Division of labour and terminal differentiation in a novel Bacillus thuringiensis strain
Division of labour and terminal differentiation in a novel Bacillus thuringiensis strain
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苏云金芽孢杆菌新菌株的分工和终末分化
DOI：
10.1038/ismej.2014.122
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发表时间：
2015-02-01
期刊：
影响因子：
11
通讯作者：
Song, Fuping
中科院分区：
文献类型：
--
作者：
Deng, Chao;Slamti, Leyla;Song, Fuping
细菌发育生物学中的一个主要挑战是理解细胞命运决定的潜在机制。一些分化的细胞类型表现出合作行为。合作是进化生物学最大的谜团之一，微生物被认为是实验验证进化理论的极佳体系。苏云金芽孢杆菌（Bt）是一种产芽孢细菌，它在基因上与炭疽杆菌（炭疽的病原体）以及蜡样芽孢杆菌（一种机会性人类病原体）密切相关。将苏云金芽孢杆菌与其亲缘菌区分开来的决定性特征是它在产孢细胞中产生晶体包涵体的能力。这些毒素在被摄入后溶解，在昆虫宿主体内是合作性的公共物品。在这项研究中，我们描述了一种苏云金芽孢杆菌菌株LM1212，它具有最终分化为晶体产生菌和芽孢形成菌的独特能力。基于lacZ和gfp报告基因的转录分析表明，这种表型是一种新型细胞分化的结果，这种分化与一种新的cry基因表达调控模式相关。分化的晶体产生表型比典型的苏云金芽孢杆菌菌株具有更高的芽孢生产率，并且更能与Cry毒素缺失的“作弊者”竞争。这种劳动分工可能在芽孢活力或Cry毒素的持久性方面提供额外的适应性优势。
A major challenge in bacterial developmental biology has been to understand the mechanisms underlying cell fate decisions. Some differentiated cell types display cooperative behaviour. Cooperation is one of the greatest mysteries of evolutionary biology and microbes have been considered as an excellent system for experimentally testing evolution theories. Bacillus thuringiensis (Bt) is a spore-forming bacterium, which is genetically closely related to B. anthracis, the agent of anthrax, and to B. cereus, an opportunistic human pathogen. The defining feature that distinguishes Bt from its relatives is its ability to produce crystal inclusions in the sporulating cells. These toxins are solubilized after ingestion and are cooperative public goods in insect hosts. In this study, we describe a Bt strain LM1212 that presents the unique ability to terminally differentiate into crystal producers and spore formers. Transcriptional analysis based on lacZ and gfp reporter genes suggested that this phenotype is the consequence of a new type of cell differentiation associated with a novel regulation mode of cry gene expression. The differentiating crystal-producer phenotype has higher spore productivity than a typical Bt strain and is better able to compete with Cry toxin null ‘cheaters’. Potentially, this division of labour provides additional fitness benefits in terms of spore viability or durability of Cry toxin.