title: Origin of the plant Tm-1-like gene via two independent horizontal transfer events and one gene fusion event.
abstract: The Tomato mosaic virus (ToMV) resistance gene Tm-1 encodes a direct inhibitor of ToMV RNA replication to protect tomato from infection. The plant Tm-1-like (Tm-1L) protein is predicted to contain an uncharacterized N-terminal UPF0261 domain and a C-terminal TIM-barrel signal transduction (TBST) domain. Homologous searches revealed that proteins containing both of these two domains are mainly present in charophyte green algae and land plants but absent from glaucophytes, red algae and chlorophyte green algae. Although Tm-1 homologs are widely present in bacteria, archaea and fungi, UPF0261- and TBST-domain-containing proteins are generally encoded by different genes in these linages. A co-evolution analysis also suggested a putative interaction between UPF0261- and TBST-domain-containing proteins. Phylogenetic analyses based on homologs of these two domains revealed that plants have acquired UPF0261- and TBST-domain-encoding genes through two independent horizontal gene transfer (HGT) events before the origin of land plants from charophytes. Subsequently, gene fusion occurred between these two horizontally acquired genes and resulted in the origin of the Tm-1L gene in streptophytes. Our results demonstrate a novel evolutionary mechanism through which the recipient organism may acquire genes with functional interaction through two different HGT events and further fuse them into one functional gene.
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Zefeng
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Fang
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Shuhui
authors.initials: S
authors.lastname: Xu
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Chenwu
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Biology, East Carolina University, Greenville, NC, 27858, USA.
authors.forename: Jinling
authors.initials: J
authors.lastname: Huang
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Plant Functional Genomics of the Ministry of Education, Yangzhou University, Yangzhou, 225009, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D060467:Disease Resistance / Q000235:genetics; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D017343:Genes, Plant; D018551:Solanum lycopersicum / Q000235:genetics / Q000821:virology; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D011995:Recombination, Genetic; D057949:Streptophyta / Q000145:classification / Q000235:genetics; D017898:Tobamovirus / Q000235:genetics