Bioinformatic Analysis Of Populus Trichocarpa Leucine-rich Reapeat Receptor Like Protein Kinase Family

Plant receptor-like kinase (RLK) family is largely comprised by Leucine-rich repeatreceptor-like kinase (LRR-RLKs). Previous analysis of this family in Arabidopsis andRice have shown that this gene family is widely involved in plant development，growth and stress responses.In this study,379LRR-RLK genes were retrieved from the Populus trichocarpagenome and further grouped into14subfamilies based on their structural andsequence similarities. The conservation and variation in motif compositions andintron/exon arrangements of PtLRR-RLK proteins from different subfamilies wereanalyzed to provide additional support for their phylogenetic relationships and moreimportantly to indicate the potential divergence in their functions. Approximately82%PtLRR-RLKs genes were located in segmental duplication blocks, indicating the roleof duplication processes in the expansion of this gene family. Expression profiling ofPtLRR-RLKs showed that they were differentially expressed in different organs andtissues. For most AtLRR-RLKs with defined functions, Populus homologuesexhibiting similar patterns could be identified, which may indicated their functionalconservation during evolution. Among12types of environmental cues analyzed bythe genome-wide microarray data, PtLRR-RLKs showed a high degree of specificresponses to unique stresses including shoot organogenesis, wounding, lowammonium feeding, hypoxia and seasonal dormancy but not to drought, re-wateringafter drought, flooding, AlCl3treatment, bacteria and fungi treatments.By combining bioinformatics and comparative genomics tools, this study providesthe first comprehensive genomic analysis of the Populus LRR-RLK gene family.Theidentification of50cluster Populus LRR-RLK genes resembling the function knownArabidopsis thaliana lay the foundation of further transgenetic study of the potentialfunctional candidates.