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EMPTY PERICARP 16 is required for mitochondrial nad2 intron 4 cis ‐splicing, complex I assembly and seed development in maize
Author(s) -
Xiu Zhihui,
Sun Feng,
Shen Yun,
Zhang Xiaoyan,
Jiang Ruicheng,
Bonnard Géraldine,
Zhang Jianhua,
Tan BaoCai
Publication year - 2016
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.13122
Subject(s) - rna splicing , intron , biology , mitochondrial dna , group ii intron , genetics , physics , gene , rna
Summary In higher plants, chloroplast and mitochondrial transcripts contain a number of group II introns that need to be precisely spliced before translation into functional proteins. However, the mechanism of splicing and the factors involved in this process are not well understood. By analysing a seed mutant in maize, we report here the identification of Empty pericarp16 ( Emp16 ) that is required for splicing of nad2 intron 4 in mitochondria. Disruption of Emp16 function causes developmental arrest in the embryo and endosperm, giving rise to an empty pericarp phenotype in maize. Differentiation of the basal endosperm transfer layer cells is severely affected. Molecular cloning indicates that Emp16 encodes a P‐type pentatricopeptide repeat ( PPR ) protein with 11 PPR motifs and is localized in the mitochondrion. Transcript analysis revealed that mitochondrial nad2 intron 4 splicing is abolished in the emp16 mutants, leading to severely reduced assembly and activity of complex I. In response, the mutant dramatically increases the accumulation of mitochondrial complex III and the expression of alternative oxidase AOX 2. These results imply that EMP 16 is specifically required for mitochondrial nad2 intron 4 cis ‐splicing and is essential for complex I assembly and embryogenesis and development endosperm in maize.