高粱抗蚜基因的遗传分析和SSR标记定位

高粱蚜是高粱生产中的一种毁灭性害虫,利用植物的固有抗性是防治害虫的最有效途径。经多年杂交选育获得1个对高粱蚜免疫的高粱品种“河农16”,用其作亲本与感蚜品系“千三”进行杂交,对亲本、F1、F2抗蚜性鉴定表明,“河农16”和F1对蚜虫表现高抗,F2抗感分离符合3∶1,该抗蚜性受一对基因控制,表现出显性遗传。用已定位到连锁群上的微卫星标记和分离群体分析法,对抗蚜基因进行了连锁分析,发现1个与抗蚜基因连锁的微卫星标记(SSR标记),与抗蚜基因的遗传距离为8.7 cM。该标记位于第9连锁群上,因而将该基因初步定位于第9连锁群。     

高粱微卫星分析中遗传完整性样本量的确定

采用微卫星分析高粱不同样本量对遗传多样性指数的影响,从而确定最佳样本量,为遗传完整性研究奠定基础。试验设置了10个样本量梯度,对群体的等位基因数目、有效等位基因数目、香农指数、观察杂合度、预期杂合度、多态位点百分数和稀有等位基因频率的变化趋势进行了分析。结果表明,10～40个样本量范围内,等位基因数目、有效等位基因数目、香农指数、多态位点百分数随着样本量的增大而增大;在40个样本量时,等位基因数目、有效等位基因数目和香农指数达到较高值,分别代表了100个群体98.5%的等位基因数、99.1%的有效等位基因数和98.5%的香农指数,之后样本量继续增加,各指标变化不显著。稀有等位基因频率在40个样本量以上,随着样本量的增加数值变化很小。以稀有等位基因频率、等位基因数、有效等位基因数和香农指数为多样性指标,在高粱遗传完整性研究中样本量大小的确定上达到一致性。因此,建议在用SSR技术对高粱进行遗传完整性分析时,样本量要选择40个单株以上。     

Evaluation of phenolics and antioxidant activity of black sorghum hybrids

Black sorghums possess very high levels of the rare 3-deoxyanthocyanidins which can be used as natural food colorants with health benefits. However, these sorghum genotypes have undesirable agronomic properties (i.e. high height, low yield, increased weathering). Black sorghum hybrids with improved agronomic properties were developed and their phenolic profiles and antioxidant activity were compared with black sorghum lines. Black sorghum hybrids were significantly lighter in colour than the lines (P < 0.001). All hybrids had a pigmented testa which was indicated by the presence of condensed tannins, which significantly increased total phenol levels and antioxidant activity. The 3-deoxyanthocyanidin, flavan-4-ol, and flavone levels were significantly lower in the hybrids (P < 0.001) and were strongly correlated to pericarp colour (P < 0.001). Flavanone levels were not significantly different among the lines and hybrids (P > 0.05) and pericarp colour did not affect their levels (P > 0.05). Even though the 3-deoxyanthocyanidin levels were lower in black sorghum hybrids than in the lines, the presence of condensed tannins in the hybrids significantly increased their antioxidant activity. Since 3-deoxyanthocanidin levels were dependent on pericarp colour, hybrids with increased blackness intensity should be developed to increase the stable 3-deoxyanthocyanidins.     

Evaluation of performance of sorghum varieties grown in Tokyo for sugar accumulation and its correlation with vacuolar invertase genes SbInv1 and SbInv2

ABSTRACT

The sugar-accumulating potential of global and local sweet and grain sorghum varieties were tested under the local conditions. The basis for this study was the dependency of sugar accumulation on temperature and photoperiod. Thus, the efficacy of cultivars as a bioenergy source would need to be determined based on their performance under the local environmental conditions. A strong correlation of sucrose content with brix was observed, enabling large-scale screening of varieties for high sucrose content. The morphological characteristics inherent in sweet sorghum, such as tall stems, greater number of leaves and a longer vegetative period, were found to correlate with the total stem sugar content. Assessment of sugars along the stem revealed maximum sugar accumulation in the upper intermediate to upper internodes in most of the varieties tested. The maximum theoretical ethanol yield (MTEY), a function of brix and juice yield, was determined as a better indicator of testing the performance of a variety as a potential source of bioethanol, mainly due to a negative correlation of stem juiciness and sucrose content in the varieties tested. Further, the relative expression of vacuolar invertase genes, SbINV1 and SbINV2, was studied, and a strong negative correlation of SbINV2 to stem sucrose content was observed. This reveals a possibility of involvement of vacuolar invertase gene, SbINV2, in sugar accumulation in sweet sorghum stems, and as a key candidate for molecular breeding studies for higher stem sugar content.     

