The antioxidant response mechanism of flavonoids in ‘Tainong 1’ mango pulp under enhanced UV-B radiation

Abstract

In this study, UV-B radiation of 96 kJ·m⁻²·d⁻¹ exposed to the ‘Tainong 1’ mango tree, and trees as the control group under natural lighting. The relative conductivity and the contents of MDA, superoxide anion, H₂O₂ were lower in the treatment group than in the control group before 60 DAF, and the opposite occurred after 60 DAF. The total flavonoid content in the treatment group was higher than that in the control group, but the opposite occurred later. The 60 DAF serves as the critical point. Before 60 DAF, the treatment enhanced the activity of each enzyme by inducing the upregulated expression of genes such as CHS, R02446, and CYP98A so that gallochol, leucoside, kaempferoside, quercetin, isoquercetin and luteolin, and then removed ROS through the reduction of flavonoids. After 60 DAF, the treatment enhanced the activity of each enzyme by inducing the upregulated expression of HCT and R02446, but the synthesized flavonoids are consumed by ROS. Meanwhile, ROS also accumulate continuously because of the enhanced continuous exposure of UV-B radiation. The downregulated expression of CYP75A led to a decline in enzyme activity. The accumulation rate of flavonoid compounds was lower than that of ROS, which led to ROS damage in pulp.

PUBLIC INTEREST STATEMENT

Understand the induction mechanism of high-dose enhanced UV-B radiation treatment for the metabolism of flavonoids and polyphenols in mango pulp, clarify the composition characteristics of monomer compounds, analyze the physiological and biochemical mechanisms of the antioxidant response of these reducing components, and explore the possibility of improving the health quality of mango pulp.

Enhancing UV-B radiation is still likely to become the future agricultural adversity for a certain period, and many crops will gradually encounter the light stress of enhanced UV-B radiation. In addition, different plant species such as Sorghum bicolor and Triticum aestivum equivalent crops have different sensitivity and damage performance of enhancing UV-B radiation, so it is necessary to study the biological effects of the enhanced UV-B radiation on specific crops.

Therefore, the molecular biological mechanism of the reduced composition of antioxidant response of mango pulp under high-dose enhanced UV-B radiation treatment is worth prospective study. This will also lay the molecular biological foundation for exploring other growth and development problems of mango pulp. At the same time, it also provides the theoretical basis for the technical guidance of tropical fruit tree cultivation.

Keywords:

• UV-B
• mango
• flavonoids
• antioxidant response

REVIEWING EDITOR:

• M. Luisa Escudero-Gilete, Universidad de Sevilla, Spain

SUBJECTS:

• Agriculture; Horticulture; Plant Biology

Authors’ contributions

On behalf of all the authors of this paper, I guarantee this paper has not been published, no more contributions, no infringement phenomenon, abiding by academic ethics. We will take all responsibilities connected with this paper ourselves forever. On behalf of all authors, I agree to participate in and publish this article. Professor Kaibing Zhou, Department of Horticulture, Hainan University, Haidian Campus of Hainan University, Haikou City, Hainan Province.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

All data generated or analysed during this study are included in this published article.

Additional information

Funding

Foundation items: National Natural Science Foundation of China (NSFC) (No. 32160677).

Notes on contributors

Kai-bing Zhou

Kai-bing Zhou is a professor, and Xian Shui, Tian-tian Chen, Jun-jie Peng and Jing-jia Du are graduate students, and they work on the research on tropical fruit tree culture and physiology. Feng Liu is a assistant researcher, and works on the research on tropical fruit tree stress physiology. Minjie Qian is a assistant professor, and works on the research on fruit tree biotechnology. In this paper, the key reduction monomer compounds in mango pulp and the key genes related to the metabolism of these compounds have been identified and screened, then it makes the base for the research on the molecular mechanism on enhanced UV-B radiation resistance and the genetic engineering breeding of mango.