Genetic dissection of hexanol content in soybean seed through genome-wide association analysis

Hexanol is a major compound contributing to the off-flavors(the bean-like odor) of soybean derived soymilk. The most effective way to reduce the off-flavors of soymilk is the screening and utilization of soybean cultivars with improved hexanol content. However, no genome-wide genetic analysis for this particular trait has been conducted to date. The objective of the present study was to dissect the genetic basis of hexanol content in soybean seed through genome-wide association analysis(GWAS). A total of 105 soybean accessions were analyzed for hexanol content in a three-year experiments and genotyped by sequencing using the specific locus amplified fragment sequencing(SLAF-seq) approach. A total of 25 724 single nucleotide polymorphisms(SNPs) were obtained with minor allele frequencies(MAF)5%. GWAS showed that 25 quantitative trait nucleotides(QTNs) were significantly associated with the hexanol concentration in soybean seed. These identified QTNs distributed on different genomic regions of the 15 chromosomes. A total of 91 genes were predicted as candidate genes underlying the seed hexanol level and six candidates were predicted possibly underlying the seed hexanol by gene based association. In this study, GWAS has been proven to be an effective way to dissect the genetic basis of the hexanol concentration in multiple genetic backgrounds. The identified beneficial alleles and candidate genes might be valuable for the improvement of marker-assisted breeding efficiency for low hexanol level and help to explore possible molecular mechanisms underlying hexanol content in soybean seed.     

Gene bank scheduling of seed regeneration: Interim report on a long term storage study

A major challenge for the management of gene banks is the maintenance of good seed health in the collections. Large germplasm collections 10 000 accessions often have been acquired from different sources over a range of dates, may differ in germination at time of deposition in the gene bank, and may have genetic differences in seed longevity. The major storage variables affecting seed longevity are temperature and seed moisture content. Two varieties of each pea(Pisum sativus L.), lentil(Lens culinaris Medikus subsp. culinaris), and chickpea(Cicer arietinum L.), were stored at three temperatures; 40, 20, and 2°C, each with three seed moisture levels of 10.9–13.8%(high), 7.9–10.3%(medium), and 7–7.8%(low), in the Australian Temperate Field Crops Collection gene bank. Seed longevity at a given storage period was estimated by the corresponding germination percentage for each treatment. This paper is an interim report on seed viability decline in the first seven years of this seed longevity study, in which viability decline towards zero was almost completed in the three seed moisture treatments at 40°C and the 20°C high seed moisture treatment, but had not declined in the other treatments. Seed longevity positively responded to a reduction in temperature and then to a reduction in seed moisture. The number of days in storage for seed germination decline to 85%(p85), and to 50%(p50) for mean seed viability, are reported by storage/varietal treatment. Both p85 and p50 showed significant inverse linear responses with seed moisture at 40°C for pea and lentil varieties, with intra-specific variation for pea. This long term trial aims to provide informed timing of seed regeneration for accessions in a gene bank.     

心理健康教育与大学生思想政治教育契合的可行性研究

心理健康教育与大学生思想政治教育在理论基础、学科体系、教育层次、教育内容、教育本质等五个方面存在共同点和内在的联系,这决定了二者在服务大学生全面成长的过程中能够而且应该相互融合、不可分割。     

青海白刺和枸杞微量元素的对应聚类分析

应用对应聚类分析对青海白刺和枸杞中微量元素的分布特征进行了研究。该方法可用于青海白刺和枸杞样品元素分析数据的直接处理,以深入研究这些样品的质量与它们的微量元素组成和样品来源的相关关系。实证分析结果表明,对应聚类分析能够揭示出样品来源与变量之间的内在联系,是一种有优势的分析方法。     

西藏灌木林空间分布影响因素分析

以西藏主要类型灌木林为研究对象,基于全区2002年森林资源分布图,分析了影响西藏各主要类型灌木林空间分布的主要环境因子,提取了包括经度、纬度、海拔、坡向、坡位和坡度等6个环境因子的数据,并对数据进行梯度划分,应用多重对应分析方法,定量研究了环境因子对西藏各主要类型灌木林空间分布的影响程度,并进行了影响因子排序。研究结果表明,总体上看,西藏主要类型灌木林的空间分布均在不同程度上受大尺度环境因子的影响,主要表现在经纬度和海拔上;在小尺度上,各环境因子通常表现为共同影响灌木林的分布。     

氯和硫元素在烟株体内的分布

运用对应分析（correspondence analysis）的方法对2002年云南红河烟厂基地生产的不同部位的烤烟进行了氯和硫元素在烟株体内的分布的研究。结果表明：氯、硫元素在烟株体内的分布从烟株的上部到下部,缺乏明显规律性。对应分析可有效地揭示烟叶部位与氯、硫元素的分布关系。     

A review: The beneficial effects and possible mechanisms of aluminum on plant growth in acidic soil

Aluminum(Al) is the third most abundant element in the earth's crust and a major factor inhibiting plant growth and reducing crop yield in acidic soil. Although there is substantial research on the phytotoxic effects and the underlying mechanisms of Al by applying Al alone hydroponically, soil is a complex medium containing numerous mineral elements that can interact with Al and other elements and their bioavailability in plants. In this review, we describe the roles of Al in promoting plant growth, enhancing phosphorus availability and efficient use in plants, and alleviating H+, iron, and manganese toxicity in acidic conditions. Furthermore, we discuss the possible mechanisms of enhanced abiotic stress tolerance induced by Al. We also elucidate the role of Al in attracting plant growth promoting rhizo-bacteria(PGPR) and their interactions with plants by increasing organic exudates.     

