Nithya Angamuthu, Babu Subramanian
School of Bio Sciences and Technology, VIT University, Vellore, 632014, India.
BMC Microbiol. 2017 Mar 14;17(1):64. doi: 10.1186/s12866-017-0974-x.
The study aimed at enumerating, identifying and categorizing the endophytic cultivable bacterial community in selected salad vegetables (carrot, cucumber, tomato and onion). Vegetable samples were collected from markets of two vegetable hot spot growing areas, during two different crop harvest seasons. Crude and diluted vegetable extracts were plated and the population of endophytic bacteria was assessed based on morphologically distinguishable colonies. The bacterial isolates were identified by growth in selective media, biochemical tests and 16S rRNA gene sequencing.
The endophytic population was found to be comparably higher in cucumber and tomato in both of the sampling locations, whereas lower in carrot and onion. Bacterial isolates belonged to 5 classes covering 46 distinct species belonging to 19 genera. Human opportunistic pathogens were predominant in carrot and onion, whereas plant beneficial bacteria dominated in cucumber and tomato. Out of the 104 isolates, 16.25% are human pathogens and 26.5% are human opportunistic pathogens.
Existence of a high population of plant beneficial bacteria was found to have suppressed the population of plant and human pathogens. There is a greater potential to study the native endophytic plant beneficial bacteria for developing them as biocontrol agents against human pathogens that are harboured by plants.
本研究旨在对选定的沙拉蔬菜（胡萝卜、黄瓜、番茄和洋葱）中的内生可培养细菌群落进行计数、鉴定和分类。在两个不同的作物收获季节，从两个蔬菜种植热点地区的市场采集蔬菜样本。将粗提和稀释后的蔬菜提取物进行平板接种，并根据形态上可区分的菌落评估内生细菌的数量。通过在选择性培养基中生长、生化试验和16S rRNA基因测序对细菌分离株进行鉴定。
在两个采样地点，黄瓜和番茄中的内生细菌数量相对较高，而胡萝卜和洋葱中的数量较低。细菌分离株属于5个类群，涵盖19个属的46个不同物种。人类机会致病菌在胡萝卜和洋葱中占主导地位，而植物有益细菌在黄瓜和番茄中占主导地位。在104株分离株中，16.25%是人类病原菌，26.5%是人类机会致病菌。
发现大量植物有益细菌的存在抑制了植物和人类病原菌的数量。研究天然内生植物有益细菌以将其开发为对抗植物携带的人类病原菌的生物防治剂具有更大的潜力。
