Casarrubia Salvatore, Martino Elena, Daghino Stefania, Kohler Annegret, Morin Emmanuelle, Khouja Hassine-Radhouane, Murat Claude, Barry Kerrie W, Lindquist Erika A, Martin Francis M, Perotto Silvia
Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy.
Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes, Centre INRAE Grand Est Nancy, Champenoux, France.
Front Microbiol. 2020 Mar 9;11:341. doi: 10.3389/fmicb.2020.00341. eCollection 2020.
The success of Ericaceae in stressful habitats enriched in heavy metals has been ascribed to the distinctive abilities of their mycorrhizal fungal partners to withstand heavy metal stress and to enhance metal tolerance in the host plant. Whereas heavy metal tolerance has been extensively investigated in some ericoid mycorrhizal (ERM) fungi, the molecular and cellular mechanisms that extend tolerance to the host plant are currently unknown. Here, we show a reduced Cd content in Cd-exposed mycorrhizal roots of colonized by a metal tolerant isolate of the fungus as compared to non-mycorrhizal roots. To better understand this phenotype, we applied Next Generation Sequencing technologies to analyze gene expression in and Zn grown under normal and Cd-stressed conditions, in the free living and in the mycorrhizal status. The results clearly showed that Cd had a stronger impact on plant gene expression than symbiosis, whereas fungal gene expression was mainly regulated by symbiosis. The higher abundance of transcripts coding for stress related proteins in non-mycorrhizal roots may be related to the higher Cd content. Regulated plant metal transporters have been identified that may play a role in reducing Cd content in mycorrhizal roots exposed to this metal.
杜鹃花科植物在富含重金属的胁迫生境中取得成功，这归因于其菌根真菌伙伴具有独特能力，能够抵御重金属胁迫并增强宿主植物的金属耐受性。虽然在一些石楠类菌根（ERM）真菌中，重金属耐受性已得到广泛研究，但目前尚不清楚将耐受性扩展至宿主植物的分子和细胞机制。在此，我们发现，与非菌根根相比，被耐金属真菌分离株 定殖的菌根根在暴露于镉时镉含量降低。为了更好地理解这一表型，我们应用新一代测序技术分析 在正常和镉胁迫条件下、在自由生活状态和菌根状态下生长时的基因表达情况，以及 和锌的情况。结果清楚地表明，镉对植物基因表达的影响比对共生关系的影响更强，而真菌基因表达主要受共生关系调控。非菌根根中编码应激相关蛋白的转录本丰度较高，这可能与较高的镉含量有关。已鉴定出受调控的植物金属转运蛋白，它们可能在降低暴露于这种金属的菌根根中的镉含量方面发挥作用。
