The auxin-resistant dgt tomato mutant grows less than the wild type but is less sensitive to ammonium toxicity and nitrogen deficiency
The low-auxin-sensitivity tomato mutant, dgt, despite displaying reduced plant growth, has been linked to greater resistance to N deficiency. This led us to test the role of auxin resistance of dgt in NH toxicity and N deficiency, compared to wild type tomato (cv. Micro-Tom, MT), grown in hydroponic media. A completely randomized design with three replications in a 2 × 4 factorial scheme was adopted, corresponding to the two tomato genotypes (MT and dgt), involving four nutritional treatments: NO (5 mM); NH (5 mM); NO (5 mM) plus exogenous auxin (10 μM IAA); and N omission. The results show that NH was toxic to MT but not to dgt. Under N deficiency, MT displayed a lower shoot NO content, a lower photosynthetic rate, and a decrease in both shoot and root dry weight. However, in dgt, no difference was observed in shoot NO content and photosynthetic rate between plants grown on NO or under N deficiency. In addition, dgt showed an increase in shoot dry weight under N deficiency. We highlight the role of auxin resistance in the adaptation of plants to NH toxicity and N deficiency.
Main Authors: | , , , , , , , , |
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Format: | artículo biblioteca |
Published: |
Elsevier BV
2020-09
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Subjects: | Low nitrogen, Ammonium toxicity, Nitrogen limitation adaptationIndoleacetic acid, |
Online Access: | http://hdl.handle.net/10261/227983 |
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Summary: | The low-auxin-sensitivity tomato mutant, dgt, despite displaying reduced plant growth, has been linked to greater resistance to N deficiency. This led us to test the role of auxin resistance of dgt in NH toxicity and N deficiency, compared to wild type tomato (cv. Micro-Tom, MT), grown in hydroponic media. A completely randomized design with three replications in a 2 × 4 factorial scheme was adopted, corresponding to the two tomato genotypes (MT and dgt), involving four nutritional treatments: NO (5 mM); NH (5 mM); NO (5 mM) plus exogenous auxin (10 μM IAA); and N omission. The results show that NH was toxic to MT but not to dgt. Under N deficiency, MT displayed a lower shoot NO content, a lower photosynthetic rate, and a decrease in both shoot and root dry weight. However, in dgt, no difference was observed in shoot NO content and photosynthetic rate between plants grown on NO or under N deficiency. In addition, dgt showed an increase in shoot dry weight under N deficiency. We highlight the role of auxin resistance in the adaptation of plants to NH toxicity and N deficiency. |
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