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Yan H, Zhuang M, Xu X, Li S, Yang M, Li N, Du X, Hu K, Peng X, Huang W, Wu H, Tse YC, Zhao L, Wang H. Autophagy and its mediated mitochondrial quality control maintain pollen tube growth and male fertility in Arabidopsis. Autophagy 2023; 19:768-783. [PMID: 35786359 PMCID: PMC9980518 DOI: 10.1080/15548627.2022.2095838] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Macroautophagy/autophagy, a major catabolic pathway in eukaryotes, participates in plant sexual reproduction including the processes of male gametogenesis and the self-incompatibility response. Rapid pollen tube growth is another essential reproductive process that is metabolically highly demanding to drive the vigorous cell growth for delivery of male gametes for fertilization in angiosperms. Whether and how autophagy operates to maintain the homeostasis of pollen tubes remains unknown. Here, we provide evidence that autophagy is elevated in growing pollen tubes and critically required during pollen tube growth and male fertility in Arabidopsis. We demonstrate that SH3P2, a critical non-ATG regulator of plant autophagy, colocalizes with representative ATG proteins during autophagosome biogenesis in growing pollen tubes. Downregulation of SH3P2 expression significantly disrupts Arabidopsis pollen germination and pollen tube growth. Further analysis of organelle dynamics reveals crosstalk between autophagosomes and prevacuolar compartments following the inhibition of phosphatidylinositol 3-kinase. In addition, time-lapse imaging and tracking of ATG8e-labeled autophagosomes and depolarized mitochondria demonstrate that they interact specifically via the ATG8-family interacting motif (AIM)-docking site to mediate mitophagy. Ultrastructural identification of mitophagosomes and two additional forms of autophagosomes imply that multiple types of autophagy are likely to function simultaneously within pollen tubes. Altogether, our results suggest that autophagy is functionally crucial for mediating mitochondrial quality control and canonical cytoplasm recycling during pollen tube growth.Abbreviations: AIM: ATG8-family interacting motif; ATG8: autophagy related 8; ATG5: autophagy related 5; ATG7: autophagy related 7; BTH: acibenzolar-S-methyl; DEX: dexamethasone; DNP: 2,4-dinitrophenol; GFP: green fluorescent protein; YFP: yellow fluorescent protein; PtdIns3K: phosphatidylinositol 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PVC: prevacuolar compartment; SH3P2: SH3 domain-containing protein 2.
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Affiliation(s)
- He Yan
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Menglong Zhuang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaoyu Xu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Shanshan Li
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Mingkang Yang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Nianle Li
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaojuan Du
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Kangwei Hu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Xiaomin Peng
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Wei Huang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Hong Wu
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China.,State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou null China
| | - Yu Chung Tse
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Lifeng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
| | - Hao Wang
- Department of Cell and Developmental Biology, College of Life Sciences, South China Agricultural University, Guangzhou, Hong Kong, China
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