The nuclear-encoded plastid ribosomal protein L18s are essential for plant development

Transcriptional Response of Wolfberry to Infestation with the Endophytic Fusarium nematophilum Strain NQ8GII4

Fusarium nematophilum NQ8GII4 is an endophytic fungus isolated from the root of healthy wolfberry (Lycium barbarum). Previous studies have reported that NQ8GII4 could dwell in wolfberry roots and enhance the defense responses in wolfberry against root rot, which is caused by F. oxysporum. To further elucidate the molecular mechanism of wolfberry disease resistance induced by NQ8GII4, in the present study, we adopted RNA sequencing analysis to profile the transcriptome of wolfberry response to NQ8GII4 infestation over a time course of 3 and 7 days postinoculation. Gene ontology enrichment analysis revealed that differentially expressed genes (DEGs) were enriched in biological regulation, response to stimulus, signaling, detoxification, immune system process, transporter activity, electron carrier activity, transcription factor activity, nucleic acid binding transcription factor, and antioxidant activity. Through Kyoto Encyclopedia of Genes and Genomes analysis, it was found that many of these DEGs were enriched in pathways related to plant-pathogen interactions, hormone signal transduction, and the phenylpropanoid biosynthesis pathway in wolfberry. This result suggested that innate immunity, phytohormone signaling, and numerous phenylpropanoid compounds comprise a complex defense network in wolfberry. Chloroplast 50S ribosomal proteins were consistently located at the core position of the response in wolfberry following infestation with NQ8GII4 analyzed by the protein-protein interaction network. This study elucidated the molecular mechanism underlying the interaction between NQ8GII4 and wolfberry, clarified the wolfberry immune response network to endophytic fungi infestation, identified candidate resistance genes in wolfberry, and provided a fundamental date for subsequent work.

WLP3 Encodes the Ribosomal Protein L18 and Regulates Chloroplast Development in Rice

Plastid ribosomal proteins play a crucial role in the growth and development of plants, mainly in the gene expression and translation of key genes in chloroplasts. While some information is known about the regulatory processes of plastid ribosomal proteins in various plant species, there is limited knowledge about the underlying mechanisms in rice. In this study, ethyl methanesulfonate (EMS) mutagenesis was used to generate a new mutant called wlp3 (white leaf and panicle3), characterized by white or albino leaves and panicles, which exhibited this phenotype from the second leaf stage until tillering. Furthermore, after a certain period, the newly emerging leaves developed the same phenotype as the rice variety ZH11, while the albino leaves of wlp3 showed an incomplete chloroplast structure and significantly low chlorophyll content. A transition mutation (T to C) at position 380 was identified in the coding region of the LOC_Os03g61260 gene, resulting in the substitution of isoleucine by threonine during translation. WLP3 encodes the ribosomal L18 subunit, which is localized in the chloroplast. Complementation experiments confirmed that LOC_Os03g61260 was responsible for the albino phenotype in rice. WLP3 has high expression in the coleoptile, leaves at the three-leaf stage, and panicles at the heading stage. Compared to the wild-type (WT), wlp3 exhibited reduced chlorophyll synthesis and significantly decreased expression levels of genes associated with plastid development. Yeast two-hybrid (Y2H) analysis revealed that WLP3 interacts with other ribosomal subunits, to influence chloroplast development. These results contribute to a better understanding of the underlying molecular mechanisms of chloroplast development and plastid gene translation.