Screening of Sugarcane Proteins Associated with Defense against Leifsonia xyli subsp. xyli, Agent of Ratoon Stunting Disease.

Sugarcane is the most important sugar crop and one of the leading energy-producing crops in the world. Ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli, poses a huge threat to ratoon crops, causing a significant yield loss in sugarcane. Breeding resistant varieties is considered the most effective and fundamental approach to control RSD in sugarcane. The exploration of resistance genes forms the foundation for breeding resistant varieties through molecular technology. The pglA gene is a pathogenicity gene in L. xyli subsp. xyli, encoding an endopolygalacturonase. In this study, the pglA gene from L. xyli subsp. xyli and related microorganisms was analyzed. Then, a non-toxic, non-autoactivating pglA bait was successfully expressed in yeast cells. Simultaneously the yeast two-hybrid library was generated using RNA from the L. xyli subsp. xyli-infected sugarcane. Screening the library with the pglA bait uncovered proteins that interacted with pglA, primarily associated with ABA pathways and the plant immune system, suggesting that sugarcane employs these pathways to respond to L. xyli subsp. xyli, triggering pathogenicity or resistance. The expression of genes encoding these proteins was also investigated in L. xyli subsp. xyli-infected sugarcane, suggesting multiple layers of regulatory mechanisms in the interaction between sugarcane and L. xyli subsp. xyli. This work promotes the understanding of plant-pathogen interaction and provides target proteins/genes for molecular breeding to improve sugarcane resistance to L. xyli subsp. xyli.

Copper-Mediated and Palladium-Catalyzed Cross-Coupling of Indoles and N-Methylpyridinium Salts: A Practical Way to Prepare 3-(Pyridin-2-yl)indoles.

Herein, a Pd/Cu bimetallic-catalyzed direct C-H heteroarylation of pyridines via the traceless protecting group strategy is described. A series of N-methyl-activated pyridines and 1-methylindoles are coupled with high regioselectivity to produce the corresponding 3-(pyridin-2-yl)indoles in moderate to good yields, wherein related electron-rich heterocycles (e.g., indole, 1-methylpyrrole, benzofuran, benzo[b]thiophene) are also applicable. Streamlined operation, good functional group tolerance, and late-stage modifications make this twofold C-H activation protocol an attractive route for the synthesis of 3-(pyridin-2-yl)indole derivatives.