Anthocyanin Biosynthesis Genes as Model Genes for Genome Editing in Plants

Abstract

CRISPR/Cas, one of the most rapidly developing technologies in the world, has been applied successfully in plant science. To test new nucleases, gRNA expression systems and other inventions in this field, several plant genes with visible phenotypic effects have been constantly used as targets. Anthocyanin pigmentation is one of the most easily identified traits, that does not require any additional treatment. It is also associated with stress resistance, therefore plants with edited anthocyanin genes might be of interest for agriculture. Phenotypic effect of CRISPR/Cas editing of PAP1 and its homologs, DFR, F3H and F3′H genes have been confirmed in several distinct plant species. DFR appears to be a key structural gene of anthocyanin biosynthesis, controlled by various transcription factors. There are still many promising potential model genes that have not been edited yet. Some of them, such as Delila, MYB60, HAT1, UGT79B2, UGT79B3 and miR156, have been shown to regulate drought tolerance in addition to anthocyanin biosynthesis. Genes, also involved in trichome development, such as TTG1, GLABRA2, MYBL2 and CPC, can provide increased visibility. In this review successful events of CRISPR/Cas editing of anthocyanin genes are summarized, and new model genes are proposed. It can be useful for molecular biologists and genetic engineers, crop scientists, plant genetics and physiologists.

Hairy CRISPR: Genome Editing in Plants Using Hairy Root Transformation

“…Further evaluation of anthocyanin pigmentation-based screenable markers showed that genes encoding proteins involved in the regulation of anthocyanin biosynthesis [ 216 ], including some of the earliest identified genes from maize [ 217 , 218 , 219 ] ( Table S2 ), belong to two large gene families, one encoding basic helix–loop–helix (bHLH) TFs and the other myeloblastosis (MYB) TFs [ 216 , 220 ]. Several members of the MYB and bHLH gene families from different plant species have also been proposed to serve as screenable markers over the last few years.…”

“…It was also reported, that detection of genome-edited rice regenerants by OsC1 screenable marker was also successful [ 227 ]. The diversity of genes regulating anthocyanin biosynthesis [ 216 ] leads to a wide choice of potential screenable markers in addition to the six already proposed. Conversely, the diversity of factors involved in the regulation of anthocyanin biosynthesis renders these factors unsuitable as universal screenable markers.…”

The comparisons of expression pattern reveal molecular regulation of fruit metabolites in S. nigrum and S. lycopersicum

“…In addition to AN2 , a number of transcription regulators were characterized in plant anthocyanin biosynthesis pathways 52 . We found that the expressions of orthologous genes of Production of Anthocyanin Pigment 1 ( PAP1 ), another MYB transcription factor known as an activator for anthocyanin biosynthetic genes in Arabidopsis , and Transparent Testa 8 ( TT8 ), a bHLH transcription activator for anthocyanin biosynthetic genes in tobacco, were enriched in the BF-cluster in S. nigrum .…”

Automatic identification and annotation of MYB gene family members in plants

“…Consumers prefer apricots with a red blush which is controlled by an anthocyanin biosynthesis activating MYB [ 42 ]. The identification of MYB candidate genes and the regulated processes is the first step towards modification through SMART breeding or genome editing [ 43 , 44 ]. This interest in MYBs sparked numerous genome-wide investigations in species with a new genome or transcriptome assembly [ 3 , 4 , 22 , 31 , 45 – 48 ].…”