四川省根肿菌的分布和生理小种及品种抗性评估

为探究四川省根肿菌Plasmodiophora brassicae分布、生理小种及品种抗性,于2014-2016年向各县(区、市)植保站问卷调研了解四川省根肿病分布,并利用Williams体系对采自四川省不同病田的22个根肿菌样进行生理小种鉴定,利用其中18个对9个普通十字花科作物品种进行室内抗性评估。结果表明,根肿病分布于四川省19市(州)89个县(区、市),占总调查数的50%。按照极高、高、中等、低、极低、无分布6个根肿病分布密度等级依次划分为23、7、11、16、32和0个县(区、市),其中11个县(区、市)根肿病病史较长,大部分根肿病极高和高密度分布以及长病史县(区、市)都在地理位置上相对集中。22个根肿菌样共鉴定出2、4、7和11号4个生理小种,其中4号为优势生理小种,占77%。四川省表现出明显生理小种地域分布差异。抗性评估发现供试品种对绝大多数供试菌都表现感病,且73%的供试组合病情指数在75以上。     

某些培养条件对甘蓝夜蛾核型多角体病毒离体增殖的影响

不同培养条件对甘蓝夜蛾核型多角体病毒 （ Ｍｂ Ｎ Ｐ Ｖ） 在同源寄主细胞系 Ｍｂ９３１１０４ 中增殖的研究。结果表明, 培养基种类、细胞密度和细胞龄期影响 Ｍ ｂ Ｎ Ｐ Ｖ 在细胞系中的增殖, 引起细胞感染率和多角体产量显著的差异。使用 Ｔ Ｃ—１００ 昆虫组织培养基, 细胞密度为３×１０５ｃｅｌｌｓ／ｍ Ｌ的对数生长期的细胞接毒最适于 Ｍ ｂ Ｎ Ｐ Ｖ 的增殖, 条件培养基对该病毒在细胞系中的增殖没有显著影响。     

Cabbage aphid control on commercial farms in the Thames Valley, UK

Cabbage aphid control on June/July-planted cabbages was studied on four commercial vegetable farms in the Thames Valley and compared with an untreated crop at Silwood Park. At the four commercial sites, where growers followed their normal control practices, counts were made of aphids, their predators and parasites, throughout the cropping season and following the application of foliar insecticide sprays. Although natural enemies appear to be important in producing a mid-season trough in aphid numbers, they are unable to cope with the increase in aphid numbers later in the crop season. This problem of late aphid control is made worse because the effectiveness of foliar treatment also declines. At present, as the use of action thresholds does not seem feasible, it is suggested that improvements should be sought in more effective techniques of granular or foliar application.     

The barley thaumatin-like protein Hv-TLP8 enhances resistance of oilseed rape plants to Plasmodiophora brassicae

A barley cDNA for the thaumatin-like protein Hv-TLP8 driven by the CaMV 35S promoter was introduced into oilseed rape ( Brassica napus ) via Agrobacterium -mediated transformation. Some transgenic lines were obtained which exhibited enhanced resistance to the clubroot pathogen ( Plasmodiophora brassicae ). To increase resistance, double haploid (DH) lines were generated from these transgenic plants. Of these, DH-line 189 showed stable inheritance of the transgenic trait and its associated resistance for at least three generations.     

球毛壳菌及其产生的鞘氨醇对油菜根肿病的室内生防作用

采用灌根接种法研究内生真菌球毛壳菌(Chaetomium globosum)对油菜根肿病的室内生防作用。结果表明,灌根接种球毛壳菌孢子悬浮液后,油菜体内的过氧化物酶、多酚氧化酶、苯丙氨酸解氨酶的活性均明显提高。球毛壳菌孢子悬浮液灌根接种油菜根部后,根肿病的发病率和病情指数均明显降低,对油菜根肿病的防效为76.88%。通过极性梯度萃取、薄层层析和HPLC从球毛壳菌发酵液中分离纯化活性物质,经质谱鉴定为C16鞘氨醇和植物鞘氨醇。鞘氨醇对根肿菌休眠孢子的萌发有明显的抑制作用,其MIC值小于0.1μg/mL,表明球毛壳菌防治油菜根肿病的机制为诱导系统抗性和次生代谢产物拮抗病原菌2种机制。     

青枯病和根肿病生防细菌BS2004的发酵培养基和培养条件优化

解淀粉芽孢杆菌BS2004是一株对不同生化型的番茄青枯病菌Ralstonia solanacearum和十字花科根肿病菌Plasmodiophora brassicae具有抑制作用的优良生防菌,主要依靠产生拮抗物质抑制病菌.为提高其抑菌活性物质的产量与防治效果,本文采用正交试验和单因素试验设计,通过摇瓶培养对其发酵培养基和培养条件进行了优化.优化后的发酵培养基配方为蛋白胨 10 g·L^-1、牛肉浸膏 1 g·L^-1、酵母粉 1 g·L^-1和Nacl 8 g·L^-1;优化后的培养条件为pH 7.5、温度 35 ℃、装瓶量 35 mL·50 mL^-1、接种量 3%（v/v）和最佳培养时间 24 h.经条件优化后培养的 BS2004对青枯病菌的抑菌圈直径达 21.75 mm,对番茄青枯病的防治效果达 80%,对十字花科根肿病的防治效果达 60%,增产 1.92 倍.     

