β-glucosidases (BGLUs) hydrolyze the β-D-glycosidic bond with retention of anomeric configuration. BGLUs were associated with many aspects of plant physiological processes, in particular biotic and abiotic stresses through the activation of phytohormones and defense compounds. However, studies on systematic analysis of the stress- or hormone-responsive BGLU genes in plant are still rare. In this study, total 51 BGLU genes of the glycoside hydrolase family 1 were identified in the genome of the model legume plant Medicago truncatula, and they were classified into five distinct clusters. Sequence alignments revealed several conserved and characteristic motifs among these MtBGLU proteins. Analyses of their putative signal peptides and N-glycosylation site suggested that the majority of MtBGLU members have dual targeting to the vacuole and/or chloroplast. Many regulatory elements possibly related with abiotic stresses and phytohormones were identified in MtBGLU genes. Moreover, Microarray and qPCR analyses showed that these MtBGLU genes exhibited distinct expression patterns in various tissues, and in response to different abiotic stress and hormonal treatments. Notably, MtBGLU21, MtBGLU22, MtBGLU28, and MtBGLU30 in cluster I were dramatically activated by NaCl, PEG, IAA, ABA, SA and GA3 treatments. Collectively, our genome-wide characterization, evolutionary analysis, and expression pattern analysis of MtBGLU genes suggested that BGLU genes play crucial roles in response to various abiotic stresses and hormonal cues in M. truncatula.

β-葡糖苷酶（BGLUs）水解β -D-糖苷键并保留异头构型。BGLUs与植物生理过程的许多方面有关，特别是通过激活植物激素和防御化合物引起的生物和非生物胁迫。然而，对植物中胁迫或激素反应性BGLU基因进行系统分析的研究仍然很少。在这项研究中，在模型豆科植物Medi藜苜蓿的基因组中鉴定了糖苷水解酶家族1的总共51个BGLU基因。，并将它们分为五个不同的集群。序列比对揭示了这些MtBGLU蛋白中的几个保守和特征性基序。对它们的假定信号肽和N-糖基化位点的分析表明，大多数MtBGLU成员对液泡和/或叶绿体具有双重靶向性。在MtBGLU基因中发现了许多可能与非生物胁迫和植物激素相关的调控元件。此外，微阵列和qPCR分析表明，这些MtBGLU基因在各种组织中表现出不同的表达模式，并且响应于不同的非生物胁迫和激素治疗。值得注意的是，MtBGLU21，MtBGLU22，MtBGLU28和MtBGLU30NaCl，PEG，IAA，ABA，SA和GA3处理可显着激活I类中的B. 总的来说，我们的全基因组的特性，进化分析和表达模式分析MtBGLU基因表明BGLU基因响应各种非生物胁迫和激素线索发挥关键作用蒺藜苜蓿。