Resveratrol Improves the Iron Deficiency Adaptation of Malus Baccata Seedlings by Regulating Iron Absorption, Phytohormone Content, and ROS Migration

Abstract

Resveratrol (Res), a phytoalexin, has been widely reported to participate in plant resistance to fungal infections. However, little information is available on its role in abiotic stress, especially in iron deficiency stress. Malus baccata is widely used as apple rootstock in China, but it is sensitive to iron deficiency. In this study, we investigated the role of exogenous Res in M. baccata seedings under iron deficiency stress. Results showed that applying 100 µmol exogenous Res could alleviate iron deficiency stress. The seedlings treated with Res had a lower etiolation rate and higher chlorophyll content and photosynthetic rate compared with the apple seedlings without Res treatment. Exogenous Res increased the iron content in the roots and leaves by inducing the expression of MbAHA genes and improving the H+-ATPase activity. As a result, the rhizosphere pH decreased, iron solubility increased, the expression of MbFRO2 and MbIRT1 was induced, and the ferric-chelated reductase activity was enhanced to absorb large amounts of Fe2+ into the root cells under iron deficiency conditions. Moreover, exogenous Res application increased the contents of IAA, ABA, and GA3 and decreased the contents of DHZR and BL for responding to iron deficiency stress indirectly. In addition, Res functioned as an antioxidant that strengthened the activities of antioxidant enzymes and thus eliminated reactive oxygen species production induced by iron deficiency stress. These findings are expected to enhance the application and examination of the physiological role of Res under iron deficiency stress in apples.

Brassinolide improves the tolerance of Malus hupehensis to alkaline stress

“…After 15 days of alkaline stress and BL treatment, the phenotype of the apple seedlings was recorded. Wilting rate, plant height, fresh weight (FW), dry weight (DW), chlorophyll content, and photosynthetic rate were measured as described by Zheng et al (2021). Total root length and fibrous root number were analyzed by root scanner (Epson, Beijing, China).…”

“…After alkaline stress and exogenous BL treatments, the total RNA of different groups was extracted using the RNAprep pure Plant Plus Kit (Tiangen, Beijing, China). Inverse transcription and qPCR assay were conducted as described by Zheng et al (2021). MhActin (accession number: MDP0000774288) was used as internal control.…”