Bhattacharyya Dipto, Lee Yong Hoon
Division of Biotechnology, Chonbuk National University, 79 Gobong-ro, Iksan-si, Jeollabuk-do 54596, Republic of Korea.
Division of Biotechnology, Chonbuk National University, 79 Gobong-ro, Iksan-si, Jeollabuk-do 54596, Republic of Korea; Advanced Institute of Environment and Bioscience, Plant Medical Research Center, and Institute of Bio-industry, Chonbuk National University, Republic of Korea.
J Plant Physiol. 2017 Jul;214:64-73. doi: 10.1016/j.jplph.2017.04.002. Epub 2017 Apr 12.
In our previous study we showed that volatile organic compounds (VOCs) from Alcaligenes faecalis JBCS1294 (JBCS1294) induced tolerance to salt stress in Arabidopsis thaliana by influencing the auxin and gibberellin pathways and upregulating the expression of key ion transporters. The aim of this study was to evaluate the contribution of each VOC and blends of the VOCs on the induction of salt tolerance and signaling pathways. The key VOCs emitted from JBCS1294 were dissolved in lanolin and applied to one side of bipartite I-plates that contained Arabidopsis seeds on Murashige and Skoog (MS) media supplemented with NaCl on the other side. Changes in plant growth were investigated using Arabidopsis mutant lines and hormone inhibitors, and gene expression was assessed by real-time PCR (qPCR). Among the VOCs, butyric acid conferred salt tolerance over a concentration range of 5.6μM (10ng)-56mM (100μg), whereas propionic and benzoic acid were effective at micromolar doses. Intriguingly, the optimized cocktail of the three VOCs increased fresh weight of Arabidopsis under salt stress compared to that achieved with each single compound. However, Arabidopsis growth was not promoted by the VOCs without salt stress. Exogenous indole-3-acetic acid (IAA) application arrested salt tolerance or growth promotion of Arabidopsis induced by volatiles from propionic acid, but not from butyric acid and an optimized volatile mixture of butyric acid, propionic acid, and benzoic acid (1PBB). High and intense auxin-responsive DR5:GUS activity was observed in the roots of Arabidopsis grown on media without salt via 1PBB, butyric acid, and benzoic acid. Growth promotion by the cocktail was inhibited in the eir1 mutant and in Col-0 plants treated with inhibitors of auxin and gibberellin. The present study clearly demonstrated the effects of individual VOCs and blends of VOCs from a rhizobacterial strain on the induction of salt stress. The results with the blend of VOCs, which mimics bacterial emissions in nature, may lead to a deeper understanding of the interaction between rhizobacteria and plants.
在我们之前的研究中，我们发现粪产碱菌JBCS1294（JBCS1294）产生的挥发性有机化合物（VOCs）通过影响生长素和赤霉素途径并上调关键离子转运蛋白的表达，诱导拟南芥对盐胁迫产生耐受性。本研究的目的是评估每种VOC以及VOCs混合物对盐耐受性诱导和信号通路的贡献。将JBCS1294释放的关键VOCs溶解在羊毛脂中，并涂抹在二分I型平板的一侧，平板另一侧的Murashige和Skoog（MS）培养基上含有拟南芥种子且添加了NaCl。使用拟南芥突变体品系和激素抑制剂研究植物生长的变化，并通过实时PCR（qPCR）评估基因表达。在这些VOCs中，丁酸在5.6μM（10ng）-56mM（100μg）的浓度范围内赋予盐耐受性，而丙酸和苯甲酸在微摩尔剂量下有效。有趣的是，与每种单一化合物相比，三种VOCs的优化混合物增加了盐胁迫下拟南芥的鲜重。然而，在没有盐胁迫的情况下，VOCs并未促进拟南芥的生长。外源施加吲哚-3-乙酸（IAA）会抑制由丙酸挥发物诱导的拟南芥的盐耐受性或生长促进，但不会抑制丁酸以及丁酸、丙酸和苯甲酸的优化挥发性混合物（1PBB）诱导的情况。在通过1PBB、丁酸和苯甲酸在无盐培养基上生长的拟南芥根中观察到高且强烈的生长素响应性DR5:GUS活性。在eir1突变体以及用生长素和赤霉素抑制剂处理的Col-0植物中，混合物对生长的促进作用受到抑制。本研究清楚地证明了来自一种根际细菌菌株的单个VOCs以及VOCs混合物对盐胁迫诱导的影响。模拟自然界中细菌排放的VOCs混合物的结果可能会使我们对根际细菌与植物之间的相互作用有更深入的了解。
