The National Engineering Laboratory of Crop Stress Resistance Breeding, Anhui Agricultural University, Hefei, China.
BMC Plant Biol. 2024 Jul 6;24(1):636. doi: 10.1186/s12870-024-05354-4.
The monocot chimeric jacalins (MCJ) proteins, which contain a jacalin-related lectin (JRL) domain and a dirigent domain (DIR), are specific to Poaceae. MCJ gene family is reported to play an important role in growth, development and stress response. However, their roles in maize have not been thoroughly investigated.
In this study, eight MCJ genes in the maize genome (designated as ZmMCJs) were identified, which displayed unequal distribution across four chromosomes. Phylogenetic relationships between the ZmMCJs were evident through the identification of highly conserved motifs and gene structures. Analysis of transcriptome data revealed distinct expression patterns among the ZmMCJ genes, leading to their classification into four different modules, which were subsequently validated using RT-qPCR. Protein structures of the same module are found to be relatively similar. Subcellular localization experiments indicated that the ZmMCJs are mainly located on the cell membrane. Additionally, hemagglutination and inhibition experiments show that only part of the ZmMCJs protein has lectin activity, which is mediated by the JRL structure, and belongs to the mannose-binding type. The cis-acting elements in the promoter region of ZmMCJ genes predicted their involvement response to phytohormones, such as abscisic acid and jasmonic acid. This suggests that ZmMCJ genes may play a significant role in both biotic and abiotic stress responses.
Overall, this study adds new insights into our understanding of the gene-protein architecture, evolutionary characteristics, expression profiles, and potential functions of MCJ genes in maize.
单子叶嵌合野麻（MCJ）蛋白含有一个野麻相关凝集素（JRL）结构域和一个定向结构域（DIR），是禾本科植物所特有的。MCJ 基因家族被报道在生长、发育和应激反应中发挥重要作用。然而，它们在玉米中的作用尚未得到深入研究。
本研究在玉米基因组中鉴定出 8 个 MCJ 基因（命名为 ZmMCJs），它们在四条染色体上的分布不均等。通过鉴定高度保守的基序和基因结构，明确了 ZmMCJs 之间的系统发育关系。对转录组数据的分析揭示了 ZmMCJ 基因的不同表达模式，导致它们分为四个不同的模块，随后使用 RT-qPCR 进行了验证。同一模块的蛋白结构发现相对相似。亚细胞定位实验表明，ZmMCJs 主要位于细胞膜上。此外，血凝和抑制实验表明，只有部分 ZmMCJs 蛋白具有凝集素活性，这是由 JRL 结构介导的，属于甘露糖结合型。ZmMCJ 基因启动子区的顺式作用元件预测它们参与对植物激素的响应，如脱落酸和茉莉酸。这表明 ZmMCJ 基因可能在生物和非生物胁迫反应中发挥重要作用。
总体而言，本研究增加了我们对玉米 MCJ 基因的基因-蛋白结构、进化特征、表达谱和潜在功能的理解。
