‘砀山酥梨’果实CCoAOMT基因的克隆与表达分析

[目的]通过克隆‘砀山酥梨’(Pyrus bretschneideri ‘Dangshansuli’)果实中咖啡酰-辅酶AO-甲基转移酶(CCoAOMT)基因的全长序列,并对其进行生物信息学及基因表达差异分析,阐释了其在梨果实木质素合成途径的作用,以期为今后利用基因调控技术来改变果实中石细胞含量从而改善梨果实品质提供一定的理论依据。[方法]以15年生‘砀山酥梨’果实为试材,根据从NCBI数据库中搜索得到关于植物木质化的CCoAOMT基因序列与梨基因组数据库调取的序列比对,利用RT-PCR技术克隆得到了木质素生物合成途径中的一种关键酶基因PbCCoAOMT,GenBank登录号为KJ577544。[结果]该基因全长1133bp,具有1个744bp的完整开放阅读框(ORF),编码247个氨基酸。序列比对及系统进化树分析表明:CCoAOMT酶是氧甲基转移酶类,与其他植物CCoAOMT编码的蛋白序列有较高的相似性,尤其与枇杷的相似度最高,达到98.79%,且亲缘关系最近。利用荧光定量PCR技术对其在果实不同发育时期表达模式的分析发现,基因表达量呈先上升后下降的趋势,与梨果实中石细胞含量的变化趋势相似。[结论]初步认为从‘砀山酥梨’中克隆得到的PbCCoAOMT基因可能参与了梨果实中木质素的代谢。

尖镰孢菌和禾谷镰孢菌引起的大豆根腐病生物防治研究

以大豆与禾谷类作物轮作体系中引起大豆根腐病的尖镰孢菌(F.oxysporum)和禾谷镰孢菌(F.graminea-rum)为研究对象,测试分离于大豆和小麦根部及根际土壤的生防菌对2种病原菌防治效果。结果表明:拮抗试验中所测试的生防菌对2种镰孢菌抑菌效果差异不显著,生防菌HJ-ZT1、HJ-MM7、HJ-ZT2、CH-Tr14、HJ-MM8和CH-Tr18的抑菌率显著高于CH-Tr51、HJ-MM35、HJ-MM9和ACM941。温室条件下生防菌处理对尖镰孢菌和禾谷镰孢菌2种病原菌的防效及对大豆的促生作用均存在差异,CH-Tr12、ACM941、SB24+HJ-MM7和化学药剂对尖镰孢菌防效效果较好,并很大程度促进植株生长;生防菌CH-Tr14、HJ-MM7和CH-Tr12对禾谷镰孢菌防治效果较好。田间试验中,生防菌处理ACM941+HJ-MM7使大豆增产10%,CH-Tr14增产9%,CH-Tr12增产8%,与化学对照增产6%差异不显著。

粉红粘帚菌代谢物对南方根结线虫卵孵化及二龄幼虫的影响(英文)

粉红粘帚菌(Gliocladium spp.)是一类对植物病原菌具有潜在生物控制作用的真菌,为了探讨粘帚菌对南方根结线虫(Meloidogyne incognita)的抑制作用,实验室条件下研究了粉红粘帚菌挥发性代谢产物和非挥发性代谢产物不同稀释度对南方根结线虫卵孵化及二龄幼虫活性的影响。结果显示非挥发性代谢产物在原液、5倍、10倍、20倍、50倍稀释浓度下,12 d后对南方根结线虫卵孵化的相对抑制率分别为80.4%、12.0%、10.5%、6.7%和5.2%,对二龄幼虫的矫正死亡率分别为32.0%、9.3%、2.0%、0.6%和0.1%,与对照组相比差异显著;挥发性代谢产物对南方根结线虫卵孵化的相对抑制率为22.5%,对二龄幼虫的相对死亡率为17.4%。因此,粉红粘帚菌的非挥发性和挥发性代谢产物对南方根结线虫卵孵化及二龄幼虫活性均有一定的抑制作用。

