AUTHOR=Yang Ning , Sun Kaining , Wang Xiao , Wang Kean , Kong Xianghua , Gao Jianwei , Wen Dan 

TITLE=Melatonin Participates in Selenium-Enhanced Cold Tolerance of Cucumber Seedlings

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.786043

DOI=10.3389/fpls.2021.786043

ISSN=1664-462X

ABSTRACT=<p>Melatonin is an important and widespread plant hormone. However, the underlying physiological and molecular mechanisms of melatonin as a secondary messenger in improving cold tolerance by selenium are limited. This study investigated the effects of selenite on the cold stress of cucumber seedlings. The results showed that exogenous application of selenite improved the cold tolerance of cucumber seedlings, which was dependent on the concentration effect. In the present experiment, 1 μM of selenite showed the best effect on alleviating cold stress. Interestingly, we found that in the process of alleviating cold stress, selenite increased the content of endogenous melatonin by regulating the expression of melatonin biosynthesis genes (<italic>TDC, T5H, SNAT</italic>, and <italic>COMT</italic>). To determine the interrelation between selenite and melatonin in alleviating cold stress, melatonin synthesis inhibitor <italic>p</italic>-chlorophenylalanine and melatonin were used for in-depth study. This study provides a theoretical basis for cucumber cultivation and breeding.</p>