Affiliation:
1. College of Biological and Agricultural Engineering, Jilin University, Changchun 130012, China
2. College of Engineering and Technology, Jilin Agricultural University, Changchun 130012, China
3. College of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, China
Abstract
Although nitrogen deficiency and sucrose are linked to anthocyanin synthesis, the potential role of sucrose in regulating anthocyanin biosynthesis under low nitrogen conditions (LN) in purple lettuce (Lactuca sativa L.) remains unclear. We found that adding exogenous sucrose enhanced anthocyanin biosynthesis but significantly inhibited lettuce growth at high concentrations. Optimal results were obtained using 1 mmol/L sucrose in a low-nitrogen nutrient solution (LN + T1). Chlorophyll fluorescence imaging indicated that the addition of exogenous sucrose induced mild stress. Meanwhile, the activities of antioxidant enzymes (SOD, CAT, and POD) and antioxidant capacity were both enhanced. The mild stress activated the antioxidant system, thereby promoting the accumulation of anthocyanins induced by exogenous sucrose. LN + T1 (low nitrogen nutrient solution supplemented with 1 mmol/L sucrose) up-regulated enzyme genes in the biosynthetic pathway of anthocyanins, including phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), dihydroflavonol reductase (DFR), flavanone 3-hydroxylase (F3H), flavonoid 3′-hydroxylase (F3′H), flavone synthase II (FNSII), and anthocyanidin synthase (ANS). Additionally, various transcription factors such as AP2/ERF, MYB, bHLH, C2H2, NAC, C2C2, HB, MADS, bZIP, and WRKY were found to be up-regulated. This study elucidates the regulatory mechanism of anthocyanin metabolism in response to the addition of exogenous sucrose under low nitrogen conditions and provides a nutrient solution formula to enhance anthocyanin content in modern, high-quality agricultural cultivation.
Funder
key research and development project of the 14th Five-Year Plan: Research and development of key technologies and devices for active collaborative data collection on mobile phenotype platforms
National Natural Foundation of China
Research on self-regulation mechanism for efficient nitrogen use in symbiotic hydroponically—grown vegetables based on trophic niche differentiation
Jiangsu Province and Education Ministry Co-Sponsored Synergistic Innovation Center of Modern Agriculture Equipment: Key technologies of intelligent plant factory based on multi-source data fusion
Jilin University graduate innovative research project
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