Anthocyanin accumulation and gene expression in maize (Zea mays) under metolachlor stress

Abstract

Anthocyanins are the most conspicuous class of flavonoids and could protect plants from biotic and abiotic stresses. Herbicides are widely used in crops and constitute a common stress to crops. To explore the accumulation of anthocyanins under metolachlor stress, the total phenolics, flavonoids and anthocyanins contents as well as the total antioxidative capacity in metolachlor-susceptible (ZD) and metolachlor-tolerant (ND) maize (Zea mays L.) cultivars were measured. The results showed that phenolics contents were not influenced by metolachlor stress in both maize cultivars, while anthocyanins were reduced in both maize cultivars. The flavonoids and the total antioxidant capacity were both increased in ZD under metolachlor stress. Analysis of anthocyanin biosynthesis genes indicated that the expression levels of PAL, CHS, DFR, ANS, BZ2 and F3'H had decreasing tendency under metolachlor stress. These genes were speculated to be the action sites of metolachlor in maize, especially F3'H. DFR, ANS and BZ2 were deduced to be responsible for higher accumulation of anthocyanins in ND compared to ZD, as higher expression levels of these genes were found in ND. This study provided a better understanding on the molecular mechanism of anthocyanins biosynthesis under metolachlor stress in maize.