The beneficial features of Bacillus thuringiensis (Bt) are not limited to its role as an insecticide; it is also able to promote plant growth interacting with plants and other plant growth-promoting rhizobacterium (PGPR). The PGPR Bt strain RZ2MS9 is a multi-trait maize growth promoter. We obtained a stable mutant of RZ2MS9 labelled with green fluorescent protein (RZ2MS9-GFP). We demonstrated that the Bt RZ2MS9-GFP successfully colonizes maize's roots and leaves endophytically. We evaluated whether RZ2MS9 has an additive effect on plant growth promotion when co-inoculated with Azospirillum brasilense Ab-V5. The two strains combined enhanced maize's roots and shoots dry weight around 50% and 80%, respectively, when compared to the non-inoculated control. However, non-differences were observed comparing RZ2MS9 alone and when co-inoculated with Ab-V5, In addition, we used co-inoculation experiments in glass chambers to analyse the plant's volatile organic compounds (VOCs) production during the maize-RZ2MS9 and maize-RZ2MS9-Ab-V5 interaction. We found that the single and co-inoculation altered maize's VOCs emission profile, with an increase in the production of indoles in the co-inoculation. Collectively, these results increase our knowledge about the interaction between the Bt and maize, and provide a new possibility of combined application with the commercial inoculant A. brasilense Ab-V5.

中文翻译：

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苏云金芽孢杆菌 RZ2MS9 是一种促进植物生长的热带根际细菌，在与 Azospirillum brasilense Ab-V5 共接种期间内生定殖玉米并改变植物挥发性有机化合物的产生

苏云金芽孢杆菌( Bt )的有益特性不仅限于其作为杀虫剂的作用；它还能够促进与植物和其他植物生长促进根际细菌 (PGPR) 相互作用的植物生长。PGPR Bt菌株 RZ2MS9 是一种多性状玉米生长促进剂。我们获得了一个用绿色荧光蛋白（RZ2MS9-GFP）标记的稳定的RZ2MS9突变体。我们证明了Bt RZ2MS9-GFP 成功地定殖玉米的根和叶内生。我们评估了当与Azospirillum brasilense共接种时 RZ2MS9 是否对植物生长促进具有累加作用抗体-V5。与未接种的对照相比，这两种菌株分别增强了玉米的根和芽干重约 50% 和 80%。然而，观察到单独的 RZ2MS9 和与 Ab-V5 共同接种时的无差异。此外，我们在玻璃室中使用共同接种实验来分析玉米-RZ2MS9 和玉米期间植物的挥发性有机化合物 (VOC) 产生-RZ2MS9-Ab-V5 相互作用。我们发现单次接种和联合接种改变了玉米的 VOCs 排放曲线，同时联合接种中吲哚的产生增加。总的来说，这些结果增加了我们对Bt与玉米相互作用的认识，并为与商业接种剂A. brasilense联合应用提供了新的可能性抗体-V5。