Differential effects of sugar-mimic alkaloids in mulberry latex on sugar metabolism and disaccharidases of Eri and domesticated silkworms: enzymatic adaptation of Bombyx mori to mulberry defense

Mulberry leaves (Morus spp.) exude latex rich in sugar-mimic alkaloids, 1,4-dideoxy-1,4-imino-d-arabinitol (d-AB1) and 1-deoxynojirimycin (DNJ), as a defense against herbivorous insects. Sugar-mimic alkaloids are inhibitors of sugar-metabolizing enzymes, and are toxic to the Eri silkworm, Samia ricini, a generalist herbivore, but not at all to the domesticated silkworm, Bombyx mori, a mulberry specialist. To address the phenomena, we fed both larvae diets containing different sugar sources (sucrose, glucose or none) with or without sugar-mimic alkaloids from mulberry latex. In S. ricini, addition of sugar-mimic alkaloids to the sucrose (the major sugar in mulberry leaves) diet reduced both growth and the absorption ratio of sugar, but it reduced neither in B. mori. The midgut soluble sucrase activity of S. ricini was low and inhibited by very low concentrations of sugar-mimic alkaloids (IC₅₀=0.9–8.2 μM), but that of B. mori was high and not inhibited even by very high concentrations (IC₅₀>1000 μM) of sugar-mimic alkaloids. In S. ricini, the addition of sugar-mimic alkaloids to the glucose diet still had considerable negative effects on growth, although it did not reduce the absorption ratio of glucose. The hemolymph of S. ricini fed sugar-mimic alkaloids contained sugar-mimic alkaloids. The trehalose concentration in the hemolymph increased significantly in S. ricini fed sugar-mimic alkaloids, but not in B. mori. The trehalase activities of S. ricini were lower and inhibited by lower concentrations of sugar-mimic alkaloids than those of B. mori. These results suggest that sugar-mimic alkaloids in mulberry latex exert toxicity to S. ricini larvae first by inhibiting midgut sucrase and digestion of sucrose, and secondly, after being absorbed into hemolymph, by inhibiting trehalase and utilization of trehalose, the major blood sugar. Further, our results reveal that B. mori larvae evolved enzymatic adaptation to mulberry defense by developing sucrase and trehalase that are insensitive to sugar-mimic alkaloids.     

家蚕幼虫BmToll9基因对肽聚糖和金黄色葡萄球菌的响应表达

【目的】Toll信号通路是昆虫中重要的免疫信号通路,其中Toll受体在保持Toll通路的正常免疫应答、抵抗外源病原体中起到关键的作用。本研究旨在探究肽聚糖和金黄色葡萄球菌Staphylococcus aureus对家蚕Bombyx mori Toll受体基因BmToll9-1和BmToll9-2表达的影响。【方法】将革兰氏阳性菌细胞壁主要成分肽聚糖和革兰氏阳性菌金黄色葡萄球菌分别注射感染家蚕5龄第1天幼虫,诱导其发生免疫反应;采用实时荧光定量PCR分析注射后不同感染时间点BmToll9-2和BmToll9-1基因在家蚕幼虫中肠、表皮、脂肪体和丝腺中的相对表达水平。【结果】往家蚕5龄幼虫中注射肽聚糖或金黄色葡萄球菌后,BmToll9-2基因出现了时间和组织的差异性表达。注射肽聚糖和金黄色葡萄球菌均能诱导5龄幼虫中肠BmToll9-2基因的表达上调,注射肽聚糖和金黄色葡萄球菌分别在3和6 h时对基因表达的诱导效果最好,且注射金黄色葡萄球菌比注射肽聚糖对基因表达的诱导效果更好。注射金黄色葡萄球菌能引起5龄幼虫表皮、脂肪体和丝腺中BmToll9-2基因的表达上调,分别于注射后24, 6和24 h时诱导效果最好。注射金黄色葡萄球菌亦能诱导同源的BmToll9-1基因的上调表达。【结论】家蚕幼虫BmToll9基因在肽聚糖或金黄色葡萄球菌注射处理后均能在不同组织中发生上调表达,推测BmToll9基因参与了家蚕对肽聚糖和金黄色葡萄球菌的免疫反应。     

