فهرست نشریات علمی دسترسی آزاد ایران

Phenylketonuria (PKU) requires a strict low-phenylalanine diet to prevent harmful accumulation in the body. Current dietary options, largely reliant on processed foods, are often unpalatable, expensive, and inaccessible in developing countries. This study aimed to naturally develop a rice strain with reduced phenylalanine levels, avoiding genetic modification, andoptimize biological stimulants for modulating phenylalanine biosynthesis. Field trials involved foliar application of cinnamic acid (0, 0.5, 1, and 1.5 g/L) and phenylalanine (0, 0.25, 0.5, and 1 g/L) on two local rice cultivars (Helal and Keshvari) during seed formation and filling, using a randomized complete block design with three replications. Key molecular traits measured included total protein content, phenylalanine ammonia-lyase (PAL) enzyme activity, and expression of genes involved in phenylalanine biosynthesis and catabolism (phenylpyruvate aminotransferase, arogenate dehydratase, and PAL). Results showed that phenylalanine application increased PAL gene expression, while cinnamic acid suppressed it. Although both stimulants significantly downregulated phenylalanine biosynthesis genes and reduced total protein content for both treatments, a decrease in total protein content occurred at the highest applied concentration. Notably, cinnamic acid significantly decreased phenylalanine levels in Keshvari (1 and 1.5 g/L), while increasing tyrosine and tryptophan concentrations at higher dosages. In addition, phenylalanine treatments at concentrations of 0.5 and 1 g/L led to decreased expression of the arogenate dehydratase gene. Moreover, the application of phenylalanine at 0.5 and 1 g/L reduced the expression of the phenylpyruvate aminotransferase gene in both rice cultivars studied. Cinnamic acid treatment can reduce phenylalanine in rice, offering a natural strategy for PKU-friendly diets.