双标图分析在农作物品种多点试验中的应用

双标图分析越来越多地被用于直观分析农作物品种多点试验数据和其他类型的两向数据。这种方法深受植物育种家和农业研究人员的推崇,认为它可以提高研究者理解和驾驭试验数据的能力;但也受到一些学者的批评,认为它是统计分析方面的旁门左道。事实上,学术界对什么是双标图的认识尚存混乱,一些双标图的使用者并不总能正确地选择和解释双标图,一些双标图的批评者对双标图分析及其研究对象也缺乏深入了解。为使研究者对双标图分析有一个客观全面的认识,本文就用双标图分析农作物品种多点试验中的几个问题进行阐述:(1)如何针对特定的研究目的选择适当的双标图;(2)如何选择适当的GGE双标图来分析多点试验数据;(3)如何使用GGE双标图的不同功能形态进行品种评价、试验点评价和品种生态区划分;(4)如何判断双标图是否充分表现试验数据中的规律;(5)如何检验双标图显示的结果是否显著。

Synopsis of Leymus Hochst.(Triticeae:Poaceae)

Leymus is a genus in the Triticeae tribe, Poaceae. The taxa of this genus are allopolyploid species which possess the Ns and Xm genomes. According to cytological, cytogenetic and molecular genetic analyses, some species of Hystrix and Elymus ought to be transferred to this genus. A world revision of the genus Leymus is needed. In this paper we summarize experimental results, provide a key to sections, species and varieties, and list all the taxa we recognize in Leymus with their synonyms. This synopsis is a new taxonomic system to be used for the revision of Leymus.

PbMC1a/1b regulates lignification during stone cell development in pear(Pyrus bretschneideri)fruit

Programmed cell death(PCD)and secondary cell wall(SCW)thickening in pear fruit are accompanied by the deposition of cellulose and lignin to form stone cells.Metacaspase is an important protease for development,tissue renewal and PCD.The understanding of the molecular mechanism whereby pear(Pyrus)metacaspase promotes PCD and cell wall lignification is still limited.In this study,the Metacaspases gene family(PbMCs)from P.bretschneideri was identified.PbMC1a/1b was associated with lignin deposition and stone cell formation by physiological data,semiquantitative real-time polymerase chain reaction(RT-PCR)and quantitative RT-PCR(qRT-PCR).Relative to wildtype(WT)Arabidopsis,the overexpression of PbMC1a/1b increased lignin deposition and delayed growth,thickened the cell walls of vessels,xylary fibers and interfascicular fibers,and increased the expression of lignin biosynthetic genes.Yeast two-hybrid(Y2H),bimolecular fluorescence complementation(BiFC)and GST pull-down assays indicated that the PbMC1a/1b protein physically interacted with PbRD21.Simultaneously,the transient expression of PbMC1a/1b and PbRD21 led to significant changes in the expression of genes and lignin contents in pear fruits and flesh calli.These results indicate that PbMC1a/1b plays an important role in cell wall lignification,possibly by interacting with PbRD21 to increase the mRNA levels of some lignin synthesis-associated genes and promote the formation of stone cells in pear fruit.

Analysis of phenotype array data from Biolog MicroPlates TM.

Biolog MicroPlates TM. are employed to characterize Trichoderma isolates based on differential assimilation of test substrates and redox reactions in a 96-well test plate. The Biolog method is potentially advantageous in being relatively simple, fast and economical, and data acquisition can be automated using a microplate reader and applicable software. Several research applications of the Biolog system are presented: i) “monophenetic groups” from cluster analyses of phenotype array data are investigated for previously undetected new species in Trichoderma, ii) metabolic characters differentiating species are identified, and multivariate analyses performed to complement molecular data in validating new species and significant variants, and iii) phenotype array data for more than 1200 Trichoderma strains are analysed to select strains that might be exploited for bioconversions and commercial production of enzymes. Phenotype arrays are much more sensitive to strain level variation than molecular techniques, however, phenotype array data do not consistently reflect phylogenies constructed from molecular data. Nevertheless, the Biolog phenotype array is an economical alternative method for surveying biological diversity, and provides data that complements molecular data in phylogenetic studies.

