Detection of Tocopherol in Oilseed Rape (Brassica napus L.) Using Gas Chromatography with Flame Ionization Detector

The variation among Chinese genotypes of Brassica napus L. for seed tocopherols content and their analysis using gas chromatography has not been comprehensively reported till to date. In the present study, the tocopherol contents of four Chinese genotypes of Brassica napus L., namely, Gaoyou 605, Zhejiang 619, Zheshuang 758, and Zheshuang 72, were evaluated using three modified sample preparation protocols （P1, P2, and P3） for tocopherol extraction. These methods were distinguished as follows. Protocol one （P1） included the evaporation of solvent after extraction without silylation. Protocol two （P2） followed the direct supernatant collection after overnight extraction without drying and silylation. Protocol three （P3） included trimethylsilylation with N,O-bis（trimethylsilyl） trifluoroacetamide. Genotypic comparison of tocopherol and its isoforms revealed that Gaoyou 605 was dominant over the other genotypes with （140.5＋ 10.5）, （316.2＋ 9.2）, and （559.1＋ 24.3） ~tg g-~ of seed meal ct-, 7-, and total （T-） tocopherol, respectively, and a 0.44＋0.04 ^- to 7-tocopherol ratio. The comparison of the sample preparation protocols, on the other hand, suggests that P3 is the most suitable method for the tocopherol extraction from Brassica oilseeds and for the analysis of tocopherols using gas chromatography flame ionization detector （GC-FID）. Trimethylsilylation is the key step differentiating P3 from P1 and P2. Variations detected in tocopherol contents among the Chinese rapeseed （B. napus） genotypes signify the need to quantify a wide range of rapeseed germplasm for seed tocopherol dynamics in short and crop improvement in long.

Mapping epistasis and environment × QTX interaction based on four-omics genotypes for the detected QTX loci controlling complex traits in tobacco

Using newly developed methods and software, association mapping was conducted for chromium content and total sugar in tobacco leaf, based on four-omics datasets. Our objective was to collect data on genotype and phenotype for 60 leaf samples at four developmental stages, from three plant architectural positions and for three cultivars that were grown in two locations. Association mapping was conducted to detect genetic variants at quantitative trait SNP(QTS) loci, quantitative trait transcript(QTT) differences,quantitative trait protein(QTP) variability, and quantitative trait metabolite(QTM) changes,which can be summarized as QTX locus variation. The total heritabilities of the four-omics loci for both traits tested were 23.60% for epistasis and 15.26% for treatment interaction.Epistasis and environment × treatment interaction had important impacts on complex traits at all-omics levels. For decreasing chromium content and increasing total sugar in tobacco leaf, six methylated loci can be directly used for marker-assisted selection, and expression of ten QTTs, seven QTPs and six QTMs can be modified by selection or cultivation.

A Novel and Pleiotropic Factor SLENDER GRAIN3 Is Involved in Regulating Grain Size in Rice

Grain size is frequently selected during domestication and breeding. It influences the preferences of consumers, thus affecting the commercial value of rice. In present study, a mutant named as SLENDER GRAIN3(sg3) was identified from cultivar Zhenong 41(Oryza sativa L. ssp. indica) with ethyl methanesulfonate(EMS) treatment. Histological analysis showed that the slender grain of sg3 mutant resulted from increased cell division longitudinally and decreased cell division horizontally. Compared with the wild type Zhenong 41, starch granules in sg3 mutant were more closely packed, thus decreasing the chalkiness. Moreover, grain yield per plant in sg3 mutant was improved by 14%. By map-based cloning, SG3 was located on the long arm of chromosome 3 with a physical distance of 82 kb, and a 9-bp deletion in the 5′-UTR of LOC_Os03 g27110 was identified, which upregulated the expression level significantly. Moreover, a molecular marker for SG3 was developed to identify the grain size during the early generation breeding in rice. The novel factor SG3 regulated the grain size mainly through changing the cell division and the endosperm formation in rice.

The genome and gene editing system of sea barleygrass provide a novel platform for cereal domestication and stress tolerance studies

The tribe Triticeae provides important staple cereal crops and contains elite wild species with wide geneticdiversity and high tolerance to abiotic stresses. Sea barleygrass (Hordeum marinum Huds.), a wildTriticeae species, thrives in saline marshlands and is well known for its high tolerance to salinity and waterlogging. Here, a 3.82-Gb high-quality reference genome of sea barleygrass is assembled de novo, with 3.69Gb (96.8%) of its sequences anchored onto seven chromosomes. In total, 41 045 high-confidence (HC)genes are annotated by homology, de novo prediction, and transcriptome analysis. Phylogenetics, nonsynonymous/synonymous mutation ratios (Ka/Ks), and transcriptomic and functional analyses provide genetic evidence for the divergence in morphology and salt tolerance among sea barleygrass, barley, andwheat. The large variation in post-domestication genes (e.g. IPA1 and MOC1) may cause interspecies differences in plant morphology. The extremely high salt tolerance of sea barleygrass is mainly attributed tolow Na+ uptake and root-to-shoot translocation, which are mainly controlled by SOS1, HKT, and NHX transporters. Agrobacterium-mediated transformation and CRISPR/Cas9-mediated gene editing systems weredeveloped for sea barleygrass to promote its utilization for exploration and functional studies of hubgenes and for the genetic improvement of cereal crops.

耐盐胁迫相关离子转运蛋白与作物耐盐育种研究的进展

植物组织特别是地上部钠离子的积累是影响耐盐性的关键因素,这一过程涉及到一些离子转运蛋白,如SOS1、HKT和NHX等。不同植物种和同一物种不同品种之间的耐盐性差异很大,这种差异与耐盐胁迫相关离子转运蛋白基因表达有关。分子标记辅助育种、诱变技术、遗传转化和基因编辑技术为耐盐作物育种提供了高效有力的技术支撑,特别是迅速发展的基因编辑技术,将从非转基因的技术手段有效地改良作物的耐盐性。