水稻干尖线虫的环介导恒温扩增技术(LAMP)快速检测方法

【目的】本研究旨在为水稻干尖线虫(Aphelenchoides besseyi Christie,1942)的快速检测鉴定和早期诊断提供一个新的检测方法。【方法】利用水稻干尖线虫18S核糖体RNA基因,设计了水稻干尖线虫LAMP的特异引物,该引物包括1对外引物、1对内引物和1对环引物,以LAMP特异引物对待测样品DNA进行恒温扩增,扩增产物通过电泳法和荧光染料法进行检测,电泳检测出现阶梯状条带或加入荧光染料显现绿色荧光,则证明待检样品中含有水稻干尖线虫。【结果】本方法可以检测鉴定水稻干尖线虫不同虫态(雌虫、雄虫、幼虫或卵)的个体,可以从多种线虫混合的样品和植物组织样品中直接检测出水稻干尖线虫,检测灵敏度达到1/1000条虫DNA。【结论】本检测方法具有准确、灵敏、稳定和结果直观的优点,且操作简便、实用性强。     

Effects of Temperature, Humidity and Different Rice Growth Stages on Vertical Migration of Aphelenchoides besseyi

The vertical migration of Aphelenchoides besseyi under different temperatures and humidities and at different rice growth stages was investigated. It was found that the optimum temperature for the development and reproduction of A. besseyi was 25-30°C. At the same temperature, the rate of vertical migration increased with rising relative humidity. Artificial inoculation tests showed that at the elongation stage, nematodes survived mainly on the upper and middle parts of rice culms, and the number of nematodes decreased by 50% at 20 days after inoculation compared with that at 5 days after inoculation. Whereas at the booting stage, nematodes accumulated in young panicles and reproduced quickly, and the average number of nematodes at 20 days after inoculation increased to 164.5, three times of that at 5 days after inoculation.     

水稻干尖线虫(Aphelenchoides besseyi)人工培养研究

利用真菌培养水稻干尖线虫的结果表明:不同的真菌培养线虫的效果有较大差异.链格孢菌(Alternariasp.)、镰刀菌(Fusarium sp.)的效果明显优于常用的灰葡萄孢菌(Botrytis cinerea),可选用于培养水稻干尖线虫.在真菌菌落上,不同的接虫量以及不同的温度和培养时间对水稻干尖线虫的培养均有一定的影响.     

Identification of alternatives for the management of foliar nematodes in floriculture

The foliar nematodes, Aphelenchoides spp, have emerged as important pests of ornamentals in North America during the last decade. Due to the ban on the use of potentially toxic pesticides, there are currently no nematicides registered to manage foliar nematodes on ornamentals. Therefore, we have evaluated a biological [Burkholderia cepacia (syn Pseudomonas cepacia)], two plant products [clove (Syzygium aromaticum) extract and Nimbecidine (azadirachtin)] and twelve chemical pesticides registered for the management of insects, mites, slugs or diseases of ornamentals, against Aphelenchoides fragariae on the most popular ornamental, hosta (Hosta spp), for two consecutive years. We found ZeroTol (270 g liter-1 peroxyacetic acid), currently labeled as a broad-spectrum fungicide/algicide, to be a very potent nematicide that killed 100% of the nematodes in water suspension. It also caused over 70% reduction in A fragariae population in soil and in the leaves without any phytotoxicity. B cepacia caused 67-85% reduction in A fragariae population in leaves and 50% reduction in the soil whereas insecticidal soap caused over 72% reduction in leaves and 61% reduction in the soil. Clove extract and Nimbecidine did not show any potential for the control of A fragariae on hosta. Although all twelve chemical pesticides were effective in reducing the population of A fragariae in the soil 45 days after treatment (DAT), only diazinon 475 g liter-1 EC, trichlorfon 800 g kg-1 SP, ethoprophos 100 g kg-1 GR, oxamyl 100 g kg-1 GR and ZeroTol caused over 70% reduction in nematode population compared with the control. In the leaves, only diazinon EC, trichlorfon SP, insecticidal soap, oxamyl GR and ZeroTol consistently caused over 70% nematode population reduction compared with the control at 45 DAT in both years. Thus, only diazinon EC, trichlorfon SP, oxamyl GR and ZeroTol consistently caused over 70% reduction in nematode population both in soil and leaves. Due to the recent ban by the US Environmental Protection Agency on the use of the first three of these formulations, only ZeroTol would serve as an effective tool to manage foliar nematodes in ornamentals. Although not as effective as ZeroTol in the soil, insecticidal soap is the only other alternative for foliar nematode management.     

