水稻干尖线虫生殖方式、生活史及温度对其存活能力的影响及其在水稻中的分布

为了解近年我国水稻主产区水稻干尖线虫Aphelenchoides besseyi种群的生物学特性，并为寻找新的水稻干尖线虫病害防控方法，通过在胡萝卜愈伤组织、灰葡萄孢菌Botrytis cinerea和水稻中培养水稻干尖线虫的方法对其生殖方式、生活史和温度对其存活能力的影响及其在水稻中的分布进行研究。结果表明，在供试的12个水稻干尖线虫种群中，只有G8-315种群可孤雌生殖；在25℃下，水稻干尖线虫在胡萝卜愈伤组织和灰葡萄孢菌上生活史均约为12 d，在水稻苗上生活史约为11 d;-20℃以下低温或42℃以上高温处理12 h，在清水、胡萝卜愈伤组织和灰葡萄孢菌中水稻干尖线虫存活率均显著下降，处理72 h水稻干尖线虫存活率均为0；带虫干燥谷粒在-80、-20和4℃低温保存6个月后，谷粒内水稻干尖线虫存活率均显著低于25℃（对照），其中-80℃保存的谷粒内水稻干尖线虫存活率为0;56、70和80℃高温处理12 h后，2个水稻品种谷粒内水稻干尖线虫存活率均显著下降，80℃处理16 h后2个水稻品种谷粒内水稻干尖线虫存活率均为0；水稻幼苗各部位均可检测出水稻干尖线虫，其中假茎部位水稻干尖线虫数量...     

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（Alternaria sp.）、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。     

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.     

叶鞘接种法在水稻干尖线虫致病力测定中的应用

采用叶鞘定量接种雌虫的处理方式,测定水稻干尖线虫对水稻的致病力。结果表明,叶鞘接种水稻干尖线虫1、3、5、10头/株均能引起水稻发病,且随干尖线虫接种量的增加,水稻的发病率呈增加趋势。同时,水稻的生长发育受到明显的抑制,其株高、谷粒数、千粒重、穗长、一次枝梗及二次枝梗长等生长指标均随接种量增加而减少,高节位分蘖数随接种量增加而增加。     

水稻黑点米形成原因初步研究

通过试验研究了水稻黑点米形成的原因。采用田间小区试验,通过98%杀螟丹可溶粉剂浸种杀灭种子中越冬干尖线虫,收获后调查各小区收获稻子中干尖线虫数量及黑点米率,初步明确了水稻黑点米形成是由于干尖线虫的刺吸引起。通过干尖线虫接种,收获的稻子出现黑点米症状,并从黑点米中分离到干尖线虫,进一步证明干尖线虫危害是导致黑点米形成的主要原因。     

水稻干尖线虫室内人工培养条件研究

在室内同一培养基质上研究了温度、光照、湿度对水稻干尖线虫繁殖量的影响。结果表明:在不同温度、光照、湿度下水稻干尖线虫的繁殖量差异明显,在温度30℃,光照6h,湿度90%条件下水稻干尖线虫的繁殖量最高。     

水稻干尖线虫快速分子检测技术研究

根据水稻干尖线虫的rDNA-ITS序列,设计出水稻干尖线虫的特异性引物,利用PCR技术对水稻干尖线虫(Aphelenchoides besseyi)部分rDNA-ITS1和部分5.8S基因核苷酸序列进行特异性扩增。实现了单条活的或4%的甲醛(FG)固定的水稻干尖线虫的快速检测。     

防治水稻干尖线虫病的拌闷种法

由线虫为害造成的水稻干尖病又名水稻白尖病。本致病线虫耐寒不耐高温,在干燥的稻种内可存活3年左右。因它以幼虫或成虫潜伏在谷粒的颖壳和米粒间越冬,所以带虫种子是本病的主要初次侵染源。通过灌溉水和土壤传播的可能性较小。稻种内的线虫,在浸种催芽时即开始活动。播种后,大多数线虫游离于水中及土壤内死亡,而少数侵入稻苗或传播为害。稻苗被害后,上部叶片尖端2～4厘米逐渐卷皱,呈白色、灰色或淡褐色的“干尖”,病健部界限明显,继则捻曲、歪扭,“干尖”因风吹或磨擦而折断脱落,常严重影响水稻产量。     

巴氏新小绥螨对水稻干尖线虫控制能力的评估

本文研究了巴氏新小绥螨Neoseiulus barkeri以水稻干尖线虫Aphelenchoides besseyi为食的生长发育特征及其对水稻干尖线虫的捕食功能.结果表明,巴氏新小绥螨以水稻干尖线虫为食时,能正常发育并完成生活史,其生长发育各个历期与取食腐食酪螨Tyrophagus putrescentiae相比无显...     

