DNA markers based on retrotransposon insertion polymorphisms can detect short DNA fragments for strawberry cultivar identification.

In this study, DNA markers were developed for discrimination of strawberry ( × L.) cultivars based on retrotransposon insertion polymorphisms. We performed a comprehensive genomic search to identify retrotransposon insertion sites and subsequently selected one retrotransposon family, designated CL3, which provided reliable discrimination among strawberry cultivars.

Efficient screening of long terminal repeat retrotransposons that show high insertion polymorphism via high-throughput sequencing of the primer binding site.

Retrotransposons have been used frequently for the development of molecular markers by using their insertion polymorphisms among cultivars, because multiple copies of these elements are dispersed throughout the genome and inserted copies are inherited genetically. Although a large number of long terminal repeat (LTR) retrotransposon families exist in the higher eukaryotic genomes, the identification of families that show high insertion polymorphism has been challenging. Here, we performed an efficient screening of these retrotransposon families using an Illumina HiSeq2000 sequencing platform with comprehensive LTR library construction based on the primer binding site (PBS), which is located adjacent to the 5' LTR and has a motif that is universal and conserved among LTR retrotransposon families.

A GAL4-based targeted activation tagging system in Arabidopsis thaliana.

Activation tagging is a powerful tool for discovering novel genes that are not easily identified by loss-of-function (lof) screening due to genetic redundancy or lethality. Although the current activation tagging system, which involves a viral enhancer sequence, has been used for a decade, alternative methods that allow organ- or tissue-specific activation are required to identify genes whose strong activation leads to loss of fertility or viability. Here, we established a GAL4/UAS activation-tagging system in Arabidopsis thaliana.

The Arabidopsis RWP-RK protein RKD4 triggers gene expression and pattern formation in early embryogenesis.

Morphogenesis of seed plants commences with highly stereotypical cell division sequences in early embryogenesis [1, 2]. Although a small number of transcription factors and a mitogen-activated protein (MAP) kinase cascade have been implicated in this process [3-8], pattern formation in early embryogenesis remains poorly understood. We show here that the Arabidopsis RKD4, a member of the RWP-RK motif-containing putative transcription factors [9], is required for this process.