Effects of dietary graded levels of cinnamon essential oil and its combination with bamboo leaf flavonoid on immune function,antioxidative ability and intestinal microbiota of broilers

Cinnamon essential oil(CEO) and its combination with bamboo leaf flavonoid(BLF) have been shown to exhibit an additive antibacterial effect in vitro, but their functions in broilers were not clear. An experiment was conducted to investigate the effects of dietary graded levels of CEO and its combination with BLF on the growth performance, immune responses, antioxidative ability, and intestinal morphology and microbiota of broilers fed a corn-soybean meal basal diet. A total of 576 1-d-old Arbor Acres commercial male broilers were randomly allotted to 9 treatments with 8 replicates of 8 birds each in a completely randomized design. Birds were fed on a basal corn-soybean meal diet(control, without plant extracts and antibiotics), or the basal diet supplemented with 50 mg of aureomycin kg~(-1), 50, 100, 200, 400, or 800 mg of CEO kg~(-1), a combination of 100 mg of CEO and 16.7 mg of BLF kg~(-1), or a combination of 200 mg of CEO kg~(-1) and 33.3 mg of BLF kg~(-1) for 42 d. Dietary treatment affected(P0.05) the serum immune globulin M(IgM) contents on d 42, liver malondialdehyde(MDA) contents on d 21, duodenal crypt depth on d 42, relative abundance of Lactobacillus in the cecal contents on d 21, and relative abundances of Escherichia coli and Bifidobacterium in the cecal contents on d 42, but had no effect(P0.16) on all other measured indices. The addition of 400 mg of CEO kg~(-1) or a combination of 200 mg CEO kg~(-1) and 33.3 mg BLF kg~(-1) increased(P0.02) serum IgM contents on d 42. Dietary supplementation with 100 or 200 mg CEO kg~(-1), or 50 mg aureomycin kg~(-1) decreased(P0.003) liver MDA contents on d 21. In addition, the supplement of 100 mg CEO kg~(-1) increased(P0.002) the Lactobacillus relative abundance in caecum on d 21 and Bifidobacterium relative abundance in caecum on d 42, and decreased(P0.0001) E. coli relative abundance in caecum on d 42. The results indicated that dietary supplementation with CEO, an alternative to aureomycin, improved the immune status, antioxidantative ability and cecal microbiota of broilers, and dietary supplementation with the combinations of CEO and BLF did not exhibit further effects. Dietary supplementation with 100 mg CEO kg~(-1) is beneficial for broilers fed a corn-soybean meal basal diet.     

Phenotypic characterization and genetic mapping of the dwarf mutant m34 in maize

Plant height is one of the most important agronomic traits associated with yield in maize.In this study,a gibberellins(GA)-insensitive dwarf mutant,m34,was screened from inbred line Ye478 by treatment with the chemical mutagen ethylmethanesulfonate(EMS).Compared to Ye478,m34 showed a dwarf phenotype with shorter internodes,and smaller leaf length and width,but with similar leaf number.Furthermore,m34 exhibited smaller guard cells in internodes than Ye478,suggesting that smaller cells might contribute to its dwarf phenotype.Genetic analysis indicated that the m34 dwarf phenotype was controlled by a recessive nuclear gene.An F2 population derived from a cross between m34 and B73 was used for mutational gene cloning and this gene was mapped to a chromosome region between umc2189 and umc1553 in chromosome 1 bin1.10,which harbored a previously identified dwarf gene Zm VP8.Sequencing analysis showed a nucleotide substitution(G1606 to A1606)in the sixth exon of ZmVP8,which resulted in an amino acid change(E531 to K531)from Ye478 to m34.This amino acid change resulted in anα-helix changing to aβ-sheet in the secondary protein structure and the‘SPEC’domain changed to a‘BOT1NT’domain in the tertiary protein structure.Taken together,these results suggested that m34 is a novel allelic mutant originally derived from Ye478 that is useful for further ZmVP8 functional analysis in maize.     

Inheritance of steroidal glycoalkaloids in potato tuber flesh

Potato(Solanum tuberosum L.) is the third most important food crop worldwide after wheat and rice in terms of human consumption. A critical domestication trait for potato was the decrease of toxic steroidal glycoalkaloids(SGAs) in tuber flesh. Here, we used a diploid F_2 segregating population derived from a cross between S. tuberosum and the wild potato species Solanum chacoense to map the quantitative trait loci(QTLs) associated with the regulation of SGAs content in tuber flesh. In a three-year study, we identified two QTLs on chromosomes 2 and 8 affecting SGAs content in tuber flesh. The QTL on chromosome 8 harbors 38 genes that are co-expressed with the GLYCOALKALOID METABOLISM genes. These findings lay the foundation for exploiting the genes controlling SGAs content in tuber flesh and they provide a theoretical basis for the use of wild germplasm in potato breeding.