近年水稻主要线虫病害的研究进展

目前,以拟禾谷根结线虫Meloidogyne graminicola、水稻干尖线虫Aphelenchoide besseyi、水稻潜根线虫Hirschmanniella oryzae、水稻茎线虫Ditylenchus angustus和旱稻孢囊线虫Heterodera elachista为主的水稻寄生线虫侵染水稻以及其它禾本科作物引致的线虫病害,已造成了严重的经济损失。近年来,对拟禾谷根结线虫的致病机制和寄主的防御机制等方面的研究已取得了显著进展,但对其它水稻寄生线虫与寄主互作机制的研究还存在较大空白。水稻寄生线虫的防治多依赖化学农药,抗性品种和生物防治等措施的实施存在一定的局限性。本文对上述5种主要水稻寄生线虫病的发生为害、致病机制以及防治方法等进行了综述,并对水稻寄生线虫致病机理的研究以及抗性品种、生物防治和诱导化合物的应用进行了探讨。     

Rice nematode problems in Nigeria: Their occurrence,distribution and pathogenesis

Abstract

In a survey of plant parasitic nematodes associated with or affecting rice throughout Nigeria, some important nematode pests, especially the white tip disease nematode, Aphelenchoides besseyi and the rice root nematodes Hirschmanniella spinicaudata and H. oryzae were identified from seed, soil and root samples from swamp rice fields respectively. The sugarcane cyst nematode, Heterodera sacchari occurred in swamp rice fields only around the major sugarcane estates in Nigeria. The root‐knot Meloidogyne incognita and the root lesion nematode, Pratylenchus brachyurus were also encountered in upland (rainfed) rice fields. The white tip disease nematode, A. besseyi occurred at low levels in soils and rice seeds throughout the country. High population levels of H. spinicaudata and H. oryzae were encountered especially in areas where monoculture of rice is practised. General chlorosis, poor tillering and significantly reduced yield have been observed due to H. spinicaudata. Rice plants attacked by H. sacchari also showed intense chlorosis, delayed and reduced tillering and reduced grain yield. The roots of attacked plants were twiggy, very necrotic and blackened. The root‐knot M. incognita and the root lesion nematodes P. brachyurus have both been observed to reduce rice yields. Rice cultivars screened for reactions to the nematodes showed varying degrees of susceptibilities. Some varieties were however resistant to the root‐knot nematode, M. incognita.     

两索线虫对晚稻田不同类型褐飞虱的寄生力研究

在3个不同水稻品种上,研究江西南昌晚稻田内两索线虫对不同翅型和性别褐飞虱的寄生能力。结果表明:在同一水稻品种上,两索线虫对不同类型褐飞虱的寄生率之间存在显著差异,其寄生率的大小顺序为:短翅型雌虫长翅型雌虫短翅型雄虫长翅型雄虫。其中,在短翅型雌虫体内,最高寄生率达45.16%;而在长翅型雄虫体内,最低寄生率仅为2.15%。在水稻品种株两优120上,两索线虫对短翅型雌虫的寄生数量达3头的占9.68%,对短翅型雌虫和长翅型雌虫寄生有2头的分别占6.45%和8.33%;在丰华占和合美(丰)上,对短翅型雌虫寄生数量最多为2头,寄生率分别为5.25%和4.35%;对不同类型褐飞虱的寄生数量为1头的均较高。可见,两索线虫对田间褐飞虱种群具有较强的寄生能力,可有效抑制褐飞虱的发生与危害。     

水稻拟禾本科根结线虫发生与防治

拟禾本科根结线虫是严重影响水稻产量的植物寄生线虫之一,已成为制约中国及亚洲地区水稻产量的重大问题。拟禾本科根结线虫寄主范围广泛,可危害高地、低洼地和深水水稻;通过巨细胞从水稻根中摄取营养物质,从而在根系上形成许多弯钩状根结;其食道腺分泌物可以直接对水稻产生危害,影响水稻细胞代谢和免疫,从而影响水稻产量。目前水稻抗根结线虫病的品种较少,主要通过化学药剂在苗床进行防治。本文对拟禾本科根结线虫的寄主范围、危害特性、侵染特点、致病机制及防治方法等进行了综述,并对将来通过基因编辑等遗传工程技术提高水稻品种抗性的策略进行了展望,以期为我国水稻拟禾本科根结线虫的防治提供理论依据。     