Identification of a Group of Novel γ-Gliadin Genes

γ-Gliadins are an important component of wheat seed storage proteins. Four novel γ-gliadin genes （Gli-ngl to Gli-ng4） were cloned from wheat （Triticum aestivum） and Aegilops species. The novel γ-gliadins were much smaller in molecular size when compared to the typical γ-gliadins, which was caused by deletion of the non-repetitive domain, glutamine-rich region, 3＂ part of the repetitive domain, and 5＇ part of the C-terminal, possibly due to illegitimate recombination between the repetitive domain and the C-terminal. As a result, Gli-ngl and Gli-ng4 only contained two and three cysteine residues, respectively. Gli-ngl, as the representative of novel γ-gliadin genes, has been sub-cloned into an Escherichia coli expression system. SDS- PAGE indicated that the both cysteine residues of Gli-ngl could participate in the formation of intermolecular disulphide bonds in vitro. Successful cloning of Gli-ngl from seed cDNA of T. aestivum cv. Chinese Spring suggested that these novel γ-gliadin genes were normally transcribed during the development of seeds. Phylogenic analysis indicated that the four novel γ-gliadin genes had a closer relationship with those from the B （S） genome of wheat.

A Potential Flood Hazard Caused by Tianchi Volcano Eruption in Changbai Mountain, Northeast China

Geohazards appear to be increasing in frequency globally. It is of necessity to actively manage these natural hazards to minimize loss of life and property. From an early warning perspective, this paper stresses the potential fatal flood hazard represented by the huge volume of water in Tianchi Lake, the unique geography of Changbai Mountain, and the limited flood control ability in the upstream of the Songhua River. Northeast Asian countries should keep a watchful eye on the Changbai volcano cooperatively, and Chinese government especially needs to prepare plans for fighting a flood in advance.

Differentially Expressed Genes of Soybean During Infection by Phytophthora sojae

To elucidate the differential gene expression patterns in soybeans during infection by Phytophthora sojae,a cDNA library for suppression subtractive hybridization （SSH） was constructed with cDNAs from soybean cultivar Suinong 10 treated with sterile distilled water as the driver and cDNAs from Suinong 10 inoculated with P.sojae as the tester.A total of 2 067 recombinant colonies from the SSH library were randomly picked,amplified,and sequenced.After discarding 312 poor quality expressed sequence tags （EST）,1 755 high quality ESTs were assembled and edited to 1 384 tentatively unique genes （TUG）,in which,586 showed significant homology to known sequences,and 798 had low homology or no match with the known sequences.A cDNA microarray containing 307 singletons from the 586 TUGs and 222 singletons from the 798 TUGs was developed to characterize differentially expressed cDNAs in the SSH library,and eight cDNAs were identified to be up-regulated after microarray analysis and then confirmed by real-time PCR.They were homologous to the protein 10,and were also related to some proteins in disease resistance response,such as pathogen-related protein,phenylalanine ammonia-lyase,isoflavone reductase,WRKY transcription factor 31,major allergen Pru ar 1,and pleiotropic drug resistance protein 12.Most of the up-regulated cDNAs encode enzymes of phytoalexin biosynthesis and pathogenesis-related proteins involved in plant disease resistance.Here,we fist reported the Pru ar 1 in soybeans.The findings of this research have contributed to better understanding of soybean resistance to P.sojae at the molecular level.

