Promoter characterization of a citrus linalool synthase gene mediating interspecific variation in resistance to a bacterial pathogen

BMC Plant Biology

Research

Li Ren¹  Changyong Zhou¹  Qiying Wang¹  Xuefeng Wang¹  Linhua Huang¹  Jun He¹  Huayu Yang¹  Xiaochun Wang¹  Yujiao Cheng¹ 

[1] National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, 400712, Chongqing, China;

关键词: Citrus;    Canker disease;    Linalool;    Terpene synthase;    Promoter;   

DOI  :  10.1186/s12870-023-04413-6

 received in 2023-01-11, accepted in 2023-08-14,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundTerpenoids play essential roles in plant defense against biotic stresses. In Citrus species, the monoterpene linalool mediates resistance against citrus canker disease caused by the gram-negative bacteria Xanthomonas citri subsp. citri (Xcc). Previous work had associated linalool contents with resistance; here we characterize transcriptional responses of linalool synthase genes.ResultsLeaf linalool contents are highly variable among different Citrus species. “Dongfang” tangerine (Citrus reticulata), a species with high linalool levels was more resistant to Xcc than “Shatian” pummelo (C. grandis) which accumulates only small amounts of linalool. The coding sequences of the major leaf-expressed linalool synthase gene (STS4) are highly conserved, while transcript levels differ between the two Citrus species. To understand this apparent differential transcription, we isolated the promoters of STS4 from the two species, fused them to a GUS reporter and expressed them in Arabidopsis. This reporter system revealed that the two promoters have different constitutive activities, mainly in trichomes. Interestingly, both linalool contents and STS4 transcript levels are insensitive to Xcc infestation in citrus plants, but in these transgenic Arabidopsis plants, the promoters are activated by challenge of a bacterial pathogen Pseudomonas syringae, as well as wounding and external jasmonic acid treatment.ConclusionsOur study reveals variation in linalool and resistance to Xcc in citrus plants, which may be mediated by different promoter activities of a terpene synthase gene in different Citrus species.

【 授权许可】

CC BY   
© BioMed Central Ltd., part of Springer Nature 2023

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