Key message

A survey of theEucalyptus grandis genome revealed the presence of 54 laccase genes. Their tissue-specific and stress-induced expression patterns suggest a role in lignification and adaptation to abiotic stresses.

Abstract

Laccases are multicopper oxidases that play important roles in the oxidation of monolignols during lignin biosynthesis and are reported to be functionally involved in plant development and stress responses. In this study, a genome-wide survey of the Eucalyptus grandis genome revealed the presence of 54 putative LAC genes (referred as EgrLAC), which were assigned to six different phylogenetic groups. Among them, 17 were predicted to be potential targets of miR397, a negative regulator of lignin biosynthesis. Based on different RNA-Seq datasets, distinct organ/tissue expression patterns of the identified EgrLAC genes were ascertained. The vast majority, however, showed enriched expression in the vascular tissues of roots and stems. Additional expression profiling of selected EgrLAC genes revealed differential expression in response to oxidative and osmotic stresses, suggesting a role in abiotic stress responses. Parallel promoter analysis of EgrLAC4, a close homologue to the Arabidopsis lignin biosynthesis-related gene AtLAC17, revealed a vascular expression pattern, mostly associated with the phloem. Overall, our data point to an involvement of the identified EgrLAC genes in lignification and in Eucalyptus adaptation to abiotic stresses.

中文翻译：

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全基因组鉴定的桉树多功能漆酶基因家族：木质素工程和胁迫耐受性的潜在目标

关键信息

对桉树基因组的一项调查显示存在54个漆酶基因。它们的组织特异性和应激诱导的表达模式表明在木质化和适应非生物胁迫中的作用。

抽象

漆酶是多铜氧化酶，在木质素生物合成过程中在单木酚的氧化中起重要作用，据报道在功能上参与植物发育和胁迫反应。在这项研究中，对桉树基因组进行了全基因组调查，结果发现存在54个推定的LAC基因（称为EgrLAC），这些基因被分配给六个不同的系统发育组。其中，有17种被预测为miR397（木质素生物合成的负调节剂）的潜在靶标。根据不同的RNA-Seq数据集，确定的EgrLAC的不同器官/组织表达模式确定基因。然而，绝大多数在根和茎的维管组织中显示出丰富的表达。选定的EgrLAC基因的其他表达谱揭示了对氧化和渗透胁迫的响应差异表达，表明在非生物胁迫响应中的作用。EgrLAC4（与拟南芥木质素生物合成相关基因AtLAC17的近缘同源物）的平行启动子分析显示了一种血管表达模式，主要与韧皮部有关。总体而言，我们的数据表明，已鉴定的EgrLAC基因参与了木质化和桉树对非生物胁迫的适应。