Detection of quantitative trait loci for kernel oil and protein concentration in a B73 and Zheng58 maize cross.

Maize (Zea mays L.) is one of the most important food crops throughout the world, and provides oil and proteins to humans and livestock. Kernel oil and protein content in maize are two complex quantitative traits. In order to identify quantitative trait loci (QTL) controlling oil and protein concentration in maize kernels, and to evaluate their genetic effects, QTL analysis was conducted on an F3:4 population derived from a cross between an inbred line with a low oil and protein concentration (Zheng58) and an inbred line with a higher oil and protein concentration (B73). A total of 189 polymorphic simple sequence repeat markers were used to construct a linkage map. Eleven QTLs for kernel oil concentration were detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.6 to 11.1% of the phenotypic variance. Ten QTLs for kernel protein concentration were also detected on nine chromosomes, except for chromosome 9. A single QTL explained 4.2 to 11.4% of the phenotypic variance. Interestingly, novel QTLs for oil concentration (qOIL08-01 and qOIL10-01) and QTLs for protein concentration (qPRO01-01 and qPRO05-01) were specific to the population studied, which could explain 7.1 to 11.1% of the phenotypic variance. These results will provide better understanding of the genetic basis of oil and protein concentrations in maize. The markers closely linked with the QTLs will facilitate breeding of maize varieties with high oil and protein concentrations through molecular marker-assisted selection.

Correlation between natriuretic peptide receptor C (NPR3) gene polymorphisms and hypertension in the Dai people of China.

Hypertension affects one-fifth of the world population. Genome-wide association studies (GWAS) have identified several single nucleotide polymorphisms (SNPs) that correlated with hyper-tension in large samples. However, the genetic mutations leading to hypertension might differ among various populations, as they have different origins and are subjected to different environmental pressures. Therefore, additional studies are urgently needed to verify the GWAS findings across different populations. This study focused on the natriuretic peptide receptor C gene (NPR3), one of the hypertension-positive genes identified in a GWAS of an East Asian population. The correlation analysis between NPR3 and hypertension was replicated in 450 Chinese Dai (235 patients vs 215 controls) and 484 Chinese Mongolian (211 patients vs 273 controls) individuals. The positive SNP identified by GWAS analysis and three other tag SNPs representing the NPR3 linkage disequilibrium (LD) block regions were selected for genotyping. The results revealed that the rs1173766 polymorphism was associated with the occurrence of hypertension (χ(2) = 6.87, P = 0.0088), and that the T allele should be protective in the Dai ethnic group. Consider-ing a close LD block at the 3' end of the NPR3 gene in the East Asian population, we speculate that there might be a mutation in the last five exons or the 3' untranslated region of NPR3 that could change the structure or expression of the NPR3 gene. However, in the Mongolian ethnic group, these SNPs were not associated with the incidence of hypertension, suggesting population heterogeneity for the genetic factors that contribute to hypertension.

Effect of exogenous gibberellin on reserve accumulation during the seed filling stage of oilseed rape.

Exogenous gibberellins (GAs) are widely applied to increase crop yields, with knowledge about the physiological functioning and biochemistry mechanisms of these phytohormones improving; however, information remains limited about the effect of GAs on seed filling. In this study, the siliques (containing the seeds) of oilseed rape (Brassica napus L.) were treated with GA3 at 3 stages of seed filling. We confirmed that GA3 regulates the deposition of storage reserves in developing seeds. The percentage of crude fat in the seeds increased during the early stage, but remained stable during the middle and late stages. In comparison, the percentage of total protein decreased during the early and middle stages, but significantly increased during the late stage. In addition, Q-PCR was employed to analyze the expression level of related genes in response to GA3. It was found that the expression of WRI and ABI3 transcription factors corresponded to crude fat content and total protein content, respectively. The expression of storage reserve related genes DGAT, MCAT, SUC2, and GPT was consistent with crude fat content, whereas the expression of Napin corresponded to total protein content. The results of this study indicate that exogenous GA3 has a different effect on storage reserve deposition in seed during different stages of seed filling, and the effect might be achieved via changing the expression of related genes.