Singh Rajnish Prakash, Jha Prameela, Jha Prabhat Nath
Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani 333031, Rajasthan, India.
Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani 333031, Rajasthan, India.
J Plant Physiol. 2015 Jul 20;184:57-67. doi: 10.1016/j.jplph.2015.07.002. Epub 2015 Jul 14.
Plant-growth-promoting bacteria (PGPB) with 1-aminocyclopropane-1-carboxylatedeaminase (ACCD) activity can protect plants from the deleterious effects of abioticstressors. An ACCD bacterial strain, SBP-8, identified as Klebsiella sp., also having other plant-growth-promoting activities, was isolated from Sorghum bicolor growing in the desertregion of Rajasthan, India. ACCD activity of SBP-8 was characterized at biochemical, physiological, and molecular levels. The presence of AcdS, a structural gene for ACCD, was confirmed by the polymerase chain reaction. Strain SBP-8 showed optimum growth and ACCD activity at increased salt (NaCl) concentrations of up to 6%, indicating its potential to survive and associate with plants growing in saline soil. Inoculation of wheat plants with SBP-8 when grow in the presence of salt (150-200 mM) and temperature (30-40 °C) stressors resulted inamelioration of stress conditions by increasing plant biomass and chlorophyll content, and are duction in plant growth inhibition (10-100%) occurred due to salt and temperature stressors. Moreover, strain SBP-8 also caused Na(+) exclusion (65%) and increased uptake of K(+) (84.21%) in the host plant. This property can protect plants from adverse effects of Na(+) on plant growth and physiology. Thus, SBP-8 improves growth of the host plant and protects from salt stressors through more than one mechanism including an effect of ACCD activity and on K(+)/Na(+) ratio in plants. The colonization efficiency of strain SBP-8 was confirmedby CFU (colony-forming unit) count, microscopy, and ERIC-PCR based DNA-finger-printing approach. Therefore, and the use of efficient colonizing plant-growth-promoting bacteria may provideinsights into possible biotechnological approaches to decrease the impact of salinity and other stressors.
具有1-氨基环丙烷-1-羧酸脱氨酶(ACCD)活性的植物促植物促生细菌(PGPB)可保护植物免受非生物胁迫的有害影响。从印度拉贾斯坦邦沙漠地区生长的双色高粱中分离出一株ACCD细菌菌株SBP-8,鉴定为克雷伯氏菌属,它还具有其他植物促生活性。在生化、生理和分子水平上对SBP-8的ACCD活性进行了表征。通过聚合酶链反应确认了ACCD结构基因AcdS的存在。菌株SBP-8在高达6%的盐(NaCl)浓度增加时表现出最佳生长和ACCD活性,表明其有在盐渍土壤中生长的植物上存活并与之共生的潜力。当小麦植株在盐(150 - 200 mM)和温度(30 - 40°C)胁迫条件下生长时,接种SBP-8可通过增加植物生物量和叶绿素含量来改善胁迫条件,并且盐和温度胁迫导致的植物生长抑制(10 - 100%)有所降低。此外,菌株SBP-8还导致宿主植物中Na(+)的排出(65%)和K(+)吸收的增加(84.21%)。这种特性可以保护植物免受Na(+)对植物生长和生理的不利影响。因此,SBP-8通过多种机制改善宿主植物的生长并保护其免受盐胁迫,包括ACCD活性的作用以及对植物中K(+)/Na(+)比率的影响。通过CFU(菌落形成单位)计数、显微镜观察和基于ERIC-PCR的DNA指纹图谱方法证实了菌株SBP-8的定殖效率。因此,使用高效定殖的植物促生细菌可能为减少盐度和其他胁迫影响的生物技术方法提供思路。