Frequency of Bacillus thuringiensis Cry1A.105 resistance alleles in field populations of the fall armyworm,Spodoptera frugiperda,in Louisiana and Florida

Fall armyworm, Spodoptera frugiperda (J.E. Smith), is a major pest of many crops and a cross-crop target of transgenic maize, cotton, and soybean containing Bacillus thuringiensis (Bt) genes. Some of the current Bt maize products for controlling lepidopteran species contain the Bt event MON 89034. The objective of this study was to determine the frequency of resistance alleles in field populations of S. frugiperda collected from Louisiana and Florida, U.S. to Cry1A.105, one of the two Bt genes in MON 89034. A total of 150 F₂ two-parent families of S. frugiperda were established using single-pair mating of field-collected individuals in 2011, which included 79 families from two locations in Louisiana and 71 families from one location in Florida. F₂ screen was conducted to detect resistance alleles in these families to Cry1A.105 protein in maize plants. Four out of the 79 Louisiana and 14 out of the 71 Florida families were identified to possess resistance alleles to the Cry1A.105 maize plants. Thus, the corresponding frequency of resistance alleles to Cry1A.105 maize was estimated to be 0.0158 with a 95% credibility interval (CI) of 0.0052–0.0323 for the Louisiana populations and 0.0559 with a 95% CI of 0.0319–0.0868 for the Florida populations. The resistant families survived on whole Cry1A.105 maize plants and demonstrated a significant level (>116-fold) of resistance to the Cry1A.105 protein in a diet-incorporated bioassay. These findings suggest that resistance allele frequency in S. frugiperda to single-gene Cry1A.105 maize in the U.S. southeast region apparently is not rare, most likely due to the selection of Cry1F resistance and its cross-resistance to Cry1A.105.     

植物基因资源异境保存遗传抽样策略

遗传资源抽样是指在一定的置信度标准下,抽取的样本能覆盖要研究的目标种或特定地域内群体现有的遗传变异.它是植物基因资源保护研究过程中首先必须要解决的问题,具有十分重要地位.对于一个有效的遗传抽样,必须要同时考虑群体间及群体内的抽样.从样本容量、群体数及实际应用等方面进行较全面的综述.     

Identification and characterization of genomic DNA sequences of the S-ribonuclease gene associated with self-incompatibility alleles S1 to S5 in European pear

The stylar products of the S‐locus for the gametophytic self‐incompatibility (GSI) system in the Rosaceae are ribonucleases (S‐RNases). Recently, sequences for 13 pear S‐RNase alleles have been published and named following a letter–symbol nomenclature (S_a to S_d and S_h to S_p). To establish the correspondence between these sequences and the self‐incompatibility alleles we have described previously (S₁ to S₅), we have amplified genomic DNA with consensus primers from the cultivars, ‘Williams’ (S₁S₂), ‘Coscia’ (S₃S₄), ‘Butirra Precoce Morettini’ (S₁S₃), ‘Santa Maria Morettini’ (S₂S₃) and ‘Doyenne du Comice’ (S₄S₅) and identified PCR products specifically associated with each S allele. Cloning and sequencing of the amplification products has revealed that they correspond to European pear sequences already deposited in the database. This allowed us to link S‐RNase sequences with S allele phenotypes and to determine a correspondence between the symbol–letter nomenclature used to name S‐RNase sequences and the number‐based nomenclature used to name S alleles. Based on this result the prediction of new cross‐incompatibilities among pear cultivars is discussed. Finally, we propose a unified number‐based nomenclature to avoid future confusion denominating S alleles in pear.     

Consequences of elimination of the Rendement Napole allele from Danish Hampshire

An elimination programme was carried out to remove the dominant Rendement Napole mutation (RN(-) ) from Danish Hampshire pigs. We reasoned that during and after the elimination of the RN(-) allele, genetic gain of production traits decreased while rate of inbreeding in the population increased compared to the period prior to elimination. The hypothesis was tested by estimating the genetic gain in seven production traits and measuring the rate of inbreeding in the population prior to and during the elimination period. Genetic gain was reduced for quantitative traits daily gain(30-100 kg) and feed conversion ratio, while gain for ultimate-pH, lean meat percentage and slaughter loss were increased slightly. There were no changes in genetic gain for daily gain(birth-30 kg) and conformation. RN polymorphism affected several of the quantitative traits. The RN(-) mutation had a dominant effect on the traits daily gain(birth-30 kg) , daily gain(30-100 kg) , slaughter loss, lean meat percentage and ultimate-pH. It exhibited overdominance for feed conversion ratio and additive effect for conformation. Rate of inbreeding decreased during the elimination of RN(-) . Our findings indicate that the consequences of the elimination programme were not as serious as were feared and that a carefully designed preselection strategy may avoid unacceptable loss of genetic gain and excessive loss of genetic variation.     

