The ecology of Bacillus thuringiensis on the phylloplane:: Colonization from soil, plasmid transfer, and interaction with larvae of Pieris brassicae
The ecology of Bacillus thuringiensis on the phylloplane:: Colonization from soil, plasmid transfer, and interaction with larvae of Pieris brassicae
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DOI：
10.1007/s00248-007-9331-1
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发表时间：
2008-07-01
影响因子：
3.6
通讯作者：
Bishop, A. H.
中科院分区：
文献类型：
--
作者：
Bizzarri, M. F.;Bishop, A. H.
将苏云金芽孢杆菌孢子与种子共接种于土壤中，在三叶草幼苗中定殖。从三叶草叶面分离的营养体形式的菌株2810-S-4和实验室菌株HD-1都能够定殖三叶草，当种子播种在无菌土壤中时，定殖密度为约1000 CFU/g叶，而在非无菌土壤中，定殖密度为约300 CFU/g叶。缺乏特征性杀虫晶体蛋白的菌株在5周的时间内产生与野生型菌株相似的定殖水平，表明晶体产生不是定殖期间的缓解因素。将小质粒pBC 16在B菌株之间转移。将供体和受体菌株以营养体形式喷洒在三叶草和小白菜（Brassica campestris var. chinensis）。转移率约为0.1 transconjugants/受体，并依赖于植物的种类。B水平。苏云金杆菌在小白菜叶片上的自然定殖对以植物为食的菜粉蝶的三龄幼虫产生可忽略不计的死亡率。相当大的增殖发生在排泄的粪便，但不是在活昆虫的肠道。粪便中的孢子可能是土壤中的细菌化的来源，并转移到其他植物中。这些发现说明了一个可能的循环，不依赖于昆虫病理学，其中B。苏云金杆菌在自然界中多样化并维持自身。
Seedlings of clover (Triflorium hybridum) were colonized by Bacillus thuringiensis when spores and seeds were co-inoculated into soil. Both a strain isolated in the vegetative form from the phylloplane of clover, 2810-S-4, and a laboratory strain, HD-1, were able to colonize clover to a density of about 1000 CFU/g leaf when seeds were sown in sterile soil and to a density of about 300 CFU/g leaf in nonsterile soil. A strain lacking the characteristic insecticidal crystal proteins produced a similar level of colonization over a 5-week period as the wild type strain, indicating that crystal production was not a mitigating factor during colonization. A small plasmid, pBC16, was transferred between strains of B. thuringiensis when donor and recipient strains were sprayed in vegetative form onto leaves of clover and pak choi (Brassica campestris var. chinensis). The rate of transfer was about 0.1 transconjugants/recipient and was dependent on the plant species. The levels of B. thuringiensis that naturally colonized leaves of pak choi produced negligible levels of mortality in third instar larvae of Pieris brassicae feeding on the plants. Considerable multiplication occurred in the excreted frass but not in the guts of living insects. Spores in the frass could be a source of recolonization from the soil and be transferred to other plants. These findings illustrate a possible cycle, not dependent on insect pathology, by which B. thuringiensis diversifies and maintains itself in nature.