Group of Mycorrhizas, Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain.
Biochemistry and Plant Biotechnology Laboratory, Department CAMN, Universitat Jaume I, Castellón, Spain.
Plant Cell Environ. 2020 Jul;43(7):1655-1668. doi: 10.1111/pce.13760. Epub 2020 Apr 2.
Strigolactones (SLs) are important ex-planta signalling molecules in the rhizosphere, promoting the association with beneficial microorganisms, but also affecting plant interactions with harmful organisms. They are also plant hormones in-planta, acting as modulators of plant responses under nutrient-deficient conditions, mainly phosphate (Pi) starvation. In the present work, we investigate the potential role of SLs as regulators of early Pi starvation signalling in plants. A short-term pulse of the synthetic SL analogue 2'-epi-GR24 promoted SL accumulation and the expression of Pi starvation markers in tomato and wheat under Pi deprivation. 2'-epi-GR24 application also increased SL production and the expression of Pi starvation markers under normal Pi conditions, being its effect dependent on the endogenous SL levels. Remarkably, 2'-epi-GR24 also impacted the root metabolic profile under these conditions, promoting the levels of metabolites associated to plant responses to Pi limitation, thus partially mimicking the pattern observed under Pi deprivation. The results suggest an endogenous role for SLs as Pi starvation signals. In agreement with this idea, SL-deficient plants were less sensitive to this stress. Based on the results, we propose that SLs may act as early modulators of plant responses to P starvation.
独脚金内酯（SLs）是根际中重要的植物外信号分子，促进与有益微生物的共生，但也影响植物与有害生物的相互作用。它们也是植物体内的激素，作为植物在营养缺乏条件下（主要是磷饥饿）响应的调节剂。在本工作中，我们研究了 SLs 作为植物早期磷饥饿信号调节剂的潜在作用。在磷饥饿条件下，合成的 SL 类似物 2'-epi-GR24 的短期脉冲促进了番茄和小麦中 SL 的积累和磷饥饿标记物的表达。在正常磷条件下，2'-epi-GR24 的应用也增加了 SL 的产生和磷饥饿标记物的表达，其作用依赖于内源性 SL 水平。值得注意的是，2'-epi-GR24 还影响了这些条件下的根代谢谱，促进了与植物对磷限制响应相关的代谢物水平，从而部分模拟了在磷饥饿下观察到的模式。结果表明 SLs 作为磷饥饿信号具有内源性作用。与这一观点一致，SL 缺陷型植物对这种胁迫的敏感性降低。基于这些结果，我们提出 SLs 可能作为植物对 P 饥饿响应的早期调节剂。
