Comprehensive Genome-Wide Identification and Transcript Profiling of GABA Pathway Gene Family in Apple (Malus domestica)

Abstract

γ-Aminobutyric Acid (GABA), a four-carbon non-protein amino acid, is a significant component of the free amino acid pool in most prokaryotic and eukaryotic organisms. GABA is involved in pH regulation, maintaining C/N balance, plant development and defence, as well as a compatible osmolyte and an alternative pathway for glutamate utilization via anion flux. Glutamate decarboxylase (GAD, EC 4.1.1.15) and GABA transaminase (GABA-T, EC 2.6.1.19) are two key enzymes involved in the synthesis and metabolism of GABA. Recently, GABA transporters (GATs), protein and aluminium-activated malate transporter (ALMT) proteins which function as GABA receptors, have been shown to be involved in GABA regulation. However, there is no report on the characterization of apple GABA pathway genes. In this study, we performed a genome-wide analysis and expression profiling of the GABA pathway gene family in the apple genome. A total of 24 genes were identified including five GAD genes (namely MdGAD 1–5), two GABA-T genes (namely MdGABA-T 1,2), 10 GAT genes (namely GAT 1–10) and seven ALMT genes (namely MdALMT1–7). These genes were randomly distributed on 12 chromosomes. Phylogenetic analyses grouped GABA shunt genes into three clusters—cluster I, cluster II, and cluster III—which had three, four, and five genes, respectively. The expression profile analysis revealed significant MdGAD4 expression levels in both fruit and flower organs, except pollen. However, there were no significant differences in the expression of other GABA shunt genes in different tissues. This work provides the first characterization of the GABA shunt gene family in apple and suggests their importance in apple response to abiotic stress. These results can serve as a guide for future studies on the understanding and functional characterization of these gene families.

Regulation of Reactive Oxygen Species during Salt Stress in Plants and Their Crosstalk with Other Signaling Molecules—Current Perspectives and Future Directions

“…The metabolic pathway of polyamines crosstalks with various signaling pathways such as those of gamma-aminobutyrate (GABA), H 2 O 2, and ABA [ 171 , 235 , 237 ]. GABA improved the salt tolerance in Lactuca sativa [ 238 ]. Additionally, polyamines also increase the production of NO and its crosstalk with various stress intermediaries, including protein kinases and Ca 2+ .…”

Comprehensive Genome-Wide Identification and Transcript Profiling of GLK transcription factors in Castanea mollissima

“…Besides, only three segmental duplications and one random duplication were identi ed in CmGLKs, indicating that duplication events of GLKs were signi cantly less in the Chinese chestnut than in other plants , Zhao et al 2021) and other gene families in different plants (Sun et al 2019, Bai et al 2019, Zheng et al 2021. This suggests that GLKs are evolutionary conserved and have a higher heterogeneity in the Chinese chestnut than GLKs in other plants and other family genes in various plant species.…”