Format: ORAL

Zijian Liu1, Xiaoxiao Zhao1, Wenfei Xian1, Jeffrey J. Doyle2, James Euan3, Shifeng Cheng1

1 Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences (AGIS, CAAS), No 7,Pengfei Road,Dapeng District,Shenzhen, Guangdong, 518120, China. E-mail: chengshifeng@caas.cn 2 School of Integrative Plant Science, Sections of Plant Biology and Plant Breeding & Genetics, Cornell University, Ithaca, NY, 14853 USA. Email: jjd5@cornell.edu 3 The James Hutton Institute, Invergowrie, Dundee DD2 5DA. Charity No. SC041796. Email: Euan.James@hutton.ac.uk

Leguminosae is the third largest angiosperm family in species richness, spreading and adapting globally in a wide range of ecology. Many legumes are economically important food crops offering highly nutritious sources of protein and micronutrients for human beings and animals, which can partly attributed to its successful establishment of the nitrogen-fixing root-nodule symbiosis (RNS) with the mutualistic nitrogen-fixing bacteria. 95% of RNS are restricted in Legumes, however, how RNS in Leguminosae rised, stabilized, and widely adapted remains an unsolved mystery. With the development ofgenomic sequencing technologies and bioinformatics, the ability to sequence everything for an entire genus or even for an entire family, is becoming a reality. We thus initiated the Legume Genome Sequencing Consortium and started the Legume Nodulation and NFNC Phylogenomics v2.0 Project. 32 representative new legume species, carefully selected from all the six sub-families (Cercidoideae, Detarioideae, Duparquetioideae, Dialioideae, Caesalpinioideae, and Papilionoideae) as the diverse comparison pairs of nodulating plants together with their closest non-nodulating relatives, are sequenced (PacBio + HiC), assembled and annotated into high-quality chromosome-level genome references. In addition, a matched phylo-pantranscriptome from these species was constructed. This effort opens new ways to explore diversity of RNS in a broad comparative context (phylogenomics), to gain a deeper and more holistic view of the evolution in protein-coding genes, conserved non-coding elements, and differential gene expression for RNS, to utlinately reveal the molecular evolutionary mechanism of RNS either by divergence from a common ancestor over 100 million years ago or by convergence following independent origins over that same time period. This study also provides great opportunity to understand the diversification and adaptation of Legumes.