Azospirillum brasilense and Azospirillum argentinense inoculation and salt stress modify antioxidant enzymes profile during in vitro rooting of jojoba

Abstract

Jojoba (Simmondsia chinensis) is an evergreen dioecious shrub widely grown in many countries to obtain a liquid wax with several uses. Salt stress is one of the main abiotic stresses that negatively affects plant growth and development and reduces crop yield. Salt stress causes oxidative stress that leads to the formation of ROS (reactive oxygen species), which causes severe damage to cell structures by oxidation of cell membranes. However, the antioxidant enzyme system is also triggered as a defense mechanism during stress conditions. The antioxidant enzymes, such as peroxidase (PO), phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO), and catalase (CAT), are regularly engaged in controlling the ROS quantities. This work analyzes the effect of bacterization with Azospirillum brasilense Cd and Azospirillum argentinense Az39 on the adventitious rooting of jojoba under salinity stress. PO, PAL, PPO, and CAT activities were determined on days 0, 3, 6, 9, 12, and 15 of culture. A. brasilense Cd and A. argentinense Az39 promoted jojoba shoots rhizogenesis in salt stress conditions and modified the activity of antioxidant enzymes during the in vitro rooting process. The changes in enzymatic profiles observed could explain the better rooting abilities of jojoba-inoculated plants under salt stress conditions and the higher abiotic stress tolerance.