Overexpression of chitinase PbChia1 from Plasmodiophora brassicae improves broad-spectrum disease resistance of Arabidopsis

ABSTRACT

Chitinase plays an important role in plant resistance against chitin-containing pathogens through hydrolysis of chitin. Clubroot caused by Plasmodiophora brassicae is a major disease for cruciferous crops and vegetables worldwide. The cell wall of P. brassicae resting spores contains chitin. Chitinase is regarded as capable of improving plant resistance to fungal diseases. However, there has been no report about the function of chitinase in P. brassicae. Here, wheat germ agglutinin staining and commercial chitinase treatment demonstrated that chitin is a functional component in P. brassicae. In addition, Chitinase PbChia1 was identified by chitin pull-down assay combined with LC-MS/MS. PbChia1 was found to be a typical secreted chitinase, which could bind chitin with chitinase activity in vitro. PbChia1 could significantly decrease the resting spores of P. brassicae and therefore relieve the severity of clubroot symptom, with a biocontrol effect of 61.29%. Overexpression of PbChia1 in Arabidopsis thaliana improved its resistance to P. brassicae, increased host survival rate and seed yield, enhanced PAMPs-triggered reactive oxygen species burst, MAPK activation and expression of immune-related genes. PbChia1 transgenic plants also showed resistance to other pathogens, such as biotrophic bacterium Pst DC3000, necrotrophic fungi Sclerotinia sclerotiorum and Rhizoctonia solani. These findings indicate that chitinase PbChia1 is a candidate gene that can confer broad-spectrum disease resistance in breeding.

KEYWORDS:

• Plasmodiophora brassicae
• chitin
• chitinase
• PbChia1
• clubroot
• disease resistance

Acknowledgements

This research was financially supported by the National Natural Science Foundation of China (32172371), and the Fundamental Research Funds for the Central Universities (2662020ZKPY003). Collaborative Fund of Huazhong Agricultural University and Agricultural Genomics Institute at Shenzhen (SZYJY2021007), and the earmarked fund of China Agriculture Research System (CARS-13).

Disclosure statement

No potential conflict of interest was reported by the authors.

Data Availability statement

The datasets are available from the corresponding author on reasonable request.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21505594.2023.2233147

Additional information

Funding

The work was supported by the Fundamental Research Funds for Central Universities of the Central South University [2662020ZKPY003]; National Natural Science Foundation of China [32172371]; Collaborative Fund of Huazhong Agricultural University and Agricultural Genomics Institute at Shenzhen [SZYJY2021007]; the earmarked fund for [CARS-12].