水稻显性核不育及其恢复性的遗传规律研究

 对萍乡显性核不育水稻的遗传规律进行了研究,结果表明该不育材料的育性是由两对显性核基因Ms和Rf互作控制的。其中Ms是显性不育基因,Rf是显性上位基因。两者共同存在时,显性上位基因能抑制显性不育基因的表达,从而使育性表现可育。其不育群体的遗传组成为Msmsrfrf+msmsrfrf或MsMsrfrf+MsMsRfRf,恢复系基因型为msmsRfRf。     

Technical overview of nuclear microsatellites for Fagus sp., and their utility in F. sylvatica from the central Balkans (Serbia)

ABSTRACT

Selectively neutral nuclear microsatellites (SSRs) are available for Fagus sp., and have been used in F. sylvatica, an ecologically and economically most important European Fagus species. We provide a comprehensive technical overview of available Fagus sp. SSRs (185 loci), carry out meta-analysis of loci used in F. sylvatica (62 loci employed in 62 surveys), and validate a set of 16 loci in 45 individuals of this species from the central Balkans (Serbia). Erroneous usage of marker’s names/authors is rather frequent, and loci successfully used in a number of studies are characterized by other authors by high prevalence of null alleles and even multilocus amplification products. Frequent occurrence of null alleles at FS4-46, used in 26 surveys to date, most likely indicates a failure to record multiple alleles at this locus. Twelve loci are reliable/informative in F. sylvatica from the Balkans (5–18 alleles/locus, H_E ranging from 0.523 to 0.850), while four loci are characterized by high prevalence of null alleles (sfc0161 and sfc1063) and multilocus amplification products (FS4-46 and Fagsyl_007038). Our findings are important for future population genetics and studies on adaptation of F. sylvatica to its environment, because the latter rely on both selectively neutral and adaptive markers under selection.     

黄河流域田间棉铃虫对转Bt基因棉抗性监测

利用改进的单雌系F1/F2代法,对黄河流域主要棉区河南安阳县、河北威县、山东武城县的棉铃虫种群进行了系统监测。在2007-2009年,连续3年保守地估计了以上3个主要植棉县棉铃虫种群对Cry1Ac的抗性基因频率。结果表明,山东武城棉铃虫种群3年的抗性等位基因频率分别为0.00086、0.00097和0.00052;安阳田间棉铃虫种群2008和2009年抗性等位基因频率分别为0.00090和0.00103;河北威县的田间棉铃虫种群抗性等位基因频率为0。所有家系F1代和F2代的相对平均发育级别均值比较结果显示,山东武城县棉铃虫种群耐受性高于其它2个地区,其次为安阳县种群,威县种群敏感度最高。总之,我国黄河流域这3个主要棉区田间棉铃虫种群对Cry1Ac毒素还没有产生明显的抗性,抗性基因频率仍处于正常水平,但是棉铃虫对Cry1Ac毒素的耐受性有升高趋势,需要进一步加强全国性的监测工作。     

Oral 1,25-dihydroxyvitamin D3 in prevention of milk fever

The effect of daily oral doses of 1,25-dihydroxy vitamin D₃ (1,25-(OH)₂D₃) on plasma mineral concentrations and incidence of milk fever was tested in 39 aged cows. Three dose levels of 1,25-(OH)₂D₃ (0, 100 and 200 µg/d) were compared in cows supplemented with 100 g Ca/d (250 g CaCO₃) and in cows receiving no Ca supplement. 1,25-(OH)₂D₃ treatments were given from day 5 before expected calving (day –5) until the day after calving (Calving = day 0).Expected minima in Ca concentrations in plasma were seen on day 1 in placebo treated cows, while Ca concentrations in 1,25-(OH)₂D₃ treated cows were normal or increased in the period from start of treatment until day 3–5. In the parturient period (day –1 to +2) 1 of 21 treated cows developed milk fever, as compared to 4 of 18 untreated. A pronounced hypocalcaemia developed, however, in the 1,25-(OH)₂D₃ treated cows from day 3 to 5 onwards, culminating day 8–11 with 7 cases of milk fever. Ca supplements reduced the development of hypocalcaemia in the 1,25-(OH)₂D₃ treated cows, but could not completely prevent the occurrence of milk fever.     

Multiple origins for black-grass (Alopecurus myosuroides Huds) target-site-based resistance to herbicides inhibiting acetyl-CoA carboxylase

We have investigated the process of evolution of target-site-based resistance to herbicides inhibiting acetyl-CoA carboxylase (ACCase) in nine French populations of black-grass (Alopecurus myosuroides Huds). To date, two different ACCase resistant alleles are known. One contains an isoleucine-to-leucine substitution at position 1781, the second contains an isoleucine-to-asparagine substitution at position 2041. Using phylogenetic analysis of ACCase sequences, we showed that 1781Leu ACCase alleles evolved from four independent origins in the nine black-grass populations studied, while 2041Asn ACCase alleles evolved from six independent origins. No geographical structure of black-grass populations was revealed. This implies that these populations, although geographically distant, are, or have until recently been, connected by gene flows. Comparison of biological data obtained from herbicide sensitivity bioassay and molecular data showed that distinct resistance mechanisms often exist in a single black-grass population. Accumulation of different resistance mechanisms in a single plant was also demonstrated. We conclude that large-scale evolution of resistance to herbicides in black-grass is a complex phenomenon, resulting from the independent selection of various resistance mechanisms in local black-grass populations undergoing contrasted herbicide and agronomical selection pressures, and connected by gene flows whose parameters remain to be determined.     

