Key Lab of Bio-Organic Fertilizer Creation, Ministry of Agriculture , Anhui Science and Technology University , Bengbu 233100 , China.
Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization , Nanjing Agricultural University , Nanjing 210095 , China.
J Agric Food Chem. 2019 Jan 9;67(1):320-330. doi: 10.1021/acs.jafc.8b05851. Epub 2018 Dec 19.
Iron (Fe) deficiency often triggers arginine overproduction in plants. However, it remains elusive whether Fe deficiency-induced increases of arginine levels are involved in beneficial rhizobacteria recruitment and that the mechanism underlying rhizobacteria induced plant Fe deficiency tolerance. Here, Bacillus subtilis STU6 increased soluble Fe content in tomato, thereby alleviating Fe deficiency-induced chlorosis. In a split-root system, STU6 significantly induced arginine exudation by Fe-deficient roots, and increased arginine levels promoted spermidine (Spd) production by STU6 and bacterial colonization. Deletion of the STU6 speB gene inhibited Spd synthesis and abrogated STU6-induced increments of soluble Fe content in the Fe-deficient plants. Increased host Spd levels by STU6 greatly stimulated the NO accumulation in the Fe-deficient roots. Furthermore, disruption of NO signaling markedly repressed STU6-mediated cell wall Fe remobilization. Collectively, our data provide important evidence that chemical dialogues between tomato and STU6 contribute to enhancement of microbe-mediated plant adaptation to Fe deficiency.
铁（Fe）缺乏通常会触发植物中精氨酸的过度产生。然而，Fe 缺乏诱导的精氨酸水平升高是否参与有益根际细菌的招募，以及根际细菌诱导植物 Fe 缺乏耐受性的机制仍然难以捉摸。在这里，枯草芽孢杆菌 STU6 增加了番茄中的可溶 Fe 含量，从而缓解了 Fe 缺乏引起的黄化。在分根系统中，STU6 显著诱导 Fe 缺乏根的精氨酸分泌，并且增加的精氨酸水平促进了 STU6 产生腐胺（Spd）和细菌定殖。STU6 的 speB 基因缺失抑制了 Spd 的合成，并消除了 STU6 在 Fe 缺乏植物中对可溶性 Fe 含量的增加。STU6 增加宿主 Spd 水平极大地刺激了 Fe 缺乏根中的 NO 积累。此外，破坏 NO 信号显著抑制了 STU6 介导的细胞壁 Fe 再动员。总之，我们的数据提供了重要证据，表明番茄和 STU6 之间的化学对话有助于增强微生物介导的植物对 Fe 缺乏的适应。