Cropping frequency and N fertilizer effects on soil water distribution from spring to fall in the semiarid Canadian prairies

In the semiarid Canadian prairies, water is the most limiting and nitrogen (N) the second most limiting factor influencing spring wheat (Triticum aestivum L.) production. The efficiency of water-and nitrogen use needs to be assessed in order to maintain this production system. The effects of cropping frequency and N fertilization on trends in soil water distribution and water use were quantified for an 18-yr (1967-1984) field experiment conducted on a medium textured Orthic Brown Chernozem (Aridic Haploboroll) in southwestern Saskatchewan, Canada. Soil water contents were measured eight times each year and plant samples were taken at five phenological growth stages. The treatments studied were continuous wheat (Cont W), summer fallow - wheat, F-(W) and summer fallow - wheat - wheat, F-W-(W) each receiving recommended rates of N and phosphorus (P) fertilizer, and (F)-W-W and (Cont W) each receiving only P fertilizer, with the examined rotation phase shown in parentheses. Soil water conserved under fallow during the summer months averaged 25 mm in the root zone, and was related to the initial water content of the soil, the amount of precipitation received, its distribution over time, and potential evapotranspiration. Under a wheat crop grown on fallow, soil water contents between spring and the five-leaf stage remained relatively constant at about 250 mm, but those under a stubble crop, with 40 mm lower spring soil water reserves, increased slightly until about the three-leaf stage. During the period of expansive crop growth (from the five-leaf to the soft dough stage) soil water was rapidly lost from all cropped phases at rates of 1.87 mm.day–1 for F-(W) (N+P), 1.23 mm.day–1 for Cont W (N+P) and 1.17 mm.day–1 for Cont W (+P). The initial loss was from the 0 - 0.3 m depth, but during the latter half of the growing season from deeper depths, although rarely from the 0.9 - 1.2 m depth. In very dry years (e.g., 1973, with 87 mm precipitation between spring and fall) summer fallow treatments lost water. In wet years with poor precipitation distribution (e.g., 1970, with 287 mm precipitation between spring and fall but 142 mm of this in one week between the three- and five-leaf stage) even cropped treatments showed evidence of leaching. The above-ground biomass water use efficiency for Cont W was 19.2 and 16.7 kg.ha–1.mm–1, respectively, for crops receiving (N+P) and P fertilizer only. Grain yield water use efficiency (8.91 kg.ha–1.mm–1) was not significantly influenced by cropping frequency nor N fertilizer. The 18 years of detailed measurements of plant and soil parameters under various crop management systems provide an invaluable source of information for developing and testing simulation models.

The Outbreeding Enhancement and Correlation Studies in F₁Hybrids of Hexaploid Wheat (<i>Triticum aestivum</i>L.) Cultivars

The current study was conducted in the experimental field of the Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, Bangladesh during the winter season 2017-2018. The study was performed to reduce the heterotic effect and phenotypic correlation among numerous yield characters for F1 hybrids of hexaploid wheat (Triticum aestivum L.). The experimental design has consisted of six parental variants (Sonalika, Balaka, Prodip, Kanchan, Agrahani and Protiva), which were crossed and nine possible cross combinations (F1 hybrids) (Prodip × Agrahani, Balaka × Agrahani, Prodip × Protiva, Protiva × Agrahani, Agrahani × Kanchan, Kanchan × Sonalika, Protiva × Prodip, Sonalika × Agrahani, and Prodip × Kanchan) were obtained. The experimental fields were selected and arranged in a randomized complete block design with four replicates, where eight characters were studied. The mean square of the analysis of variance showed that the hybrids differed significantly (p ≤ 0.01) for all studied characters except for maturity to 75% of days and height of the plant, while the parents only had no differences in grain yield. The mean square of the parent and the F1 hybrid indicated that considerable heterosis existed in the F1 hybrids. In general, correlation coefficients indicated that the maturity to 75% of days was significant but negatively correlated with most of the yield traits, suggesting that the genotypes which became mature early may have lower yields. Plant height was also negatively correlated with grain spike−1, seed index, and harvest index. The grain yield plant−1 was significant and positively correlated with all yield traits. Correlation indicates that single or multiple production-related ingredients can be used as selection time to select plants with higher yield traits with larger grains.

