Abstract

Host defense peptides (HDPs) are components of plant defensive barriers that resist microbial infection. Members of the Snakin/GASA protein family in plants have functions of regulating plant growth, defense, and bacteriostasis. Most mangrove plants grow in coastal zones. In order to survive in harsh environments, mangrove plants have evolved complex adaptations against microbes. In this study, Snakin/GASA family members were identified and analyzed in the genomes of three mangrove species. Twenty-seven, thirteen, and nine candidate Snakin/GASA family members were found inAvicennia marina,Kandelia obovata, andAegiceras corniculatum, respectively. These Snakin/GASA family members were identified and categorized into three subfamilies via phylogenetic analysis. The genes coding for the Snakin/GASA family members were unevenly distributed on chromosomes. Collinearity and conservative motif analyses showed that the Snakin/GASA family members inK. obovataandA. corniculatumunderwent multiple gene duplication events. Snakin/GASA family member expression in normal leaves and leaves infected with pathogenic microorganisms of the three mangrove species was verified using real-time quantitative polymerase chain reaction. The expression ofKoGASA3and4,AcGASA5and10, andAmGASA1,4,5,15,18, and 23 increased after microbial infection. This study provides a research basis for the verification of HDPs from mangrove plants and suggests directions for the development and utilization of marine biological antimicrobial peptides.Keywords:host defense peptides (HDPs);mangrove plants;Snakin/GASA family members;Avicennia marina;Kandelia obovata;Aegiceras corniculatum;bioinformatic analyses