A stearoyl‐acyl carrier protein desaturase, NbSACPD‐C, is critical for ovule development in Nicotiana benthamiana. (19th September 2014)

• Record Type: Journal Article
• Authors: Zhang, Jiantao; Li, Jianhui; Garcia‐Ruiz, Hernan; Bates, Philip D.; Mirkov, Theodore Erik; Wang, Xiaofeng
• Is Part Of: Plant journal. Volume 80:Number 3(2014:Nov.)
• Page Start: 489
• Page End: 502
• Publication Date: 2014-09-19
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12649
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" id="tpj12649-abs-0001"> <title>Summary</title> <p>Stearoyl‐acyl carrier protein desaturase (SACPD) activity is essential for production of the major unsaturated fatty acids (UFAs) in plant lipids. We report here the characterization of three <italic>SACPD</italic> genes from <italic>Nicotiana benthamiana</italic>, <italic> NbSACPD‐A</italic>, <italic> ‐B</italic>, and <italic>‐C</italic>. All three genes share high similarity to <italic>AtSSI2/FAB2</italic> (Suppressor of Salicylic acid‐Insensitivity2/Fatty Acid Biosynthesis2), the primary <italic>SACPD</italic> isoform in Arabidopsis. Knocking down the expression of individual or combinations of <italic>NbSACPDs</italic> by an artificial microRNA approach resulted in significantly reduced accumulation of 18C UFAs 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 <italic>NbSACPD‐A</italic>, <italic> ‐B</italic>, or <italic>‐C</italic> KD plants, strikingly, <italic>NbSACPD‐C </italic>KD plants produced small fruits with aborted ovules. Reciprocal crosses with wild‐type and <italic>NbSACPD‐C </italic>KD plants revealed that knocking down <italic>NbSACPD‐C</italic> expression caused female, but not male, sterility. Furthermore, arrested ovule development and significantly altered lipid composition in ovaries were observed in <italic>NbSACPD‐C</italic> KD plants, consistent with the predominant <italic>NbSACPD‐C</italic> expression in ovules. The ovule development defect was fully complemented by coexpressing an amiRNA‐resistant <italic>NbSACPD‐C</italic> variant in the <italic>NbSACPD‐C </italic>KD background, further supporting a specific requirement for NbSACPD‐C in female fertility. Our results thus indicated that NbSACPD‐C plays a critical role maintaining membrane lipid composition in ovule development for female fertility in <italic>N. benthamiana</italic>, complementing and extending prior understanding on the well‐demonstrated roles of SACPDs in biotic and abiotic stresses.</p> </abstract>