小麦低分子量谷蛋白亚基基因5′侧翼保守序列染色体组特异性DNA变异的分析及验证

根据33个低分子量麦谷蛋白亚基(LMW-GS)基因5′侧翼序列的相似性进行聚类分析,可将其划分成8个类群,这与基于N末端推导氨基酸序列进行的类群划分结果完全一致.序列比对发现,各类群基因5′侧翼保守序列间存在DNA多态性,共发现34个多态性位点,其中18个为潜在单核苷酸多态性位点(SNPs,singlenucleotidepolymorphisms).除1个LMW-GS类群之外,其余7个类群的5′侧翼序列均具有类群特异性DNA变异位点.根据类群间的DNA多态性对这7个类群设计了特异引物,利用普通小麦(TriticumaestivumL.)品种中国春及其第1同源群双端体系对其进行染色体定位分析,揭示了1AS,1BS和1DS上分别有第2,1和4类群.对PCR产物的克隆测序进一步验证了不同染色体组上的LMW-GS基因类群间5′侧翼序列具有特异性.这些结果表明,LMW-GS基因的编码区及其5′侧翼保守序列可能是协调进化的.本文报道的7对引物可对7类LMW-GS基因的完整编码区进行特异扩增,因而能在小麦复杂的遗传背景下有目的地对某一类LMW-GS基因进行分离克隆,这有助于弄清单个LMW-GS对小麦品质的贡献.同时,在小麦育种中,这些标记对于有效地选择与品质密切相关的LMW-GS组分有一定应用价值.

Analysis and validation of genome-specific DNA variations in 5′flanking conserved sequences of wheat low-molecular-weight glutenin subunit genes

The thirty-three 5′ flanking conserved sequences of the known low-molecular-weight subunit (LMW-GS) genes have been divided into eight clusters, which was in agreement with the classification based on the deduced N-terminal protein sequences. The DNA polymorphism between the eight clusters was obtained by sequence alignment,; a total of 34 polymorphic positions were observed in the approximately 200 bp regions, among which 18 polymorphic positions were candidate SNPs. Seven cluster-specific primer sets were designed for seven out of eight clusters containing cluster-specific bases, with which the genomic DNA of the ditelosomic lines of group 1 chromosomes of a wheat variety ‘Chinese Spring’ was employed to carry out chromosome assignment. The subsequent cloning; DNA sequencing of PCR fragments validated the sequences specificity of the 5′ flanking conserved sequences between LMW-GS gene groups in different genomes. These results suggested that the coding; 5′ flanking regions of LMW-GS genes are likely to have evolved in a concerted fashion. The seven primer sets developed in this study could be used to isolate the complete ORFs of seven groups of LMW-GS genes, respectively,; therefore possess great value for further research in the contributions of a single LMW-GS gene to wheat quality in the complex genetic background; the efficient selections of quality-related components in breeding programs.

Phylogeny and taxonomic revision of Thelonectria discophora(Ascomycota,Hypocreales,Nectriaceae)species complex

Specimens regarded as Thelonectria discophora(Thelonectria,Nectriaceae,Hypocreales)constitute a conspicuous group of saprobic fungi on decaying plant material,characterized by red perithecia each with a broad mammiform(nipple-like)apex.The asexual state is characterized by a cylindrocarpon-like morphology,with 3–5 septate macroconidia,unicellular microconidia and chlamydospores that are rarely produced in culture.In the past,T.discophora was regarded as one species with a wide geographic distribution.However,a recent study rejected the monophyly and cosmopolitan distribution of this species,and showed the existence of at least 16 cryptic species distributed in three main groups.By combining the results of phylogenetic analyses of six nuclear loci and morphological studies,we revised the taxonomy of the T.discophora species complex,resulting in the description of 12 new species and four new combinations based on historic names.Even though molecular phylogenetic analyses strongly support the segregation of these species,and are in agreement with previous studies,individual diagnostic morphological characters for each species could not be identified.However,discrete morphological traits corresponding to each of the three main groups of species were discovered.Lineages could be differentiated based on the average values of morphological traits as well as the presence/absence of characteristic asexual propagules and colony growth at 30C.Descriptions,illustrations are provided for the recognized species.