Paeonia ostii is an emerging woody oil crop, but drought severely inhibits its growth and promotion in arid or semiarid areas, and little is known about the mechanism governing this inhibition. In this study, the full-length cDNA of a caffeoyl-CoA O-methyltransferase gene (CCoAOMT) from P. ostii was isolated, and determined to be comprised of 987 bp. PoCCoAOMT encoded a 247-amino acid protein, which was located in the nucleus and cytosol. Significantly higher PoCCoAOMT transcription was detected in P. ostii treated with drought stress. Subsequently, the constitutive overexpression of PoCCoAOMT in tobacco significantly conferred drought stress tolerance. Under drought stress, transgenic lines exhibited lower reactive oxygen species (ROS) accumulation, and higher antioxidant enzyme activities and photosynthesis. Moreover, the expression levels of senescence-associated genes were significantly downregulated, whereas the expression levels of lignin biosynthetic genes and PoCCoAOMT were significantly upregulated in transgenic lines. Similarly, transgenic lines produced significantly higher lignin, especially guaiacyl-lignin. These results suggest that PoCCoAOMT is a vital gene in promoting lignin synthesis and ROS scavenging to confer drought stress tolerance in P. ostii.

中文翻译：

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牡丹咖啡酰辅酶A O-甲基转移酶通过促进木质素合成和ROS清除赋予干旱胁迫耐受性


芍药是一种新兴的木本油料作物，但干旱严重抑制了其在干旱、半干旱地区的生长和发育，但对其抑制机制知之甚少。在这项研究中，从 P. ostii 中分离出了咖啡酰辅酶 A O-甲基转移酶基因 (CCoAOMT) 的全长 cDNA，并确定其由 987 bp 组成。 PoCCoAOMT 编码一个 247 个氨基酸的蛋白质，位于细胞核和细胞质中。在经干旱胁迫处理的 P. ostii 中检测到显着较高的 PoCCoAOMT 转录。随后，PoCCoAOMT 在烟草中的组成型过表达显着赋予了干旱胁迫耐受性。在干旱胁迫下，转基因品系表现出较低的活性氧（ROS）积累，以及较高的抗氧化酶活性和光合作用。此外，转基因株系中衰老相关基因的表达水平显着下调，而木质素生物合成基因和PoCCoAOMT的表达水平显着上调。类似地，转基因品系产生显着更高的木质素，尤其是愈创木基木质素。这些结果表明，PoCCoAOMT 是促进木质素合成和 ROS 清除以赋予 P. ostii 干旱胁迫耐受性的重要基因。