Influential factors and transcriptome analyses of immature diploid embryo anthocyanin accumulation in maize

Cloned genes and genetic regulation of anthocyanin biosynthesis in maize, a comparative review

Anthocyanins are plant-based pigments that are primarily present in berries, grapes, purple yam, purple corn and black rice. The research on fruit corn with a high anthocyanin content is not sufficiently extensive. Considering its crucial role in nutrition and health it is vital to conduct further studies on how anthocyanin accumulates in fruit corn and to explore its potential for edible and medicinal purposes. Anthocyanin biosynthesis plays an important role in maize stems (corn). Several beneficial compounds, particularly cyanidin-3-O-glucoside, perlagonidin-3-O-glucoside, peonidin 3-O-glucoside, and their malonylated derivatives have been identified. C1, C2, Pl1, Pl2, Sh2, ZmCOP1 and ZmHY5 harbored functional alleles that played a role in the biosynthesis of anthocyanins in maize. The Sh2 gene in maize regulates sugar-to-starch conversion, thereby influencing kernel quality and nutritional content. ZmCOP1 and ZmHY5 are key regulatory genes in maize that control light responses and photomorphogenesis. This review concludes the molecular identification of all the genes encoding structural enzymes of the anthocyanin pathway in maize by describing the cloning and characterization of these genes. Our study presents important new understandings of the molecular processes behind the manufacture of anthocyanins in maize, which will contribute to the development of genetically modified variants of the crop with increased color and possible health advantages.

The RUBY reporter enables efficient haploid identification in maize and tomato

In vivo haploid induction has been extended from maize to monocotyledonous plants like rice, wheat, millet and dicotyledonous plants such as tomato, rapeseed, tobacco and cabbage. Accurate identification of haploids is a crucial step of doubled haploid technology, where a useful identification marker is very pivotal. R1-nj is an extensively used visual marker for haploid identification in maize. RFP and eGFP have been shown to be feasible in identifying haploid. However, these methods are either limited to specific species, or require specific equipment. It still lacks an efficient visual marker that is practical across different crop species. In this study, we introduced the RUBY reporter, a betalain biosynthesis system, into maize and tomato haploid inducers as a new marker for haploid identification. Results showed that expression of RUBY could result in deep betalain pigmentation in maize embryos as early as 10 days after pollination, and enabled 100% accuracy of immature haploid embryo identification. Further investigation in tomato revealed that the new marker led to deep red pigmentation in radicles and haploids can be identified easily and accurately. The results demonstrated that the RUBY reporter is a background-independent and efficient marker for haploid identification and would be promising in doubled haploid breeding across different crop species.