ABSTRACT Galactose-binding lectins (GBLs) are a subdivision of jacalin-related lectins and known to perform an essential role in plant protective mechanisms against plant pathogens, fungi, and viruses. A cDNA sequence encoding GBL was cloned and the gene has an open reading frame (ORF) of 657 bp, encoding a protein of 219 amino acids. The protein is predicted to have a molecular weight and isoelectric point (pI) of 23.76 kDa and 6.29, respectively. GBL has a jacalin-type lectin domain and fits into the JRL superfamily. The evolutionary relationship of GBL revealed that the GBL from Morus multicaulis was firmly related to that of Morus rotundibila, Morus alba, Morus notabilis, Artocarpus integer, Artocarpus nitidus and Champedak (cgb). qRT-PCR analysis showed that the gene was expressed in all the tissues tested, leaf, and bud displaying the highest transcript levels. There was a general decrease in the mRNA transcript level under cold and salt stress as compared to the mRNA transcript level of the control. SDS-PAGE and western blot results showed that His-tagged fusion GBL protein was positively expressed in E. coli. In total, our findings disclosed the molecular basis for the signal transduction mechanisms when abiotic stress is induced in a mulberry tree.

中文翻译：

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桑葚半乳糖结合凝集素（GBL）基因的克隆和非生物胁迫表达分析及其在大肠杆菌中的原核表达

摘要半乳糖结合凝集素 (GBL) 是与 jacalin 相关的凝集素的细分，已知在植物保护机制中对植物病原体、真菌和病毒发挥重要作用。克隆了编码 GBL 的 cDNA 序列，该基因具有 657 bp 的开放阅读框 (ORF)，编码 219 个氨基酸的蛋白质。预计该蛋白质的分子量和等电点 (pI) 分别为 23.76 kDa 和 6.29。GBL 具有 jacalin 型凝集素结构域，适合 JRL 超家族。GBL 的进化关系表明，来自 Morus multicaulis 的 GBL 与 Morus rotundibila、Morus alba、Morus notabilis、Artocarpus integer、Artocarpus nitidus 和 Champedak (cgb) 的 GBL 密切相关。qRT-PCR 分析表明该基因在所有受试组织、叶片、和芽显示最高的转录水平。与对照的 mRNA 转录水平相比，冷和盐胁迫下 mRNA 转录水平普遍降低。SDS-PAGE和蛋白质印迹结果显示His标记的融合GBL蛋白在大肠杆菌中呈阳性表达。总的来说，我们的发现揭示了桑树诱导非生物胁迫时信号转导机制的分子基础。