Rice contains a biosynthetic gene cluster associated with production of the casbane-type diterpenoid phytoalexin ent-10-oxodepressin.
New Phytol
; 231(1): 85-93, 2021 07.
Article
en En
| MEDLINE
| ID: mdl-33892515
ABSTRACT
Diterpenoids play important roles in rice microbial disease resistance as phytoalexins, as well as acting in allelopathy and abiotic stress responses. Recently, the casbane-type phytoalexin ent-10-oxodepressin was identified in rice, but its biosynthesis has not yet been elucidated. Here ent-10-oxodepressin biosynthesis was investigated via co-expression analysis and biochemical characterisation, with use of the CRISPR/Cas9 technology for genetic analysis. The results identified a biosynthetic gene cluster (BGC) on rice chromosome 7 (c7BGC), containing the relevant ent-casbene synthase (OsECBS), and four cytochrome P450 (CYP) genes from the CYP71Z subfamily. Three of these CYPs were shown to act on ent-casbene, with CYP71Z2 able to produce a keto group at carbon-5 (C5), while the closely related paralogues CYP71Z21 and CYP71Z22 both readily produce a keto group at C10. Together these C5 and C10 oxidases can elaborate ent-casbene to ent-10-oxodepressin (5,10-diketo-ent-casbene). OsECBS knockout lines no longer produce casbane-type diterpenoids and exhibit impaired resistance to the rice fungal blast pathogen Magnaporthe oryzae. Elucidation of ent-10-oxodepressin biosynthesis and the associated c7BGC provides not only a potential target for molecular breeding, but also, gives the intriguing parallels to the independently assembled BGCs for casbene-derived diterpenoids in the Euphorbiaceae, further insight into plant BGC evolution, as discussed here.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oryza
/
Sesquiterpenos
/
Diterpenos
Tipo de estudio:
Risk_factors_studies
Idioma:
En
Revista:
New Phytol
Asunto de la revista:
BOTANICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
China