Identification and functional characterization of knotted like homeobox genes in potato

Abstract

KNOX genes are ubiquitous to green plants and they are known to play vital role inplant development and patterning KNOX genes belong to a Three Amino acid LoopExtension TALE superclass of transcription factors Burglin et al 1997 KNOX TFsform a dimer with another family of TFs from TALE superclass viz The BELL TFs and acomplex network of KNOX BELL heterodimers regulate the target genes in a tissuespecific manner Bellaoui et al 2001 Smith et al 2002 Hay and Tsiantis 2010 In lowerplants KNOX genes regulate gamete identity and zygotic development Lee et al 2008 Sakakibara et al 2013 In angiosperms KNOX I genes are shown to regulate diversedevelopmental programs such as meristem maintenance leaf development floraldevelopment tuberization and so on Hay and Tsiantis 2010 Ragni et al 2007 Uchida etal 2010 In spite of an important role KNOX genes play in plant development only ahandful of KNOX target genes are identified so far Giacomo et al 2013 To have adeeper understanding about how the KNOX genes function it is crucial to identify theirtargets from various plant species Another important research question is how KNOXgene expression is regulated Our knowledge about regulation of KNOX gene expressionis limited to a few studies which have shown that KNOX gene expression is repressedoutside its expression domain by different epigenetic regulators Hay and Tsiantis 2010 It would be interesting to understand how KNOX gene expression is regulated acrossdifferent developmental pathways to generate diverse plant forms To investigate the KNOX gene function the model system chosen in the currentstudy is potato Solanum tuberosum The focus of this study is to understand the role ofKNOX genes in potato development and tuberization Previous to the present study onlyone potato KNOX gene Potato Homeobox1 POTH1 was studied and it was demonstratedto regulate vegetative development newline