Reproduction and Development ofAphelenchoides Besseyi

The mode of reproduction of the Indian population ofAphelenchoides besseyi was studied under different temperatures and on different fungal species used for culturing the nematode. Although parthenogenetic reproduction in this species was recorded on all the fungi tested, the influence of the different fungal species on development and population buildup varied. There was a significant increase in nematode fecundity when one or two males were placed along with single females in the medium, as compared with when no male was introduced. Increasing the number of males further to eight depressed fecundity as compared with the treatment with two males.     

水稻小穗头上的线虫形态特征鉴定

 对水稻生产上较大面积发现的“小穗头”现象，即稻穗长度缩短，籽粒明显减少, 米粒小且米色黑褐，部分籽粒为秕粒，剑叶形态正常，无干尖现象的成因进行了探讨。从水稻品种武育粳3号“小穗头”谷粒中分离到一种滑刃属线虫，百粒线虫数达2014条，单个谷粒带虫量最多可达74条，病穗中谷粒带虫率为92%。经外部形态和内部结构观察表明，虫体侧区具4条侧线，尾尖突为星状，具3~4刺突；雌虫后阴子宫囊短于肛阴距1/2，内无精子，卵母细胞多行排列，为2~4排；雄虫交合刺有一中等发育的缘突。虫体测量数据与Fortuner(1970)所测水稻干尖线虫的原始数据基本相符。因此，将该线虫鉴定为水稻干尖线虫Aphelenchoides besseyi Christie, 1942贝西滑刃线虫。     

Assessment of Rice Cultivars in China for Field Resistance to Aphelenchoides besseyi

The effect ofAphelenchoides besseyi on 27 cultivars of rice （23japonica and 4 indica） was assessed in the field for two seasons during 2010 and 2011. The vigorous pathogenic nematodes culturing on Botrytis cinerea were used for this experiment. Inoculation was carried out at the tilling stage; the growth parameters and nematode population were recorded at the end of growth of rice plants. The results showed that the cultivars differed in their response to infection. Most of cultivars were lack of the characteristic symptom of white tip, which was seen less frequently than the other two symptoms, namely small grains and erect panicles; moreover, the expression of symptoms was probably hereditary. The infection lowered the values of all the measured biological parameters, namely length of the stem and of the panicle, the number of filled grains per panicle, and 100-grain weight, in all the cultivars. The final nematode population indicated that the threshold of economic damage had also been exceeded in 10 cultivars, and none of them was immune. Three japonica cultivars proved most vulnerable whereas Tetep, an indica type, showed a level of resistance potentially useful in controlling A. besseyi.     

香菇菌筒腐烂病研究初报

香菇菌筒腐烂病在福建省的香菇反季节栽培区发生流行，其病原为蘑菇滑刃线虫（Ａｐｈｅｌｅｎｃｈｏｉｄｅｃｏｍｐｏｓｔｉｃｏｌａ）和雅各布滑刃线虫（Ａ．ｊａｃｏｂｉ）．这２种线虫还能侵染凤尾菇、蘑菇、金针菇、猴头菇、竹荪、灰树花、灵芝等菌丝体．清除发病菌筒、冲洗病畦和畦面覆盖地膜能有效防治病害