Abstract
Key message
By measuring the cytokinin content directly and testing the sensitivity to the cytokinin inhibitor lovastatin, we demonstrated that tasg1 cytokinin metabolism is different from wild-type.
Abstract
Our previous studies have indicated that compared with wild-type (WT) plants, a wheat stay-green mutant tasg1 exhibited delayed senescence. In this study, we found that the root development of tasg1 occurred later than that of WT. The number of lateral roots was fewer, but the lateral root length was longer in tasg1 than in WT, which resulted in a lower root to shoot ratio in tasg1 than WT. The levels of cytokinin (CK), CK activity, and expression of CK metabolic genes were measured. We found that the total CK content in the root tips and leaf of tasg1 was greater than in WT. The accumulation of mRNA of the CK synthetic gene (TaIPT) in tasg1 was higher than in WT at 9 and 11 days during seedling growth, but the expression of CK oxidase gene (TaCKX) was significantly lower in tasg1. Furthermore, the CK inhibitor lovastatin was used to inhibit CK activity. When treated with lovastatin, both the chlorophyll content and thylakoid membrane protein stability were significantly lower in tasg1 than WT, consistent with the inhibited expression of senescence-associated genes (TaSAGs) in tasg1. Lovastatin treatment also inhibited the antioxidative capability of wheat seedlings, and tasg1 was more sensitive to lovastatin than WT, as indicated by the MDA content, protein carbonylation, and antioxidant enzyme activity. The decreased antioxidative capability after lovastatin treatment may be related to the down-regulation of some antioxidase genes. These results suggest that the CK metabolism was altered in tasg1, which may play an important role in its ability to delay senescence.
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Abbreviations
- WT:
-
Wild type
- CK:
-
Cytokinin
- EMS:
-
Ethyl methane sulphonate
- TTC:
-
Triphenyl tetrazolium chloride
- IPA:
-
Isopentenyl adenine
- ZR:
-
Zeatin riboside
- DHZR:
-
Dihydrozeatin riboside
- MDA:
-
Malondialdehyde
- SOD:
-
Superoxide dismutase
- APX:
-
Ascorbate peroxidase
- CAT:
-
Catalase
- POD:
-
Guaiacol peroxidase
- qRT-PCR:
-
Quantitative reverse transcription PCR
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This work was supported by National Natural Science Foundation of China (No. 31370304).
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We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.
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Communicated by B. Li.
W. Wang and Q. Hao have contributed equally to this work.
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Wang, W., Hao, Q., Tian, F. et al. The stay-green phenotype of wheat mutant tasg1 is associated with altered cytokinin metabolism. Plant Cell Rep 35, 585–599 (2016). https://doi.org/10.1007/s00299-015-1905-7
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DOI: https://doi.org/10.1007/s00299-015-1905-7