The growth of young roots is crucial for the development and yield of rice. However, the molecular mechanisms underlying young rice root development remain unclear. Our research indicates that the rice B-type cytokinin response regulator factor ORR3 negatively regulates the development of young rice roots. ORR3 is highly expressed in the root meristematic zone of young rice roots. In transgenic lines overexpressing ORR3, the lengths of primary roots and adventitious roots, as well as the corresponding root meristematic zone lengths, are significantly reduced. This is due to a decrease in both the number and size of longitudinal cells in the root meristematic zone. On the one hand, ORR3 can inhibit root apical cell division and reduce the number of longitudinal cells in the root meristematic zone by affecting the auxin synthesis and transport pathways. On the other hand, ORR3 may directly activate the transcription of cell wall metabolism-related genes, thereby restricting the size of cells in the root meristematic zone. In summary, ORR3 negatively regulates rice young root growth by responding to cytokinin signals to influence auxin signal transduction and cell wall metabolism pathways, thereby negatively regulating the number and size of cells in the root meristematic zone.

Potato (Solanum tuberosum L.) is an important food crop and in recent years, Verticillium wilt has become one of the major diseases limiting potato production. To study potato Verticillium wilt, a highly pathogenic strain was isolated from field samples in Heilongjiang. After sequencing and morphological identification, the strain was confirmed as a host-specialized Verticillium nonalfalfae (V. nonalfalfae), Vn011. The genome analysis revealed 151 orphan genes in Vn011, and comparative transcriptomic analysis before and after potato inoculation showed differential expression of 21 genes, including several encoding low-complexity regions (LCRs) and transmembrane (TM) domains. These domains are known to be involved in pathogen signaling, protein folding, and phase separation processes. This study presents the whole-genome sequence of Vn011, having predicted and analyzed the expression changes of orphan genes during the infection process of V. nonalfalfae in potato, and provides new insights into the pathogenic mechanisms of the pathogen. Further research on these orphan genes will not only enhance the understanding of the evolutionary adaptation of V. nonalfalfae, but may also provide new molecular targets for the control of potato wilt disease.