The sequencing of the bitter genome reveals the biosynthetic and reversible mechanism of reedin

is one of the rare medicinal crops with good economic value and development potential. Bitter is a stone bamboo python, originated in southwestern China, with high aluminum, drought- and cold-resistant characteristics, suitable for high-altitude drought or soil fertility in the region. Bitter seeds have high nutritional value, high protein content and rich in essential amino acids that humans can not synthesize, but also contain a variety of vitamins and minerals, especially bitter seeds contain a large number of medicinal flavonoid compound reeds. Bitter flour, which contains no gluten protein, is an excellent cereal substitute for gluten-sensitive people and has become increasingly popular in recent years. However, there are bottlenecks in the breeding and processing of bitters, which limit the increase of their yield and the promotion of large-scale cultivation.
Liang Chengzhi of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, together with George Jun of Shanxi Academy of Agricultural Sciences and professor Wang Jun of South China Agricultural University, and other teams have obtained the 489.3Mb sequence of the high-quality reference genome for the first time, and annotated 33,366 protein-coded genes. The study found that bitters experienced a recent independent genome-wide replication event about 60 million years ago, which led to the amplification and retention of many resistant-related genes in the genome. Based on comparative genomics and transcriptomics, genes encoding various enzymes on the reedin metabolic pathway and MYB transcription factors that regulate the expression of these genes were identified. In addition, the study found a large number of new genes that may be associated with plant aluminum, drought and cold resistance, the product of which includes some transport proteins and associated transcription factors. This study shows that the ability to withstand high levels of abstinance is most likely due to the amplification of related gene families involved in signal transductivity, membrane transport, and gene transcription regulation. This study helps turn bitters into a model plant for studying resistance. All along, bitter hybrid breeding has been difficult in production practice, mainly because its flower organs are too small (about 2mm). The obtainion of this reference genome will help to create a large flower of bitters through mutant screening combined with comparative genomics research, so that hybrid breeding becomes a routine breeding work, so as to increase the yield of bitters as soon as possible, or increase the size of seeds, make the processing of bitters easy, and eliminate bitter factors (reed hydrolyzed enzymes in seeds), thereby promoting the development of the bitters.
the study was published online August 31, 2017 in the journal
(DOI: 10.1016/j.molp.2017.08.013). Zhang Lijun, associate researcher of Shanxi Academy of Agricultural Sciences, and Li Xiuxiu, ph.D. student of Liang Chengzhi Research Group, engineer Ma Bin, Gao Qiang and doctoral student Du Willlong are co-authors of the paper. (Source: Science.com)