Expression Profiles of Genes Involved in Fatty Acid and Triacylglycerol Synthesis in Castor Bean (Ricinus communis L.)

Abstract

Castor seed triacylglycerols (TAGs) contain 90% ricinoleate (12-hydroxy-oleate) which has numerous industrial applications. Due to the presence of the toxin ricin and potent allergenic 2S albumins in the seed, it is desirable to produce ricinoleate from temperate oilseeds. To identify regulatory genes or genes for enzymes that may up-regulate multiple activities or entire pathways leading to the ricinoleate and TAG synthesis, we have analyzed expression profiles of 12 castor genes involved in fatty acid and TAG synthesis using quantitative reverse transcription-polymerase chain reaction technology. A collection of castor seeds with well-defined developmental stages and morphologies was used to determine the levels of mRNA, ricinoleate and TAG. The synthesis of ricinoleate and TAG occurred when seeds progressed to stages of cellular endosperm development. Concomitantly, most of the genes increased their expression levels, but showed various temporal expression patterns and different maximum inductions ranging from 4- to 43,000-fold. Clustering analysis of the expression data indicated five gene groups with distinct temporal patterns. We identified genes involved in fatty acid biosynthesis and transport that fell into two related clusters with moderate flat-rise or concave-rise patterns, and others that were highly expressed during seed development that displayed either linear-rise or bell-shaped patterns. Castor diacylglycerol acyltransferase 1 was the only gene having a higher expression level in leaf and a declining pattern during cellular endosperm development. The relationships among gene expression, cellular endosperm development and ricinoleate/TAG accumulation are discussed.

New features of triacylglycerol biosynthetic pathways of peanut seeds in early developmental stages

“…3). The results, especially the expression patterns of DGAT and PDAT during peanut pod development, are quite consistent with the previous study (Chen et al 2007;Li et al 2010). These results indicated that peanut pod first accumulate high levels of the enzymes for the oil biosynthesis in the early stage of peanut pod development before the latter stage (15 DASP), when high rates of the oil biosynthesis might be obtained.…”

Expression of Genes Controlling Unsaturated Fatty Acids Biosynthesis and Oil Deposition in Developing Seeds of Sacha Inchi (Plukenetia volubilis L.)

“…Quantitative expression data of each gene were subjected to gene expression clustering analysis using the k-mean clustering method [26,27] provided within the software expression analyzer and display (EXPANDER) [28]. Input data were first standardized using mean = 0 and variance = 1, and fixed norm and then pursued clustering with k-mean method.…”

<i>Wrinkled</i> 1 (WRI1) Homologs, AP2-Type Transcription Factors Involving Master Regulation of Seed Storage Oil Synthesis in Castor Bean (<i>Ricinus communis</i>L.)

“…About 90% of the seed TAGs is composed of ricinoleic acid (12-hydroxy-oleate), which is unusual hydroxylated fatty acid highly valued for chemical and pharmacological application [2]. It has been proposed that castor bean has a potential to produce biodiesel, because of its unique properties that the seed has high oil content, toxic storage protein (ricin) confers oil source without competition to food resource and the plant can tolerate to severe environments where food crops are unfavorable [3].…”