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TRANSPARENT TESTA 2 regulates embryonic fatty acid biosynthesis by targeting FUSCA 3 during the early developmental stage of A rabidopsis seeds
Author(s) -
Wang Zhong,
Chen Mingxun,
Chen Tianlong,
Xuan Lijie,
Li Zhilan,
Du Xue,
Zhou Longhua,
Zhang Guoping,
Jiang Lixi
Publication year - 2014
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.12426
Subject(s) - proanthocyanidin , biosynthesis , embryo , arabidopsis , biology , biochemistry , embryonic stem cell , gene , embryogenesis , fatty acid , phenotype , microbiology and biotechnology , chemistry , mutant , antioxidant , polyphenol
Summary TRANSPARENT TESTA 2 ( TT 2) regulates the biosynthesis of proanthocyanidins in the seed coat of A rabidopsis. We recently found that TT 2 also participates in inhibition of fatty acid ( FA ) biosynthesis in the seed embryo. However, the mechanism by which TT 2 suppresses the accumulation of seed FA remains unclear. In this study, we show that TT 2 is expressed in embryos at an early developmental stage. TT 2 is directly bound to the regulatory region of FUSCA 3 ( FUS 3 ), and mediates the expression of numerous genes in the FA biosynthesis pathway. These genes include BCCP 2 , CAC 2 , MOD 1 and KASII , which encode proteins involved in the initial steps of FA chain formation, FAD 2 and FAD 3 , which are responsible for FA desaturation, and FAE 1 , which catalyzes very‐long‐chain FA elongation. Loss of function of TT 2 results in reduced expression of GLABRA 2 but does not cause a significant reduction in the mucilage attached to the seed coats, which competes with FA for photosynthates. TT 2 is expressed in both maternal seed coats and embryonic tissues, but proanthocyanidins are only found in wild‐type seed coats and not in embryonic tissues. The amount of proanthocyanidins in the seed coat is negatively correlated with the amount of FA s in the embryo.