Lee Kyung Dong, Gray Elizabeth J, Mabood Fazli, Jung Woo-Jin, Charles Trevor, Clark Scott R D, Ly Anh, Souleimanov Alfred, Zhou Xiaomin, Smith Donald Lawrence
Department of Oriental Medicine Materials, Dongshin University, 252 Daeho-dong, Naju, Jeonnam, 520-714, South Korea.
Planta. 2009 Mar;229(4):747-55. doi: 10.1007/s00425-008-0870-6. Epub 2008 Dec 13.
The mechanisms by which many plant growth promoting rhizobacteria (PGPR) affect plants are unknown. We recently isolated a rhizosphere bacterium (Bacillus thuringiensis NEB17), that promotes soybean growth and screened the liquid growth medium in which it grew for plant growth stimulating materials. We have also shown that it produces a bacteriocin (named by us as thuricin-17 and a member of the recently described class IId bacteriocins). Here we show that application of this bacteriocin to leaves (spray) or roots (drench) directly stimulates the growth of both a C(3) dicot (soybean) and a C(4) monocot (corn). This growth stimulation is similar in nature to that previously seen when plants are treated with Nod factors. Strain NEB17 contains three copies of the gene for thuricin 17 that code for identical amino acid sequences. These two lines of evidence suggest that the dual functions of these proteins may have constrained their evolution. This is the first report of direct plant growth enhancement by a bacteriocin.
许多植物促生根际细菌（PGPR）影响植物的机制尚不清楚。我们最近分离出一种促进大豆生长的根际细菌（苏云金芽孢杆菌NEB17），并对其生长的液体培养基进行筛选以寻找植物生长刺激物质。我们还表明它能产生一种细菌素（我们将其命名为thuricin-17，是最近描述的II类d细菌素的成员）。在此我们表明，将这种细菌素施用于叶片（喷雾）或根部（浇灌）可直接刺激C3双子叶植物（大豆）和C4单子叶植物（玉米）的生长。这种生长刺激本质上类似于植物用根瘤因子处理时先前观察到的情况。菌株NEB17含有thuricin 17基因的三个拷贝，这些拷贝编码相同的氨基酸序列。这两条证据表明这些蛋白质的双重功能可能限制了它们的进化。这是关于细菌素直接促进植物生长的首次报道。
