic acid (JA) and salicylic acid (SA) in selected resistant (Bd3-1), moderately susceptible (Bd21), and susceptible (Bd30-1) accessions were examined. We found more JA in the resistant accession upon pathogen infection than that in moderately or susceptible accessions. SA in resistant, moderately susceptible, and susceptible accessions did not accumulate specifically in the resistant response. The accumulation of SA was not specifically detected in the resistant accession suggesting resistance to R. solani is carried through the SA-independent defense pathway. This knowledge is useful to investigate non-host resistant mechanism in Brachypodium against the pathogen that causes rice sheath blight disease.