biostudies-literatureWang QMinisterio de Ciencia, Innovación y UniversidadesMEC | Agencia Estatal de InvestigaciónMOST | National Key Research and Development Program of ChinaComunidad de MadridNational Natural Science Foundation of Chinae2215569119https://www.ebi.ac.uk/biostudies/studies/S-EPMC9897438biostudies-literatureUnknown119(50)The flattened leaf form is an important adaptation for efficient photosynthesis, and the developmental process of flattened leaves has been intensively studied. Classic microsurgery studies in potato and tomato suggest that the shoot apical meristem (SAM) communicates with the leaf primordia to promote leaf blade formation. More recently, it was found that polar auxin transport (PAT) could mediate this communication. However, it is unclear how the expression of leaf patterning genes is tailored by PAT routes originating from SAM. By combining experimental observations and computer model simulations, we show that microsurgical incisions and local inhibition of PAT in tomato interfere with auxin transport toward the leaf margins, reducing auxin response levels and altering the leaf blade shaProceedings of the National Academy of Sciences of the United States of AmericaPolar auxin transport modulates early leaf flattening.PMC9897438322300102019YFA0903901SEV-2016-0672 (2017-2021)2017-T1/BIO-5654PGC2018-093387-A-I00Wang QGuan CJiao YWabnik KMarconi MfalsePolar auxin transport modulates early leaf flattening.The flattened leaf form is an important adaptation for efficient photosynthesis, and the developmental process of flattened leaves has been intensively studied. Classic microsurgery studies in potato and tomato suggest that the shoot apical meristem (SAM) communicates with the leaf primordia to promote leaf blade formation. More recently, it was found that polar auxin transport (PAT) could mediate this communication. However, it is unclear how the expression of leaf patterning genes is tailored by PAT routes originating from SAM. By combining experimental observations and computer model simulations, we show that microsurgical incisions and local inhibition of PAT in tomato interfere with auxin transport toward the leaf margins, reducing auxin response levels and altering the leaf blade sha2022-01-01T00:00:00Z2022 Dec2025-04-05T13:31:30.686Z2025-04-05T13:31:30.686ZS-EPMC98974383646977310.1073/pnas.2215569119