Effects of Physiological Status of Parent Plants and Culture Medium Composition on the Anther Culture of Sorghum

Abstract

Anthers at various maturation stages were collected from seven genotypes of Sorghum bicolor, and cultured on MS medium supplemented with 3 mg L^?1 2,4-D and 2.0 mg L^?1 kinetin. The rate of callus induction was high in young anthers, and decreased with maturation of the anther. Young anthers were collected from the plants grown in the greenhouse (greenhouse anthers), in the field (field anthers), and in the chambers kept at 20, 25 or 30 °C. Then they were cultured on MS medium containing 2.0 mg L^?1 kinetin, 1.0 mg L^?1 IAA and 2.5 mg L^?1 2,4-D, on which the rate of callus induction was the highest. The average callus-induction percentage was 6.4% in the field anthers, and 3.7% in the greenhouse anthers. Callus induction was low in the anthers collected from the plants grown at 30° C. Among the genotypes examined, TX403 produced calli at the highest frequency. The rate of plant regeneration from anther-calli was the highest on the medium containing 2.5 mg L^?1 kinetin and 3.0 mg L^?1 IAA. The regeneration rate of green plantlets on this medium was 27% on the average, and was 46.2 and 28.6% in PP290 and TX403, respectively. The chromosome number in root-tip cells was unstable, but was 20 in most of the regenerated plantlets.     

Modelling the β-amylase activity during red sorghum malting when Bacillus subtilis is used to control mould growth

Steeping in dilute alkaline (0.2% NaOH) followed by resteeping in biocontrol (starters of Bacillus subtilis S499) has been used during red sorghum malting. The effect of steeping and germination conditions has been described using 2 functions: a Weibull 4-parameter model combined with a General Linear Model with Logarithm Link with significant goodness. Steeping conditions (combined use of NaOH and B. subtilis S499) affects the synthesis capacity of grain: when B. subtilis culture used in the steeping step is diluted, ln α increases, suggesting a loss of treatment efficacy. The germination temperature affects the β-amylase synthesis rate during the induction phase: the germination temperature increase is accompanied by a decrease of the β-amylase synthesis rate. During the repression phase of β-amylase synthesis, the effect of malting conditions was found to taper.     

Hydraulic Resistance of Sorghum (C4) and Sunflower (C3)

Summary

It is well known that C4 crops have a lower water requirement than C3 crops. Reasons for the difference are not well understood. Therefore, hydraulic resistance of sorghum [Sorghum bicolor (L.) Moench] (C4) and sunflower (Helianthus annuus L.) (C3) was determined to see if it might be one explanation for the lower water use of crops with the C4 photosynthetic pathway. Plants were grown under greenhouse conditions in pots with soil, which was well watered (soil matric potential of ～0 MPa) or allowed to dry (soil matric potential of ?0.038 MPa and ?0.065 MPa for sorghum and sunflower, respectively). Hydraulic resistance was calculated in two ways: (1) using the classic Ohm's law analogue, which assumes that the relation between flux (transpiration) and difference in water potentials of the soil and plant is linear and (2) using an equation that considers diurnal changes in leaf water content along with transpiration and difference in water potentials. Because change in leaf-water content during a day was small, hydraulic resistances calculated by the two methods resulted in similar values. Sorghum had a linear relationship between flux and difference in potentials (constant hydraulic resistance), but sunflower had a nonlinear one (variable hydraulic resistance). The hydraulic resistance of watered sunflower increased only slightly during a day and averaged about 40 MPa m² s mol^?1, which was 3.5 times less than that of watered or water-stressed sorghum (-140 MPa m² s mol^?1). The hydraulic resistance of water-stressed sunflower increased steeply during a day and by the end of the day it had a hydraulic resistance that approached that of sorghum.     

