2002—2014年陕西省小麦条锈菌生理小种变化动态和小麦品种(系)的抗病性

为明确陕西省小麦条锈菌的群体结构、变异动态和新育成小麦品种(系)的抗病性,为病害流行预测、防治以及抗病育种提供依据,本研究于2002—2014年从陕西省8个市(区)的28个县(区)和毗邻的甘肃省、四川省和湖北省部分地区共采集鉴定小麦条锈菌标样2 779份,监测到条锈菌生理小种和致病类型45个,其中,CYR33和CYR32为目前陕西省小麦条锈菌主要流行小种,新致病类型G22-9和G22-14虽然目前出现频率不高,但对贵农系列、92R系列以及Moro均有毒性,且出现频率呈上升趋势。目前小麦条锈菌群体中Hybrid46致病类群和水源11致病类群占绝对优势,这与我国小麦品种抗病基因单一化有较大关系,应加强开发和利用新的、多元化的抗源材料。对2 952份陕西省新育成小麦品种(系)抗病性测试结果表明,其整体抗性水平呈上升趋势。综合条锈菌生理小种监测和抗病性分析结果,目前小麦抗条锈病育种应以抗CYR33和CYR32为主,同时注意对G22-9和G22-14的抗病性研究。     

防治糜子丝黑穗病的杀菌剂筛选及田间防治效果研究

为筛选防治糜子丝黑穗病的高效药剂,采用琼脂平板孢子萌芽法测定了6种杀菌剂对糜子丝黑穗病菌的室内毒力,并通过两年田间小区试验评价了杀菌剂对糜子丝黑穗病的药效及糜子植株生长的影响。室内毒力测定结果表明,戊唑醇对丝黑穗病菌的毒力最强,EC₅₀值为0.1127 μg/mL,其次为烯唑醇、苯醚甲环唑、甲基硫菌灵和多菌灵,EC₅₀值分别为1.0634,6.1775,12.4969和54.4021 μg/mL,福美双的毒力最弱,EC₅₀值为1169.6448 μg/mL。药剂处理与对照相比,发芽率均有显著降低,随浓度的增高,种子活力下降,其中烯唑醇对种子萌发抑制作用最大,发芽率和发芽势均最小。田间药效试验结果与室内毒力测定结果一致,戊唑醇防效最好,其次为烯唑醇、甲基硫菌灵、多菌灵,苯醚甲环唑仅在浓度高时防效较好,福美双防治效果最差。植株生长影响评价结果表明,多菌灵显著降低主茎倒二叶面积、主茎倒三叶面积、叶干重和分蘖数。与对照相比,各药剂处理下的单株粒重均有不同程度的减少,但产量均增加,其中戊唑醇处理下的产量两年均最高,而福美双在2014年没有显著增产效果。因此,在6种供试药剂中,戊唑醇能以最低浓度获得最好的防治效果,可在实际生产中推广利用。     

节节麦、鬼蜡烛——燕麦孢囊线虫的两种新寄主

禾谷孢囊线虫病(cereal cyst nematode,CCN)是由燕麦孢囊线虫Heterodera avenae Wollen.引起的一种重要的小麦病害,在世界上40多个国家均有发生[1].我国于1987年首次发现燕麦孢囊线虫[2],至2012年,已传播到湖北、河南、河北、北京、山东、山西、安徽、江苏、青海、内蒙古、陕西、甘肃、宁夏、天津、西藏、新疆等16个省市自治区[3],危害程度与范围呈逐年加重和扩大的趋势,已对我国小麦生产构成严重威胁.该病造成小麦平均减产20％～40％,严重时高达73％～89％[4].因此,CCN是制约小麦和大麦生产的主要因素之一.     

Evaluation of Malus germplasm resistance to marssonina apple blotch

Marssonina apple blotch, caused by Diplocarpon mali (anamorph: Marssonina coronaria), is a serious disease of apple (Malus x domestica Borkh.). We evaluated the resistance of 28 cultivars and 39 species or biotypes after inoculating leaves with conidial suspensions in vitro and in vivo. Five accessions of the 28 apple cultivars showed a good level of resistance, while 16 displayed intermediate type. In contrast, resistance was good for eight accessions of species or biotypes and moderate for 19 accessions. Among these 67 candidates, more than 19 % had resistance against Marssonina apple blotch, indicating that resistant resources are abundant in that germplasm. These high-performing accessions can make valuable contributions to breeding programs for resistance against this disease.     

GFPuv标记猕猴桃溃疡病菌的生物学特性 及其在土壤、根系中的定殖

【目的】获得具有荧光标记的猕猴桃溃疡病菌（Pseudomonas syringae pv. actinidiae）菌株,为进一步揭示其侵染致病过程奠定基础。【方法】电击法对病菌进行GFPuv基因标记,应用荧光显微镜和平板稀释法研究标记菌株在土壤和根部的定殖情况。【结果】GFPuv标记的猕猴桃溃疡病菌菌株在荧光显微镜下发出强烈的绿色荧光,8株标记菌基因组DNA中均扩增出约700 bp的目的片段。标记菌株PSAmx7-GFPuv1的菌体形态、生长曲线、最适温度、最适pH、致病性均与野生型无显著差异,其绿色荧光可稳定遗传。标记菌在灭菌土壤中可存活3个月左右,在未灭菌土壤中也能存活3周;灌根1 d检测,根表、根内组织中可分离到目标菌落,随后标记菌株数量呈现“先增后降”的趋势。【结论】电击法成功地将GFPuv基因转入猕猴桃溃疡病菌;导入的GFPuv 基因对宿主菌的生物学特性没有影响;标记菌可在灭菌土壤中长期存活,并在根部定殖和增殖。     

