title: Regulation, overexpression, and target gene identification of Potato Homeobox 15 (POTH15) - a class-I KNOX gene in potato.
abstract: Potato Homeobox 15 (POTH15) is a KNOX-I (Knotted1-like homeobox) family gene in potato that is orthologous to Shoot Meristemless (STM) in Arabidopsis. Despite numerous reports on KNOX genes from different species, studies in potato are limited. Here, we describe photoperiodic regulation of POTH15, its overexpression phenotype, and identification of its potential targets in potato (Solanum tuberosum ssp. andigena). qRT-PCR analysis showed a higher abundance of POTH15 mRNA in shoot tips and stolons under tuber-inducing short-day conditions. POTH15 promoter activity was detected in apical and axillary meristems, stolon tips, tuber eyes, and meristems of tuber sprouts, indicating its role in meristem maintenance and leaf development. POTH15 overexpression altered multiple morphological traits including leaf and stem development, leaflet number, and number of nodes and branches. In particular, the rachis of the leaf was completely reduced and leaves appeared as a bouquet of leaflets. Comparative transcriptomic analysis of 35S::GUS and two POTH15 overexpression lines identified more than 6000 differentially expressed genes, including 2014 common genes between the two overexpression lines. Functional analysis of these genes revealed their involvement in responses to hormones, biotic/abiotic stresses, transcription regulation, and signal transduction. qRT-PCR of selected candidate target genes validated their differential expression in both overexpression lines. Out of 200 randomly chosen POTH15 targets, 173 were found to have at least one tandem TGAC core motif, characteristic of KNOX interaction, within 3.0kb in the upstream sequence of the transcription start site. Overall, this study provides insights to the role of POTH15 in controlling diverse developmental processes in potato.
authors.affiliation: Biology Division, Dr. Homi Bhabha Road, IISER Pune, Pune - 411008, Maharashtra, India.
authors.forename: Ameya S
authors.initials: AS
authors.lastname: Mahajan
authors.affiliation: Biology Division, Dr. Homi Bhabha Road, IISER Pune, Pune - 411008, Maharashtra, India.
authors.forename: Kirtikumar R
authors.initials: KR
authors.lastname: Kondhare
authors.affiliation: School of Biology, IISER TVM, Thiruvananthapuram (Trivandrum) - 695016, Kerala, India.
authors.forename: Mohit P
authors.initials: MP
authors.lastname: Rajabhoj
authors.affiliation: Biology Division, Dr. Homi Bhabha Road, IISER Pune, Pune - 411008, Maharashtra, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Dept. of Botany, SPP University (formerly University of Pune), Pune - 411007, Maharashtra, India.
authors.forename: Tejashree
authors.initials: T
authors.lastname: Ghate
authors.affiliation: Biological Sciences, IISER Bhopal, Bhopal - 462066, Madhya Pradesh, India.
authors.forename: Nevedha
authors.initials: N
authors.lastname: Ravindran
authors.affiliation: Biology Division, Dr. Homi Bhabha Road, IISER Pune, Pune - 411008, Maharashtra, India.
authors.forename: Farhat
authors.initials: F
authors.lastname: Habib
authors.affiliation: Division of Crop Improvement, Central Potato Research Institute, Shimla - 171001, India.
authors.forename: Sundaresha
authors.initials: S
authors.lastname: Siddappa
authors.affiliation: Biology Division, Dr. Homi Bhabha Road, IISER Pune, Pune - 411008, Maharashtra, India akb@iiserpune.ac.in.
authors.forename: Anjan K
authors.initials: AK
authors.lastname: Banerjee
mesh_terms: D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D017343:Genes, Plant / Q000235:genetics* / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000502:physiology; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000502:physiology; D011198:Solanum tuberosum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology
chemical_list: D018398:Homeodomain Proteins; D010940:Plant Proteins
keywords: KNOX target genes; Potato Homeobox 15 (POTH15); RNA sequencing; Solanum tuberosum.; leaf development; photoperiod; shoot apical meristem