光皮桦6个南方天然群体的遗传多样性

为揭示中国特有珍贵用材树种光皮桦(Betula luminifera)天然群体的遗传多样性和遗传结构, 采用AFLP分子标记, 分析了采自浙江、福建、江西、广西和贵州5个省区6个天然群体的120份样品。9对引物获得了355个位点, 其中多态性位点323个。分析结果表明光皮桦天然群体具有较高的遗传多样性, 多态位点百分率(PPL)达90.99%, 各群体的PPL和Nei’s基因多样性(h_j)分别为93.20-98.60%和0.3143-0.3645; 总群体遗传多样性指数(H_t)为0.3616, 群体间遗传分化系数(F_st)为0.0650, 群体间总的基因流较高(N_m= 3.5962)。AMOVA分析表明群体间的遗传变异占总变异的11.49%, 浙江临安群体和贵州修文群体间的遗传距离最大(0.0665), 江西龙南群体和广西龙胜群体间的遗传距离最小(0.0173), 且遗传结构分析显示这两个群体的部分个体可能来自同一近祖。Mantel检测发现, 群体间的遗传距离与地理距离没有显著相关性(r = 0.423, P = 0.113), 而与两两群体所在地的均温差呈显著相关(r = 0.449, P = 0.017)。结合群体实地调查, 可以得出光皮桦天然群体的遗传多样性和遗传结构的形成不仅与其广域分布、自然杂交、种子特性以及生活史有关, 而且与群体被人为砍伐、生境片断化等因素有重要关系。基于上述结果我们提出了光皮桦天然种群的保护策略。     

Lipid transfer particle catalyzes transfer of carotenoids between lipophorins of Bombyx mori

The yellow color of Bombyx mori hemolymph is due to the presence of carotenoids, which are primarily associated with lipophorin particles. Carotenoids were extracted from high density lipophorin (HDLp) of B. mori and analyzed by HPLC. HDLp contained 33 μg of carotenoids per mg protein. Over 90% of carotenoids were lutein while -carotene and β-carotene were minor components. When larval hemolymph was subjected to density gradient ultracentrifugation, a second minor yellow band was present, which was identified as B. mori lipid transfer particle (LTP). During other life stages examined however, this second band was not visible. To determine if coloration of LTP may fluctuate during development, we determined its concentration in hemolymph and compared it to that of lipophorin. Both proteins were present during all life stages and their concentrations gradually increased. The ratio of lipophorin: LTP was 1015:1 during the fourth and fifth instar larval stages, and 2030:1 during the pupal and adult stages. Thus, there was no correlation between the yellow color attributed to LTP and its hemolymph concentration. It is possible that yellow coloration of the LTP fraction corresponds to developmental stages when the particle is active in carotene transport. To determine if LTP is capable of facilitating carotene transfer, we took advantage of a white hemolymph B. mori strain which, when fed artificial diet containing a low carotene content, gives rise to a lipophorin that is nearly colorless. A spectrophotometric, carotene specific, transfer assay was developed which employed wild type, carotene-rich HDLp as donor particle and colorless low density lipophorin, derived from the white hemolymph strain animals, as acceptor particle. In incubations lacking LTP carotenes remained associated with HDLp while inclusion of LTP induced a redistribution of carotenes between the donor and acceptor in a time and concentration dependent manner. Time course studies suggested the rate of LTP-mediated carotene transfer was relatively slow, requiring up to 4 h to reach equilibrium. By contrast, studies employing ³H-diacylglycerol labeled HDLp as donor particle in lipid transfer assays revealed a rapid equilibration of label between the particles. Thus, it is plausible that the slower rate of LTP-mediated carotene transfer is due to its probable sequestration in the core of HDLp.     

Characterization and purification of the biologically active v-sis protein generated in silkworm larvae with the Bombyx mori nuclear polyhedrosis virus vector system

The v-sis oncogene of simian sarcoma virus encodes a protein which is homologous to the human platelet-derived growth factor B-chain. The biologically active v-sis protein was expressed in silkworm larvae using the Bombyx mori nuclear polyhedrosis virus vector system. The v-sis protein purified from infected silkworm larvae is a 30 kDa disulfide-linked homodimer. Mitogenic activity of the v-sis protein was comparable to that of PDGF and inhibited by the pretreatment with anti-PDGF antibody. These results show that the recombinant v-sis protein is biologically and antigenically related to PDGF.     

