Akademik Veri Yönetim Sistemi
GENETIC RESOURCES AND CROP EVOLUTION AN INTERNATIONAL JOURNAL, cilt.73, sa.5, ss.1-29, 2026 (SCI-Expanded, Scopus)
Gamma-aminobutyric acid (GABA) is a critical metabolite involved in
regulating plant defense responses against biotic and abiotic stresses,
as well as coordinating growth and developmental processes. In this
study, the GABA pathway gene family was comprehensively analyzed in the
genome of alfalfa (Medicago sativa L.), leading to the identification of a total of 47 genes, including 19 MsGAD, 12 MsGAT, 8 MsGABA-P, 4 MsGABA-T, and 4 MsSSADH. These genes distributed across 24 different chromosomes. Phylogenetic analyses revealed that MsGAD genes clustered into Classes I, III, and IV, whereas MsGAT genes clustered into Classes I and IV. The genes MsGABA-P, MsGABA-T, MsSSADH
clustered into Class I. Extensive synteny analyses demonstrated that
23, 25, 32, and 36 genes showed collinear relationships between Medicago sativa and Arabidopsis thaliana, Medicago truncatula, Lens culinaris, and Phaseolus vulgaris, respectively. Ka/Ks ratio analyses indicated that the MsGAD4-1b/MsGAD4-1c
gene pair arose through tandem duplication, while the remaining gene
pairs resulted from segmental duplication events, with all gene pairs
evolving under purifying selection pressure. Promoter analyses revealed
that GABA pathway genes harbor numerous cis-regulatory elements
responsive to hormones, developmental processes, light, and various
environmental stresses. Transcriptome data indicated variable expression
levels of GABA pathway genes across different tissues, with the
exception of MsGAD3-2, which was not expressed in leaf tissue.
Protein–protein interaction network analyses further revealed that GABA
pathway proteins interact either directly or indirectly with each other,
as well as with proteins involved in stress responses and developmental
regulation. These findings suggested that alfalfa GABA pathway genes
exhibit tissue-specific and stress-responsive expression profiles.