Since the late 1980s, the oak decline has affected the Zagros oak forests in western Iran. Persian oak (Quercus brantii L.) the most important tree species of these forests has been damaged more than any other plant species. In the present study, the RNA sequencing technique was used for the first time to identify key genes and molecular mechanisms involved in Persian oak decline. The RNA was extracted from the leaves of healthy and declined oak trees, and sequenced using the Illumina HiSeq 2500 platform (2 × 150 bp paired-end reads). De novo transcriptome assembly of Persian oak revealed 56,743 unigenes and 6049 differentially expressed genes (DEGs) between declined and control samples. The results of gene ontology analysis showed that most of the DEGs involved in oak decline belong to the group of stress-responsive genes. In general, oak decline samples showed significant reductions in gene expression associated with “photosynthesis and storage of sugar” and “protein synthesis and related processes.” Additionally, DEGs related to the starch degradation pathway were up-regulated, whereas DEGs associated with acetate-mevalonate (MVA), biosynthesis of lignin, and lignases pathways were down-regulated. The present study's findings can be an effective step in identifying the genes involved in oak decline and deciphering the relationship between this phenomenon and biotic and abiotic stresses.

自 20 世纪 80 年代后期以来，橡树的减少影响了伊朗西部的扎格罗斯橡树林。波斯橡树 ( Quercus brantiiL.) 这些森林中最重要的树种受到的破坏比任何其他植物物种都多。在本研究中，首次使用 RNA 测序技术鉴定了波斯橡树衰退的关键基因和分子机制。从健康和衰退的橡树的叶子中提取 RNA，并使用 Illumina HiSeq 2500 平台（2 × 150 bp 配对末端读数）进行测序。波斯橡树的从头转录组组装揭示了衰退样本和对照样本之间的 56,743 个单基因和 6049 个差异表达基因 (DEG)。基因本体分析结果表明，大部分参与橡树衰退的DEGs属于应激反应基因组。一般来说，橡树衰退样本显示与“光合作用和糖分储存”和“蛋白质合成及相关过程”相关的基因表达显着减少。此外，与淀粉降解途径相关的 DEG 被上调，而与乙酸甲羟戊酸 (MVA)、木质素生物合成和木质酶途径相关的 DEG 被下调。本研究的发现可能是识别与橡树衰退有关的基因以及破译这种现象与生物和非生物胁迫之间关系的有效步骤。