Increased Lysine and Seed Storage Protein in Rice Plants Recovered from Calli Selected with Inhibitory Levels of Lysine plus Threonine and S-(2-Aminoethyl)cysteine

Abstract

Experiments were designed to test whether variation in percent lysine in seed proteins could be recovered in plants regenerated from callus subjected to inhibitory levels of lysine plus threonine. Anther-derived callus was subjected to I millimolar lysine plus threonine for three successive passages and then once to the same concentration of S42-aminoethyl)cysteine. Plants were regenerated from the resistant callus. Plants recovered directly from tissue culture were normal in color, size and were 50% or less fertile. Second and third generation plants produced a wide range of variants including albinos, deep green plants both short and tall, and totally fertile as well as partially fertile plants. All The most advanced in vitro techniques among the major cereal crops exist in rice, Oryza sativa. Rice plants were recovered from anther-derived callus of an indica subspecies cultured three times in the presence of 2 mm AEC (24). Plants recovered from AEC selected cells had increased protein and lysine over the controls (24,26). Even though substantial infertility was induced by the in vitro procedures in rice, segregants with normal seed set from both selfed and crossed progeny had increased seed protein as well as lysine (26, 28).The experiments described here were designed to recover cells resistant to inhibitory levels of L+T and AEC from antherderived calli. Another purpose was to characterize the progeny of these regenerated plants, and determine if regenerated plants and selfed progeny expressed the phenotype corresponding to the selection pressure applied in vitro. There are no previous examples of the recovery and characterization of rice plants from cells resistant to inhibitory levels of L+T. MATERIALS AND METHODSAnther-derived calli of rice, Oryza sativa, were subjected to inhibitory levels of L+T followed by AEC. Plants were regenerated and selfed, progeny were characterized for levels of seed storage proteins and percent lysine in the proteins. The plants were also evaluated for overall morphology.Source. Cell selections were done with the cultivar Calrose 76, subspecies japonica (21). The genotype is widely used as a commercial cultivar and as a source for rice breeding, as well as

Reducing Rice Seed Storage Protein Accumulation Leads to Changes in Nutrient Quality and Storage Organelle Formation

“…S2). Rice high-Lys mutants also contain increased levels of embryo globulins (Schaeffer and Sharpe, 1987). A similar situation has been observed in maize kernels.…”

“…Classically, o2 and floury2 mutants, in which Lys-deficient zeins were reduced, were identified as high-Lys maize lines (Mertz et al, 1964;Nelson et al, 1965), and the highLys phenotype was mimicked by suppression of a-zeins (Segal et al, 2003;Huang et al, 2006). HighLys mutants have been also identified in rice (Schaeffer and Sharpe, 1987). However, these high-Lys mutants had chalky and floury phenotypes, and their agronomic traits were inferior to the wild type owing to brittleness and insect susceptibility.…”

Effects of rice protein hydrolysates prepared by microbial proteases and ultrafiltration on free radicals and meat lipid oxidation

“…Rice is rich in a specific group of flavonoids and other unique compounds that have been found to exert significant free radical scavenging activities and inhibit cholesterol oxidation in vitro (Qiu, Liu, & Beta, 2009;Xu, Hua, & Godber, 2001). Although rice has a relatively low protein content but rice protein is superior in lysine content which is a limiting essential amino acid in cereal proteins (Schaeffer & Sharpe, 1987). Furthermore, the main rice protein does not contain gliadin, a specific protein found in the cereal grains responsible for allergic gastrointestinal tract coeliac disease (Dieterich et al, 1997).…”

Two Feedback-Insensitive Enzymes of the Aspartate Pathway in Nicotiana sylvestris

“…In barley, wheat, maize, carrot, and Arabidopsis, recessive AEC-resistant mutants were characterized by a decrease of AEC uptake (5,(21)(22)(23)29). Rice plants resistant to AEC, regenerated from anther-derived caffi, resulted in seeds of higher protein-bound lysine and storage protein content (27). One Nicotiana sylvestris AEC-resistant plant (RAEC-1) regenerated from protoplast culture exhibited in leaves up to 28 times more free lysine than the wild type (26).…”