Natural variations of TFIIA? gene and LOB1 promoter contribute to citrus canker disease resistance in Atalantia buxifolia.

ABSTRACT: Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most devastating diseases in citrus industry worldwide. Most citrus cultivars such as sweet orange are susceptible to canker disease. Here, we utilized wild citrus to identify canker-resistant germplasms, and found that Atalantia buxifolia, a primitive (distant-wild) citrus, exhibited remarkable resistance to canker disease. Although the susceptibility gene LATERAL ORGAN BOUNDARIES 1 (LOB1) could also be induced in Atalantia after canker infection, the induction extent was far lower than that in sweet orange. In addition, three of amino acids encoded by transcription factor TFIIA? in Atalantia (AbTFIIA?) exhibited difference from those in sweet orange (CsTFIIA?) which could stabilize the interaction between effector PthA4 and effector binding element (EBE) of LOB1 promoter. The mutation of AbTFIIA? did not change its interaction with transcription factor binding motifs (TFBs). However, the AbTFIIA? could hardly support the LOB1 expression induced by the PthA4. In addition, the activity of AbLOB1 promoter was significantly lower than that of CsLOB1 under the induction by PthA4. Our results demonstrate that natural variations of AbTFIIA? and effector binding element (EBE) in the AbLOB1 promoter are crucial for the canker disease resistance of Atalantia. The natural mutations of AbTFIIA? gene and AbLOB1 promoter in Atalantia provide candidate targets for improving the resistance to citrus canker disease.

SUBMITTER: Tang X 

PROVIDER: S-EPMC7861543 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature