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Hao GJ, Li LS, Zhao XY, Ying J, Zhang MM, Cui XC, Sun T, Li E, Su LY, Shen J, Zhou X, Zhu X, Li S, Zhang Y. Canonical Rab5 GTPases are essential for pollen tube growth through style in Arabidopsis. New Phytol 2023. [PMID: 37301984 DOI: 10.1111/nph.19059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Accepted: 05/13/2023] [Indexed: 06/12/2023]
Abstract
Pollen tubes have dynamic tubular vacuoles. Functional loss of AP-3, a regulator of one vacuolar trafficking route, reduces pollen tube growth. However, the role of canonical Rab5 GTPases that are responsible for two other vacuolar trafficking routes in Arabidopsis pollen tubes is obscure. By using genomic editing, confocal microscopy, pollen tube growth assays, and transmission electron microscopy, we demonstrate that functional loss of canonical Rab5s in Arabidopsis, RHA1 and ARA7, causes the failure of pollen tubes to grow through style and thus impairs male transmission. Functional loss of canonical Rab5s compromises vacuolar trafficking of tonoplast proteins, vacuolar biogenesis, and turgor regulation. However, rha1;ara7 pollen tubes are comparable to those of wild-type in growing through narrow passages by microfluidic assays. We demonstrate that functional loss of canonical Rab5s compromises endocytic and secretory trafficking at the plasma membrane (PM), whereas the targeting of PM-associated ATPases is largely unaffected. Despite that, rha1;ara7 pollen tubes contain a reduced cytosolic pH and disrupted actin microfilaments, correlating with the mis-targeting of vacuolar ATPases (VHA). These results imply a key role of vacuoles in maintaining cytoplasmic proton homeostasis and in pollen tube penetrative growth through style.
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Affiliation(s)
- Guang-Jiu Hao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Lu-Shen Li
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xin-Ying Zhao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Jun Ying
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Miao-Miao Zhang
- College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xue-Chun Cui
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Tiantian Sun
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - En Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Le-Yan Su
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Jinbo Shen
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Xiang Zhou
- FAFU-UCR Joint Center for Horticultural Plant Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Xiaoyue Zhu
- FAFU-UCR Joint Center for Horticultural Plant Biology and Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, China
| | - Sha Li
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, 271018, China
| | - Yan Zhang
- College of Life Sciences, Nankai University, Tianjin, 300071, China
- Frontiers Science Center for Cell Responses, Nankai University, Tianjin, 300071, China
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