Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS_(S) and MS_(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants.

枯草芽孢杆菌EA-CB0575是一种与香蕉和番茄作物相关的植物生长细菌（PGPB）。根定殖是PGPB微生物的重要特征，其增强与植物生长促进机制有关的细菌作用。因此，在植物与微生物相互作用的研究中，检测不同培养系统中根部的细菌定植很重要。在这项研究中，评估了荧光原位杂交（FISH）和催化的报道分子沉积-FISH（CARD–FISH），以确定枯草芽孢杆菌EA-CB0575对固液和液态Murashige和Skoog培养基上种植的香蕉和番茄根的定殖能力。（MS _（S）和MS _（L））和在土壤中种植番茄。结果显示，在不同培养系统中，香蕉和番茄植株在接种后0-30天会发生枯草芽孢杆菌定植，细菌细胞沿番茄和香蕉根的分布不同。FISH和CARD–FISH方法均成功检测到枯草芽孢杆菌菌落，但由于其增强的荧光信号，CARD–FISH被证明具有优越性。细菌的存在与两种植物物种中植物生长的促进有关，为根际定植与植物生长的改善提供了线索。FISH和CARD–FISH分析结果表明，在体外香蕉植株的根部存在天然菌群，而在番茄植株的根部则没有。