State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China.
Int J Mol Sci. 2018 Oct 24;19(11):3312. doi: 10.3390/ijms19113312.
Malate dehydrogenase plays crucial roles in energy homeostasis, plant development and cold and salt tolerance, as it mediates the reversible conversion of malate to oxaloacetate. However, the evolutionary pattern of genes in apple remains elusive. In this study, a total of 20 genes were identified from the "Golden Delicious" apple draft genome. We revealed the physiological and biochemical properties, gene structure, and conserved motifs of genes. Chromosomal localization and / ratio analysis of genes revealed different selective pressures acted on duplicated genes. Exploration of the phylogenetic relationships revealed six clades and similar frequencies between old and recent duplications, and significant differences in the evolutionary rates of the gene family were observed. One gene, MDP0000807458, which was highly expressed during apple fruit development and flower bud differentiation, was under positive selection. Thus, we speculated that MDP0000807458 is a likely candidate gene involved in regulation of flower bud differentiation and organic acid metabolism in apple fruits. This study provides a foundation for improved understanding of the molecular evolution of genes and further facilitates the functional analysis of MDP0000807458 to unravel its exact role in flower bud differentiation and organic acid metabolism.
苹果中的苹果酸脱氢酶基因的进化模式仍然难以捉摸。在这项研究中，从“金冠”苹果的草图基因组中鉴定出了 20 个基因。我们揭示了基因的生理生化特性、基因结构和保守基序。基因的染色体定位和/或比值分析表明，复制基因受到了不同的选择压力。对系统发育关系的探索揭示了 6 个分支，以及新旧复制之间相似的频率，并观察到基因家族的进化速率存在显著差异。一个基因 MDP0000807458 在苹果果实发育和花芽分化过程中高度表达，受到正选择。因此，我们推测 MDP0000807458 是一个与苹果果实花芽分化和有机酸代谢调控相关的候选基因。本研究为进一步了解基因的分子进化提供了基础，并有助于对 MDP0000807458 的功能分析，以揭示其在花芽分化和有机酸代谢中的确切作用。
