In the National Peony Germplasm Resource Bank of Yangzhou University, foliar melatonin spraying significantly enhanced the stem strength of peony flowers. Courtesy of Yangzhou University
Recently, the Journal of Experimental Botany published the latest research paper by Professor Tao Jun’s team at Yangzhou University online. The study found that melatonin has new functions that enhance the strength of plant stems.
Peony is a traditional famous flower and an emerging high-grade cut flower in China. The large flowers of peony and the insufficient strength of the stem can easily cause the flower stem to bend and the flowers to sag, which seriously affects the quality of the peony cut flowers and reduces the value of the product. Therefore, how to improve the strength of flower stems and improve the straightness of flower stems is an urgent problem to be solved in the production of peony cut flowers in China.
The study found that the endogenous melatonin content of different varieties of peony was positively correlated with the strength of the flower stem. Foliar melatonin spraying significantly enhanced the stem strength of peony flowers; PlTDC, a gene related to the biosynthesis of paeoniflorin, was used by VIGS technology to significantly reduce the endogenous melatonin content of paeoniflorin and weaken the strength of flower stems; and hyperexpression of peony PlTDC could significantly increase the endogenous melatonin content of tobacco and enhance the strength of stems.
The research team conducted a transgenic study of the peony PlCOMT1 gene, which is involved in both melatonin and lignin biosynthesis, and found that it had a doubling effect on endogenous melatonin content and stem strength.
Further studies have found that the main regulatory mechanism of melatonin enhancing the stem strength of peony flowers is to promote lignin accumulation and change the S/G lignin ratio on the one hand, and melatonin can increase the thickness of xylem secondary cell wall on the other hand.
The study proposes a new biological function of melatonin, which provides a new way to improve the quality of peony cut flower stems.
Professor Zhao Daqiu of the university is the first author of the paper, and Tao Jun is the corresponding author. The research has been funded by the National Natural Science Foundation of China and the Jiangsu Forestry Science and Technology Innovation and Promotion Project. (Source: China Science Daily, Li Chen, Wu Xiping)
Related paper information:https://doi.org/10.1093/jxb/erac165