Veremeichik Galina N, Solomatina Taisia O, Khopta Anastasia A, Brodovskaya Evgenia V, Gorpenchenko Tatiana Yu, Grigorchuk Valeria P, Bulgakov Dmitrii V, Bulgakov Victor P
Federal Scientific Center of the East Asia Terrestrial Biodiversity of the Russian Academy of Sciences Far Eastern Branch, FGBUN FNC Bioraznoobrazia Nazemnoj Bioty Vostocnoj Azii Dal'nevostocnogo Otdelenia Rossijskoj Akademii Nauk, Vladivostok, 690022, Russia.
Planta. 2024 Dec 23;261(1):20. doi: 10.1007/s00425-024-04597-7.
Long-term cultured calli may experience a biosynthetic shift due to the IAA-dependent expression of the rolA gene, which also affects ROS metabolism. The "hairy root" syndrome is caused by the root-inducing Ri-plasmid of Rhizobium rhizogenes, also known as Agrobacterium rhizogenes. The Ri-plasmid contains genes known as rol genes or root oncogenic loci, which promote root development. The important implications of the rolA gene from the T-DNA include reduced plant size, resistance to infections, and the activation of specialised metabolism. Nevertheless, rolA does not belong to the plast gene group because its function is still uncertain. Recent investigations have shown two important effects of the rolA gene. First, the production of secondary metabolites has changed in long-term cultivated rolA-transgenic calli of Rubia cordifolia L. Second, the expression of both the rolA and rolB genes has a strong auxin-dependent antagonistic effect on reactive oxygen species (ROS) homeostasis. In this work, we attempted to elucidate two rolA gene phenomena: what caused the secondary metabolism of long-term cultured calli to change? How does the individual expression of the rolA gene affect ROS homeostasis? We analysed SNPs in the 5' untranslated region and coding region of the rolA gene. These mutations do not affect the known essential amino acids of the RolA proteins. Notably, in the promoter of the rolA gene, an ACTTTA motif for auxin-mediated transcription factors was identified. Using two separate cell cultures, we demonstrated the strong auxin dependence of rolA gene expression. The expression of genes involved in ROS metabolism decreased in response to an auxin-mediated increase in rolA gene expression. Two assumptions can be made. The long-term cultivation of calli may cause changes in the hormonal state of the culture over time, which may modulate the action of the RolA protein. Moreover, auxin-dependent expression of the rolA gene led to a decrease in ROS metabolism. It can be assumed that the antagonistic interaction between rolA and rolB prevents strong rolB-induced auxin sensitivity and oxidative bursts to balance the cell state.
长期培养的愈伤组织可能会由于rolA基因的生长素依赖性表达而经历生物合成转变，这也会影响活性氧代谢。“毛状根”综合征是由发根农杆菌（也称为根瘤土壤杆菌）的致根Ri质粒引起的。Ri质粒包含称为rol基因或根致癌位点的基因，这些基因促进根的发育。来自T-DNA的rolA基因的重要影响包括植株变小、抗感染能力以及特殊代谢的激活。然而，rolA不属于质体基因组，因为其功能仍不确定。最近的研究表明了rolA基因的两个重要作用。第一，在长期培养的茜草rolA转基因愈伤组织中，次生代谢产物的产生发生了变化。第二，rolA和rolB基因的表达对活性氧（ROS）稳态具有强烈的生长素依赖性拮抗作用。在这项工作中，我们试图阐明rolA基因的两个现象：是什么导致长期培养的愈伤组织的次生代谢发生变化？rolA基因的个体表达如何影响ROS稳态？我们分析了rolA基因5'非翻译区和编码区的单核苷酸多态性。这些突变不影响已知的RolA蛋白必需氨基酸。值得注意的是，在rolA基因的启动子中，鉴定出了一个用于生长素介导的转录因子的ACTTTA基序。使用两种单独的细胞培养物，我们证明了rolA基因表达对生长素的强烈依赖性。随着生长素介导的rolA基因表达增加，参与ROS代谢的基因表达下降。可以做出两个假设。愈伤组织的长期培养可能会随着时间的推移导致培养物激素状态的变化，这可能会调节RolA蛋白的作用。此外，rolA基因的生长素依赖性表达导致ROS代谢下降。可以假设rolA和rolB之间的拮抗相互作用可防止rolB诱导的强烈生长素敏感性和氧化爆发，以平衡细胞状态。
