Abstract

Key Message A resistant E. grandis genotype showed a constitutive overexpression of genes related to resistance to myrtle rust caused by A. psidii .

Abstract Myrtle rust caused by Austropuccinia psidii is considered one of the most important fungal diseases affecting Eucalyptus spp. plantations in Brazil. Although the selection and planting of resistant eucalypt genotypes have been the major strategies to manage the disease in Brazil, the molecular mechanisms involved in resistance are still unclear. In this study, we evaluated the gene expression profile of two contrasting Eucalyptus grandis genotypes in resistance level to rust by RNA-Seq. The two genotypes showed a very different background gene expression level even without A. psidii infection. The resistant genotype had a constitutive overexpression of a large number of protein-coding genes compared to the susceptible genotype. These genes were mainly associated with signal transduction, photosynthesis, regulation and response to salicylic acid (SA), and protein kinase leucine-rich receptors (PK-LRR). PK-LRR and SA mediated disease resistance are well known to be effective against obligate biotroph pathogens, such as A. psidii. In addition, at 24 h after infection, the susceptible genotype was able to activate some response, however, several resistance-related proteins had their expression level reduced with A. psidii infection. Here, we present the first analysis of E. grandis genotypes transcriptomes infected by A. psidii and it reveals a constitutive overexpression of several resistance-related genes in the resistant genotype compared to the susceptible one. Our findings have the potential to be used as candidate molecular markers for resistance to myrtle rust.

中文翻译：

---

桉树基因型的转录组分析显示与铁锈（Austropuccinia psidii）抗性有关的基因组成型过表达。

摘要

关键信息 耐药的 大肠埃希菌（E. grandis） 基因型显示与 拟南芥 （A. psidii）引起的对紫锈病的抗性相关的基因组成型表达。

摘要psiducciuccinia psidii引起的桃金娘锈被认为是影响桉树属最重要的真菌疾病之一。巴西的人工林。尽管在巴西选择和种植抗性桉树基因型已成为控制该病的主要策略，但尚不清楚抗性中涉及的分子机制。在这项研究中，我们评估了两个相反的桉树基因型在通过RNA-Seq对锈病的抗性中的基因表达谱。两种基因型显示背景基因表达水平也有很大不同，即使没有psidii感染。与易感基因型相比，抗性基因型具有大量蛋白质编码基因的组成型过表达。这些基因主要与信号转导，光合作用，对水杨酸（SA）和蛋白激酶富含亮氨酸的受体（PK-LRR）的响应有关。PK-LRR和SA介导的抗病性是公知对专性biotroph病原体，如有效A. psidii。另外，在感染后24小时，易感基因型能够激活一些应答，但是，几种抗药性相关蛋白的表达水平随着psidii感染而降低。在这里，我们介绍了由A. psidii感染的E. grandis基因型转录组的第一个分析它揭示了与易感基因型相比，抗性基因型中的几个抗性相关基因的组成型过表达。我们的发现有可能被用作抗桃金娘锈病的候选分子标记。