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A stearoyl‐acyl carrier protein desaturase, N b SACPD ‐ C , is critical for ovule development in N icotiana benthamiana
Author(s) -
Zhang Jiantao,
Li Jianhui,
GarciaRuiz Hernan,
Bates Philip D.,
Mirkov Theodore Erik,
Wang Xiaofeng
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.12649
Subject(s) - nicotiana benthamiana , chemistry , microbiology and biotechnology , ovule , biochemistry , biology , gene , embryo
Summary Stearoyl‐acyl carrier protein desaturase ( SACPD ) activity is essential for production of the major unsaturated fatty acids ( UFA s) in plant lipids. We report here the characterization of three SACPD genes from N icotiana benthamiana , N b SACPD ‐ A , ‐ B , and ‐ C . All three genes share high similarity to At SSI 2/ FAB 2 (Suppressor of Salicylic acid‐Insensitivity2/Fatty A cid B iosynthesis2), the primary SACPD isoform in A rabidopsis. Knocking down the expression of individual or combinations of N b SACPD s by an artificial micro RNA approach resulted in significantly reduced accumulation of 18 C UFA s and elevated levels of 18:0‐ FA (Fatty acids) in leaves, indicating that all three genes participated in fatty acid desaturation. The triple knockdown ( KD ) plants displayed severe growth phenotypes, including spontaneous cell death and dwarfing. While no vegetative morphologic abnormality was observed in Nb SACPD ‐A , ‐ B , or ‐ C KD plants, strikingly, Nb SACPD ‐C KD plants produced small fruits with aborted ovules. Reciprocal crosses with wild‐type and Nb SACPD ‐C KD plants revealed that knocking down Nb SACPD ‐C expression caused female, but not male, sterility. Furthermore, arrested ovule development and significantly altered lipid composition in ovaries were observed in N b SACPD ‐ C KD plants, consistent with the predominant N b SACPD ‐ C expression in ovules. The ovule development defect was fully complemented by coexpressing an ami RNA ‐resistant Nb SACPD ‐C variant in the Nb SACPD ‐C KD background, further supporting a specific requirement for Nb SACPD ‐C in female fertility. Our results thus indicated that Nb SACPD ‐C plays a critical role maintaining membrane lipid composition in ovule development for female fertility in N . benthamiana , complementing and extending prior understanding on the well‐demonstrated roles of SACPD s in biotic and abiotic stresses.