Characterization, evolution, and abiotic stress responses of leucine-rich repeat receptor- like protein kinases in Liriodendron chinense

Abstract

Abstract Background The Liriodendron chinense similar to all other flowering plants is vulnerable to plant extinction due to the severity of the abiotic stresses in the wake of the global climate change. Thereby, affecting its growth and development, and geographical distribution. Nonetheless, the Liriodendron chinense plays an essential role in the socio-economic and ecological sectors. The LRR-RLK genes comprise one of the largest groups of receptor-like kinases in plants, crucial for plant development and stress regulation; and the LRR-RLK genes have not been elucidated in the Liriodendron chinense. Result In this study, we identified 232 LchiLRR-RLK genes that were unevenly distributed on 17 chromosomes and 24 contigs, of which 67 paralogous gene pairs portrayed gene linkages; that contributed to LchiLRR-RLK gene family expansion through tandem (35.82%) and segmental (64.18%) duplications. Additionally, the synonymous and nonsynonymous ratios showed that the LchiLRR-RLK genes underwent a purifying or stabilizing selection during the evolutionary process. Investigation in the protein structures and domain conservation exhibited that LchiLRR-RLK carried conserved PK and LRR domains that also promoted their clustering in different subfamilies implicating gene evolutionary conservation. A deeper analysis of LchiLRR-RLK full protein sequences phylogeny showed 13 families that had a common ancestor protein. Interspecies gene collinearity showed more orthologous gene pairs between L. chinense and P. trichocarpa, suggesting various similar biological functions between the two plant species. Analysis of the functional roles of the LchiLRR-RLK genes using the qPCR demonstrated that they are involved in abiotic stress regulation, especially, members of subfamilies VIII, III, and Xa. Conclusion Conclusively, the LRR-RLK genes are conserved in the L. chinense and function to regulate the temperature and salt stresses, and this research provides new insights into understanding LchiLRR-RLK genes and their regulatory effects in abiotic stresses.