Redox homeostasis and enzyme network dynamics regulate dormancy transition and germination metabolism in Bixa orellana L.
摘要
An integrative redox enzymatic network analysis was conducted to elucidate the regulatory mechanisms underlying dormancy release and germination in Bixa orellana L. (annatto or sindoor plant). This plant species exhibits severe physical and physiological dormancy, resulting in poor germination and further its cultivation on commercial scale for replacing the hazardous synthetic dyes. The pretreatments, included 1 h warm (65 °C) water incubation, 24 h normal water incubation and 500 ppm GA3 application, and enhanced germination from 21.7 to 28.3% in control to 83.3, 90.0 and 93.3%, respectively, demonstrating successful physiological activation at the optimum treatments value. Enzymatic analysis revealed a noticeable increase in MDA content to 30.5 ± 0.3 nmolg−1 FW, along with increases in CAT and POD activities to 9.0 ± 0.2 µmol H2O2 min−1 g−1 FW and 18.0 ± 0.3 Ug−1 FW, respectively at the optimum temperature treatment for germination. Similarly increase in amylase and protease enzyme activity was recorded. The germination rate declined above the threshold temperature treatment values demonstrating the stress during seed germination. The Protein–protein interaction analysis of four enzymes viz. catalase, peroxidase, amylase and protease revealed specific interaction modules coordinating redox defence and reserve mobilization. These findings indicate stress responsive enzymes function as integrated components of coordinated molecular networks, rather than as independent catalytic units, enabling a resilient and adaptable biochemical system that supports germination in varying environmental conditions.
Graphical abstract