Kang S-M, Radhakrishnan R, You Y-H, Khan A-L, Lee K-E, Lee J-D, Lee I-J
School of Applied Biosciences, Kyungpook National University, Daegu, Korea.
Korean Agricultural Culture Collection, Agricultural Microbiology Division, National Academy of Agricultural Science, RDA, Daegu, Korea.
Plant Biol (Stuttg). 2015 Sep;17(5):1013-22. doi: 10.1111/plb.12341. Epub 2015 Jul 14.
This study aimed to elucidate the role played by Enterobacter asburiae KE17 in the growth and metabolism of soybeans during copper (100 μm Cu) and zinc (100 μm Zn) toxicity. When compared to controls, plants grown under Cu and Zn stress exhibited significantly lower growth rates, but inoculation with E. asburiae KE17 increased growth rates of stressed plants. The concentrations of plant hormones (abscisic acid and salicylic acid) and rates of lipid peroxidation were higher in plants under heavy metal stress, while total chlorophyll, carotenoid content and total polyphenol concentration were lower. While the bacterial treatment reduced the abscisic acid and salicylic acid content and lipid peroxidation rate of Cu-stressed plants, it also increased the concentration of photosynthetic pigments and total polyphenol. Moreover, the heavy metals induced increased accumulation of free amino acids such as aspartic acid, threonine, serine, glycine, alanine, leucine, isoleucine, tyrosine, proline and gamma-aminobutyric acid, while E. asburiae KE17 significantly reduced concentrations of free amino acids in metal-affected plants. Co-treatment with E. asburiae KE17 regulated nutrient uptake by enhancing nitrogen content and inhibiting Cu and Zn accumulation in soybean plants. The results of this study suggest that E. asburiae KE17 mitigates the effects of Cu and Zn stress by reprogramming plant metabolic processes.
本研究旨在阐明阿氏肠杆菌KE17在铜（100 μM铜）和锌（100 μM锌）毒性作用下对大豆生长和代谢所起的作用。与对照相比，在铜和锌胁迫下生长的植物生长速率显著降低，但接种阿氏肠杆菌KE17提高了受胁迫植物的生长速率。重金属胁迫下植物的植物激素（脱落酸和水杨酸）浓度及脂质过氧化率较高，而总叶绿素、类胡萝卜素含量和总多酚浓度较低。细菌处理降低了铜胁迫植物的脱落酸和水杨酸含量以及脂质过氧化率，同时还提高了光合色素和总多酚的浓度。此外，重金属诱导了天冬氨酸、苏氨酸、丝氨酸、甘氨酸、丙氨酸、亮氨酸、异亮氨酸、酪氨酸、脯氨酸和γ-氨基丁酸等游离氨基酸的积累增加，而阿氏肠杆菌KE17显著降低了受金属影响植物中游离氨基酸的浓度。与阿氏肠杆菌KE17共同处理通过提高氮含量和抑制大豆植株中铜和锌的积累来调节养分吸收。本研究结果表明，阿氏肠杆菌KE17通过重新编程植物代谢过程减轻了铜和锌胁迫的影响。
