共生菌毒素对亚洲玉米螟和玉米小斑菌杀虫抑菌活性的测定

利用从全国采集的土样中收集到的28个品系的昆虫病原线虫,分离并筛选出28株高毒力共生菌菌株,对高毒力菌株的杀虫毒素进行初步提取,并以亚洲玉米螟和玉米小斑菌作为供试昆虫和供试真菌,对其杀虫抑菌活性进行测定。结果表明：共生菌毒素对两种病虫害均有一定的胃毒活性和抑菌作用,其中菌株5-5B毒素的杀虫抑菌活性最为明显,处理后120 h对亚洲玉米螟的平均校正死亡率为43.70%,抑菌圈直径为34.00 mm。     

玉米小斑病重要流行环节的初步定量研究Ⅰ.孢子萌发侵入、病斑潜育显症及扩展

对玉米小斑病的重要流行环节—孢子萌发侵入、病斑潜育显症扩展进行了定量研究。结果表明:叶面渗出物和花粉对孢子萌发及附着胞形成有明显的促进作用。叶面保湿时间(x)和附着胞形成率(y)的关系大体呈一“S”型曲线,两者关系可用回归方程y=exp〔-4.497exp(-0.098x)〕描述。温度(x)和附着胞形成率(y)的关系呈单峰曲线,两者关系可用回归方程y=sin(-3.371x 0.376x2-0.004x3)描述。随着生育期的推进玉米对小斑病侵染的抵抗力增强。增施磷、钾肥可降低小斑病的侵染率。小斑病在玉米上的潜育期为4~6 d,显症期约为7 d;病斑日龄(x)与病斑长度(y)的关系呈倒“J”型曲线,两者关系可用回归方程y=sin(42.645x-10.940x2 0.950x3)描述。     

C型雄不育玉米组培筛选专一性抗病株体

在培养2个C型胞质雄不育玉米杂交种的胚性愈伤组织时,加入玉米小斑病菌专化侵染性C小种两个菌株C7和C87-200的混合毒素,筛选出抗毒愈伤组织,经继代分化,获得抗病雄性不育再生植株。发现花粉育性和抗病基因不连锁,其下一代R#-1穗行仍表达抗病及雄性不育性状。     

Genome-wide association studies in a barley (Hordeum vulgare) diversity set reveal a limited number of loci for resistance to spot blotch (Bipolaris sorokiniana)

Spot blotch caused by Bipolaris sorokiniana is an important disease in barley worldwide, causing considerable yield losses and reduced grain quality. In order to identify QTL conferring resistance to spot blotch, a highly diverse worldwide barley set comprising 449 accessions was phenotyped for seedling resistance with three isolates (No 31, SH 15 and SB 61) and for adult plant resistance at two locations (Russia and Australia) in two years. Genotyping with the 50 k iSelect barley SNP genotyping chip yielded 33,818 informative markers. Genome-wide association studies (GWAS) using a compressed mixed linear model, including population structure and kinship, revealed 38 significant marker-trait associations (MTA) for spot blotch resistance. The MTA corresponded to two major QTL on chromosomes 1H and 7H and a putative new minor QTL on chromosome 7H explaining between 2.79% and 13.67% of the phenotypic variance. A total of 10 and 14 high-confidence genes were identified in the respective major QTL regions, seven of which have a predicted involvement in pathogen recognition or defence.     

牧草根际3种平脐蠕孢菌培养性状及对营养的利用能力

首次对我国典型草原牧草根际特异平脐蠕孢菌、高粱平脐蠕孢菌及麦根腐平脐蠕孢菌3种真菌的培养特性进行了研究.结果表明,3种平脐蠕孢菌菌丝生长的温限均为10～35℃,最适温度30℃.在试验的11种碳源中,D-果糖等碳源对3种平脐蠕孢菌菌丝生长有明显的促进作用,菊糖、氯醛糖有较强的抑制作用.在试验的12种氮源中,亮氨酸、L-谷氨酸、硝酸铵有明显的促进作用,而L-精氨酸、尿素、碳酸铵、甘氨酸有较强的抑制作用.高粱平脐蠕孢菌对多种碳、氮源利用能力较强,麦根腐平脐蠕孢菌则较弱.3种平脐蠕孢菌在不同碳、氮源培养基上菌落颜色、大小、边缘整齐度有明显差异.     

青稞普通根腐病的调查与病原鉴定

青稞在我国西北青藏高原地区广泛种植,根腐病对青稞的生产构成了严重威胁.2016年6-8月,分别对甘肃省甘南藏族自治州、青海省海东市和海北藏族自治州等地苗期和成株期青稞根腐病进行了调查,并采集疑似青稞普通根腐病样品.采用常规的组织分离法分离其病原,测定致病性,进行柯赫氏法则验证.通过形态特征和分子生物学鉴定相结合的方法确...     

椰子平脐蠕孢叶斑病病原鉴定及生物学特性测定

2012年10月,在海南省文昌市的椰子苗圃中,发现了一种新的叶斑病。显微观察表明,病原菌分生孢子稍弯曲,浅褐色,纺锤状或梭状,具有5~9个假隔膜、分生孢子梗多单生,直立或稍弯曲,表明其为平脐蠕孢属(Bipolari.sp)。ITS序列分析表明其和4株狗尾草平脐蠕孢的序列同源性(HE792936.1,JX462256,GUO73108.1,FJ606786.1)的同源性为99%。生物学特性研究结果表明:该菌菌丝适宜生长温度为20~30℃,菌丝生长和孢子最适萌发温度分别是25℃和30℃;最适p H值为4~11;玉米粉培养基(CAM)及马铃薯葡萄糖琼脂培养基(PDA)最适合菌丝生长,最佳碳源为蔗糖,甘油不适合菌丝生长;最佳氮源为蛋白胨,其次是磷酸氢二铵;完全光照有利于菌丝生长。菌丝及分生孢子的致死温度和时间分别是56℃,15 min。     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

茭白胡麻叶斑病病原菌分离与鉴定

茭白胡麻叶斑病发生普遍且严重,已成为茭白的常见病害。为了明确病原菌,先后从茭白主产区采集胡麻叶斑病病叶,各产区分离纯化5～10株病原菌。通过对菌株DNA的内转录间隔区ITS基因、3-磷酸甘油醛脱氢酶GPDH基因、延伸因子EF-1α基因的序列进行分析。结合形态学观察、致病力测定等方法对茭白胡麻叶斑病病菌进行鉴定。结果表明,茭白胡麻叶斑病病原菌为稻平脐蠕孢Bipolaris oryzae,与水稻胡麻叶斑病病原菌一致。本文的研究成果可为茭白胡麻叶斑病的防治提供一种新的思路。