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Li Y, Yuan W, Li L, Dai H, Dang X, Miao R, Baluška F, Kronzucker HJ, Lu C, Zhang J, Xu W. Comparative analysis reveals gravity is involved in the MIZ1-regulated root hydrotropism. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:7316-7330. [PMID: 32905588 DOI: 10.1093/jxb/eraa409] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 09/07/2020] [Indexed: 06/11/2023]
Abstract
Hydrotropism is the directed growth of roots toward the water found in the soil. However, mechanisms governing interactions between hydrotropism and gravitropism remain largely unclear. In this study, we found that an air system and an agar-sorbitol system induced only oblique water-potential gradients; an agar-glycerol system induced only vertical water-potential gradients; and a sand system established both oblique and vertical water-potential gradients. We employed obliquely oriented and vertically oriented experimental systems to study hydrotropism in Arabidopsis and tomato plants. Comparative analyses using different hydrotropic systems showed that gravity hindered the ability of roots to search for obliquely oriented water, whilst facilitating roots' search for vertically oriented water. We found that the gravitropism-deficient mutant aux1 showed enhanced hydrotropism in the oblique orientation but impaired root elongation towards water in the vertical orientation. The miz1 mutant exhibited deficient hydrotropism in the oblique orientation but normal root elongation towards water in the vertical orientation. Importantly, in contrast to miz1, the miz1/aux1 double mutant exhibited hydrotropic bending in the oblique orientation and attenuated root elongation towards water in the vertical orientation. Our results suggest that gravitropism is required for MIZ1-regulated root hydrotropism in both the oblique orientation and the vertical orientation, providing further insight into the role of gravity in root hydrotropism.
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Affiliation(s)
- Ying Li
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - Wei Yuan
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - Luocheng Li
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - Hui Dai
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - Xiaolin Dang
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - Rui Miao
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
| | - František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | - Congming Lu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Taian, Shandong, China
| | - Jianhua Zhang
- Department of Biology, Hong Kong Baptist University, Stake Key Laboratory of Agrobiotechnology and Chinese University of Hong Kong, Hong Kong
| | - Weifeng Xu
- Center for Plant Water-use and Nutrition Regulation and College of Life Sciences, Joint International Research Laboratory of Water and Nutrient in Crop and college of Resource and Environment, Fujian Agriculture and Forestry University, Jinshan, Fuzhou, China
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