Q型烟粉虱为害对不同辣椒品种叶绿素及营养物质的影响

为明确辣椒品种对烟粉虱的抗性机制,以不同抗性程度的辣椒为试验材料,研究了其受Q型烟粉虱危害后体内生理指标的变化。结果显示,Q型烟粉虱危害后,辣椒叶绿素和可溶性糖含量均较对照(未接虫)增加,其中抗性品种(苏椒5号、新研988椒王)叶绿素含量增加显著(P0.05);可溶性糖含量以抗性品种增幅最大(P0.05),中抗品种(萧新九号、湘辛三号)次之(P0.05),感虫品种(港上红尖椒、大禹牛角王)的增幅最小。烟粉虱危害后所有参试品种除中抗品种湘辛三号外,其余品种的可溶性蛋白含量均较对照降低;所有参试品种的游离脯氨酸含量均显著降低(P0.05),感虫品种港上红尖椒、大禹牛角王的游离脯氨酸含量均显著高于高抗及中抗品种(P0.05)。因此,辣椒品种对Q型烟粉虱的抗性强弱与叶片叶绿素含量、可溶性糖含量、游离脯氨酸含量有关,而与可溶性蛋白含量无明显相关。     

不同药剂处理对猕猴桃根结线虫的防治效果

为了筛选出能够有效防治猕猴桃根结线虫的药剂。采用田间药剂施用筛选的方法,研究了12.5%阿维·噻唑膦EC等7种药剂对猕猴桃根结线虫的防治效果。结果表明供试的不同药剂对猕猴桃根结线虫均有一定的防效,能控制土壤中2龄幼虫的数量和抑制根结的形成,其中12.5%阿维·噻唑膦EC防治效果最好,药后45 d、180 d对根结线虫和二龄若虫的防治效果分别为78.40%、69.90%和83.83%、80.26%;10%噻唑膦GR与5%阿维菌素GR防效较好;2亿/毫升淡紫拟青霉+生物菌培养基B++(微生物肥)防效较差。12.5%阿维·噻唑膦EC、10%噻唑膦GR和5%阿维菌素GR可作为猕猴桃根结线虫防治的首选药剂。     

孔雀草与淡紫拟青霉协同作用防治烟草根结线虫效果

[目的]明确孔雀草与淡紫拟青霉2种生防因子协同作用防治烟草根结线虫的效果,为烟草根结线虫病的生物防治提供参考。[方法]通过田间试验研究烤烟间作孔雀草同时联合使用淡紫拟青霉对烤烟生长特性以及对根结线虫病发病情况的影响。[结果]孔雀草与淡紫拟青霉联合使用不仅能显著提高淡紫拟青霉对烟草根结线虫防治效果的稳定性,还能明显提高烤烟的农艺性状。烤烟间作孔雀草能显著增加烟株的叶片宽度,施用淡紫拟青霉能显著增加烤烟的叶片长度;在株高、茎围、最大叶长和最大叶宽上,孔雀草与淡紫拟青霉联合使用时均明显优于单一处理。单一施用淡紫拟青霉对根结线虫的平均防效为67.2%,施用淡紫拟青霉的同时间作孔雀草,平均防效在73%以上。[结论]孔雀草与淡紫拟青霉协同作用防治根结线虫有显著的增效作用。     

茉莉酸介导的番茄韧皮部表达谱对根结线虫侵染的响应

为了研究茉莉酸介导的基因对根结线虫侵染的响应,以番茄野生型和茉莉酸缺失突变体为试材,采用数字表达谱技术检测分析根结线虫侵染后主茎韧皮部中的差异表达基因。结果表明,茉莉酸缺失突变体中有2 427个基因差异表达,其中1 390个差异基因可富集到112个KEGG(Kyoto Encyclopedia of Genes and Genomes)通路。18个差异基因涉及茉莉酸合成前体α-亚麻酸代谢,100个差异基因参与植物和病原体的相互作用。     

Identification and resistant characterization of legume sources against Meloidogyne incognita

Root-knot nematodes(RKNs; Meloidogyne spp.) are becoming a serious problem in legume production. This study identified Vigna genotypes exhibiting resistance to M. incognita(RKN) and characterized the modes of the resistance to M. incognita. In total, 279 accessions from 21 Vigna species were screened for resistance based on a galling index(GI) and an egg mass index(EI). Seven accessions were highly resistant to RKN with GI≤25, namely JP74716(V. mungo var. mungo; cultivated black gram), JP107881(V. nepalensis), JP229392(V. radiata var. sublobata; wild mungbean), Aus TRCF118141(V. unguiculata subsp. unguiculata; cultivated cowpea), Aus TRCF306385(V. unguiculata subsp. unguiculata), Aus TRCF322090(V. vexillata var. vexillata; wild zombi pea) and JP235929(V. vexillata var. vexillata). JP229392 and Aus TRCF322090 were the most resistant accessions having EI values of 18.74 and 1.88, respectively. Continuous culture of M. incognita on both JP229392 and Aus TRCF322090 resulted in a weakness in pathogenic ability for this RKN. The resistance in JP229392 and Aus TRCF322090 to RKN appeared to be antibiosis that was associated with reduced nematode penetration, retardation of nematode development and impeding giant cell formation. The Vigna germplasm resistance to RKN identified in this study could be utilized as gene sources for the development of RKN-resistant Vigna cultivars.     

