College of Horticulture, Northwest A&F University, Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling, Shaanxi, People's Republic of China.
PLoS One. 2012;7(2):e32153. doi: 10.1371/journal.pone.0032153. Epub 2012 Feb 15.
The completion of the grape genome sequencing project has paved the way for novel gene discovery and functional analysis. Aldehyde dehydrogenases (ALDHs) comprise a gene superfamily encoding NAD(P)(+)-dependent enzymes that catalyze the irreversible oxidation of a wide range of endogenous and exogenous aromatic and aliphatic aldehydes. Although ALDHs have been systematically investigated in several plant species including Arabidopsis and rice, our knowledge concerning the ALDH genes, their evolutionary relationship and expression patterns in grape has been limited.
METHODOLOGY/PRINCIPAL FINDINGS: A total of 23 ALDH genes were identified in the grape genome and grouped into ten families according to the unified nomenclature system developed by the ALDH Gene Nomenclature Committee (AGNC). Members within the same grape ALDH families possess nearly identical exon-intron structures. Evolutionary analysis indicates that both segmental and tandem duplication events have contributed significantly to the expansion of grape ALDH genes. Phylogenetic analysis of ALDH protein sequences from seven plant species indicates that grape ALDHs are more closely related to those of Arabidopsis. In addition, synteny analysis between grape and Arabidopsis shows that homologs of a number of grape ALDHs are found in the corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the speciation of the grape and Arabidopsis. Microarray gene expression analysis revealed large number of grape ALDH genes responsive to drought or salt stress. Furthermore, we found a number of ALDH genes showed significantly changed expressions in responses to infection with different pathogens and during grape berry development, suggesting novel roles of ALDH genes in plant-pathogen interactions and berry development.
The genome-wide identification, evolutionary and expression analysis of grape ALDH genes should facilitate research in this gene family and provide new insights regarding their evolution history and functional roles in plant stress tolerance.
葡萄基因组测序项目的完成为新基因的发现和功能分析铺平了道路。醛脱氢酶（ALDHs）是一个基因超家族，编码 NAD（P）（+）依赖性酶，可催化广泛的内源性和外源性芳香族和脂肪族醛的不可逆氧化。尽管在包括拟南芥和水稻在内的几种植物物种中已经对 ALDHs 进行了系统研究，但我们对葡萄中 ALDH 基因、它们的进化关系和表达模式的了解还很有限。
方法/主要发现：在葡萄基因组中鉴定出 23 个 ALDH 基因，并根据醛脱氢酶基因命名委员会（AGNC）制定的统一命名系统将其分为十个家族。葡萄 ALDH 家族内的成员具有几乎相同的外显子-内含子结构。进化分析表明，片段和串联重复事件都对葡萄 ALDH 基因的扩张做出了重大贡献。来自 7 种植物物种的 ALDH 蛋白序列的系统发育分析表明，葡萄 ALDHs 与拟南芥的关系更为密切。此外，葡萄与拟南芥之间的同基因分析表明，许多葡萄 ALDH 的同源基因都存在于拟南芥相应的同基因块中，这表明这些基因是在葡萄和拟南芥分化之前产生的。微阵列基因表达分析显示，大量葡萄 ALDH 基因对干旱或盐胁迫有反应。此外，我们发现一些 ALDH 基因在应对不同病原体感染和葡萄浆果发育过程中表达发生显著变化，表明 ALDH 基因在植物-病原体相互作用和浆果发育中具有新的作用。
葡萄 ALDH 基因的全基因组鉴定、进化和表达分析应有助于该基因家族的研究，并为其进化历史和在植物胁迫耐受中的功能作用提供新的见解。
