苏云金芽胞杆菌幕虫亚种晶胞粘连现象与晶体蛋白基因cry26 Aa所在质粒有关

The plasmid harboring cry26 Aa may contribute to the phenomenon of spore-crystal connection in Bacillus thuringiensis subsp. finitimus

苏云金芽胞杆菌幕虫亚种T02菌株的伴胞晶体在芽胞外壁内侧形成,呈现晶胞粘连的现象。在此菌株中克隆了cry26 Aa和cry28 Aa两个基因,并对晶胞粘连现象与质粒的相关性做了系统研究。通过消除幕虫亚种T02菌株的质粒,得到了仅消除cry26 Aa所在质粒的菌株BMB1151和无质粒的菌株BMB1152。通过穿梭载体将cry26 Aa和cry28 Aa两个基因分别和同时转化无质粒突变株BMB1152并表达,形成的晶体与芽胞独立存在不能粘连,表明在幕虫亚种染色体背景下仅仅cry的表达不能形成晶胞粘连现象,从而推断晶胞粘连现象可能与幕虫亚种两个基因所在的质粒有关;进一步的研究发现将cry26 Aa在仅消除cry26 Aa所在质粒的突变株BMB1151中表达,形成的晶体与芽胞也分别独立存在不能粘连,从而进一步推断幕虫亚种晶胞粘连现象与cry26 Aa所在质粒有关。

Parasporal crystal in B. thuringiensis subsp, finitimus T02 forms inside the exosporium and remains attached to the spore after mother cell lysis. Two crystal protein gene cry26Aα and cry28Aα were cloned from this strain. The relationship between the phenomenon of spore-crystal connection and the plasmids was investigated in this work. Mutants BMB1151 curing of the plasmid harboring cry26Aα, and BMB1152 curing of all plasmids were obtained from B. thuringiensis subsp, finitimus T02.The spore-crystal connection didn＇t appeared when cry26Aα and cry28Aα were transformed back into the strain BMB1152 by shuffle vector alone or in combination together. It suggested the plasmids of B. thuringiensis subsp, finitimus T02 may contribute to the phenomenon. When gene cry26Aα was transformed back into in the strain BMB1151, spore-crystal connection didn＇t form either. So the plasmid harboring cry26Aα may also contribute to the phenomenon of spore-crystal connection in B. thuringiensis subsp, finitimus TO2.