Premium
An allele of Zm PORB 2 encoding a protochlorophyllide oxidoreductase promotes tocopherol accumulation in both leaves and kernels of maize
Author(s) -
Zhan Wei,
Liu Jie,
Pan Qingchun,
Wang Hong,
Yan Shijuan,
Li Kun,
Deng Min,
Li Wenqiang,
Liu Nannan,
Kong Qian,
Fernie Alisdair R.,
Yan Jianbing
Publication year - 2019
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.14432
Subject(s) - biology , phytol , tocopherol , genetics , protochlorophyllide , biochemistry , gene , genotype , vitamin e , biosynthesis , antioxidant
Summary Phytol is one of the key precursors for tocopherol synthesis in plants, however, the underlying mechanisms concerning the accumulation of tocopherol remain poorly understood. In this study, qVE 5 , a major QTL affecting tocopherol accumulation in maize kernels was identified via a positional cloning approach. qVE 5 encodes a protochlorophyllide oxidoreductase ( Zm PORB 2 ), which localizes to the chloroplast. Overexpression of Zm PORB 2 increased tocopherol content in both leaves and kernels. Candidate gene association analysis identified a 5/8‐bp insertion/deletion (InDel058) in the 5′ untranslated region (UTR) as the causal polymorphism in affecting Zm PORB 2 expression and being highly associated with tocopherol content. We showed that higher expression of Zm PORB 2 correlated with more chlorophyll metabolites in the leaf following pollination. RNA ‐sequencing and metabolic analysis in near isogenic lines ( NIL s) support that Zm PORB 2 participates in chlorophyll metabolism enabling the production of phytol, an important precursor of tocopherol. We also found that the tocopherol content in the kernel is mainly determined by the maternal genotype, a fact that was further confirmed by in vitro culture experiments. Finally, a PCR ‐based marker based on Indel058 was developed in order to facilitate the high tocopherol (vitamin E) maize breeding.