Enhanced Resistance to Fungal and Bacterial Diseases Due to Overexpression of BSR1, a Rice RLCK, in Sugarcane, Tomato, and Torenia

Abstract

Sugarcane smut caused by Sporisorium scitamineum is one of the most devastating sugarcane diseases. Furthermore, Rhizoctonia solani causes severe diseases in various crops including rice, tomato, potato, sugar beet, tobacco, and torenia. However, effective disease-resistant genes against these pathogens have not been identified in target crops. Therefore, the transgenic approach can be used since conventional cross-breeding is not applicable. Herein, the overexpression of BROAD-SPECTRUM RESISTANCE 1 (BSR1), a rice receptor-like cytoplasmic kinase, was conducted in sugarcane, tomato and torenia. BSR1-overexpressing tomatoes exhibited resistance to the bacteria Pseudomonas syringae pv. tomato DC3000 and the fungus R. solani, whereas BSR1-overexpressing torenia showed resistance to R. solani in the growth room. Additionally, BSR1 overexpression conferred resistance to sugarcane smut in the greenhouse. These three BSR1-overexpressing crops exhibited normal growth and morphologies except in the case of exceedingly high levels of overexpression. These results indicate that BSR1 overexpression is a simple and effective tool for conferring broad-spectrum disease resistance to many crops.

Improvement of Broad-Spectrum Disease-Resistant Rice by the Overexpression of BSR1 via a Moderate-Strength Constitutive Promoter and a Pathogen-Inducible Promoter

“…The BSR1 gene has also been introduced into plants other than rice and has been shown to confer disease resistance. In Arabidopsis , the overexpression of BSR1 under the 35S promoter containing two enhancers resulted in disease resistance to three pathogens, including the bacterium Pst DC3000 as well as fungi C. higginsianum and R. solani [ 13 , 26 ]. When overexpressed in various plants under the same promoter as in Arabidopsis , BSR1 confers disease resistance to Pst DC3000 and R. solani in tomatoes and to R. solani in torenia.…”

“…When overexpressed in various plants under the same promoter as in Arabidopsis , BSR1 confers disease resistance to Pst DC3000 and R. solani in tomatoes and to R. solani in torenia. BSR1 -overexpressed sugarcane is resistant to one of the most serious diseases caused by the fungus Sporisorium scitamineum [ 26 ]. When BSR1 was appropriately expressed in these plants, the transgenic plants exhibited normal growth and morphology similar to that of the WT and retained disease resistance, although a dwarf phenotype was observed in sugarcane with the highest expression level of BSR1 [ 26 ].…”

“…BSR1 -overexpressed sugarcane is resistant to one of the most serious diseases caused by the fungus Sporisorium scitamineum [ 26 ]. When BSR1 was appropriately expressed in these plants, the transgenic plants exhibited normal growth and morphology similar to that of the WT and retained disease resistance, although a dwarf phenotype was observed in sugarcane with the highest expression level of BSR1 [ 26 ]. By selecting appropriate promoters and fine-tuning the expression level of BSR1 , it would be possible to generate plants with broad-spectrum disease resistance without compromising the growth in other crops as well as in rice.…”

BSR1, a Rice Receptor-like Cytoplasmic Kinase, Positively Regulates Defense Responses to Herbivory

“…Among many RLCKs, BSR1 is unique in that its overexpression mediates enhanced resistance. Overexpression of BSR1 confers strong resistance against various fungal and bacterial pathogens in rice, sugarcane, A. thaliana , tomato, and torenia [ 32 , 36 , 37 ].…”

Receptor-like cytoplasmic kinase ScRIPK in sugarcane regulates disease resistance and drought tolerance in Arabidopsis

“…A Glycine soja calcium-dependent calmodulin-binding receptor-like kinase ( GsCBRLK ) is induced by drought, salinity, and abscisic acid (ABA), and its overexpression in Arabidopsis enhances plant tolerance to high salinity and ABA ( Yang et al., 2010 ). A rice RLCK, BRORD-SPECTRUM RESISTANCE 1 ( OsBSR1 ), is overexpressed in tomato, torenia, Arabidopsis , and sugarcane, and those OsBSR1 -overexpressing transgenic plants exhibit resistance to bacteria and/or fungus ( Maeda et al., 2023 ). The RLCK member AtCRK36 interacts with and phosphorylates AtARCK1 to form a complex and negatively control abiotic stress signal transduction ( Tanaka et al., 2012 ).…”