Study on ROS accumulation, stored mRNA degradation, and molecular marker selection during the aging process of sweet corn seeds

Objective To investigate the relationships between stored mRNA degradation, reactive oxygen species (ROS) accumulation, and the decline of seed viability during the aging of Zea mays L. saccharata Sturt (sweet corn) seeds, and identify molecular markers for monitoring seed aging, thereby providing a theoretical basis for establishing a seed quality evaluation model based on stored mRNAs and ROS.

Method Two sweet corn varieties, ‘Nongtian 99’ and ‘Nongtian 20’, were subjected to artificial accelerated aging treatment (0–21 days). The ΔΔCt of stored mRNAs (Zm00001d003301, Zm00001d046591 and Zm00001d009990) were measured using RT-qPCR, while ROS fluorescence intensity and seed vigor indices were determined simultaneously. Regression analysis was employed to evaluate the correlations of these two parameters with aging time and seed vigor.

Result After 21 days of aging, the germination rate, germination potential, germination index, and vigor index of ‘Nongtian 99’ decreased significantly by 100%. For ‘Nongtian 20’, the corresponding indices decreased significantly by 91.8%, 100.0%, 95.3%, and 99.4%, respectively. Analysis of variance indicated significant variety differences in seed aging tolerance (P < 0.0001), with ‘Nongtian 20’ exhibiting greater aging resistance. Both ROS relative fluorescence intensity and ΔΔCt showed significant negative correlations with seed vigor indices (r = −0.97 to −0.83 and r = −0.96 to −0.72, respectively). The regression models between ROS relative fluorescence intensity and aging time yielded high coefficients of determination (R² = 0.978–0.997). Stored mRNA ΔΔCt followed a quadratic regression model with aging time (R² = 0.969–0.983), peaking at mid-aging stage (15–18 days). Stepwise regression models incorporating ΔΔCt and seed vigor indices achieved R² of 0.514–0.956, and combining two genes improved model accuracy.

Conclusion Stored mRNA degradation and ROS accumulation are core mechanisms in sweet corn seed aging. Stored mRNA degradation follows a nonlinear dynamic, accelerating initially and slowing later, whereas ROS accumulation increases linearly. Their combined use enables comprehensive monitoring across the entire aging process. This study provides new insights into molecular marker screen and dynamic monitoring for sweet corn seed aging.