WY195, a new inducible promoter from the rubber powdery mildew pathogen, can be used as an excellent tool for genetic engineering

Abstract Background: In recent years, the rational use of inducible promoters and organ/tissue-specific promoters have become a focus of promoter research because these enable greater control of expression.Results: The WY195 promoter in the genome of Oidium heveae, the rubber powdery mildew pathogen, was predicted using PromoterScan and its promoter function was verified by the transient expression of the b-glucuronidase (GUS) gene. WY195 drove high levels of GUS expression in dicotyledons (Nicotiana tabacum, Hevea brasiliensis Reyan 7-33-97 and Hylocereus undatus) and monocotyledons (Oryza sativa ssp. japonica cv. Nipponbare, Hordeum vulgare and Zea mays). qRT-PCR indicated that GUS expression regulated by the WY195 promoter was 17.54-fold greater than that obtained using the CaMV 35S promoter in dicotyledons (N. tabacum), and 5.09-fold greater than that obtained using the ACT1 promoter in monocotyledons (O. sativa). Furthermore, WY195-regulated GUS gene expression was induced under high-temperature and drought conditions. Soluble proteins extracted from WY195-hpaXm transgenic tobacco was bioactive. Defensive micro-HR induced by the transgene expression of hpaXm was observed on transgenic tobacco leaves. Disease resistance bioassays showed that WY195-hpaXm transgenic tobacco enhanced the resistance to tobacco mosaic virus (TMV).Conclusions: WY195 is an excellent endogenous inducible promoter with great potential for development as a new tool for genetic engineering and should also promote O. heveae molecular research, which to date has been a challenge owing to the obligate parasitic nature of this pathogen.