{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T05:04:27Z","timestamp":1789967067621,"version":"4.0.1"},"reference-count":38,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T00:00:00Z","timestamp":1789948800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Plant Sci."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>The quality of flue-cured tobacco depends on nutrient acquisition, carbon\u2013nitrogen allocation, and quality-related secondary metabolism, particularly phenylpropanoid and flavonoid pathways. However, whether fertilizer placement and exogenous soil metabolite formulations can jointly improve leaf nutritional physiology and cured-leaf quality remains unclear.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      A field experiment was conducted with the flue-cured tobacco cultivar Yunyan 87 (\n                      <jats:italic>Nicotiana tabacum<\/jats:italic>\n                      L.). Six treatments combined two fertilizer placement methods, strip application and well-cellar application, with two soil metabolite formulations at the same total fertilizer application rate. Nitrogen, phosphorus, and potassium contents and the activities of polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), and sucrose-phosphate synthase (SPS) were determined in mature middle leaves. Sensory evaluation of cured leaves was integrated with transcriptomic, metabolomic, multi-omics, and weighted gene co-expression network analyses.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Compared with conventional strip application (CK1), well-cellar application (CK2) increased leaf nitrogen, phosphorus, and potassium contents by 4.45%, 7.57%, and 6.89%, respectively, with significant increases in nitrogen and potassium. Relative to CK2, A3 (well-cellar application with soil metabolite formulation 1) and A4 (well-cellar application with soil metabolite formulation 2) increased PPO activity by 29.49% and 28.16%, respectively, and PAL activity by 81.08% and 73.91%, respectively, whereas SPS activity showed only a non-significant upward trend. A3, which combined well-cellar application with soil metabolite formulation 1, showed the best overall sensory profile, with improved aroma quality, reduced irritancy and off-odors, and greater smoke softness. Transcriptomic and metabolomic analyses showed that treatment-responsive genes and metabolites were mainly associated with plant hormone signaling, photosynthesis, sugar and amino acid metabolism, and phenylpropanoid and flavonoid biosynthesis. Integrated omics analysis revealed treatment-dependent changes in phenylpropanoid\u2013flavonoid metabolism. Weighted gene co-expression network analysis (WGCNA) identified a darkgreen module containing 4,363 genes that was significantly correlated with several flavonoid-related metabolites, including quercetin, kaempferol, myricetin, and 5,7-dihydroxyflavanone (\n                      <jats:italic>r<\/jats:italic>\n                      \u00a0=\u00a00.56\u20130.69), and eight candidate hub genes were identified.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Well-cellar application combined with soil metabolite formulation 1 may improve nitrogen and potassium status in mature leaves and coordinate phenylpropanoid\u2013flavonoid metabolism and quality-precursor accumulation, thereby enhancing the overall sensory quality of cured leaves. These findings highlight fertilizer placement as an important determinant of soil metabolite formulation performance and provide a theoretical basis for precision rhizosphere fertilization and the rational use of soil metabolite formulations in flue-cured tobacco production.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fpls.2026.1949823","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T04:29:16Z","timestamp":1789964956000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Fertilizer placement modulates the effects of soil metabolite formulations on nutrient status, phenylpropanoid\u2013flavonoid metabolism, and sensory quality in flue-cured tobacco"],"prefix":"10.3389","volume":"17","author":[{"given":"Xu","family":"Wei","sequence":"first","affiliation":[{"name":"College of Agronomy and Biotechnology, Southwest University\/Engineering Research Center of South Upland Agriculture, Ministry of Education","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongxun","family":"Li","sequence":"additional","affiliation":[{"name":"Guizhou Academy of Tobacco Science","place":["Guiyang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Longchang","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Agronomy and Biotechnology, Southwest University\/Engineering Research Center of South Upland Agriculture, Ministry of Education","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Zhang","sequence":"additional","affiliation":[{"name":"Anshun Municipal Company of Guizhou Provincial Tobacco Company","place":["Anshun, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yechun","family":"Lin","sequence":"additional","affiliation":[{"name":"Guizhou Academy of Tobacco Science","place":["Guiyang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kai","family":"Cai","sequence":"additional","affiliation":[{"name":"Guizhou Academy of Tobacco Science","place":["Guiyang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shengqiang","family":"Peng","sequence":"additional","affiliation":[{"name":"China Tobacco Hebei Industrial Co., Ltd.","place":["Shijiazhuang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiawen","family":"Yuan","sequence":"additional","affiliation":[{"name":"Anshun Municipal Company of Guizhou Provincial Tobacco Company","place":["Anshun, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lili","family":"Chen","sequence":"additional","affiliation":[{"name":"Guizhou Academy of Tobacco Science","place":["Guiyang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yihe","family":"Sun","sequence":"additional","affiliation":[{"name":"Guizhou Academy of Tobacco Science","place":["Guiyang, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1016\/j.micres.2023.127564","article-title":"Harnessing root exudates for plant microbiome engineering and stress resistance in plants","volume":"279","author":"Afridi","year":"2024","journal-title":"Microbiol. 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