Re-identification of the halotolerant, biosurfactant-producing Bacillus licheniformis strain JF-2 as Bacillus mojavensis strain JF-2

Bacillus strain JF-2 (ATCC 39307) is a halotolerant, biosurfactant-producing bacterium that was initially described as a member of the species Bacillus licheniformis based on a limited set of phenotypic characteristics. Here, genetic and phenotypic analyses were employed to determine the relationship of Bacillus strain JF-2 to other Bacillus strains. The restriction patterns with AluI and analysis of gyrA and 16S rRNA gene sequences grouped Bacillus strain JF-2 with B. mojavensis^T and not with B. licheniformis^T. DNA–DNA similarity showed JF-2 was 75% similar to B. mojavensis^T and only 11% similar to B. licheniformis^T. Both strain JF-2 and B. mojavensis^T required DNA for anaerobic growth, but B. licheniformis^T did not. B. mojavensis^T and strain JF-2 did not grow anaerobically in thioglycollate medium or aerobically with propionate while B. licheniformis^T grew under these conditions. DNA–DNA similarity, gene sequence data and phenotypic characteristics all support the assignment of JF-2 as a member of the species B. mojavensis.     

Phenotypic and genotypic characterization of rhizobia from diverse geographical origin that nodulate Pachyrhizus species

Legumes from the genus Pachyrhizus, commonly known as yam bean, are cultivated in several countries from the American continent and constitute an alternative source for sustainable starch, oil and protein production. The endosymbionts of these legumes have been poorly studied although it is known that this legume is nodulated by fast and slow growing rhizobia. In this study we have analyzed a collection of strains isolated in several countries using different phenotypic and molecular methods. The results obtained by SDS-PAGE analysis, LPS profiling and TP-RAPD fingerprinting showed the high diversity of the strains analyzed, although all of them presented slow growth in yeast mannitol agar (YMA) medium. These results were confirmed using 16S-23S internal transcribed spacer (ITS) region and complete sequencing of the 16S rRNA gene, showing that most strains analyzed belong to different species of genus Bradyrhizobium. Three strains were closely related to B. elkanii and the rest of the strains were related to the phylogenetic group constituted by B. japonicum, B. liaoningense, B. yuanmingense and B. betae. These results support that the study of rhizobia nodulating unexplored legumes in different geographical locations will allow the discovery of new species able to establish legume symbioses.     

Genetic diversity in Arabidopsis thaliana L. Heynh. investigated by cleaved amplified polymorphic sequence (CAPS) and inter-simple sequence repeat (ISSR) markers

In this study, we investigated genetic diversity among 37 accessions in Arabidopsis thaliana from Eurasia, North Africa and North America using morphological traits and two polymerase chain reaction (PCR)-based marker systems: cleaved amplified polymorphic sequences (CAPS) and inter-simple sequence repeats (ISSR). Cluster analysis based on genetic similarities calculated from CAPS data grouped the accessions roughly according to their geographical origin: one large group contained accessions from Western, Northern and Southern Europe as well as North Africa, a second group consisted of Eastern European and Asian continental accessions. North American accessions were interspersed into these groups. Contrary to the CAPS analysis, the dendrogram obtained from the ISSR data did not reflect the geographical origin of the accessions, and the calculated genetic distances did not match the CAPS results. This could be attributable to an uneven genomic distribution of ISSR markers as substantiated by a database search for ISSR binding sites in A. thaliana genomic DNA sequence files, or to the ISSR's different mode of evolution. We recommend CAPS markers for diversity analysis in A. thaliana because a careful selection of markers can ascertain an even representation of the entire genome.     

Precise molecular weight determination of PCR products of the rRNA intergenic spacer region using electrospray quadrupole mass spectrometry for differentiation of B. subtilis and B. atrophaeus, closely related species of bacilli

