Effects of Salicylic Acid and Methyl Jasmonate Treatments on Flavonoid and Carotenoid Accumulation in the Juice Sacs of Satsuma Mandarin In Vitro

• Main Authors: Risa Yamamoto, Gang Ma, Lancui Zhang, Miki Hirai, Masaki Yahata, Kazuki Yamawaki, Takehiko Shimada, Hiroshi Fujii, Tomoko Endo, Masaya Kato
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Applied Sciences
• Subjects: flavonoid; carotenoid; salicylic acid; methyl jasmonate; citrus fruit; juice sacs
• Online Access: https://www.mdpi.com/2076-3417/10/24/8916

Salicylic acid and jasmonic acid are two important plant hormones that trigger the plant defense responses and regulate the accumulation of bioactive compounds in plants. In the present study, the effects of salicylic acid (SA) and methyl jasmonate (MeJA) on flavonoid and carotenoid accumulation were investigated in the juice sacs of Satsuma mandarin in vitro. The results showed that SA treatment was effective to enhance the contents of eriocitrin, narirutin, poncirin, and β-cryptoxanthin in the juice sacs (<i>p</i> < 0.05). In contrast, the MeJA treatment inhibited flavonoid and carotenoid accumulation in the juice sacs (<i>p</i> < 0.05). Gene expression results showed that the changes of flavonoid and carotenoid contents in the SA and MeJA treatments were highly regulated at the transcriptional level. In addition, a transcriptional factor <i>CitWRKY70</i> was identified in the microarray analysis, which was induced by the SA treatment, while suppressed by the MeJA treatment. In the SA and MeJA treatments, the change in the expression of <i>CitWRKY70</i> was consistent with that of flavonoid and carotenoid biosynthetic key genes. These results indicated that <i>CitWRKY70</i> might be involved in the regulation of flavonoid and carotenoid accumulation in response to SA and MeJA treatments in the juice sacs of citrus fruit.