Blueberry VcLon1 protease increases iron use efficiency by alleviating chloroplast oxidative stress

Abstract

Aim to unveil the functions of VcLon1 in plant Fe use efficiency. RT-PCR was used to analyze the expression profile of VcLon1. VcLon1 was expressed in Nicotiana benthamiana, and its homologous tobacco gene was silenced using RNAi. The differences in biomass growth, oxidative stress and chloroplast ultrastructure between wild type and transgenic Nicotiana benthaminana were analyzed after being subjected to Fe deficiency stress. The RT-PCR showed that the expression of VcLon1 was significantly higher in young leaves than in old leaves or in leaves treated with Fe deficiency stress, indicating that VcLon1 is involved in reactive oxygen species (ROS) homeostasis induced by senescence or Fe deficiency. Compared with wild-type, overexpression of VcLon1 in Nicotiana benthamiana reduced damage to chloroplast structure induced by Fe deficiency. Furthermore, the contents of H2O2, MDA and carbonylated protein in leaves were kept at a low level, and antioxidant enzyme activities in chloroplasts such as SOD and APX are also generally higher in chloroplasts with VcLon1 overexpression. In contrast, the oxidative stress levels in NbLon1 RNAi silenced Nicotiana benthamiana leaves showed opposite trends. Under Fe deficiency stress, VcLon1 reduces oxidative damage in plants by degrading carbonylated proteins in organelles such as chloroplasts and effectively maintains the structure and function of organelles and the activity of functional proteins, contributing to Fe use efficiency in plants.