Assessment of 16S–23S rRNA intergenic spacer region (ISR) sequence variability is an important supplement to 16S rRNA sequencing for differentiating closely related bacterial species. Species differentiation can also be achieved by determination of approximate size of PCR (polymerase chain reaction) products of ISRs, based on their relative electrophoretic mobility on agarose gels. Closely-related species can have ISR PCR products that are similar in size. More precise molecular weight (M.W.) determination of these products might allow improved discrimination of such species. Electrospray quadrupole mass spectrometry (ESI-Q-MS) has the potential to provide such precision. For ESI-Q-MS analysis, size limitation of PCR products is currently limited to around 130 base pairs (bp). Bacillus subtilis and Bacillus atrophaeus are two closely related species with few distinguishing phenotypic characteristics. B. subtilis has recently been sub-divided into two subgroups, W23 (type strain, W23) and 168 (type strain, 168). PCR products amplified from the ISR including the 5′ terminal end of the 23S rRNA and a conserved portion of the ISR were analyzed by ESI-Q-MS. A 119 or 120 bp PCR product was produced for B. atrophaeus strains. However, strains of B. subtilis subgroups W23 and 168 each produced 114 bp products. In summary, a mass spectrometry method was developed for differentiation of B. subtilis and B. atrophaeus. Also, the genetic similarity of B. subtilis subgroups W23 and 168 was confirmed. Accurate determination of the molecular weight of PCR products from the 16S–23S rRNA intergenic spacer region using electrospray quadrupole mass spectrometry has great potential as a general technique for characterizing closely related bacterial species.     

四川省草莓主产区灰葡萄孢菌的遗传多样性

为明确四川省草莓灰葡萄孢Botrytis cinerea群体遗传结构及其多样性水平,采用ISSR分子标记技术对分离自四川省10个县（市）的195株灰葡萄孢菌进行了遗传多态性分析。结果表明,四川省灰葡萄孢菌多态性丰富,6条ISSR引物共产生了63个多态性位点,应用Popgene32软件计算四川省不同主产区域（除德阳广汉种群外）种群的Nei’s基因多样性指数（H）和Shannon信息指数（I）均达到了H>0.2、I>0.3的水平,表明四川省的灰葡萄孢菌具有丰富的遗传多样性;灰葡萄孢菌群体的遗传多样性（Ht）均值为0.2976,种群内遗传多样性（Hs=0.2458）远远高于种群间（Dst=0.0518）的遗传多样性;遗传分化系数（Gst）均值0.1742,基因流（Nm）均值2.3696,说明该地区灰葡萄孢菌种群间遗传分化不明显,群体内基因交流频繁。通过UPGMA法和Omishare Tools热图软件均可将10个采集点分为3个类群,来自绵阳江油的菌株单独构成一个类群,来自成都崇州和德阳广汉的菌株构成一个类群,其余的菌株构成另外一个类群;利用Structure 2.3软件对195份灰葡萄孢菌进行群体结构分析,可将134份菌株划分成21个群,另外61个菌株被列为混合群体。     

Biochemical and molecular characteristics of indigenous strains of the entomopathogenic fungus Beauveria bassiana of Central India

Forty-eight isolates of indigenous strains of Beauveria bassiana from various insect hosts collected from Central India were characterised by employing protease zymography and RAPD analysis. Results of protease zymographic profiles were reproducible and significant enough to contribute to the biochemical diversity of this species. RAPD analysis revealed the presence of high level of genetic diversity and indicated that 0-66% significant differences has evolved between these isolates. The sets of amplified bands showing identical pattern to others were grouped at 100% similarity level. A wide range in the value (0.25-1.00) of Jaccard similarity coefficient was observed among all the isolates. The grouping of the indigenous strains, obtained from numerical analysis of these data, appears to be related to the host specificity in B. bassiana. Clear groups were seen for strains isolated from Lepidopteran and Coleopteran insect hosts.     

Yeasts as biological agents to control Botrytis cinerea

Yeasts, isolated from different sources, were identified and tested for inhibition using YMA-MB plates seeded with Botrytis cinerea strains. A total of 42 yeast strains of 20 different species were tested in vitro for antagonism against 18 pathogenic B. cinerea strains. Pichia membranifaciens, P. anomala and Debaryomyces hansenii displayed the most important inhibitory effect against Botrytis strains. In small-scale trials, post-harvest application of P. membranifaciens CYC 1106 to apple wounds inhibited B. cinerea CYC 20010. Purified killer toxin from P. membranifaciens CYC 1106 inhibited B. cinerea CYC 20010. Results indicated that certain yeasts, or their toxins such us P. membranifaciens CYC 1106 killer toxin, might have potential as novel agents to control B. cinerea.     

