Find in Library

Low temperature is an important environmental factor that affects the growth and development of trees and leads to the introduction of failure in the genetic improvement of trees. <i>Acer pseudosieboldianum</i> is a tree species that is well-known for its bright red autumn leaf color. These trees are widely used in landscaping in northeast China. However, due to their poor cold resistance, introduced <i>A. pseudosieboldianum</i> trees suffer severe freezing injury in many introduced environments. To elucidate the physiological indicators and molecular mechanisms associated with freezing damage, we analyzed the physiological indicators and transcriptome of <i>A. pseudosieboldianum</i>, using kits and RNA-Seq technology. The mechanism of <i>A. pseudosieboldianum</i> in response to freezing stress is an important scientific question. In this study, we used the shoots of four-year-old <i>A. pseudosieboldianum</i> twig seedlings, and the physiological index and the transcriptome of <i>A. pseudosieboldianum</i> under low temperature stress were investigated. The results showed that more than 20,000 genes were detected in <i>A. pseudosieboldianum</i> under low temperature (4 °C) and freezing temperatures (−10 °C, −20 °C, −30 °C, and −40 °C). There were 2505, 6021, 5125, and 3191 differential genes (DEGs) between −10 °C, −20°C, −30°C, −40 °C, and CK (4 °C), respectively. Among these differential genes, 48 genes are involved in the MAPK pathway and 533 genes are involved in the glucose metabolism pathway. In addition, the important transcription factors (MYB, AP2/ERF, and WRKY) involved in freezing stress were activated under different degrees of freezing stress. A total of 10 sets of physiological indicators of <i>A. pseudosieboldianum</i> were examined, including the activities of five enzymes and the accumulation of five hormones. All of the physiological indicators except SOD and GSH-Px reached their maximum values at −30 °C. The enzyme activity of SOD was highest at −10 °C, and that of GSH-Px was highest at −20 °C. Our study is the first to provide a more comprehensive understanding of the differential genes (DEGs) involved in <i>A. pseudosieboldianum</i> under freezing stress at different temperatures at the transcriptome level. These results may help to clarify the molecular mechanism of cold tolerance of <i>A. pseudosieboldianum</i> and provide new insights and candidate genes for the genetic improvement of the freezing tolerance of <i>A. pseudosieboldianum</i>.