Improving survival of inter-generic grafts of nematode-susceptible watermelon cultivars and nematode-resistant Cucumis species

Abstract

Inter-generic grafting of highly nematode susceptible watermelon (Citrullus lanatus) cultivars onto nematode-resistant wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myricoarpus) had on average 36% graft survival ratios, which was attributed to unequal stem diameters at the graft union. Cucumis species had smaller stem diameters at the graft union, whereas Citrullus had bigger ones. The objective of the study was to improve inter-generic graft compatibility of Citrullus and Cucumis through optimizing the sizes of stem diameters during grafting. Cucumis species were raised in a 160-hole seedling tray and primed seeds of Citrullus were raised in a 200-hole seedling tray seven days after emergence of Cucumis in order to reduce the stem diameters. At grafting, stem diameter ratios in various treatments were equal to one, whereas at 66 days after grafting the ratios were grater than one, with the exception of those of intact plants. Survival of grafts from grafting to 66 days after grafting was 100%, translating into relative improvement of 186%. Improved survival of grafts would invariably promote the potential uses of inter-generic grafting among wild and cultivated watermelon in management of soil-borne pathogens.     

一种对桃小食心虫高毒力的斯氏线虫Steinernema sp.(CB-2Y)

本研究在室内用“沙埋法”比较了两种斯氏属昆虫病原线虫Steinernema sp.(CB-2Y)和S.feltiae Agriotos对桃小食心虫的侵染力,结果表明CB-2Y线虫对桃小食心虫幼虫和冬茧的侵染力都高于Agriotos线虫。接线虫笫7天桃小食心虫LD50,CB-2Y组为49条线虫,而Agriotos组为158条;冬茧的LD50分别为1330条和24046条。在桃小冬茧开始活动期(6月15日)分别施用两种线虫,一个月后检查桃小食心虫成虫羽化率,CB-2Y线虫的控制效果明显优于Agriotos,在1024条线虫/桃小食心虫冬茧时(75条/cm~2),越冬代桃小食心虫的羽化率分别为8.2％和29.2％。     

一种昆虫病原线虫共生菌的分离鉴定及致病性研究

从广东省阳江县的土壤中,分离到一种病原斯氏线虫(Steinernema sp.8503),从线虫3龄幼虫体,又分离出8503菌株。此菌为共生菌,革兰氏阴性、非孢子型杆菌,2.0～12.0×0.6～1.3微米,鞭毛为周毛,硝酸盐不产生亚硝酸盐,过氧化氢酶阴性,脲素酶阴性,磷酸脂酶阴性,卵磷酯酶阳性,七叶苷水解阳性,不具荧光,对昆虫有致病性,从一系列的生化特性和线虫的带菌率、细菌囊和细菌的形状、分布等检查,此菌为大肠杆菌科的Xenorhabdus nemalophilus。对促进线虫在人工培养基的繁殖,提高线虫的产量和毒力均有一定的价值。     

Application of a putative fatty-acid binding protein to discriminate serologically the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from other Meloidogyne species

Two major proteins, Mcf-A67 and Mcf-B66, were identified by mini two-dimensional polyacrylamide gel electrophoresis in order to distinguish the two European quarantine root-knot nematodes, Meloidogyne chitwoodi and M. fallax, from eight other species. These quarantine proteinic markers have been microsequenced after enzymatic digestion. The internal amino acid sequences exhibit similarities to members of a family of low molecular weight intracellular lipid-binding proteins. Moreover, to explore a simple, rapid, and inexpensive way to identify the two quarantine nematodes, dot blot hybridizations were performed using an antiserum (A67) produced from the longest amino-acid sequence of the protein Mcf-A67. Although several proteins stained on the M. chitwoodi and M. fallax western blot membranes, the two nematodes were easily distinguished from other root-knot nematodes, on dot blot assays with soluble proteins extracted from a single female. Because of its specificity and sensitivity, the use of the A67 antiserum to improve the diagnosis of the two European quarantine root-knot nematodes is discussed.     

Pathogenicity of the root-knot nematode Meloidogyne javanica on potato

Host–parasite relationships and pathogenicity of Meloidogyne javanica on potatoes (newly recorded from Malta) were studied under glasshouse and natural conditions. Potato cvs Cara and Spunta showed a typical susceptible reaction to M. javanica under natural and artificial infections, respectively. In potato tubers, M. javanica induced feeding sites that consisted of three to four hypertrophied giant cells per adult female. Infection of feeder roots by the nematode resulted in mature large galls which usually contained at least one mature female and egg mass. In both tubers and roots, feeding sites were characterized by giant cells containing granular cytoplasm and many hypertrophied nuclei. Cytoplasm in giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P ) [0–64 eggs + second-stage juveniles (J2s) per cm³ soil] and growth of cv. Spunta potato seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m  + (1 −  m ) z ^{( P − T )}] was fitted to fresh shoot weight and shoot height data of nematode-inoculated and control plants. Tolerance limits ( T ) for fresh shoot weight and shoot height of cv. Spunta plants infected with M. javanica were 0·50 and 0·64 eggs + J2s per cm³ soil, respectively. The m parameter in that model (i.e. the minimum possible y -values) for fresh shoot weight and shoot height were 0·60 and 0·20, respectively, at P  = 64 eggs + J2s per cm³ soil. Root galling was proportional to the initial nematode population density. Maximum nematode reproduction rate was 51·2 at a moderate initial population density ( P  = 4 eggs + J2s per cm³ soil).