Characterization of Agronomy, Grain Physicochemical Quality, and Nutritional Property of High-Lysine 35R Transgenic Rice with Simultaneous Modification of Lysine Biosynthesis and Catabolism

Lysine is the first limiting essential amino acid in rice. We previously constructed a series of transgenic rice lines to enhance lysine biosynthesis (35S), down-regulate its catabolism (Ri), or simultaneously achieve both metabolic effects (35R). In this study, nine transgenic lines, three from each group, were selected for both field and animal feeding trials. The results showed that the transgene(s) caused no obvious effects on field performance and main agronomic traits. Mature seeds of transgenic line 35R-17 contained 48–60-fold more free lysine than in wild type and had slightly lower apparent amylose content and softer gel consistency. Moreover, a 35-day feeding experiment showed that the body weight gain, food efficiency, and protein efficiency ratio of rats fed the 35R-17 transgenic rice diet were improved when compared with those fed wild-type rice diet. These data will be useful for further evaluation and potential commercialization of 35R high-lysine transgenic rice

The complete mitochondrial genome of <i>Sarcophaga angarosinica</i> (Diptera: Sarcophagidae)

Sarcophaga (Liosarcophaga) angarosinica (Rohdendorf, 1937) (Diptera: Sarcophagidae) is a species of both medical and ecological significance. In this study, the complete mitochondrial genome (mitogenome) of S. angarosinica was sequenced and characterized. The mitogenome has a total length of 15,215 bp, including 13 protein-coding genes, two ribosomal RNAs, 22 transfer RNAs, and an adenine and thymine-rich region. This mitogenome comprises 39.5% adenine, 9.4% guanine, 14.4% cytosine, and 36.8% thymine. Phylogenetic analysis revealed that S. angarosinica is closely related to Sarcophaga similis. This study enriches the genetic data on S. angarosinica and will contribute to establishing the phylogenetic relationships among flesh flies.</p

Molecular Structure and Physicochemical Properties of Starches from Rice with Different Amylose Contents Resulting from Modification of OsGBSSI Activity

OsGBSSI, encoded by the <i>Waxy</i> (<i>Wx</i>) gene, is the key enzyme in the synthesis of amylose chains. Transgenic rice lines with various GBSSI activities were previously developed via site-directed mutagenesis of the <i>Wx</i> gene in the glutinous cultivar Guanglingxiangnuo (GLXN). In this study, grain morphology, molecular structure, and physicochemical properties were investigated in four transgenic lines with modified OsGBSSI activity and differences in amylose content. A milky opaque appearance was observed in low- and non-amylose rice grains due to air spaces in the starch granules. Gel permeation chromatography (GPC) and high-performance anion-exchange chromatography (HPAEC) analyses showed that although OsGBSSI can synthesize intermediate and extra-long amylopectin chains, it is mainly responsible for the longer amylose chains. Amylose content was positively correlated with trough viscosity, final viscosity, setback viscosity, pasting time, pasting temperature, and gelatinization temperature and negatively with gel consistency, breakdown viscosity, gelatinization enthalpy, and crystallinity. Overall, the findings suggest that OsGBSSI may be also involved in amylopectin biosynthesis, in turn affecting grain appearance, thermal and pasting properties, and the crystalline structure of starches in the rice endosperm

Characterization of Grain Quality and Starch Fine Structure of Two <i>Japonica</i> Rice (Oryza Sativa) Cultivars with Good Sensory Properties at Different Temperatures during the Filling Stage

Temperature during the growing season is a critical factor affecting grain quality. High temperatures at grain filling affect kernel development, resulting in reduced yield, increased chalkiness, reduced amylose content, and poor milling quality. Here, we investigated the grain quality and starch structure of two <i>japonica</i> rice cultivars with good sensory properties grown at different temperatures during the filling stage under natural field conditions. Compared to those grown under normal conditions, rice grains grown under hot conditions showed significantly reduced eating and cooking qualities, including a higher percentage of grains with chalkiness, lower protein and amylose contents, and higher pasting properties. Under hot conditions, rice starch contained reduced long-chain amylose (MW 10^7.1 to 10^7.4) and significantly fewer short-chain amylopectin (DP 5–12) but more intermediate- (DP 13–34) and long- (DP 45–60) chain amylopectin than under normal conditions, as well as higher crystallinity and gelatinization properties