Karthika S, Midhun Sebastian Jose, Jisha M S
School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
School of Biosciences, Mahatma Gandhi University, Kottayam, Kerala, 686560, India.
Microb Pathog. 2020 May;142:104049. doi: 10.1016/j.micpath.2020.104049. Epub 2020 Feb 8.
Plant growth-promoting rhizobacteria are indigenous beneficial bacteria that will enhance plant growth as well as suppress phytopathogens. In the present study, the isolate KTMA4 showed the highest inhibition against major phytopathogens of tomato; Fusarium oxysporum (66%) and Alternaria solani (54%) after seven days of incubation. Analysis of the 16S rRNA gene sequence revealed that the isolate KTMA4 is Bacillus cereus (MG547975). The isolate produced in vitro plants growth-promoting factors such as Indole-3-acetic acid, ammonia, catalase, siderophore and 1-aminocyclopropane-1-carboxylate deaminase and it has nitrogen fixation ability. The bacterial strain has also produced lytic enzymes such as amylase, cellulase, xylanase, lipase, and protease. Moreover, the bacterium Bacillus cereus KTMA4 effectively produced biofilm, biosurfactants and salt-tolerant (5% NaCl). The bacterium exhibited intrinsic antibiotic resistance. The in vivo studies using tomato plants grown from seeds treated with the bacterial strain KTMA4 demonstrated an enhancement in seed germination percentage (86.66 ± 2.88) and vigour index (637.5 ± 21.65) over the uninoculated control (germination percentage- 28.33 ± 2.88 and vigour index- 42.5 ± 4.33). 60 days of greenhouse study revealed that the bacterial isolate enhanced the plant growth significantly (P ≤ 0.05) compared to the uninoculated control and the treated plants. Therefore the study suggests that the newly isolated rhizosphere bacterial strain can be used as a potential biocontrol agent against a multitude of fungal pathogens as well as a biofertilizer inoculant for tomato cultivation.
植物促生根际细菌是一类本地有益细菌，可促进植物生长并抑制植物病原体。在本研究中，分离株KTMA4对番茄的主要植物病原体表现出最高的抑制作用；培养7天后，对尖孢镰刀菌（66%）和链格孢菌（54%）的抑制率最高。16S rRNA基因序列分析表明，分离株KTMA4为蜡样芽孢杆菌（MG547975）。该分离株在体外产生了促进植物生长的因子，如吲哚-3-乙酸、氨、过氧化氢酶、铁载体和1-氨基环丙烷-1-羧酸脱氨酶，并且具有固氮能力。该细菌菌株还产生了淀粉酶、纤维素酶、木聚糖酶、脂肪酶和蛋白酶等裂解酶。此外，蜡样芽孢杆菌KTMA4能有效产生生物膜、生物表面活性剂且耐盐（5%氯化钠）。该细菌表现出内在的抗生素抗性。使用经细菌菌株KTMA4处理的种子培育的番茄植株进行的体内研究表明，与未接种的对照相比，种子发芽率（86.66±2.88）和活力指数（637.5±21.65）有所提高（未接种对照的发芽率为28.33±2.88，活力指数为42.5±4.33）。60天的温室研究表明，与未接种的对照和处理过的植株相比，该细菌分离株显著促进了植物生长（P≤0.05）。因此，该研究表明，新分离的根际细菌菌株可作为一种潜在的生物防治剂，用于对抗多种真菌病原体，也可作为番茄种植的生物肥料接种剂。
