Dataset Information

OsPG1 Encodes a Polygalacturonase that Determines Cell Wall Architecture and Affects Resistance to Bacterial Blight Pathogen in Rice.

ABSTRACT:

Background

Plant cell walls are the main physical barrier encountered by pathogens colonizing plant tissues. Alteration of cell wall integrity (CWI) can activate specific defenses by impairing proteins involved in cell wall biosynthesis, degradation and remodeling, or cell wall damage due to biotic or abiotic stress. Polygalacturonase (PG) depolymerize pectin by hydrolysis, thereby altering pectin composition and structures and activating cell wall defense. Although many studies of CWI have been reported, the mechanism of how PGs regulate cell wall immune response is not well understood.

Results

Necrosis appeared in leaf tips at the tillering stage, finally resulting in 3-5 cm of dark brown necrotic tissue. ltn-212 showed obvious cell death and accumulation of H₂O₂ in leaf tips. The defense responses were activated in ltn-212 to resist bacterial blight pathogen of rice. Map based cloning revealed that a single base substitution (G-A) in the first intron caused incorrect splicing of OsPG1, resulting in a necrotic phenotype. OsPG1 is constitutively expressed in all organs, and the wild-type phenotype was restored in complementation individuals and knockout of wild-type lines resulted in necrosis as in ltn-212. Transmission electron microscopy showed that thicknesses of cell walls were significantly reduced and cell size and shape were significantly diminished in ltn-212.

Conclusion

These results demonstrate that OsPG1 encodes a PG in response to the leaf tip necrosis phenotype of ltn-212. Loss-of-function mutation of ltn-212 destroyed CWI, resulting in spontaneous cell death and an auto-activated defense response including reactive oxygen species (ROS) burst and pathogenesis-related (PR) gene expression, as well as enhanced resistance to Xanthomonas oryzae pv. oryzae (Xoo). These findings promote our understanding of the CWI mediated defense response.

SUBMITTER: Cao Y

PROVIDER: S-EPMC8060378 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:TITLE: Transcriptional profiling of Rgene-mediated responses in rice PROJECT DESCRIPTION: The dominant gene Xa7 and the recessive gene xa5 of rice confer resistance to several races of the bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). To reveal the modes of action and the defense responses these genes initiate, we decided to obtain the global transcriptional profiles of the rice cultivars IRBB7, IRBB5 (which harbor Xa7 and xa5, respectively) and IR24 undergoing early infection by the Xoo Race 2 strain PXO86. Both IRBB7 and IRBB5 are resistant to PXO86 (which carry the corresponding avirulence genes avrXa7 and avrxa5), whereas IR24 is susceptible. We inoculated by vacuum infiltration the three rice cultivars ten days after seed germination (or 2 weeks after sowing) and collected inoculated tissue at 5 different timepoints within the first day after inoculation. The transcriptional profiles obtained will provide valuable insight into the similarities and differences between incompatible interactions mediated by a dominant and a recessive Rgene, in comparison to a compatible interaction. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, David O Nino-Liu. The equivalent experiment is OS4 at PLEXdb.] genotype: IR24 - time: 0 hai(3-replications); genotype: IR24 - time: 3 hai(3-replications); genotype: IR24 - time: 6 hai(3-replications); genotype: IR24 - time: 12 hai(3-replications); genotype: IR24 - time: 24 hai(3-replications); genotype: IRBB5 - time: 0 hai(3-replications); genotype: IRBB5 - time: 3 hai(3-replications); genotype: IRBB5 - time: 6 hai(3-replications); genotype: IRBB5 - time: 12 hai(3-replications); genotype: IRBB5 - time: 24 hai(3-replications); genotype: IRBB7 - time: 0 hai(3-replications); genotype: IRBB7 - time: 3 hai(3-replications); genotype: IRBB7 - time: 6 hai(3-replications); genotype: IRBB7 - time: 12 hai(3-replications); genotype: IRBB7 - time: 24 hai(3-replications)