2S albumin gene expression in castor plant (Ricinus communis L.)

Abstract

In the castor plant (Ricinus communis L.), 2S albumins are highly allergenic seed proteins and are detrimental to the reintroduction of castor as a U.S. crop. Others have shown that the two 2S albumins are encoded by a single gene and processed from a precursor protein in castor. Little is known about the expression pattern of the 2S albumin gene. As part of a genetic approach to eliminating 2S albumin from castor, we investigated the developmental expression of this gene in castor seed. To assess seed developmental age quickly and accurately, we established a set of simple criteria, which included two visual markers, seed coat color and endosperm volume, and defined three phases that encompass the course of castor seed development. Northern analysis indicated that the 2S albumin mRNA is highly abundant in the mid-phase of seed development. A comparison of 2S albumin genomic DNA and cDNA clones from two castor cultivars indicated that only a single gene is expressed. Protein domain sequence analysis revealed that castor 2S albumin contains the trypsin/α-amylase inhibitor family domain, suggesting a role for the albumin in insect resistance. FIG. 1. The morphological changes of PI215769 castor seeds during development. (A) Whole seed; (B) transverse cross section. Endosperm is shown in opaque color. DAP, days after pollination.

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

“…1d). Then the cellular endosperm continued maturation up to 54 DAP without showing visible changes [15]. During the course of cellular endosperm development (26-54 DAP), the seeds gradually lost water and gained storage lipid to a maximum level of 60% at 54 DAP (Fig.…”

“…We have previously characterized the morphological changes of developing castor seeds and established a time-course for assessing endosperm development [15]. Castor endosperm development has a nuclear endosperm development pattern that starts with a free-nuclear stage and then progresses into cellularization and maturation.…”

“…The whole course takes about 54 DAP. At 61 DAP and after, seeds are completely mature and begin desiccation [15]. During the first 19 DAP, castor seeds grew rapidly to full size ( [15], Fig.…”

“…At 61 DAP and after, seeds are completely mature and begin desiccation [15]. During the first 19 DAP, castor seeds grew rapidly to full size ( [15], Fig. 1d), and consisted mostly of water at 90% of seed fresh weight and small amounts of lipid at about 5% (Fig.…”

“…1d). Between 26 and 40 DAP, the endosperm underwent cellularization, expanding and eventually filling the most of the seed at 40 DAP ( [15], Fig. 1d).…”