Genetic structure of a population of Ganoderma boninense on oil palm

Ganoderma boninense (the causal agent of basal stem rot of oil palm in Papua New Guinea) has a tetrapolar mating system with multiple alleles. Investigations into the population structure of G. boninense , using interfertility between isolates as a marker, revealed that the population on oil palm was comprised predominantly of genetically distinct individuals, although a number of isolates were found to share single mating alleles. No direct hereditary relationship was found between isolates on neighbouring or spatially separated diseased palms, indicating that outcrossing had probably occurred over several generations in the founder population prior to colonization of oil palm. In this study, a total of 81 A and 83 B mating type alleles (factors) were detected with 18 allelic repeats at the A locus and 17 at the B locus. Alleles appeared to be randomly dispersed throughout the population in each study block, although there was a significantly ( P  < 0·01) higher proportion of allelic repeats between estates separated by several kilometres compared to within estates. This is the first study on the population structure of this species and confirms that sexual reproduction is a significant component of the epidemiology of this disease.     

Production of all eight genotypes of null alleles at 'waxy' loci in bread wheat, Triticum aestivum L.

Null alleles of the three loci coding for ‘waxy’ proteins in bread wheat have been identified. Plants carrying different null alleles were collected and segregation of the null alleles in both selfed and doubled haploid progeny of plants simultaneously heterozygous for the null alleles at each of the three loci were examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Mendelian segregation of these alleles in both types of progeny was shown, indicating that they can easily be utilized in breeding programmes. Iodine staining of the eight possible null phenotypes showed that only the triple null type had zero amylose in its endosperm starch.     

芥黄蜜环菌交配型复等位基因的研究

从大兴安岭长白山采集１７号芥黄蜜环菌,用分离的单孢菌株进行交配型测定,证实中国该种为双因子异宗配合机制,选取各号标本的４种交配型菌株进行循环配对实验,结果发现该种的交配型基因座的多样性很高,共有１３对复等位基因,证明该种在世界分布区域内具有较强的生态适应能力。是目前国际首次用实验测定的蜜环菌交配基因数目。     

华山新麦草籽粒硬度吲哚蛋白基因的分离与序列分析

采用AS-PCR技术,从华山新麦草基因组DNA中分离获得了其籽粒硬度吲哚蛋白Pina(HM 448475)和Pin b(HM448476)的基因序列.DNA序列分析显示,这2条序列相似性仅为69.25％,它们与小麦、山羊草、黑麦、燕麦和大麦亲缘种属植物等的Pin a和Pin b基因序列具有93％以上的一致性;推导的氨基酸序列分析显示,序列HM 448475(Pin a)和HM 448476(Pin b)都具有籽粒硬度吲哚蛋白基因的19个氨基酸残基组成的信号肽,与脂类易于结合的色氨酸结构域WRWWKWWK( Pin a)或WPTKWWK( Pin b),以及位置固定的10个半胱氨酸残基等典型结构特征,同时,这2条序列与小麦、山羊草等亲缘植物的Pin a和Pin b基因氨基酸相比,分别有15个和8个主要位点的差异;系统进化树分析显示,序列( HM 448475)可能为Pin a基因家族中的一个新类型,而序列(HM 448476)与智利大麦的Hordoindoline b基因具有相对较近的亲缘关系.研究表明,华山新麦草含有与麦类作物差异较大的控制籽粒硬度的等位基因.该研究对保护利用华山新麦草、丰富小麦籽粒硬度基因资源具有一定的理论意义和应用价值.     

鸡生长激素基因内含子4新等位基因的序列分析

试验以粤黄鸡矮脚黄系等不同肉鸡、蛋鸡品种（系）作为试验材料，对新发现的生长激素基因内含子4等位基因的PCR产物作纯化测序，研究多态性产生的机理及碱基变异情况。结果发现cGH内含子4长约1170bp，内含子4的A、B、C、D等位基因长分别为1170bp、1164bp、1168bp，它们之间存在不同程度的碱基差异，而第580碱基的突变（A→G）和第688碱基的突变（A→G）分别产生了MspⅠ酶切位点，是多态性形成的根本原因。“PCR产物双带”的形成是由于cGH基因内含子4其中一条链上第420－470位碱基全部缺失，不同等位基因间存在碱基缺失、插入和替换，测序结果与酶切后电泳结果相吻合。