田菁茎瘤固氮根瘤菌对小麦种子侵染的促生作用及其在根系内的定殖

选取8个常见小麦品种,通过室内限菌试验筛选出对于田菁茎瘤固氮根瘤菌Azorhizobium caulinodans ORS571 (A.caulinodans) 侵染响应敏感的品种,研究了浸种侵染、菌液浓度和添加葡萄糖对接菌小麦幼苗生长的影响,并结合荧光显微镜检测绿色荧光蛋白（GFP）标记A.caulinodans在小麦幼苗根系内的分布与定殖规律。结果表明:小偃22为响应敏感品种;在室内限菌条件下,浸种侵染小偃22幼苗平均根长和平均株高分别较对照增加了17.04%和8.37%;最适菌液浓度为1.0108个/mL;在菌液中添加1g/L葡萄糖有助于A.caulinodans浸种侵染和定殖。荧光显微镜检测结果显示,GFP标记A.caulinodans从小麦幼苗根毛和侧根裂隙处进入,定殖于根维管组织等部位。田间试验结果进一步表明A.caulinodans浸种侵染对不同小麦品种均具较明显的促生作用。     

Genetic analysis of wheat (Triticum aestivum L.) and related species with SSR markers

Genetic diversity among 19 Triticum aestivum accessions and 73 accessions of closely related species was analyzed using simple sequence repeat (SSR) markers. Forty-four out of 497 SSR markers were polymorphic. In total 274 alleles were detected (mean 6.32 alleles per locus). The polymorphic information content (PIC) of the loci ranged from 0.3589 to 0.8854 (mean 0.7538). The D genome contained the highest mean number of alleles (6.32) followed by the A and B genomes (6.13 and 5.94, respectively). The correlation between PIC and allele number was significant in all genome groups (0.7540, 0.7361 and 0.7482 for A, B and D genomes, respectively). Among the seven homologous chromosome groups, genetic diversity was lowest in group 7 and highest in group 5. In cluster and principal component analyses, all accessions grouped according to their genomes were consistent with their taxonomic classification. Accessions with the A and D genomes were clustered into two distinct groups, and AABB accessions showed abundant genetic diversity and a close relationship. Triticum durum and T. turgidum were clustered together, consistent with their morphological similarity. Cluster analysis indicated emmer is closely related to hexaploid wheat. Compared with common wheat, higher genetic variation was detected in spelt, T. aestivum subsp. yunnanense and subsp. tibetanum. In addition, a close genetic relationship between T. polonicum and T. macha was observed. The results of the clustering and principal component analyses were essentially consistent, but the latter method more explicitly displayed the relationships among wheat and closely related species.     

利用酵母双杂交膜系统筛选与小麦蓝矮植原体免疫膜蛋白互作的异沙叶蝉蛋白

In order to investigate interactive proteins in leafhopper (Psammotettix alienus L.) with WBD phytoplasma, the protein interaction analysis was performed by using WBD phytoplasma IMP (immunodominant membrane protein) as bait protein to screen a cDNA library of leafhopper using a split-ubiquitin yeast membrane system. Through the screening test, 30 clones were obtained from the cDNA library and 8 proteins were identified by searching against NCBI database, such as tubulin, peptidyl-prolyl cis-trans isomerase, Cdc42 protein, ribosomal proteins and ATP-F0 subunit protein, etc. The interactions between IMP and 8 putative proteins were further confirmed by co-transformation and β- Galactosidase assays. This study could be useful for understanding the molecular interaction mechanism between WBD phytoplasma and insect vector and the specificity of transmission.     

两种唐松草鉴定为小麦叶锈菌的转主寄主

 引起小麦叶锈病的小麦叶锈菌(Puccinia triticina)是转主寄生菌,其转主寄主主要为唐松草属(Thalictrum)种类,也包括扁果草属(Isopyrum), 牛舌草属(Anchusa), 铁线莲属(Clematis)和蓝蓟属(Echium)的个别种类。然而,迄今,中国仅有亚欧唐松草和瓣蕊唐松草被报道为小麦叶锈菌转主寄主。本文对采集于陕西的东亚唐松草(T. minus var. hypoleucum)、甘肃的贝加尔唐松草(T. baicalense),通过人工接种小麦叶锈菌确定它们是否能够作为小麦叶锈菌的转主寄主。同时,本文作者收集自然条件下贝加尔唐松草组织上受侵染产生的锈子器样品,通过其ITS区序列分析以确定小麦叶锈菌的有性循环是否在田间条件下发生。结果表明,小麦叶锈菌的担孢子均可侵染东亚唐松草和贝加尔唐松草,完成其性子器和锈子器阶段,产生的锈孢子可侵染感病小麦产生夏孢子堆,从而证实东亚唐松草和贝加尔唐松草均可作为小麦叶锈菌的转主寄主。来自贝加尔唐松草22个锈子器样品的ITS区序列比对,表明其与NCBI网上提交的小麦叶锈菌享有95%~96%的序列同源性。由此推测,自然条件下,中国小麦叶锈菌可能侵染感病唐松草完成有性循环。