北京地区昆虫病原线虫的自然发生情况初步调查

用大蜡螟诱集法,对在北京地区采集的175个土样进行了线虫分离,得到斯氏属线虫5个,异小杆属线虫6个,小杆线虫2个。土样有线虫率为13.1％。土样有线虫率与植被、土壤质地有关。从4种植被下采集土样的有线虫率分别是:果园28.2％、菜地10.5％、大田作物7.7％、未耕地0。4种土壤质地中土样有线虫率为:松沙土20.8％、砂壤土15.1％、中壤土12.2％、轻壤土5.4％。本土线虫对桃小食心虫、韭菜蛆、小木蠹蛾、二化螟的侵染力均高于引进的线虫。     

旱稻孢囊线虫（Heterodera elachista）孵化特性研究

为了解旱稻孢囊线虫的孵化特性,从水稻根系及根系附近土壤分离孢囊,在室内离体条件下研究不同温度及水稻根系分泌物、土壤浸液、水稻根汁等因子对2龄幼虫孵化的影响,并观察不同温度下2龄幼虫的存活能力.结果表明:旱稻孢囊线虫孵化的适宜温度范围为28～32℃,且在该温度范围初孵2龄幼虫的存活率高、存活时间相对较长,35℃下孵化率及初孵2龄幼虫的存活率、存活时间均明显下降,40℃下无线虫孵化,20℃下孢囊线虫孵化率仅为0.9％,4℃下可延长2龄幼虫的存活时间.水稻分泌物、水稻土壤浸液和水稻20倍根汁对旱稻孢囊线虫孵化具有刺激作用,5倍根汁和4 mmol/L氯化锌溶液对线虫的孵化有抑制作用.上述结果可为制定旱稻孢囊线虫防治措施提供依据.     

First report of the plant‐parasitic nematode Aphelenchoides besseyi (Nematoda: Aphelenchoididae) on rice in Romania

The rice leaf nematode, Aphelenchoides besseyi, was isolated in 2017 from rice seeds cultivated in Romania. Identification was based on morphology and confirmed with a real‐time PCR test. This paper provides the first report of A. besseyi in Romania.     

Relationship between physiological response of French beans of different age to Meloidogyne incognita and subsequent yield loss

A study was made of the effect of a single generation of the root-knot nematode Meloidogyne incognita on the growth of potted French bean plants ( Phaseolus vulgaris ) inoculated at different stages of plant maturity. In separate experiments. 3-, 11- and 13-day-old plants were inoculated before primary leaf expansion (BPLE). at the appearance of trifoliate leaves (TRIF) and at the flower bud (BDS) stages respectively, with 0, 2000, 4000 or 8000 second-stage juvenile nematodes and maintained in a growth chamber under controlled conditions. The photosynthetic rate of the plants inoculated at the TRIF and BDS stages decreased significantly with increasing inoculum level 7 days after inoculation. Although the respiration rate did not significantly change throughout the experimental period, the ratio of photosynthetic to respiration rate decreased significantly with increasing nematode inoculum level and duration of infection. Chlorophyll content, plant dry weight and the numbers of buds, flowers, pods and seeds were significantly lower in infected plants than in the controls; this effect increased with increasing levels of nematode inoculum for all three plant stages. The leaf area was significantly smaller only when nematode infection occurred at the BPLE stage. The plants which were youngest at the time of nematode infection produced the lowest yield; this appeared to result from the effect of nematodes on photosynthesis and related physiological processes.     

Expression of Oryzacystatin I and II in Alfalfa Increases Resistance to the Root-Lesion Nematode

ABSTRACT Digestive cysteine proteinases have been isolated from plant-parasitic nematodes as well as coleopteran and hemipteran insects. Phytocystatins, inhibitors of cysteine proteinases, are found in a number of plants where they may play a role in defense against pathogens and pests. The cDNAs of the phytocystatins from rice, oryzacystatin I (OC-I) and oryzacystatin II (OC-II), were expressed in alfalfa (Medicago sativa) plants under the control of the potato protease inhibitor II (PinII) promoter and the plants were evaluated for resistance to the root-lesion nematode (Pratylenchus penetrans). A PinII-beta-glucuronidase (GUS) gene was introduced into alfalfa to determine the pattern of gene expression from this promoter. Constitutive GUS expression was observed in leaf and root vascular tissue, and in some plants, expression was observed in leaf mesophyll cells. Mechanical wounding of leaves increased GUS expression approximately twofold over 24 h. Inoculation with root-lesion nematodes resulted in localized GUS expression. Populations of root-lesion nematodes in alfalfa roots from one line containing the PinII::OC-I transgene and one line containing the PinII::OC-II transgene were reduced 29 and 32%, respectively, compared with a transgenic control line. These results suggest that oryzacystatins have the potential to confer increased resistance to the root-lesion nematode in alfalfa.