Genome-wide identification and analysis of Catharanthus roseus RLK1-like kinases in Nicotiana benthamiana

Genome wide characterization and expression analysis of CrRLK1L gene family in wheat unravels their roles in development and stress-specific responses

Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) genes encode a subfamily of receptor-like kinases (RLK) that regulate diverse processes during plant growth, development, and stress responses. The first CrRLK1L was identified from the Catharanthus roseus, commonly known as Madagascar periwinkle. Subsequently, CrRLK1L gene families have been characterized in many plants. The genome of T. aestivum encodes 15 CrRLK1L genes with 43 paralogous copies, with three homeologs each, except for -2-D and -7-A, which are absent. Chromosomal localization analysis revealed a markedly uneven distribution of CrRLK1L genes across seven different chromosomes, with chromosome 4 housing the highest number of genes, while chromosome 6 lacked any CrRLK1L genes. Tissue-specific gene expression analysis revealed distinct expression patterns among the gene family members, with certain members exhibiting increased expression in reproductive tissues. Gene expression analysis in response to various abiotic and biotic stress conditions unveiled differential regulation of gene family members. Cold stress induces CrRLK1Ls -4-B and -15-A while downregulating -3-A and -7B. Drought stress upregulates -9D, contrasting with the downregulation of -7D. CrRLK1L-15-B and -15-D were highly induced in response to 1 hr of heat, and combined drought and heat stress, whereas -10-B is downregulated. Similarly, in response to NaCl stress, only CrRLK1L1 homeologs were induced. Fusarium graminearum and Claviceps purpurea inoculation induces homeologs of CrRLK1L-6 and -7. The analysis of cis-acting elements in the promoter regions identified elements crucial for plant growth and developmental processes. This comprehensive genome-wide analysis and expression study provides valuable insights into the essential functions of CrRLK1L members in wheat.

Genome-Wide Identification and Analysis of Catharanthus roseus Receptor-like Kinase 1-like Proteins in Eggplant

As an important member of the plant receptor-like kinases, Catharanthus roseus receptor-like kinase 1-like (CrRLK1L) plays vital roles in plant growth and development, as well as biotic and abiotic stress response. Numerous CrRLK1Ls have been identified and analyzed in various plant species, while our knowledge about eggplant (Solanum melongena L.) CrRLK1Ls is still scarce. Utilizing state-of-the-art genomic data, we conducted the first genome-wide identification and analysis of CrRLK1L proteins in eggplant. In this study, 32 CrRLK1L proteins were identified and analyzed in eggplant. A subsequent gene structure and protein domain analysis showed that the identified eggplant CrRLK1Ls possessed typical features of CrRLK1Ls. A subcellular localization prediction demonstrated that these proteins mostly localized on the plasma membrane. A collinearity analysis showed that some eggplant CrRLK1L genes had predicted intraspecies or interspecies evolutionary duplication events. Promoter analysis suggests that eggplant CrRLK1Ls may be involved in plant hormone signaling, host-pathogen interactions, and environmental responses. Based on transcriptomic gene expression analysis, it is indicated that eggplant CrRLK1Ls may be involved in the resistance response of eggplant to Botrytis cinerea. Together, these results will give us a theoretical foundation and guidance for elaborating the biological functions of CrRLK1Ls in eggplant growth, development, and resistance response.

Characterization of Malectin/Malectin-like Receptor-like Kinase Family Members in Foxtail Millet (Setaria italica L.)

