Sustainable Agricultural Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Henry A. Wallace Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.
Center of Plant Biology, Department of Horticulture and Landscape Architecture, Purdue University, W. Lafayette, IN 47907, USA.
Cells. 2020 Jul 22;9(8):1749. doi: 10.3390/cells9081749.
Polyamines (PAs) regulate growth in plants and modulate the whole plant life cycle. They have been associated with different abiotic and biotic stresses, but little is known about the molecular regulation involved. We quantified gene expression of PA anabolic and catabolic pathway enzymes in tomato ( cv. Ailsa Craig) leaves under heat versus cold stress. These include and , and , /, , two , three , two ; ; ( and ) and ( and ). The spatiotemporal transcript abundances using qRT-PCR revealed presence of their transcripts in all tissues examined, with higher transcript levels observed for , and in most tissues. Cellular levels of free and conjugated forms of putrescine and spermidine were found to decline during heat stress while they increased in response to cold stress, revealing their differential responses. Transcript levels of , , and increased in response to both heat and cold stresses. However, transcript levels of , , , and increased in response to heat while those of and increased in response to cold stress, respectively. Transcripts of , , and declined in response to heat stress while transcripts declined under cold stress. These results show differential expression of PA metabolism genes under heat and cold stresses with more impairment clearly seen under heat stress. We interpret these results to indicate a more pronounced role of PAs in cold stress acclimation compared to that under heat stress in tomato leaves.
多胺（PAs）调节植物生长，并调节整个植物生命周期。它们与不同的非生物和生物胁迫有关，但对涉及的分子调节知之甚少。我们在热应激与冷应激下定量测定了番茄（cv. Ailsa Craig）叶片中 PA 合成和分解途径酶的基因表达。这些酶包括：、、、/、、、、、、和。使用 qRT-PCR 进行的时空转录丰度分析显示，它们的转录本存在于所有检查的组织中，大多数组织中观察到更高的、和转录水平。发现游离和结合形式的腐胺和亚精胺的细胞水平在热应激期间下降，而在冷应激下增加，揭示了它们的差异反应。、、和的转录水平均响应热和冷应激而增加。然而，、、、和的转录水平分别响应热和冷应激而增加，而和的转录水平响应冷应激而增加。、和的转录水平响应热应激而下降，而在冷应激下下降。这些结果表明，PA 代谢基因在热应激和冷应激下的表达存在差异，热应激下的损伤更为明显。我们将这些结果解释为表明 PAs 在番茄叶片的冷应激适应中比在热应激下发挥更显著的作用。
