烟粉虱MED隐种蜕皮激素受体基因cDNA克隆、转录与组织表达

蜕皮激素受体(ecdysone receptor,Ec R)是调控昆虫蜕皮、变态和生殖等过程中基因表达的重要调控因子。为研究Ec R在烟粉虱Bemisia tabaci生长发育中的作用,利用RT-PCR和RACE等技术扩增了烟粉虱MED隐种Ec R基因的c DNA全长序列,并利用实时荧光定量PCR技术检测其在烟粉虱不同发育时期相对表达量的变化。Bt Ec R c DNA序列全长2 844 bp,含有一个1 518 bp的开放阅读框,共编码505个氨基酸,预测蛋白分子量为56 k D,等电点为6.43,含有特殊结构功能域:DNA结合域(DBD_Ec R)和配体结合域(LBD_Ec R),该序列编码的蛋白质序列与其它已报道的昆虫Ec R蛋白序列具有很高的相似性,命名为Bt Ec R(Gen Bank登录号:KR534774)。Bt Ec R在MED隐种若虫、雌成虫各发育时期均有表达,若虫期在伪蛹前期达到最高值,成虫期呈现先升高后降低的趋势,且在羽化后第7天达到最高值,约为羽化第1天的23倍。研究结果为揭示Bt Ec R在烟粉虱整个生长发育过程中的作用提供了重要依据。     

渭北旱塬沟壑区苹果节水灌溉制度分析

为了探讨渭北旱塬沟壑区盛果期苹果不同水文年的节水灌溉制度,选取洛川县为代表性区域,利用该县近56年的月气象资料,基于水量平衡原理,分析了陕西省两个不同成熟期的苹果品种(中熟嘎拉、晚熟富士)在不同节水灌溉模式下(管灌、滴灌)各水文年的充分与非充分灌溉制度。结果表明:1不同成熟期苹果各水文年均应补灌,补灌时间和灌水量主要集中在新梢旺长期和果实膨大期。2中熟品种充分灌溉在湿润年、平水年、干旱年、特旱年的灌水次数分别为2、3、3、4次,相应灌溉定额滴灌为60、85、120、165 mm,管灌为90、130、180、245 mm;非充分灌溉各水文年的灌水次数为1、2、3、4次,相应灌溉定额滴灌为45、70、110、150 mm,管灌为65、110、170、220mm。3晚熟品种充分灌溉在相应水文年的灌水次数分别为2、3、4、4次,相应灌溉定额滴灌为65、90、125、160 mm,管灌为95、140、195、240 mm;非充分灌溉各水文年的灌水次数为2、3、3、4次,相应滴灌灌溉定额为55、75、120、150mm,管灌灌溉定额为85、125、175、220 mm。     

小麦抗旱性研究进展与展望

利用优异基因资源改良小麦抗旱性是应对干旱和保障粮食安全的重要途径。结合国内外小麦抗旱性研究的最新进展和本研究组的研究实践,概述了现行主要抗旱性鉴定方法的适用对象和评价指标,以及小麦抗旱种质创新、抗旱基因资源发掘与利用等方面的研究成果,同时提出未来小麦抗旱性研究的重点任务和发展方向,即建立基于高通量表型鉴定的抗旱性综合评价技术体系,建立基于高通量基因型鉴定的抗旱基因资源发掘平台,创建基于综合运用多学科技能的智慧育种策略,以期为加快小麦抗旱性遗传改良提供信息资源和理论参考。     

地衣芽胞杆菌HS10原生质电转化体系的研究

地衣芽胞杆菌Bacillus licheniformis HS10及其粗蛋白对多种病原真菌具有防治效果,为挖掘其生防功能基因,本研究通过对原生质体的制备、再生培养基、渗透压稳定剂、电击参数等试验条件进行优化,建立了地衣芽胞杆菌HS10原生质体电转化法。结果表明最佳转化条件为:转接培养10h达到对数生长后期的菌体,浓缩4倍后,利用终浓度1mg/mL的溶菌酶,于37℃、150r/min酶解20min,酶解效率达到99.34%,1×SMM洗涤3次,调整菌浓度至1.0×108 cfu/mL,并通过1.6kV、5ms的电击后,迅速在SMMP溶液中100r/min、37℃恢复6~10h,涂布于含Kan和Erm的再生培养基DM3平板。将该方法用于突变体库构建的质粒pMarA(8 253bp)和基因敲除质粒pMADΔCP(13 043bp)的大片段质粒转化,分别获得了37cfu/μg DNA和10cfu/μg DNA阳性转化子。该遗传转化体系为地衣芽胞杆菌HS10中相关基因功能的研究提供了技术支撑。     

乳酸菌清除霉菌毒素作用及其机制

霉菌毒素广泛存在于食品和饲料当中,严重地危害人类和动物的健康。如何有效清除霉菌毒素一直是重要的研究课题。乳酸菌具有多种生物学功能,近年来研究表明,乳酸菌具有清除霉菌毒素能力。为了更好地理解乳酸菌清除霉菌毒素的作用,文章就近年来乳酸菌对霉菌毒素的清除机制加以综述。     

