理化因子对白僵菌附着胞形成的影响

研究了2种营养液、3种化学诱导物、6种基物以及微生态条件对球孢白僵菌分生孢子萌发和附着胞形成的影响.结果表明:白僵菌分生孢子在0.01%YEM、1%1/4SDY培养基中附着胞形成率最高.在1×106 ～5×106 mL-1的孢子浓度下,接种4 mL 0.01%YEM,同时在(26±1) ℃、pH7.0、先黑暗后光照培养条件下最有利于附着胞形成.不饱和脂肪酸对附着胞的形成有诱导作用或抑制作用.基物的表面结构、疏水性以及硬度与附着胞的形成有关.     

主要虫生真菌的分子生物学研究进展

综合评述了用现代分子生物学技术研究白僵菌、绿僵菌等虫生真菌的进展。内容主要包括两个方面,一是利用原生质体融合、基因工程等技术进行基因水平上的菌株改良,二是利用酶谱分析技术、分子遗传学技术进行遗传差异的研究。     

球孢白僵菌几丁质酶的定位研究

采用酶解球孢白僵菌菌丝细胞壁以获得原生质体,用超声破碎器破碎细胞,并用差速离心等方法,对此丝状病原真菌细胞中几丁质酶的定位进行了研究.采用球孢白僵菌 Eu-120株,分别用几丁质酶、蜗牛酶和纤维素酶,以不同比例混合进行脱壁处理.通过测定培养物上清液及原生质体溶解物的几丁质酶活性,发现此培养物上清液中的酶活性占其总酶活性的81.46%,而原生质体溶解物中酶活性极少.研究表明,球孢白僵菌几丁质酶主要存在于细胞的周质空间,并在菌生长过程中通过细胞壁分泌至细胞外.     

Root-Associated Entomopathogenic Fungi Modulate Their Host Plant’s Photosystem II Photochemistry and Response to Herbivorous Insects

The escalating food demand and loss to herbivores has led to increasing interest in using resistance-inducing microbes for pest control. Here, we evaluated whether root-inoculation with fungi that are otherwise known as entomopathogens improves tomato (Solanum lycopersicum) leaflets’ reaction to herbivory by Spodoptera exigua (beet armyworm) larvae using chlorophyll fluorescence imaging. Plants were inoculated with Metarhizium brunneum or Beauveria bassiana, and photosystem II reactions were evaluated before and after larval feeding. Before herbivory, the fraction of absorbed light energy used for photochemistry (Φ_PSII) was lower in M. brunneum-inoculated than in control plants, but not in B. bassiana-inoculated plants. After herbivory, however, Φ_PSII increased in the fungal-inoculated plants compared with that before herbivory, similar to the reaction of control plants. At the same time, the fraction of energy dissipated as heat (Φ_NPQ) decreased in the inoculated plants, resulting in an increased fraction of nonregulated energy loss (Φ_NO) in M. brunneum. This indicates an increased singlet oxygen (¹O₂) formation not detected in B. bassiana-inoculated plants, showing that the two entomopathogenic fungi differentially modulate the leaflets’ response to herbivory. Overall, our results show that M. brunneum inoculation had a negative effect on the photosynthetic efficiency before herbivory, while B. bassiana inoculation had no significant effect. However, S. exigua leaf biting activated the same compensatory PSII response mechanism in tomato plants of both fungal-inoculated treatments as in control plants.     

Beauveria bassiana ATCC 7159 Containsan L-Specific a-Amino Acid Benzamidase

Summary.  Biotransformation of a series of racemic N-benzoyl α-amino acids by the fungus Beauveria bassiana ATCC 7159 results in isolation of the corresponding D-amino acid benzamides in high enantiomeric purity and yield. Received December 20, 1999. Accepted January 21, 2000     

木毒蛾白僵菌优良菌株的自然筛选及应用研究

本研究通过对林间采集的天然木毒蛾僵虫蛹进行组织分离和单孢分离纯化 ,选取 12个典型单孢菌株在马铃薯虫尸琼脂培养基上的表现性状以及与不同菌株的室内外毒力测定试验比较 ,从中筛选出 Bm1-1、Bm2 - 7、Bm3- 3三个木毒蛾白僵菌优良菌株 ,并将最具优良品质的 Bm1- 1菌株进行大量生产和大面积应用防治示范 ,取得了显著的效果     

油茶毒蛾高毒力白僵菌菌株的筛选

通过比较4株白僵菌菌株的产孢量及其对油茶毒蛾的致病力,结果发现白僵菌菌株Bf08,B01,产孢量分别为(5.1±0.4)×108,(3.4±0.4)×108孢子/cm2,接种油茶毒蛾后其LT50分别为5.64,6.62 d,说明对这两个菌株油茶毒蛾的毒力很强,是可用于油茶毒蛾防治的优良白僵菌菌株。     

松墨天牛优良白僵菌菌株筛选

从浙江省松墨天牛１松毛虫等不同寄主上采集了６个球孢白僵菌自然菌株,并从日本及国内主要生产厂家收集６个菌株,共计１２个菌株。经过对其营养生长、产孢量、孢子活力、孢子耐热能力、孢子抗紫外线能力和室内对松墨天牛幼虫毒力等指标的研究,结果发现采自象山松墨天牛幼虫的菌株Ｂｘｓ和来自日本松墨天牛的菌株Ｆ－２６３对松墨天牛幼虫的毒力最强,并且上述各指标均表现优良。尤其是Ｂｘｓ菌株,其产孢量和抗紫外线能力大大高于