Development of a multiplex allele‐specific primer PCR assay for simultaneous detection of QoI and CAA fungicide resistance alleles in Plasmopara viticola populations

BACKGROUND: DNA‐based diagnosis has become a common tool for the evaluation of fungicide resistance in obligate phytopathogenic fungus Plasmopara viticola. RESULTS: A multiplex allele‐specific primer PCR assay has been developed for the rapid detection of fungicide resistance in P. viticola populations. With this assay, a glycine‐to‐alanine substitution at codon 143 of the P. viticola cytochrome b gene, which conferred QoI fungicide resistance, and a glycine‐to‐serine substitution at codon 1105 of the P. viticola cellulose synthase gene PvCesA3, which conferred CAA fungicide resistance, were detected simultaneously. CONCLUSION: It is suggested that the present assay is a reliable tool for the rapid and simultaneous detection of QoI and CAA fungicide resistance alleles in P. viticola populations. The assay required only 2 h from the sampling of symptoms to the detection of resistance alleles to both fungicides. Copyright © 2012 Society of Chemical Industry     

淡色库蚊对拟除虫菊酯抗性与kdr等位基因频率的关系

利用接触筒法检测淡色库蚊6个野外种群成蚊对溴氰菊酯、高效氯氰菊酯和氯菊酯的抗性水平,同时利用PASA(PCR amplification of specific alleles)方法检测每个种群kdr等位基因的频率。结果表明:不同种群的溴氰菊酯抗性水平与抗性等位基因频率有显著的相关性(R2=0.836,P=0.011),但高效氯氰菊酯和氯菊酯抗性水平与抗性等位基因频率无显著的相关性(R2分别为0.493和0.530,P值分别为0.120和0.101);对3种拟除虫菊酯抗性平均值直线回归分析显示,抗性等位基因频率与生物测试结果呈显著直线相关(R2=0.840,P=0.010)。     

Occurrence of the R1 allele conferring resistance to late blight in potato R-gene differentials and commercial cultivars

A total of 23 Scottish and 14 Dutch potato R-gene differentials as well as five Austrian, two Dutch and two German commercial potato cultivars were screened for the R1 allele conferring resistance to Phytophthora infestans carrying Avr1 , via PCR amplification and sequencing. A single 1400 bp fragment with complete sequence identity to the corresponding part of the R1 allele, was obtained from genomic DNA of all potato R-gene differential clones whose denomination indicates R1 or a combination of R1 and other major resistance factors. The R1 allele was detected, as expected, in all these clones. This fragment also occurred in one Austrian and one German cultivar. Unexpectedly, the same R1 allele also was detected within all R5, R6 and R9 differentials.     

大豆育成品种农艺性状QTL与SSR标记的关联分析

利用85个SSR标记,对大豆育成品种群体(190份代表性材料)的基因组进行扫描,在检测群体结构基础上搜索连锁不平衡位点,并采用TASSEL软件的GLM方法对11个大豆农艺性状QTL进行关联分析。结果表明：(1) 在公共图谱上共线性或非共线性的SSR位点组合均广泛存在连锁不平衡(LD),但不平衡程度D′>0.5的组合数只占总位点组合的1.71%,共线位点D′值随遗传距离衰减较快;(2) SSR数据遗传结构分析表明,育成品种群体由7个亚群体组成,矫正后全群体共有45个位点累计136个位点(次)与11个大豆农艺性状QTL关联,其中22个位点(次)与家系连锁定位的QTL区间相重,有43个位点(次) 2年重复出现;(3) 一些标记同时与2个或多个性状关联,可能是性状相关或一因多效的遗传基础;(4) 育成品种群体关联位点与地方品种群体和野生群体只有少数相同,群体间育种性状的遗传结构有相当大差异;(5) 发掘出农艺性状优异等位变异及其载体品种,包括增效最大的产量等位变异Satt347-300 (+932 kg hm^-2,中豆26),生物量等位变异Satt365-294(+3 123 kg hm^-2,黄毛豆),蛋白质含量等位变异Be475343-198 (+0.41%,淮豆4号),脂肪含量等位变异Satt150-273 (+2.32%,科丰15)等。在此基础上作了设计育种的探讨。