玉米/鹰嘴豆间作条件下不同施磷量对灌耕灰钙土无机磷组分的影响

在甘肃引黄灌区的灌耕灰钙土区域,通过玉米／鹰嘴豆间作种植,采用蒋柏藩、顾益初石灰性土壤无机磷分级方法研究了施磷水平和间作种植方式对玉米、鹰嘴豆土壤无机磷素形态的影响。结果表明：研究区各无机磷形态含量顺序为O－P＞Ca10－P＞Ca8－P＞Al－P＞Fe－P＞Ca2－P ,施磷能够显著提高玉米和鹰嘴豆土壤中Ca2－P、Ca8－P、Al－P和Fe－P的含量,O－P和Ca10－P的含量不随施磷量增加发生显著性变化;与单作相比,间作种植对鹰嘴豆土壤带各无机磷组分含量没有显著影响,但间作玉米种植带土壤各组分无机磷含量均低于单作土壤,其中不施磷肥处理下Fe－P、施纯磷40 kg·hm－2处理下Al－P及施纯磷80 kg·hm－2处理下Ca10－P的含量显著低于单作土壤。     

马铃薯黑痣病生防菌的筛选和鉴定及其生长条件的研究

从甘肃省景泰县条山农场不同连作年限的马铃薯地块中取根际土样品,分离筛选马铃薯黑痣病病原菌-立枯丝核菌(Rhizoctonia solani)的拮抗菌。采用土壤平板稀释、对峙法筛选拮抗菌;结合形态特征、生理生化及16Sr DNA分子鉴定;采用单因素试验设计对G1菌株的生长条件进行初步试验。通过初筛和复筛,从108株细菌中获得1株对立枯丝核菌拮抗效果稳定、拮抗能力较强的细菌G1。采用平板对峙法测定其拮抗作用,抑菌带宽度达6mm,抑菌圈直径2.5 cm,抑菌率为66.7%。结合形态特征、生理生化及16Sr DNA分子鉴定,G1为类芽孢杆菌(Paenibacillus sp.);采用单因素试验设计对G1菌株的生长条件进行初步试验。结果表明,菌株G1在4℃~45℃,p H 5~10,盐浓度0~50 g·L-1都能生长,碳源、氮源利用广泛,最适条件为:温度37℃,p H 7,蔗糖为碳源,蛋白胨为氮源,盐浓度为10 g·L-1。拮抗菌G1被鉴定为类芽孢杆菌,该菌株抑菌带较宽、抑菌效果稳定,生长条件与马铃薯生长的大田环境基本相符,具有作为一株优良生防菌的必要条件。     

转基因大豆外源基因的漂移风险

转基因作物外源基因的漂移已为国内外学者所证实。我国每年进口转基因大豆的数量巨大,转基因大豆外源基因的漂移对我国传统的大豆作物和生态环境是一个潜在威胁。本文论述了转基因大豆的概况和外源基因漂移的风险,并对进境转基因大豆的检测监管进行了思考。     

Induction effects of host plants on insecticide susceptibility and detoxification enzymes of Bemisia tabaci (Hemiptera: Aleyrodidae)

BACKGROUND: The polyphagous B‐biotype Bemisia tabaci (Gennadius) has developed a high resistance to commonly used insecticides in China. To illustrate the induced changes by host plant, bioassay and biochemical research on five different host populations were investigated. RESULTS: Except for bifenthrin, all tested insecticides showed lower toxicity to the B. tabaci poinsettia population compared with other host populations. Moreover, four insecticides, the exceptions being abamectin and fipronil, showed highest toxicity towards the tomato population. The LC₅₀ values of the poinsettia population, particularly towards acetamiprid, were 14.8‐, 10.3‐ and 7.29‐fold higher than those of tomato, cucumber and cabbage respectively. The CarE activities of B. tabaci cabbage and cucumber populations were all significantly higher than those of poinsettia, cotton and tomato populations. The ratio of the cabbage population was 1.97‐, 1.79‐ and 1.30‐fold higher than that of poinsettia, cotton and tomato respectively. The frequency profiles for this activity also have obvious differences. The GST and P450 activities of the cucumber population were the lowest in the five host populations. CONCLUSION: Long‐term induction of host plants for B‐biotype B. tabaci could influence their susceptibilities to several insecticides. Rational selection and usage of insecticides for particular hosts will be helpful for resistance management and control of this species. Copyright © 2010 Society of Chemical Industry     

Insecticidal compounds from the essential oil of Chinese medicinal herb Atractylodes chinensis

BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, the essential oil of Atractylodes chinensis (DC.) Koidz was found to possess strong insecticidal activity against the common vinegar fly, Drosophila melanogaster L. The essential oil was extracted via hydrodistillation, and its constituents were determined by GC‐MS analysis. RESULTS: The main components of A. chinensis essential oil were β‐eudesmol (21.05%), β‐selinene (11.75%), γ‐elemene (7.16%) and isopetasam (5.36%). Bioactivity‐directed chromatographic separation on repeated silica gel columns led to the isolation of five compounds, namely atractylon, α‐elemol, β‐eudesmol, hinesol and β‐selinene. β‐Selinene, α‐elemol and hinesol showed pronounced contact toxicity against D. melanogaster adults, with LD₅₀ values of 0.55, 0.65 and 0.71 µg adult^?1 respectively. Atractylon and β‐eudesmol were also toxic to the fruit flies (LD₅₀ = 1.63 and 2.65 µg adult^?1 respectively), while the crude oil had an LD₅₀ value of 2.44 µg adult^?1. CONCLUSION: The findings suggested that the essential oil of Atractylodes chinensis and its active constituents may be explored as natural potential insecticides. Copyright © 2011 Society of Chemical Industry