Leucine-rich repeat receptor-like kinases(LRR-RLK)comprise the largest class of receptor-like kinases in plants.This gene family plays important roles in diverse processes during development,biotic and abiotic stress responses.In this study,471 members were identified from the whole-genome sequence of soybean and further divided into 14 subfamilies by their sequence similarities and phylogenetic tree.All soybean LRR-RLK genes were unevenly distributed on 20 chromosomes,of which both chromosome 8 and 18 have the most members(39 genes).Moreover,the gene structure and motif compositions in the same subgroups showed similar patterns.In addition,94 out of 464 genes(20.3%)in this family were located in tandem repeats and composed 33 clusters while 344 LRR-RLK genes(73.7%)were located in regions of segmental duplications,suggesting that segmental duplication is the main mechanism expansion model of soybean LRR-RLK gene family.Expression profiling of LRR-RLKs suggested that some GmLRR-RLKs showed specific transcript accumulation in one tissue,indicated that these LRR-RLK proteins might function in tissue-specific regulation.Some genes clustered in the same subgroup of the phylogenetic tree had similar expression pattern,suggesting the existence of redundancy among the LRRRLK genes in these subgroups.