A Protective Role of Phenylalanine Ammonia-Lyase from Astragalus membranaceus against Saline-Alkali Stress.

Phenylalanine ammonia-lyase (PAL, E.C.4.3.1.5) catalyzes the benzene propane metabolism and is the most extensively studied enzyme of the phenylpropanoid pathway. However, the role of genes in , a non-model plant showing high capability toward abiotic stress, is less studied. Here, we cloned and found that it encodes a protein that resides in the cytoplasmic membrane. The mRNA of was strongly induced by NaCl or NaHCO treatment, especially in the root. Overexpressing in resulted in higher PAL enzyme activities, lower levels of malondialdehyde (MDA), and better root elongation in the seedlings under stress treatment compared to the control plants. The protective role of under saline-alkali stress was also observed in 30-day soil-grown plants, which showed higher levels of superoxide dismutase (SOD), proline, and chlorophyll compared to wild-type . Collectively, we provide evidence that is responsive to multiple abiotic stresses and that manipulating the expression of can be used to increase the tolerance to adverse environmental factors in plants.