Ekspresi Gen Antioksidan pada Tanaman Padi Hitam Tercekam Aluminium

Abstract

Aluminium (Al) toxicity is one of the major problems that hinder rice productivity in acidic soils because it triggers the accumulation of reactive oxygen species (ROS) and oxidative stress in plants. This study aimed to analyze the relative expression of enzymatic antioxidant genes, namely Superoxide Dismutase (SOD) and Ascorbate Peroxidase (APX), in three black rice varieties (Karekan, Baki Barat, and Sanggali) subjected to aluminium stress at a concentration of 30 ppm for 14 days. The research methodology involved control and aluminium stress treatments, followed by RNA isolation, cDNA synthesis, and quantitative molecular analysis using the Livak-based qRT-PCR method. The results of the quantitative analysis showed significant variations in molecular regulation and tolerance levels among the varieties. The Karekan variety exhibited the best defense mechanism (tolerant) through an upregulation of SOD gene expression by a factor of 4.14, followed by an upregulation of the APX gene by a factor of 1.88. The Baki Barat variety was classified as having moderate tolerance, with a relatively high upregulation of the SOD gene by a factor of 2.40, followed by an upregulation of the APX gene by a factor of 1.05. In contrast, the Sanggali variety exhibited a sensitive/intolerant trait, characterized by a low increase in SOD gene regulation of 1.66 and a decrease in APX gene regulation of 0.41, which was smaller than that of the control. This study concludes that the efficiency of the cellular antioxidant defense system in black rice plants is determined by the synergistic capacity of the SOD and APX genes to neutralize ROS, and identifies the Karekan cultivar as a potential candidate for the breeding of acid-tolerant rice plants.