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Ascorbic acid (AsA) is the most abundant water-soluble antioxidant in plants, and it plays a crucial role in plant growth, development and abiotic stress tolerance. In the present study, six key Arabidopsis or rapeseed genes involved in AsA biosynthesis were constitutively overexpressed in an elite Japonica rice cultivar. These genes encoded the -mannose pyrophosphorylase (GMP), -mannose-3',5'-epimerase (GME), -galactose phosphorylase (GGP), -galactose-1-phosphate phosphatase (GPP), -galactose dehydrogenase (GDH), and -galactono-1,4-lactone dehydrogenase (GalLDH). The effects of transgene expression on rice leaf AsA accumulation were carefully evaluated. In homozygous transgenic seedlings, AtGGP transgenic lines had the highest AsA contents (2.55-fold greater than the empty vector transgenic control), followed by the AtGME and AtGDH transgenic lines. Moreover, with the exception of the AtGPP lines, the increased AsA content also provoked an increase in the redox state (AsA/DHA ratio). To evaluate salt tolerance, AtGGP and AtGME transgenic seedlings were exposed to salt stress for one week. The relative plant height, root length and fresh weight growth rates were significantly higher for the transgenic lines compared with the control plants. Altogether, our results suggest that GGP may be a key rate-limiting step in rice AsA biosynthesis, and the plants with elevated AsA contents demonstrated enhanced tolerance for salt stress. [ABSTRACT FROM AUTHOR]

Abstract: In rice grains, high amylose content (AC) is correlated with poor grain quality, particularly in indica hybrid rice. To obtain indica hybrid rice with improved cooking and eating qualities, we introduced the antisense Waxy (Wx) gene into 2 elite parental lines of indica hybrid rice by using co-transformation methods. Subsequently, we selected several elite homozygous transgenic lines that did not contain the selectable marker. The expression of the endogenous Wx gene of the selected transgenic lines was significantly downregulated, resulting in low AC in the mature seeds; moreover, the AC in some lines reduced to the level observed in glutinous rice. With the decrease in AC, the gel consistency of the transgenic rice became softer, and the gelatinization temperature tended to be higher than those of the wild types, especially in the case of the Longtefu-derived transformants. We also analyzed the pasting properties of the selected transgenic low-AC lines, and we noted an improvement in the pasting properties of the transgenic rice lines. The results from a field trial indicated that the grain weights of the transgenic lines with lower AC exhibit remarkable reduction compared with those of the wild types. [Copyright &y& Elsevier]

In China, rice (Oryza sativa L.) is a major cereal crop of great importance maintaining the food security and sustainable agricultural development. Jiangsu is one of the main provinces for rice production. After more than 40 years of development, the yield and quality of rice grain have made great progress. Rice grain quality is a complex trait involving production, processing, marketing and consumption of the grain. In this review, we summarize the progress on the genetic basis of main grain quality traits in the rice variety breeding in Jiangsu province and point out the achievement of each milestone. With a focus on the genetic regulation of grain appearance, eating and cooking quality and nutritional quality, we describe the classic genetic rules and molecular basis of rice grain quality traits and review the function of major genes that regulate corresponding traits. The genetics and improvement of grain quality achieved in Jiangsu province was highlighted on the domestic and international rice breeding programs. In particular, with the advance of breeding conception in terms of functional genomics and genetic regulatory networks, the specific molecular design for grain quality improvement will be the future direction of rice genetic breeding program of Jiangsu Province.

Objective: To investigate the effect of compressive stress on the factors for liver regeneration including NF-kappaB, signal transducers and activators of transcription 3 (STATS), c-fos and c-jun in hepatocytes Chang cell line., Methods: Human hepatocytes Chang cell line were subjected to compressive stress at 1000 microstain or 2000 microstain, expression of NF-kappaB P65, p-STAT3, c-fos and c-jun were detected by Western blot or RT-PCR at 30 min, 1 h, 2 h, 3 h, 4 h, 6 h after application of compressive stress to indicate the priming of hepatocytes proliferation., Results: Enhanced expressions of NF-kappaB P65 and p-STAT3 were observed in hepatocytes under compressive stress indicated by Western blot, the magnitude of compressive stress loaded significantly affected the level of expression of NF-kappaB P65 at 2 h (P = 0.046) and p-STAT3 at 1 h (P = 0.039), the peak of expression of p-STAT3 was at 30 minutes after stress-loading while NF-kappaB P65 was at 1 hour; RT-PCR showed that expression of c-fos was not significantly different between 1000 microstain and 2000 microstain at each time point, and expression of c-jun was significantly different at 30 minutes (P = 0.026), 1 h (P = 0.031), 2 h (P = 0.033) after compressive stress loading., Conclusion: These results indicate that compressive stress may play an important role in initiating the process of liver regeneration.