Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, P.le Aldo Moro 5, 00185, Roma, Italy.
Dipartimento di Biologia, Università degli Studi di Firenze, via Madonna del Piano 6, 50019, Sesto f.no, FI, Italy.
Plant Physiol Biochem. 2021 Aug;165:10-18. doi: 10.1016/j.plaphy.2021.04.037. Epub 2021 May 14.
The rolB oncogene is one of the so-called rol genes found in the T-DNA region of the Agrobacterium rhizogenes Ri plasmid and involved in the hairy root syndrome, a tumour characterized by adventitious root overgrowth on plant stem. rolB produces in plants a peculiar phenotype that, together with its root-inducing capacity, has been connected to auxin sensitivity. The gene is able to modify the plant genetic programme to induce meristem cells and direct them to differentiate not only roots, but also other cells, tissues or organs. Besides its essential function in hairy root pathogenesis, the rolB role has been progressively extended to cover several physiological aspects in the transgenic plants: from secondary metabolites production and ROS inhibition, to abiotic and biotic stress tolerance and photosynthesis improvement. Some of the observed effects could be determined, at least in part, through microRNAs molecules, suggesting an epigenetic control rolB-mediated. These multifaceted capacities could allow plants to withstand adverse environmental conditions, enhancing fitness. In spite of this expanding knowledge, functional analyses did not detect yet any definitive rolB-derived biochemical product, even if more than one enzymatic activity has been ascribed to it. Moreover, phylogenetic and evolutionary studies evidenced no homology with any plant sequences but, otherwise, it belongs to the Plast family, a group of rolB-homologous bacterial genes. Finally, the finding of sequences similar to rolB in plants not infected by A. rhizogenes suggests a hypothetical plant origin for this gene, implying different possibilities about its evolution.
rolB 癌基因是根癌农杆菌 Ri 质粒 T-DNA 区中所谓的 rol 基因之一，与毛状根综合征有关，毛状根综合征是一种植物茎上不定根过度生长的肿瘤特征。rolB 在植物中产生一种特殊的表型，其与诱导生根的能力有关，与生长素敏感性有关。该基因能够修饰植物的遗传程序，诱导分生细胞分化，不仅诱导生根，还诱导其他细胞、组织或器官分化。除了在毛状根发病机制中的重要功能外，rolB 的作用逐渐扩展到转基因植物的几个生理方面：从次生代谢产物的产生和 ROS 抑制，到非生物和生物胁迫耐受性和光合作用的改善。观察到的一些效应至少部分可以通过 microRNAs 分子来确定，这表明 rolB 介导的表观遗传控制。这些多方面的能力可以使植物能够耐受不利的环境条件，提高适应性。尽管有了这些扩展的知识，但功能分析尚未检测到任何明确的 rolB 衍生的生化产物，尽管已经赋予它多种酶活性。此外，系统发育和进化研究表明它与任何植物序列都没有同源性，但它属于 Plast 家族，这是一组 rolB 同源细菌基因。最后，在未被根癌农杆菌感染的植物中发现与 rolB 相似的序列表明该基因具有假设的植物起源，这暗示了其进化的不同可能性。
