Characterization of seed fatty acid accumulation in DELLA mutant lines of Arabidopsis

Li, Zhilan; Jiang, Yuxiao; Hua, Shuijin; Ren, Yun; Jiang, Chiyu; Zhou, Longhua; Chen, Xiaoyang; Jiang, Lixi

Characterization of seed fatty acid accumulation in DELLA mutant lines of Arabidopsis

2013

Arabidopsis seeds accumulate considerable fatty acids (FA/s) from embryo until maturity. The environmental stimuli and the regulatory factors that determine FA accumulation, however, remain unclear. In this study, we investigated the role of DELLAs, the negative regulatory factors in the gibberellin transduction pathway, in seed oil formation in Arabidopsis. Seed morphology, weight-per-thousand seeds, oil content, and FA composition were compared among the seeds of the DELLA ga1-3 rga-t2 rgl2-1 (triple), ga1-3 rga-t2 rgl1-1rgl2-1 (quadruple), ga1-3 gai-t6 rga-t2 rgl1-1 rgl 2-1 (penta), and wild type (WT), Landsberg erecta (Ler). Significant differences between the WT and the penta mutant for the above traits were observed. Compared with WT, the penta seeds were characterized by a decrease of 22 % seed oil in term of μg/mg, an increment of 10 % seed oil in term of FA/seed, and an alteration of FA composition. In general, the dynamics of FA accumulation in the penta and WT developing seeds (2–16 days after anthesis, DAA) were not obviously different. However, there was higher FA accumulation in penta seeds from 6 DAA compared with WT. RNA gel blotting indicated that the fatty acid desaturase genes were expressed in seeds as well as in leaves. The different transcript levels of the genes between the penta mutant and WT unveiled a part of the reasons accounting for the differences observed. To our knowledge, this is the first report on the effect of DELLAs on the dynamic process of seed oil formation of a flowering plant.

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