Purification, characterization and evaluation of insecticidal activity of trypsin inhibitor from Albizia lebbeck seeds

A Bowman-Birk inhibitor with activity against gut proteases of Helicoverpa armigera was extracted in 0.1 M sodium phosphate buffer from defatted seed flour of Albizia lebbeck. It was purified to 29.62 folds with 51.43% recovery using ammonium sulfate precipitation, gel filtration chromatography on Sephadex G-100 column and ion exchange chromatography on DEAE-Sephadex A50. The purified protein had a molecular weight of 12,303 daltons as determined by SDS-PAGE. It was found to be heat stable up to 60°C and had two pH optima of 7.5 and 9.0. The inhibitor exhibited non-competitive pattern of inhibition with a low Ki value of 0.2 μM. The inhibitor was found to be susceptible to varying concentrations of reducing agents like DTT and 2-mercaptoethanol, thereby indicating the role of disulphide bridges in maintaining its three dimensional structure and stability. The purified inhibitor caused mortality and suppressed larval growth of Pieris brassicae larvae. It was also found to be effective against gut trypsin extracted from Spodoptera littoralis. The sequence of the genes encoding for such inhibitors can be determined and the genes expressing protease inhibitors can be used in vegetable crops to confer resistance against insect pests and other plant pathogens.     

RAPD markers linked to a clubroot-resistance locus in Brassica rapa L.

Linkage of random amplified polymorphic DNA (RAPD) markers with resistance genes to clubroot (Plasmodiophora brassicae Wor.) in Brassica rapa L. was studied in a doubled haploid (DH population obtained by microspore culture. Thirty-six DH lines were obtained from F₁ plants from a cross between susceptible ‘Homei P09’ and resistant ‘Siloga S2’ plants. ‘Homei P09’ was a DH line obtained by microspore culture of the Chinese cabbage variety ‘Homei’, which is highly responsive in microspore culture. The resistant line ‘Siloga S2’ was obtained by two rounds of selfing of the fodder turnip ‘Siloga’. Three RAPD markers, RA12-75A, WE22B and WE49B, were found to be linked to a clubroot-resistance locus. These three markers were linked in the DH lines and an F₂ population and should be useful for marker-assisted selection in breeding programs. This revised version was published online in July 2006 with corrections to the Cover Date.     

云南白菜根肿病有机防治技术的研究

选择高锰酸钾、石灰或草木灰、腐熟农家肥等有机投入品对根肿病的控制效果和施用方法进行了初步尝试。实验结果表明,有机肥、石灰、石灰水、高锰酸钾可以作为控制根肿病防治的物质,随着使用时间和使用方式的不同,对根肿病和蔬菜的产量的影响不同。石灰或草木灰塘施或对水浇施,腐熟农家肥和石灰或高锰酸钾配合使用对根肿病的发生均有较好的抑制作用;单施农家肥和高锰酸钾对根肿病控制效果不理想,用腐熟农家肥作底肥＋1%石灰水播种后浇塘＋1%石灰水三叶期浇根＋1%石灰水六叶期再浇根的组合模式可以有效地控制对根肿病的发生与危害。     

Association of RFLP markers with trait loci affecting clubroot resistance and morphological characters in Brassica oleracea L.

Summary Resistance to Plasmodiophora brassicae Wor. race 7, the causal agent of the disease clubroot, was examined in an F₂ population of a cross between a clubroot resistant broccoli (Brassica oleracea var. italica) and a susceptible cauliflower (B. oleracea var. botrytis). A genetic linkage map was constructed in the same population based on the segregation of 58 dispersed restriction fragment length polymorphism (RFLP) markers. Associations between the inheritance of RFLP marker genotypes and segregation for disease resistance, morphological and maturity characteristics were examined. For each triat examined, several chromosomal regions marked by RFLP probes appeared to contain trait loci, suggesting that each trait was under polygenic control. RFLP marker linkage to a major factor imparting dominance for clubroot resistance from the broccoli parent was observed in this population. Additionally, RFLP marker linkage to an independently segregating factor contributing clubroot resistance from the cauliflower parent was observed, indicating that it should be possible to use RFLP markers to facilitate selection of transgressive segregants having the combined resistance from both parental sources. In some instances, RFLP markers from the same or closely linked chromosomal regions were associated with both clubroot resistance and morphological traits. Analysis of RFLP marker genotypes at linked loci should facilitate the selection of desired disease resistant morphotypes.