Developmental characteristics of grapevine seedlings root border cells and their response to ρ-hydroxybenzoic acid

Abstract

ρ-hydroxybenzoic acid (4-HBA) is one of the major autotoxins that cause grapevine replant disease. Root border cells (RBCs) play an important role in plant defense. Although RBCs have been investigated in many plants, relevant information in grapevines is limited. In this study, we aimed to investigate the developmental characteristics of RBCs in the grapevine (Vitis riparia × Vitis labrusca) ‘Beta’ and their response to 4-HBA stress. RBCs were observed under a laser scanning confocal microscope. The phenolic acid composition of RBCs slime was determined by high-performance liquid chromatography. The level of gene expression was determined by quantitative real-time polymerase chain reaction. Grapevine RBCs have high biological activity, contain starch granules, and are surrounded by a mucilage layer. Root treatments using different concentrations of 4-HBA affected the development of RBCs and root growth, and induced the secretion of salicylic acid from the RBCs, which can stimulate, induce, and maintain the activity of antioxidant enzymes to some extent in the cells under 4-HBA stress. Grapevine RBCs may resist 4-HBA stress by increasing its number and enhancing their secondary metabolism and SA accumulation, which can induce the antioxidant defense system of the cells.