Search

Abstract Background As one of the major food crops in the world, rice is vulnerable to cadmium (Cd) pollution. Understanding of the molecular mechanisms of Cd uptake, transport and detoxification in rice is essential for the breeding of low-Cd rice. However, the molecular mechanisms underlying the response of rice to Cd stress remains to be further clarified. Results In this study, a novel Cd-responsive gene OsHARBI1-1 was identified in the rice genome and its expression pattern and function were characterized. Bioinformatics analysis showed that the promoter region of OsHARBI1-1 had multiple cis-acting elements in response to phytohormones and stress, and the expression of OsHARBI1-1 was induced by phytohormones. OsHARBI1-1 protein was targeted to the nucleus. qRT-PCR analysis results showed that the expression of OsHARBI1-1 in the roots was repressed while the expression in the shoots was increased under Cd stress. Heterologous expression of OsHARBI1-1 in yeast conferred tolerance to Cd and reduced Cd content in the cells. Meanwhile, the expression of OsHARBI1-1 in Arabidopsis thaliana (A. thaliana) enhanced the tolerance of A. thaliana to Cd stress. In addition, compared with the wild type plants, the POD activity of transgenic plants was increased, while the SOD and CAT activities were decreased. Interestingly, the accumulation of Cd in the roots of A. thaliana expressing OsHARBI1-1 was significantly increased, whereas the Cd accumulation in the shoots was slightly decreased. Compared to the WT plants, the expression of genes related to Cd absorption and chelation was upregulated in transgenic A. thaliana under Cd stress, while the expression of genes responsible for the translocation of Cd from the roots to the shoots was downregulated. Moreover, the expression of phytohormone-related genes was significantly influenced by the expression of OsHARBI1-1 with and without Cd treatment. Conclusions Findings of this study suggest that OsHARBI1-1 might play a role in the response of plants to Cd response by affecting antioxidant enzyme activities, Cd chelation, absorption and transport, and phytohormone homeostasis and signaling.

Background: As one of the major food crops in the world, rice is vulnerable to cadmium (Cd) pollution. Understanding of the molecular mechanisms of Cd uptake, transport and detoxification in rice is essential for the breeding of low-Cd rice. However, the molecular mechanisms underlying the response of rice to Cd stress remains to be further clarified. Results: In this study, a novel Cd-responsive gene OsHARBI1-1 was identified in the rice genome and its expression pattern and function were characterized. Bioinformatics analysis showed that the promoter region of OsHARBI1-1 had multiple cis-acting elements in response to phytohormones and stress, and the expression of OsHARBI1-1 was induced by phytohormones. OsHARBI1-1 protein was targeted to the nucleus. qRT-PCR analysis results showed that the expression of OsHARBI1-1 in the roots was repressed while the expression in the shoots was increased under Cd stress. Heterologous expression of OsHARBI1-1 in yeast conferred tolerance to Cd and reduced Cd content in the cells. Meanwhile, the expression of OsHARBI1-1 in Arabidopsis thaliana (A. thaliana) enhanced the tolerance of A. thaliana to Cd stress. In addition, compared with the wild type plants, the POD activity of transgenic plants was increased, while the SOD and CAT activities were decreased. Interestingly, the accumulation of Cd in the roots of A. thaliana expressing OsHARBI1-1 was significantly increased, whereas the Cd accumulation in the shoots was slightly decreased. Compared to the WT plants, the expression of genes related to Cd absorption and chelation was upregulated in transgenic A. thaliana under Cd stress, while the expression of genes responsible for the translocation of Cd from the roots to the shoots was downregulated. Moreover, the expression of phytohormone-related genes was significantly influenced by the expression of OsHARBI1-1 with and without Cd treatment. Conclusions: Findings of this study suggest that OsHARBI1-1 might play a role in the response of plants to Cd response by affecting antioxidant enzyme activities, Cd chelation, absorption and transport, and phytohormone homeostasis and signaling. [ABSTRACT FROM AUTHOR]

Abstract Background As a vital osmoticum, proline has an important role in enhancing the tolerance of plants to environmental stress. It is unclear whether the application of exogenous proline can improve the tolerance of Brassica juncea to cadmium (Cd). Results This study investigated the effects of different concentrations of proline (20, 40, 60, 80, and 100 mg/L) under Cd stress at different times (0 d, 2 d, and 7 d) on the growth and physiology of B. juncea. Treatment with exogenous proline not only increased the content of proline in B. juncea but also alleviated Cd-induced seedling growth inhibition via the maintenance of higher photosynthetic pigment content and cell viability and a decrease in the content of Cd. Moreover, it increased the activities of antioxidant enzymes and the glutathione/glutathione disulfide ratio to reduce the accumulation of reactive oxygen species. Compared with other concentrations, 60 mg/L of exogenous proline was the most effective at mitigating Cd toxicity in B. juncea. Conclusions Exogenous proline treatment enhanced the tolerance to Cd via a decrease in Cd accumulation and reestablishment of the redox homeostasis in B. juncea.

Background: As a vital osmoticum, proline has an important role in enhancing the tolerance of plants to environmental stress. It is unclear whether the application of exogenous proline can improve the tolerance of Brassica juncea to cadmium (Cd). Results: This study investigated the effects of different concentrations of proline (20, 40, 60, 80, and 100 mg/L) under Cd stress at different times (0 d, 2 d, and 7 d) on the growth and physiology of B. juncea. Treatment with exogenous proline not only increased the content of proline in B. juncea but also alleviated Cd-induced seedling growth inhibition via the maintenance of higher photosynthetic pigment content and cell viability and a decrease in the content of Cd. Moreover, it increased the activities of antioxidant enzymes and the glutathione/glutathione disulfide ratio to reduce the accumulation of reactive oxygen species. Compared with other concentrations, 60 mg/L of exogenous proline was the most effective at mitigating Cd toxicity in B. juncea. Conclusions: Exogenous proline treatment enhanced the tolerance to Cd via a decrease in Cd accumulation and reestablishment of the redox homeostasis in B. juncea. [ABSTRACT FROM AUTHOR]