Karthik Chinnannan, Oves Mohammad, Thangabalu R, Sharma Ranandkumar, Santhosh S B, Indra Arulselvi P
Department of Biotechnology, School of Biosciences, Periyar University, Periyar Palkalai Nagar, Salem 636 011, Tamil Nadu, India.
Center of Excellence in Environmental Studies (CEES), King Abdulaziz University, Jeddah 21589, Saudi Arabia.
J Adv Res. 2016 Nov;7(6):839-50. doi: 10.1016/j.jare.2016.08.007. Epub 2016 Sep 4.
Contamination of agriculture land by heavy metals is a worldwide risk that has sped up noticeably since the beginning of the industrial revolution. Hence, there arise the demands of heavy metal tolerant plant growth promoting bacterial strains for specific metal contaminated agricultural sites restoration. In this study, 36 bacterial isolates were screened out from the rhizospheric soil of Phaseolus vulgaris. Among these, two bacterial strains AR6 and AR8 were selected based on their higher Cr(VI) tolerance (1200 and 1100 μg/mL, respectively) and the maximum production of plant growth promoting substances. In the molecular characterization study, both the bacterial strains showed 99% homology with Cellulosimicrobium funkei KM032184. In greenhouse experiments, the exposure of Cr(VI) to P.vulgaris inhibited the growth and photosynthetic pigments and increased the enzymatic and non-enzymatic antioxidant expressions. However, rhizosphere bacterial inoculations alleviated the negative effect of Cr(VI) and enhanced the seed germination rate (89.54%), shoot (74.50%),root length (60%), total biomass (52.53%), chlorophyll a (15.91%), chlorophyll b (17.97%), total chlorophyll (16.58%) and carotenoid content (3.59%). Moreover, bacterial inoculations stabilized and modulated the antioxidant system of P. vulgaris by reducing the accumulation of Cr in plant tissues. The present finding shows the Cr(VI) tolerance and plant growth promoting properties of the rhizosphere bacterial strains which might make them eligible as biofertilizer of metal-contaminated soils.
自工业革命开始以来,重金属对农业土地的污染已成为一个全球性风险,且污染速度明显加快。因此,对于用于特定金属污染农田修复的耐重金属促植物生长细菌菌株的需求应运而生。在本研究中,从菜豆根际土壤中筛选出36株细菌分离株。其中,基于它们对Cr(VI)的较高耐受性(分别为1200和1100μg/mL)以及促植物生长物质的最大产量,选择了两株细菌菌株AR6和AR8。在分子特征研究中,这两株细菌菌株与弗氏纤维微菌KM032184均显示出99%的同源性。在温室实验中,将Cr(VI)施加于菜豆会抑制其生长和光合色素,并增加酶促和非酶促抗氧化剂的表达。然而,根际细菌接种减轻了Cr(VI)的负面影响,并提高了种子发芽率(89.54%)、地上部(74.50%)、根长(60%)、总生物量(52.53%)、叶绿素a(15.91%)、叶绿素b(17.97%)、总叶绿素(16.58%)和类胡萝卜素含量(3.59%)。此外,细菌接种通过减少植物组织中Cr的积累,稳定并调节了菜豆的抗氧化系统。目前的研究结果表明了根际细菌菌株对Cr(VI)的耐受性和促植物生长特性,这可能使它们有资格作为金属污染土壤的生物肥料。