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Hereditas(Beijing) ›› 2019, Vol. 41 ›› Issue (6): 534-547.doi: 10.16288/j.yczz.19-026

• Research Article • Previous Articles     Next Articles

The role analysis of APX gene family in the growth and developmental processes and in response to abiotic stresses in Arabidopsis thaliana

Zeqin Li1,Jintao Li1,Jie Bing2,Genfa Zhang2()   

  1. 1. School of Forensic Medicine, Shanxi Medical University, Taiyuan 030001, China
    2. Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, China
  • Received:2019-02-08 Revised:2019-04-27 Online:2019-06-20 Published:2019-06-12
  • Contact: Zhang Genfa E-mail:gfzh@bnu.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(81701868);Supported by the National Natural Science Foundation of China(31470399);Supported by the National Natural Science Foundation of China(31872672);The Key Research and Development (R&D) Projects of Shanxi Province(201803D31069)

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Abstract:

Oxidative stress caused by reactive oxygen species (ROS) is one of the major abiotic stresses in plants. Under adverse growth conditions, the incoordination of various metabolic processes in plant cells can result in increased hydrogen peroxide (H2O2), thus causing a variety of threats and injuries to plant cells. Ascorbate peroxidase (APX) is an important enzyme to remove H2O2 in plants. In Arabidopsis thaliana, there are eight APX gene family members, including APX1?APX6, sAPX and tAPX. In this study, we analyzed the expression patterns of the eight APX genes in the wild-type and apx mutant plants at different developmental stages and under different abiotic stress conditions. Meanwhile, the tolerance of each apx mutant to salt, drought and heat stresses was studied. qRT-PCR analysis showed that during development (from 4 to 8 weeks old), APX1 and APX2 exhibited the highest and lowest expression levels, respectively. In addition, the expression levels of APX4, sAPX and tAPX decreased during development, while the expression of APX6 increased with the maturity of the plants. Moreover, under different abiotic stress conditions, APX1, APX2 and APX6 were significantly induced by heat stress, sAPX actively responded to salt stress, and APX3 and APX5 exhibited obvious responses to salt, drought and heat stresses. Further tolerance analysis showed that the resistance of all apx mutants to salt and drought stresses was lower than that of the wild-type plant at both germination and maturity stages. At germination stage, all apx mutants were more sensitive to drought stress than to salt stress. At maturity stage, the apx1 and apx6 mutants were more sensitive to salt and drought stresses than the wild-type and other apx mutant plants. The physiological indexes indicated that the H2O2 content in all mutants, especially in the apx1, sapx and tapx, was significantly higher than that in the wild type 10 days after drought stress treatment, the malondialdehyde (MDA) content in all mutants was significantly higher than that in the wild type 5 days after salt stress treatment, while heat stress treatment for 2 h resulted in a significant increase in the contents of H2O2 and MDA in apx1, apx2 and apx6, especially in apx2. Taken together, our study revealed that all eight APX members of Arabidopsis participate in the growth and developmental processes and the abiotic stress responses, with some specific APXs playing a major role in a certain process.

Key words: Arabidopsis thaliana, ascorbate peroxidase (APX), reactive oxygen species (ROS), abiotic stress response