Physiological and antioxidant responses of Medicago sativa-rhizobia symbiosis to cyanobacterial toxins (Microcystins) exposure
Physiological and antioxidant responses of Medicago sativa-rhizobia symbiosis to cyanobacterial toxins (Microcystins) exposure
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DOI：
10.1016/j.toxicon.2013.10.003
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发表时间：
2013-12-15
期刊：
影响因子：
2.8
通讯作者：
Oudra, Brahim
中科院分区：
文献类型：
--
作者：
El Khalloufi, Fatima;Oufdou, Khalid;Oudra, Brahim
淡水中的有毒蓝藻会对受污染的水灌溉的植物的生长发育产生强烈的有害影响。本研究通过生物量、光合色素和抗氧化酶：过氧化物酶（POD）、多酚氧化酶（PPO）和过氧化氢酶（CAT）分析，研究了含微囊藻毒素（MC）的蓝藻提取物对紫花苜蓿-根瘤菌共生的影响。以紫花苜蓿为材料，接种两种内共生根瘤菌RhOL1 （MC不敏感菌株）和RhOL3 （MC较敏感菌株），研究了在蓝藻毒素胁迫下，根瘤菌对植物生长反应的影响。通过对两株根瘤菌的rrs和atpD基因序列分析，鉴定为meliloti Ensifer。在两种共生培养中，长期暴露于MC提取物均导致茎、根和根瘤干重下降。接种RhOL3后植株的下降速率高于与RhOL1共生的植株，主要在MC浓度为20 μ g -1时，蓝藻毒素还降低了光合色素含量，并在细胞水平上产生了氧化应激。MC处理后的紫花苜蓿叶片、根系和根瘤中POD、PPO和CAT活性均显著升高，且在接种RhOL3处理后，这些酶活性均较高，特别是在MC浓度为20 μ g L-1的情况下。研究了油菜与微囊藻毒素的关系，以便以后建议在作物暴露于MC污染的水灌溉时可能使用这些共生面。(C) 2013 Elsevier Ltd.版权所有。
Toxic cyanobacteria in freshwaters can induce potent harmful effects on growth and development of plants irrigated with contaminated water. In this study, the effect of cyanobacteria extract containing Microcystins (MC) on Medicago sativa-rhizobia symbiosis was investigated in order to explore plants response through biomass production, photosynthetic pigment and antioxidant enzymes analysis: Peroxidase (POD), Polyphenoloxidase (PPO) and Catalase (CAT). Alfalfa plants were inoculated with two endosymbiotic rhizobial strains: RhOL1 (MC less sensitive strain) and RhOL3 (MC more sensitive strain), to evaluate the rhizobial contribution on the plant response cultured under cyanobacterial toxins stress. The two rhizobia strains were identified as Ensifer meliloti by sequence analysis of their rrs and atpD genes. The chronic exposure to MC extract showed shoot, root and nodules dry weight decrease, in both symbiosis cultures. The rate of decline in plants inoculated with RhOL3 was higher than that in symbiosis with RhOL1 mainly at 20 mu g L-1 of MC. Cyanotoxins also reduced photosynthetic pigment content and generated an oxidative stress observed at cellular level. POD, PPO and CAT activities were significantly increased in leaves, roots and nodules of alfalfa plants exposed to MC. These enzyme activities were higher in plants inoculated with RhOL3 especially when alfalfa plants were exposed to 20 mu g L-1 of MC. The present paper reports new scientific finding related to the behavior of rhizobia-M. sativa associations to MC (Microcystins) for later recommendation concerning the possible use of these symbiosis face to crops exposure to MC contaminated water irrigation. (C) 2013 Elsevier Ltd. All rights reserved.