Department of Plant Biology, Ecology and Evolution, Oklahoma State University, Stillwater, OK, 74078, USA.
United States Department of Agriculture - Agricultural Research Service, Plant Science Research Laboratory, USDA-ARS), Stillwater, OK, 74075, USA.
Plant Mol Biol. 2021 Mar;105(4-5):527-541. doi: 10.1007/s11103-020-01107-7. Epub 2021 Jan 2.
This report shows detailed characterization of LOX gene family in sorghum and provides new insight of sorghum LOX genes in genetic structure and their roles in plant response to infestation by sugarcane aphids. Lipoxygenases (LOXs) are monomeric, nonheme iron-containing dioxygenases that initiate the fatty acid oxidation pathway creating oxylipins and plant hormone jasmonate both have a key role in plant development and defense. To date, a comprehensive and systematic analysis of sorghum LOXs is still deficient. Thus, we performed a genome-wide analysis of the sorghum LOXs genome and identified nine LOXs genes. Detailed examination of protein sequences and phylogenetic analysis categorized the sorghum LOXs into two subclasses, 9-LOXs (SbLOX1, SbLOX3, SbLOX4, SbLOXm, and SbLOXo), 13-LOXs (SbLOX9, SbLOX5, and SbLOX2), and the unclassified SbLOX8. This classification was further supported by sequence similarity/identity matrix and subcellular localization analysis. The lipoxygenase domains, motifs, and vital amino acids were highly conserved in all sorghum LOX genes. In silico analysis of the promoter region of SbLOXs identified different hormones responsive cis-elements. Furthermore, to explore the roles of sorghum LOXs during sugarcane aphid feeding and exogenous MeJA application, expression analysis was conducted for all the eight LOXs in resistant (Tx2783) and susceptible (Tx7000) sorghum lines, respectively. As detailed in this report, the data generated from both genome-wide identification and expression analysis of lipoxygenase genes suggest the putative functions of two 13-LOXs (SbLOX9 and SbLOX5) and three 9-LOXs (SbLOX1, SbLOX3, and SbLOXo) in biosynthesis of jasmonic acid, green leaf volatiles and death acids, and all of them are involved in defense-related functions in plants. Furthermore, this report represents the first genome-wide analysis of the LOX gene family in sorghum, which will facilitate future studies to characterize the roles of each individual LOXs gene in aphid resistance and defense responses to other stresses.
本报告详细描述了高粱 LOX 基因家族的特征，并提供了高粱 LOX 基因在遗传结构及其在植物抵御甘蔗蚜虫侵害中的作用的新见解。脂氧合酶（LOXs）是单体、非血红素铁结合的双加氧酶，它启动脂肪酸氧化途径，产生氧自由基和植物激素茉莉酸，这两者在植物发育和防御中都起着关键作用。迄今为止，对高粱 LOXs 的全面和系统分析仍然不足。因此，我们对高粱 LOX 基因组进行了全基因组分析，鉴定了 9 个 LOX 基因。通过对蛋白质序列的详细检查和系统发育分析，将高粱 LOX 分为两类，9-LOXs（SbLOX1、SbLOX3、SbLOX4、SbLOXm 和 SbLOXo）、13-LOXs（SbLOX9、SbLOX5 和 SbLOX2）和未分类的 SbLOX8。这种分类进一步得到了序列相似性/同一性矩阵和亚细胞定位分析的支持。所有高粱 LOX 基因中的脂氧合酶结构域、基序和重要氨基酸高度保守。对 SbLOXs 启动子区域的计算机分析确定了不同激素响应的顺式元件。此外，为了探索高粱 LOXs 在甘蔗蚜虫取食和外源 MeJA 应用过程中的作用，我们分别对抗性（Tx2783）和敏感性（Tx7000）高粱品系中的 8 个 LOX 进行了表达分析。如本报告所述，脂氧合酶基因的全基因组鉴定和表达分析产生的数据表明，两个 13-LOXs（SbLOX9 和 SbLOX5）和三个 9-LOXs（SbLOX1、SbLOX3 和 SbLOXo）在茉莉酸、绿叶挥发物和死亡酸的生物合成中具有潜在功能，它们都参与了植物的防御相关功能。此外，本报告代表了高粱 LOX 基因家族的首次全基因组分析，这将有助于未来对每个 LOX 基因在蚜虫抗性和对其他胁迫的防御反应中的作用进行特征分析。
