Summary: The potato virus Y (PVY) is a plant virus that causes massive crop losses globally, especially in Solanaceae crops. A strain of the plant growth‐promoting rhizobacterium (PGPR), Serratia marcescens ‐S3 was found to inhibit PVY replication in Nicotiana benthamiana . However, there have been no in‐depth studies demonstrating the underlying mechanism. In the current study, we found that ubiquitination of NbHsc70‐2 is an important way for Serratia marcescens ‐S3 to trigger induced systemic resistance (ISR). After the treatment with S. marcescens ‐S3, the protein level of NbHsc70‐2 reduced significantly. Inhibiting of ubiquitination increased the accumulation of NbHsc70‐2 in plants and reduced S. marcescens ‐S3‐mediated resistance to PVY. Furthermore, transgenic engineered Nicotiana benthamiana NbHsc70‐2 ^KO and NbHsc70‐2 ^USM were constructed using CRISPR‐Cas9‐mediated NbHsc70‐2 knock‐out and ubiquitination respectively. S. marcescens ‐S3 significantly reduced the inhibition of NbHsc70‐2 protein accumulation in NbHsc70‐2 ^KO and NbHsc70‐2 ^USM . The virulence of PVY was stronger in NbHsc70‐2 ^USM than the wild‐type plants. These results showed that S. marcescens ‐S3 increases the ubiquitination of NbHsc70‐2 to inhibit the recruitment of molecular chaperone NbHsc70‐2 to reduce its replication and infection of PVY.

Background: The ATP-binding cassette (ABC) G subfamily, a key member of the ABC protein family, mediates plant stress responses by transporting metabolites across membranes, but its mechanism of action in tomato (Solanum lycopersicum L.) remains poorly understood. Methods: We systematically analyzed the evolutionary relationships, structural characteristics, stress-responsive expression patterns, and functional roles in response to saline-alkali stress of the SlABCG gene family in tomato, using a combination of approaches including phylogenetic analysis (MEGA), gene structure and motif analysis (GSDS, MEME), cis-acting element prediction, homology analysis, transcriptome analysis, protein-protein interaction prediction, and qRT-PCR validation. Results: We identified a total of 41 SlABCG genes from the tomato genome. These genes, together with 43 ABCG genes from Arabidopsis thaliana, were clustered into five distinct clades. There are 35 collinear gene pairs between the SlABCG gene family in tomato and the ABCG gene family in Arabidopsis, while 39 collinear gene pairs exist among ABCG genes within the tomato genome itself.The promoter regions of SlABCG genes contain cis-acting elements associated with responses to salicylic acid, low temperature, and gibberellin stresses. Transcriptome sequencing revealed that six SlABCG genes responded to saline-alkali stress. Gene regulatory network prediction revealed that multiple genes related to saline-alkali stress were regulated. Expression profile analysis of the 25 upregulated genes revealed that all of them were significantly upregulated during the saline-alkali stress treatment. Conclusions: In summary, our results provide deep insights into the characteristics of the SlABCG subfamily, facilitate the design of effective analysis strategies, and offer data support for exploring the roles of ABCG transporters under different stress conditions.