Plant malectin/malectin-like receptor-like kinases (MRLKs) play crucial roles throughout the life course of plants. Here, we identified 23 SiMRLK genes from foxtail millet. All the SiMRLK genes were named according to the chromosomal distribution of the SiMRLKs in the foxtail millet genome and grouped into five subfamilies based on phylogenetic relationships and structural features. Synteny analysis indicated that gene duplication events may take part in the evolution of SiMRLK genes in foxtail millet. The expression profiles of 23 SiMRLK genes under abiotic stresses and hormonal applications were evaluated through qRT-PCR. The expression of SiMRLK1, SiMRLK3, SiMRLK7 and SiMRLK19 were significantly affected by drought, salt and cold stresses. Exogenous ABA, SA, GA and MeJA also obviously changed the transcription levels of SiMRLK1, SiMRLK3, SiMRLK7 and SiMRLK19. These results signified that the transcriptional patterns of SiMRLKs showed diversity and complexity in response to abiotic stresses and hormonal applications in foxtail millet.

Genome-Wide Re-Identification and Analysis of CrRLK1Ls in Tomato

The Catharanthus roseus receptor-like kinase 1-like (CrRLK1L), which is a vital member of the plant receptor-like kinase family, plays versatile roles in plant growth, development, and stress response. Although the primary screening of tomato CrRLK1Ls has been reported previously, our knowledge of these proteins is still scarce. Using the latest genomic data annotations, a genome-wide re-identification and analysis of the CrRLK1Ls in tomatoes were conducted. In this study, 24 CrRLK1L members were identified in tomatoes and researched further. Subsequent gene structures, protein domains, Western blot analyses, and subcellular localization analyses all confirmed the accuracy of the newly identified SlCrRLK1L members. Phylogenetic analyses showed that the identified SlCrRLK1L proteins had homologs in Arabidopsis. Evolutionary analysis indicated that two pairs of the SlCrRLK1L genes had predicted segmental duplication events. Expression profiling analyses demonstrated that the SlCrRLK1L genes were expressed in various tissues, and most of them were up- or down-regulated by bacteria and PAMP treatments. Together, these results will lay the foundation for elaborating the biological roles of SlCrRLK1Ls in tomato growth, development, and stress response.

TMT-based quantitative membrane proteomics identified PRRs potentially involved in the perception of MSP1 in rice leaves

Pathogen-associated molecular patterns (PAMPs) play a key role in triggering PAMPs triggered immunity (PTI) in plants. In the case of the rice-Magnaporthe oryzae pathosystem, fewer PAMPs and their pattern recognition receptors (PRRs) have been characterized. Recently, a M. oryzae snodprot1 homolog protein (MSP1) has been identified that functions as PAMP and triggering the PTI responses in rice. However, the molecular mechanism underlying MSP1-induced PTI is currently elusive. Therefore, we generated MSP1 overexpressed transgenic lines of rice, and a tandem mass tag (TMT)-based quantitative membrane proteomic analysis was employed to decipher the potential MSP1-induced signaling in rice using total cytosolic as well as membrane protein fractions. This approach led to the identification of 8033 proteins of which 1826 were differentially modulated in response to overexpression of MSP1 and/or exogenous jasmonic acid treatment. Of these, 20 plasma membrane-localized receptor-like kinases (RLKs) showed increased abundance in MSP1 overexpression lines. Moreover, activation of proteins related to the protein degradation and modification, calcium signaling, redox, and MAPK signaling was observed in transgenic lines expressing MSP1 in the apoplast. Taken together, our results identified potential PRR candidates involved in MSP1 recognition and suggested the overview mechanism of the MSP1-induced PTI signaling in rice leaves. SIGNIFICANCE: In plants, recognition of pathogen pathogen-derived molecules, such as PAMPs, by plant plant-derived PRRs has an essential role for in the activation of PTI against pathogen invasion. Typically, PAMPs are recognized by plasma membrane (PM) localized PRRs, however, identifying the PM-localized PRR proteins is challenging due to their low abundance. In this study, we performed an integrated membrane protein enrichment by microsomal membrane extraction (MME) method and subsequent TMT-labeling-based quantitative proteomic analysis using MSP1 overexpressed rice. Based on these results, we successfully identified various intracellular and membrane membrane-localized proteins that participated in the MSP1-induced immune response and characterized the potential PM-localized PRR candidates in rice.