Phylogenomics reveals multiple losses of nitrogen-fixing root nodule symbiosis.
Maximilian GriesmannYue ChangXin LiuYue SongGeorg HabererMatthew B CrookBenjamin Billault-PenneteauDominique LauresserguesJean KellerLeandro ImanishiYuda Purwana RoswanjayaWouter KohlenPetar PujicKai BattenbergNicole AlloisioYuhu LiangHenk W M HilhorstMarco G SalgadoValérie HocherHassen GherbiSergio SvistoonoffJeff J DoyleShixu HeYan XuShanyun XuJing QuQiang GaoXiaodong FangYuan FuPhilippe NormandAlison M BerryLuis Gabriel WallJean-Michel AnéKatharina PawlowskiXue LiuHuanming YangManuel SpannaglKlaus F X MayerGane Ka-Shu WongMartin ParniskePierre-Marc DelauxShifeng ChengPublished in: Science (New York, N.Y.) (2018)
The root nodule symbiosis of plants with nitrogen-fixing bacteria affects global nitrogen cycles and food production but is restricted to a subset of genera within a single clade of flowering plants. To explore the genetic basis for this scattered occurrence, we sequenced the genomes of 10 plant species covering the diversity of nodule morphotypes, bacterial symbionts, and infection strategies. In a genome-wide comparative analysis of a total of 37 plant species, we discovered signatures of multiple independent loss-of-function events in the indispensable symbiotic regulator NODULE INCEPTION in 10 of 13 genomes of nonnodulating species within this clade. The discovery that multiple independent losses shaped the present-day distribution of nitrogen-fixing root nodule symbiosis in plants reveals a phylogenetically wider distribution in evolutionary history and a so-far-underestimated selection pressure against this symbiosis.