Structure and properties of regenerated Antheraea pernyi silk fibroin in aqueous solution

Antheraea pernyi silk fibroin fibers were dissolved by aqueous lithium thiocyanate to obtain regenerated A. pernyi silk fibroin solution. By means of circular dichroism, ¹³C NMR and Raman spectroscopy, the molecular conformation of regenerated A. pernyi silk fibroin in aqueous solution was investigated. The relationship of environmental factors and sol–gel transformation behavior of regenerated A. pernyi silk fibroin was also studied. The molecular conformations of regenerated A. pernyi silk fibroin mainly were -helix and random coil in solution. There also existed a little β-sheet conformation. It was obviously different with Bombyx mori silk fibroin, whose molecular conformation in solution was only random coil but no -helix existence. With the increase of temperature and solution concentration and with the decrease of solution pH value, the gelation velocity of regenerated A. pernyi silk fibroin solution increased. Especially, it showed that A. pernyi silk fibroin was more sensitive to temperature than B. mori silk fibroin during the sol–gel transformation. The velocity increased obviously when the temperature was above 30 °C. During the sol–gel transformation, the molecular conformation of regenerated A. pernyi silk fibroin changed from random coil to β-sheet structure. The results of these studies provided important insight into the preparation of new biomaterials by silk fibroin protein.     

Genetic diversity among silkworm (Bombyx mori L., Lep., Bombycidae) germplasms revealed by microsatellites.

To determine genetic relationships among strains of silkworm, Bombyx mori L., 31 strains with different origins, number of generations per year, number of molts per generation, and morphological characters were studied using simple sequence repeat (SSR) markers. Twenty-six primer pairs flanking microsatellite sequences in the silkworm genome were assayed. All were polymorphic and unambiguously separated silkworm strains from each other. A total of 188 alleles were detected with a mean value of 7.2 alleles/locus (range 2-17). The average heterozygosity value for each SSR locus ranged from 0 to 0.60, and the highest one was 0.96 (Fl0516 in 4013). The mean polymorphism index content (PIC) was 0.66 (range 0.12-0.89). Unweighted pair group method with arithmetic means (UPGMA) cluster analysis of Nei's genetic distance grouped silkworm strains based on their origin. Seven major ecotypic silkworm groups were analyzed. Principal components analysis (PCA) for SSR data support their UPGMA clustering. The results indicated that SSR markers are an efficient tool for fingerprinting cultivars and conducting genetic-diversity studies in the silkworm.     

巴尔通体在滇西南蝙蝠中高度流行并具有丰富的遗传变异特征

蝙蝠是很多病原微生物的自然宿主, 全球多项研究表明蝙蝠是巴尔通体(Bartonella species)的主要宿主。为了解滇西南地区蝙蝠中巴尔通体的流行特征, 我们于2015-2017年间在云南省4个地区应用网捕法捕获蝙蝠3种305只。经种类鉴定后采集肝脾组织, 提取核酸, 通过TaqMan实时荧光定量PCR方法检测巴尔通体的tmRNA基因ssrA, 并进行测序鉴定和系统发育分析。结果发现172只蝙蝠检出该基因, 总感染率为56.4%; 其中临沧、西双版纳、保山和瑞丽4个采样点的蝙蝠感染率分别为50.0% (22/44)、61.7% (29/47)、62.1% (18/29)和55.7% (103/185)。中菊头蝠(Rhinolophus affinis)、小菊头蝠(R. blythi)和棕果蝠(Rousettus leschenaultii)的感染率分别为50.0% (22/44)、62.1% (18/29)和56.9% (132/232), 差异没有统计学意义(χ² = 1.135, P = 0.567), 表明巴尔通体在云南当地的蝙蝠种群中高度流行。定量PCR扩增产物2次扩增后测序获得37个巴尔通体ssrA序列, 属于10个系统发育分支, 其中1个为伊丽莎白巴尔通体(B. elizabethae)、特利波契巴尔通体(B. tribocorum)和克拉斯诺夫巴尔通体(B. krasnovii)的近缘种。其余序列与已知巴尔通体距离较远, 与亚洲、欧洲和美洲等其他地域来源于蝙蝠的巴尔通体近缘。遗传多样性分析显示, ssrA基因的核苷酸多样性指数(π)为0.11381 ± 0.00928, 基因型多样性指数(Hd)为0.985 ± 0.010, 形成29个基因型(单倍型), 说明云南蝙蝠巴尔通体具有丰富的遗传多样性。通过对本研究标本与全球相关序列的系统发育网络重建, 分析全球蝙蝠巴尔通体的地理和宿主分布特征, 可以看出巴尔通体与蝙蝠之间存在显著的宿主特异性关联。因此可初步确定蝙蝠-巴尔通体具有协同进化特征, 同时受到地理隔离的影响。     