高粱苗期耐盐性转录组分析和基因挖掘

【目的】探究高粱耐盐胁迫响应机制,挖掘高粱耐盐胁迫基因,为高粱耐盐育种提供理论基础。【方法】 以高粱感盐品种L甜和耐盐品种石红137为供试材料,采用水培试验。待高粱植株长至三叶一心期,使用2%NaCl溶液对幼苗进行盐胁迫,分别设置0（对照）、1和24 h处理,每个处理3次重复。测定不同处理样品株高、根长、干物重、Na ⁺含量和叶绿素相对含量（SPAD值）,并依托Illumina HiSeq 2000平台进行转录组测序分析。利用FPKM方法计算基因表达量,在差异表达基因检测过程中,将差异表达倍数（fold change）≥2且FDR<0.001作为筛选标准。通过Gene Ontology和KEGG Pathway数据库对参与高粱不同时间盐胁迫差异表达基因进行分析注释。 【结果】 盐胁迫处理对高粱株高、根长、干物重等性状无显著影响,对钠离子含量和SPAD值影响显著。石红137株高、根长、钠离子含量和SPAD值均高于L甜。转录组测序结果鉴定得到已知基因26 628个,新基因866个。石红137中的差异基因数目高于L甜。石红137中,0 h VS 1 h、0 h VS 24 h、1 h VS 24 h三组的差异基因数目分别为375、4 206和3 750个。感盐品种L甜中,0 h VS 1 h、0 h VS 24 h、1 h VS 24 h三组的差异基因数目分别为167、2 534和1 612个。GO分析共获得25个功能注释,分别为光合作用、细胞物质代谢、翻译过程以及激素合成等与盐胁迫相关的差异表达基因。KEGG分析发现盐胁迫1 h表达差异基因富集在植物激素信号转导途径,涉及脱落酸（abscisic acid,ABA）、生长素（auxin,AUX）、细胞分裂素（cytokinin,CTK）、赤霉素（gibberellins,GS）、乙烯（ethylene,ETH）过程等共71个基因。盐胁迫24 h表达差异基因富集于光合作用相关途径,涉及Lhca、Lhcb、磷酸烯醇式丙酮酸羧化酶（phosphoenolpyruvate carboxylase,PPC）、磷酸核酮糖激酶（phosphorylribonucleic kinase,PRK）等20个基因。类黄酮生物合成代谢途径差异可能是引起石红137和L甜的耐盐能力差异的原因之一,花青素还原酶（anthocyanidin reductase,ANR）和黄酮醇合成酶（flavonol synthase,FLS）参与类黄酮生物合成途径。【结论】 高粱的盐胁迫过程是一个复杂的生物过程,依赖于多个基因在复杂网络中的平衡表达。盐胁迫条件下,高粱应对环境刺激受到激素信号转导和光合作用的控制。类黄酮生物合成途径在耐盐品种中起到了重要作用。     

延安市高粱新品种引进试验

为了筛选出适合延安市种植的高粱品种,从山西省和辽宁省引入优良高粱品种开展了品种比较试验,并按照最适播种条件进行统一播种和管理。结果表明,综合抗性、产量和品质等因素,晋杂25、辽粘6号、辽粘3号、辽2297和龙杂产量较高,抗性较强,适合进一步试验推广。     

Increasing protein content and digestibility in sorghum grain with a synthetic biology approach

Despite great genetic diversity, sorghum grain consistently suffers from poor protein digestibility. The physicochemical packaging of protein bodies which consist of protease-resistant β- and γ-kafirin is considered a major obstacle. A synthetic β-kafirin gene, which shares the endosperm-specific promoter and signal peptide with the native β-kafirin gene (Sobic.009G001600.1), was transformed into sorghum inbred line Tx430. The gene was modified with ten additional proteolytic sites. These sites were designed to be amenable to cleavage by pepsin and/or chymotrypsin proteinases. Five independent transgenic lines were regenerated by microprojectile transformation. Notably, considerably more protein was observed in the peripheral endosperm of transgenic lines under scanning electron microscopy. Microscopy revealed invaginated or irregularly shaped protein bodies in the endosperm of transgenic lines. Grains of transgenic lines contained 11–37% more protein, which was 11–21% more pepsin digestible and 7–25% more chymotrypsin digestible than Tx430. Additionally, the abundant synthetic β-kafirin protein (5.6% of total protein) was detected by mass spectrometry data analysis in the transgenic line 9-1. Field-grown homozygous transgenics retained higher protein content, larger seed size and no reduction in grain number per plant. The results illustrated that plant synthetic biology could play an important role in improving sorghum nutritional value.