Abstract
Planar morphogenesis, a distinct feature of multicellular organisms, is crucial for the development of ovule, progenitor of seeds. Both receptor-like kinases (RLKs) such as STRUBBELIG (SUB) and auxin gradient mediated by PIN-FORMED1 (PIN1) play instructive roles in this process. Fine-tuned intercellular communications between different cell layers during ovule development demands dynamic membrane distribution of these cell-surface proteins, presumably through vesicle-mediated sorting. However, the way it's achieved and the trafficking routes involved are obscure. We report that HAPLESS13 (HAP13)-mediated trafficking of SUB is critical for ovule development. HAP13 encodes the μ subunit of adaptor protein 1 (AP1) that mediates protein sorting at the trans-Golgi network/early endosome (TGN/EE). The HAP13 mutant, hap13-1, is defective in outer integument growth, resulting in exposed nucellus accompanied with impaired pollen tube guidance and reception. SUB is mis-targeted in hap13-1. However, unlike that of PIN2, the distribution of PIN1 is independent of HAP13. Genetic interference of exocytic trafficking at the TGN/EE by specifically downregulating HAP13 phenocopied the defects of hap13-1 in SUB targeting and ovule development, supporting a key role of sporophytically expressed SUB in instructing female gametogenesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Protein Complex 1 / genetics*
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Arabidopsis / genetics
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Arabidopsis / growth & development
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Arabidopsis Proteins / biosynthesis
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Arabidopsis Proteins / genetics*
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Endosomes / genetics
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Gametogenesis, Plant / genetics
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Gene Expression Regulation, Plant
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Indoleacetic Acids / metabolism
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MADS Domain Proteins / biosynthesis
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MADS Domain Proteins / genetics
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Membrane Transport Proteins / biosynthesis
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Membrane Transport Proteins / genetics*
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Ovule / genetics*
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Ovule / growth & development
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Plant Development / genetics
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Protein Transport / genetics
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Receptor Protein-Tyrosine Kinases / biosynthesis
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Receptor Protein-Tyrosine Kinases / genetics*
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Signal Transduction
Substances
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AP1 protein, Arabidopsis
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AP1M2 protein, Arabidopsis
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Adaptor Protein Complex 1
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Arabidopsis Proteins
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Indoleacetic Acids
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MADS Domain Proteins
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Membrane Transport Proteins
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PIN1 protein, Arabidopsis
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PIN2 protein, Arabidopsis
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Receptor Protein-Tyrosine Kinases
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SUB protein, Arabidopsis
Grants and funding
This work was supported by Major Research Plan (2013CB945102) from the Ministry of Science, Technology of China, by Shandong Provincial Natural Science Foundation (ZR2014CM027 to SL), and by Shandong Provincial Funds for Outstanding Young Scientists (to YZ). YZ’s laboratory is partially supported by Tai-Shan Scholar Program by Shandong Provincial Government. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.