A target protease activity of serpins in insect hemolymph

Two zymogens of the serine enzymes (prophenoloxidase activating enzyme and BAEEase, an enzyme hydrolyzing ethyl ester), which are thought to be components of prophenoloxidase cascade in silkworm (Bombyx mori) plasma, were activated through the action of microbial cell wall components. The two active enzymes of the zymogens were studied with regard to the regulation of their activities by two endogenous serpins (silkworm anti-trypsin and silkworm anti-chymotrypsin).

BAEEase activity was shown to be inactivated by silkworm antitrypsin, whereas the inactivation of prophenoloxidase activating enzyme by either of silkworm antitrypsin and silkworm antichymotrypsin could not be demonstrated under the experimental conditions.     

Microsatellite markers application on domesticated silkworm and wild silkworm

Abstract Twenty-seven sets of simple sequence repeat (SSR) primers were developed through hybridizing of (CA)n, (CT)n and (GT)n and sequencing the positive clones in libraries constructed by using p50 silkworm strain. Of those primer pairs, 26 sets of SSR primers amplified well in two regional wild silkworm strains. Ten domesticated silkworm strains and two regional wild silkworm strains were used for comparing the polymorphisms and for constructing a phylogenetic tree employing the UPGAM method. The result showed that the genetic distances within Japanese strains are closer than those of Chinese strains. And this result also implies that Japanese strains diverged from domesticated silkworm later than Chinese strains. According to the clustering result, the domesticated silkworm is firstly clustered in one class, but could be classified into two groups. Within a strain, the individual polymorphism of wild silkworm was significantly higher in abundance than those of domesticated silkworm. The S SR primers of domesticated silkworm could be used in genetic studies for wild silkworm.     

Biochemical studies of amylases in the silkworm, Bombyx mori L.: Comparative analysis in diapausing and nondiapausing strains

Different amylase enzymes were identified by analysis of digestive fluid and haemolymph in diapausing and nondiapausing strains of silkworm, Bombyx mori. The diapausing strain showed negligible digestive amylase activity at a pH range of 3–11, while the nondiapausing strain registered strikingly higher amylase activity at pH 9.2. Higher levels of undigested starch was found in the faecal matter of the diapausing strain, which is consistent with the negligible digestive amylase activity. Development specific expression of haemolymph amylase activity was seen in nondiapausing and diapausing strains. In the nondiapausing strain the digestive amylase activity was at its peak during intermoult and depressed during moult. PAGE analysis revealed the occurrence of only anodal digestive and haemolymph amylases in the diapausing strain, whereas both cathodal and anodal enzymes were seen in the digestive fluid and haemolymph of the nondiapausing strain.     

球孢白僵菌种群在松林中的寄主转移及遗传多样性对松毛虫持续控制的影响

通过林间接种式放菌及其后一周年的野外调查,从林间采集到30种寄主昆虫及从土壤、落叶和气流中分离到119株球孢白僵菌.酯酶同工酶分析表明,它们属于32个不同酯酶型,呈现出丰富的遗传多样性.释放菌株所属的酯酶型02包括从11种昆虫上分离出的18个菌株,表明林间释放的菌株已成功地在不同寄主昆虫种群中宿存下来,并以常发的地方病状态存在于松毛虫及松灰象甲等12种昆虫种群之中;当林间目标寄主缺乏时,其它寄主可将食物链维系下去.其它酯酶型分别包括1～23个菌株.一周年内的寄主转移动态结果表明,球孢白僵菌在松林生态系统中不同寄主间可转移寄生.每个酯酶型中的菌株对松毛虫的毒力相差很大.表明球孢白僵菌在松林中的延续和扩散流行不是1条路线,每个酯酶型至少代表食物网上的1条支链.有些环节的寄主连接了不同的酯酶型,使松林中食物网变得十分复杂.另外,从土壤、枯枝落叶层、林冠层和空气中分离到的球孢白僵菌分属于不同的酯酶型,表明松林中还存在着复杂的腐生食物链,有利于松毛虫及其它害虫的持续控制.