Glucose-dependent acidification strategy by nectar-dwelling bacteria mediates pollen tube burst

Glucose-dependent acidification strategy by nectar-dwelling bacteria mediates pollen tube burst | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Glucose-dependent acidification strategy by nectar-dwelling bacteria mediates pollen tube burst Yoshinobu Kato, Hiroki Miura, Seiji Takayama, Sota Fujii This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7063044/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 07 May, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Floral nectary gland serves as an ecological hub, including a habitat for microorganisms introduced by pollinators. Although nectar supplies abundant carbon sources, it is limited in nitrogen sources. To address this unbalanced nutritional condition, it is considered that some nectar-dwelling bacteria including those belong to genus Acinetobacter obtain nutrients from pollen protoplasm by inducing pollen tube burst. Here, using gas chromatography-mass spectrometry, we identified gluconic acid in A. nectaris and A. pollinis as the substance responsible for triggering pollen tube burst via acidification of the surrounding environments. Through whole-genome sequencing and functional analysis, we identified a membrane-bound pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase which produces gluconic acid. Notably, nectar-dwelling Acinetobacter species consistently retain PQQ biosynthetic genes, and expression of the PQQ precursor peptide gene was upregulated in the presence of glucose, suggesting that these bacteria can synthesize PQQ and gluconic acid immediately upon entering the nectary gland. Taken together with previous findings, this glucose-dependent acidification is beneficial for both efficient carbon source utilization and nutrient landscape modification, a bacterial adaptive strategy well-suited to the competitive nectar environment. Biological sciences/Microbiology/Bacteria/Bacterial secretion Biological sciences/Microbiology/Bacteria/Bacterial genomics Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SupplementaryTable1.pdf Supplementary Table 1 | List of RefSeq or GenBank assembly IDs identified through reciprocal BLASTp searches. SupplementaryTable2.pdf Supplementary Table 2 | Gene expression levels of a PQQ-dependent glucose dehydrogenase and PQQ biosynthetic factors normalized by transcripts per million (TPM). SupplementaryTable3.pdf Supplementary Table 3 | Oligonucleotides used in this study. SupplementaryTable4.pdf Supplementary Table 4 | List of RefSeq or GenBank assembly IDs used for reconstructing the phylogenomic tree. SupplementaryTable5.pdf Supplementary Table 5 | List of RefSeq or GenBank IDs used for reciprocal BLASTp analysis. Cite Share Download PDF Status: Published Journal Publication published 07 May, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7063044","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":500478448,"identity":"6a5dcd83-e369-4dd1-ad72-3356ce021a67","order_by":0,"name":"Yoshinobu 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