Genetic Analysis of a Collection of Rice Germplasm (Oryza sativa L.) through High-Density SNP Array Provides Useful Information for Further Breeding Practices.

Traditional breeding strategies mainly focus on the evaluation of trait performance, but pay less attention to the changing genetic background. A comprehensive understanding of the genetic diversity of germplasms is crucial for the deliberate improvement of specific traits. A collection of 154 highland rice varieties were collected as the initial genetic resource in our breeding program to improve the pathogen resistance and eating and cooking qualities. These varieties were analyzed using a whole-genome SNP array and were clustered into three groups. Further analysis revealed that the favorable alleles of pathogen resistance genes are mostly absent in our collected varieties. However, it showed that most varieties possess favorable alleles of Waxy (Wx) and ALKALI DEGENERATION (ALK), which are able to enhance the eating and cooking qualities. Moreover, only about one fifth of all varieties harbors favorable the allele of fragrance gene Betainealdehyde dehydrogenase (BADH2). Together, these results give an overall view of the genetic constitution of the target traits, which provide useful information for future genetic improvement in breeding practices.

From Green Super Rice to green agriculture: Reaping the promise of functional genomics research.

Producing sufficient food with finite resources to feed the growing global population while having a smaller impact on the environment has always been a great challenge. Here, we review the concept and practices of Green Super Rice (GSR) that have led to a paradigm shift in goals for crop genetic improvement and models of food production for promoting sustainable agriculture. The momentous achievements and global deliveries of GSR have been fueled by the integration of abundant genetic resources, functional gene discoveries, and innovative breeding techniques with precise gene and whole-genome selection and efficient agronomic management to promote resource-saving, environmentally friendly crop production systems. We also provide perspectives on new horizons in genomic breeding technologies geared toward delivering green and nutritious crop varieties to further enhance the development of green agriculture and better nourish the world population.

Effect of gestation dietary methionine-to-lysine ratio on methionine metabolism and antioxidant ability of high-prolific sows.

The uptake and metabolism of methionine (Met) are critical for epigenetic regulation, redox homeostasis, and embryo development. Our previous study showed that appropriate supplementation of dietary Met promoted the birth weight and placental angiogenesis of high-prolific sows. To further explore the metabolic effect of Met on pregnant sows, we have evaluated the influence of dietary Met level on Met metabolism, and the relationship between metabolites of Met and reproductive performance, antioxidant ability, and placental angiogenesis throughout the gestation of high-prolific sows. Sixty sows (the 3rd parity, Large White) were randomly divided into 5 groups that were fed diets with standardized ileal digestible (SID) methionine-to-lysine (Met:Lys) ratios of 0.27 (control), 0.32, 0.37, 0.42, and 0.47 from the mating day (gestational d 0, G0d) until the farrowing day. HPLC-MS/MS analysis was used to simultaneously evaluate the metabolites related to Met, e.g. S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), homocysteine (Hcy), cysteine (Cys), and glutathione (GSH). The concentration of SAM and SAH in plasma had significant fluctuations, especially in late pregnancy. Increasing dietary Met supplementation significantly improved the plasma SAM and methylation potential (SAM-to-SAH ratio) at d 114 of pregnancy (G114d). Moreover, a positive association of the plasma SAM concentration at G114d was observed with the litter weight of born alive (P < 0.05; R 2 = 0.58). Furthermore, Hcy concentration in plasma was at the lowest level for 0.37 ratio group at G114d. However, it significantly increased during late pregnancy. Moreover, there were negative correlations between plasma Hcy concentration at G114d (P < 0.05) and the placental vascular density in the fold and stroma (P < 0.05). Compared with the control group, the expression of vascular endothelial growth factor-A (VEGF-A) in the placenta tissue of 0.37 ratio group increased significantly (P < 0.05). Collectively, these findings indicate that dietary Met:Lys ratio (0.37 to 0.57) in the pregnant diet dose not influence the antioxidant ability of the high-prolific sows; however, the improvement of fetal development and placental angiogenesis of high-prolific sows by supplementation of Met are closely associated to the key Met-related metabolite of SAM and Hcy, respectively.

Effects of Different Methionine Sources on Methionine Metabolism in the IPEC-J2 Cells.

As one of the essential amino acids, methionine (Met) plays an important role in biological events such as methylation and antioxidant properties besides its function in protein synthesis. Different Met sources have been used in animal production, but their effects on Met metabolic pathways are not well understood. In the present study, we investigated the effects of different Met sources (L-Met, DL-Met, DL-2-hydroxy-4-(methylthio)butanoic acid (DL-HMTBA), and DL-methionyl-DL-methionine (DL-MM)) on the metabolism of Met in small intestinal porcine epithelial cell line (IPEC-J2) and the contents of extracellular Met sources. The results showed that concentrations of intracellular Met, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and the ratio of SAM to SAH in the DL-HMTBA group were significantly lower than that in other Met source groups, while the content of 5-methyltetrahydrofolate (5-MTHF) was significantly higher. Moreover, the mRNA levels of MAT2A, AHcy, CBS, MTHFR, and MTR in the DL-HMTBA group were significantly higher than those in other Met source groups. Further study showed that the total content of extracellular Met sources was highest in the DL-HMTBA group, followed by DL-MM group, followed by L-Met and DL-Met groups. These results demonstrated that DL-HMTBA mainly affects the transmethylation and remethylation of Met and it can promote the trans-sulfur metabolism of Met when compared with other Met sources. In addition, most DL-HMTBA and a small amount of DL-MM can escape the intestinal first-pass metabolism and then provide more extracellular Met sources than L-Met and DL-Met. Therefore, this study can provide a theoretical basis for the selection of Met sources in livestock.