Chen Bin J W, Hajiboland Roghieh, Bahrami-Rad Sara, Moradtalab Narges, Anten Niels P R
College of Biology and the Environment, Nanjing Forestry University, Nanjing, China.
Department of Plant Science, University of Tabriz, Tabriz, Iran.
Front Plant Sci. 2019 Jun 11;10:751. doi: 10.3389/fpls.2019.00751. eCollection 2019.
Plants can detect the presence of their neighbors belowground, often responding with changes in root growth for resource competition. Recent evidence also implies that perception of neighbors may also elicit defense responses, however, the associated metabolic activities are unclear. We investigated primary and defense-related secondary metabolisms and hormone expressions in tobaccos () grown either with own roots or roots of another conspecifics in hydroponic condition. The results showed that non-self root interaction significantly reduced photosynthetic activity and assimilate production, leading to a reduction of growth. Non-self interaction also modified plant phenylpropanoids metabolism, yielding higher lignin content (i.e., structural resistance) at whole plant level and higher phenolics accumulation (i.e., chemical defense) in roots. All these metabolic responses were associated with enhanced expressions of phytohormones, particularly jasmonic acid, salicylic acid and cytokinin in roots and abscisic acid in leaves, at the early stage of non-self interaction. Since the presence of neighbors often increase the probability of attacks from, e.g., pathogens and pests, this defense activation may act as an adaptation of plants to these possible upcoming attacks.
植物能够感知地下邻居的存在，常常通过改变根系生长来应对资源竞争。最近的证据还表明，对邻居的感知可能也会引发防御反应，然而，相关的代谢活动尚不清楚。我们研究了水培条件下，烟草（Nicotiana tabacum）在自身根系或另一个同种植物根系存在情况下，其初级代谢和与防御相关的次级代谢以及激素表达情况。结果表明，非自身根系相互作用显著降低了光合活性和同化物产量，导致生长减缓。非自身相互作用还改变了植物苯丙烷类代谢，在整株水平上产生了更高的木质素含量（即结构抗性），在根系中积累了更多的酚类物质（即化学防御）。所有这些代谢反应都与植物激素表达增强有关，特别是在非自身相互作用早期，根系中的茉莉酸、水杨酸和细胞分裂素以及叶片中的脱落酸。由于邻居的存在通常会增加例如病原体和害虫攻击的可能性，这种防御激活可能是植物对这些即将到来的可能攻击的一种适应。
