Editing of the rice importin gene IMPα1b results in sequestration of TAL effectors from plant cell nuclei

Abstract

Transcription activator-like effectors (TALEs) produced by plant pathogenic bacteria mainly belonging to the genus Xanthomonas cause plant diseases through activation of host susceptibility genes in plant cell nuclei. How TALEs enter plant cell nuclei was not clear until recent studies about PthXo1 and TALI, two TALEs produced by Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), the rice (Oryza sativa) pathogens that cause bacterial blight and bacterial leaf streak, respectively. Here, we report that rice importin IMPα1b serves as a nuclear transport receptor in rice plants to facilitate the nuclear import of PthXo1 and TALI from Xoo and Xoc, respectively. While wild-type (WT) rice plants support the nuclear import of PthXo1 and TALI, nuclear trafficking is defective in OsIMPα1b loss-of-function mutants generated by clustered regularly interspaced short palindromic repeats (CRISPR)–CRISPR-associated 9 (Cas9)-based gene editing. In the edited plants infected by Xoo, OsIMPα1b sequesters PthXo1 from the nucleus, the PthXo1-targeted rice susceptibility gene is no longer activated, and bacterial virulence and blight disease are alleviated as a result. In the edited plants infected by Xoc, OsIMPα1b sequesters TALI from the nucleus, the role of TALI in suppressing rice defense responses is nullified, and rice defense responses are in turn activated to inhibit bacterial virulence and alleviate bacterial leaf streak severity.

Rice small secreted peptide, OsRALF26, recognized by FERONIA‐like receptor 1 induces immunity in rice and Arabidopsis

“…At 1 day after His-OsRALF26 mat treatment, callose was clearly detected as fluorescence under UV (Figure 4f), and the average area of callose deposition was significantly increased (Figure 4g). Bacterial molecular pattern flg22 was used as a positive control and also induced callose deposition, as previously reported (Li et al, 2021;Peng et al, 2022). Taken together, our results suggest that OsRALF26 is able to trigger a series of immune responses involving a ROS burst, induction of PR genes, and callose deposition.…”

Insights into the early transcriptomic response against watermelon mosaic virus in melon

“…Ubiquitin family proteins (MELO3C004438) can target different viral components to prevent virus spread, inhibit viral replication or to mitigate disease symptoms [80,81]. Transmembrane proteins (MELO3C004435) and importins (MELO3C004204) can act as susceptibility factors and have also been related to silencing responses [82][83][84][85]. Exoribonucleases (MELO3C004356) can negatively regulate the accumulation of viruses [86,87].…”

Breeding Melons for Resistance to Viral and Fungal Diseases. Exploiting the Multi-Resistant Accession TGR-1551

“…Ubiquitin family proteins (MELO3C004438) can target different viral components to prevent virus spread, inhibit viral replication or to mitigate disease symptoms (Czosnek et al, 2013;. Transmembrane proteins (MELO3C004435) and importins (MELO3C004204) can act as susceptibility factors and have also been related to silencing responses (Chen et al, 2021;Parween & Sahu, 2022;Peng et al, 2022;Zhai et al, 2021). Exoribonucleases (MELO3C004356) can negatively regulate the accumulation of viruses (Pan, 2019;Pouclet et al, 2023).…”