AUTHOR=Lu Qing , Li Haifen , Hong Yanbin , Zhang Guoqiang , Wen Shijie , Li Xingyu , Zhou Guiyuan , Li Shaoxiong , Liu Hao , Liu Haiyan , Liu Zhongjian , Varshney Rajeev K. , Chen Xiaoping , Liang Xuanqiang 

TITLE=Genome Sequencing and Analysis of the Peanut B-Genome Progenitor (Arachis ipaensis)

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.00604

DOI=10.3389/fpls.2018.00604

ISSN=1664-462X

ABSTRACT=<p>Peanut (<italic>Arachis hypogaea</italic> L.), an important leguminous crop, is widely cultivated in tropical and subtropical regions. Peanut is an allotetraploid, having A and B subgenomes that maybe have originated in its diploid progenitors <italic>Arachis duranensis</italic> (A-genome) and <italic>Arachis ipaensis</italic> (B-genome), respectively. We previously sequenced the former and here present the draft genome of the latter, expanding our knowledge of the unique biology of <italic>Arachis</italic>. The assembled genome of <italic>A. ipaensis</italic> is ~1.39 Gb with 39,704 predicted protein-encoding genes. A gene family analysis revealed that the FAR1 family may be involved in regulating peanut special fruit development. Genomic evolutionary analyses estimated that the two progenitors diverged ~3.3 million years ago and suggested that <italic>A. ipaensis</italic> experienced a whole-genome duplication event after the divergence of <italic>Glycine max</italic>. We identified a set of disease resistance-related genes and candidate genes for biological nitrogen fixation. In particular, two and four homologous genes that may be involved in the regulation of nodule development were obtained from <italic>A. ipaensis</italic> and <italic>A. duranensis</italic>, respectively. We outline a comprehensive network involved in drought adaptation. Additionally, we analyzed the metabolic pathways involved in oil biosynthesis and found genes related to fatty acid and triacylglycerol synthesis. Importantly, three new <italic>FAD2</italic> homologous genes were identified from <italic>A. ipaensis</italic> and one was completely homologous at the amino acid level with FAD2 from <italic>A. hypogaea</italic>. The availability of the <italic>A. ipaensis</italic> and <italic>A. duranensis</italic> genomic assemblies will advance our knowledge of the peanut genome.</p>