Structural and Phylogenetic In Silico Characterization of Vitis vinifera PRR Protein as Potential Target for Plasmopara viticola Infection.

Fungi infection, especially derived from Plasmopara viticola, causes severe grapevine economic losses worldwide. Despite the availability of chemical treatments, looking for eco-friendly ways to control Vitis vinifera infection is gaining much more attention. When a plant is infected, multiple disease-control molecular mechanisms are activated. PRRs (Pattern Recognition Receptors) and particularly RLKs (receptor-like kinases) take part in the first barrier of the immune system, and, as a consequence, the kinase signaling cascade is activated, resulting in an immune response. In this context, discovering new lectin-RLK (LecRLK) membrane-bounded proteins has emerged as a promising strategy. The genome-wide localization of potential LecRLKs involved in disease defense was reported in two grapevine varieties of great economic impact: Chardonnay and Pinot Noir. A total of 23 potential amino acid sequences were identified, exhibiting high-sequence homology and evolution related to tandem events. Based on the domain architecture, a carbohydrate specificity ligand assay was conducted with docking, revealing two sequences as candidates for specific Vitis vinifera-Plasmopara viticola host-pathogen interaction. This study confers a starting point for designing new effective antifungal treatments directed at LecRLK targets in Vitis vinifera.

Lectin Receptor-Like Protein Kinase OsNRFG6 is Required for Embryo Sac Development and Fertilization in Neo-Tetraploid Rice.

Great yield-enhancing prospects of autotetraploid rice was restricted by various polyploidy-induced reproductive dysfunction. To surmount these challenges, our group has generated a series of valuable fertile tetraploid lines (denoted as neo-tetraploid rice) through 20-year efforts. With this context, a G-type lectin receptor-like kinase, OsNRFG6, was identified as a pivotal factor associated with reproductive regulation in neo-tetraploid rice. Nevertheless, it is still elusive about a comprehensive understanding of its precise functional roles and underlying molecular mechanisms during reproduction of neo-tetraploid rice. Here, we demonstrated that OsNRFG6 executed a constitutive expression pattern and encoded proteins localizing in perinucleus and endoplasmic reticulum. Subsequently, four independent mutant lines of OsNRFG6 within neo-tetraploid rice background were further identified, all displaying low seed-setting rate due to abortive embryo sacs and defective double fertilization. RNA-seq and RT-qPCR revealed a significant down-regulation of OsNRFG6 and female reproductive genes such as OsMEL1 and LOG in ovaries prior to and post-fertilization, attributing this effect to OsNRFG6 mutation. Furthermore, through yeast-two hybrids, bimolecular fluorescence complementation assays, and luciferase complementation imaging assays, it was determined that OsNRFG6 could interact with itself and two female reproductive proteins (LOG and OsDES1) to form protein complexes. These results elucidate the reproductive functions and molecular pathway governed by OsNRFG6 in regulating fertility of neo-tetraploid rice, offering insights into molecular understanding of fertility improvement in polyploid rice.

Identification and functional analysis of LecRLK genes in Taxodium 'Zhongshanshan'.

BACKGROUND: Lectin receptor-like protein kinases (LecRLKs) can transform external stimuli into intracellular signals and play important regulatory roles in plant development and response to environmental stressors. However, research on the LecRLK gene family of conifers has seldom been reported. METHODS: Putative LecRLK genes were identified in the transcriptome of Taxodium 'Zhongshanshan'. The classification, domain structures, subcellular localization prediction, and expression patterns of LecRLK genes, as well as co-expressed genes, were analyzed using bioinformatics methods. Fifteen representative genes were further selected for qRT-PCR analysis in six tissues and under five different environmental stressor conditions. RESULTS: In total, 297 LecRLK genes were identified, including 155 G-type, 140 L-type, and 2 C-type. According to the classification, G-type and L-type LecRLK genes both can be organized into seven groups. The domain architecture of G-type proteins were more complex compared with that of L- and C-type proteins. Conservative motifs were found in G-type and L-type diverse lectin domains. Prediction and transient expression experiments to determine subcellular localization showed that LecRLKs were mainly concentrated in the cell membrane system, and some members were located at multiple sites at the same time. RNA-seq-based transcriptomics analysis suggested functional redundancy and divergence within each group. Unigenes co-expressed with LecRLKs in the transcriptome were found to be enriched in pathways related to signal transduction and environmental adaptation. Furthermore, qRT-PCR analysis of representative genes showed evidence of functional divergence between different groups. CONCLUSIONS: This is the first study to conduct an identification and expression analysis of the LecRLK gene family in Taxodium. These results provide a basis for future studies on the evolution and function of this important gene family in Taxodium.

Genome-wide analysis of lectin receptor-like kinases in Populus.

BACKGROUND: Receptor-like kinases (RLKs) belong to a large protein family with over 600 members in Arabidopsis and over 1000 in rice. Among RLKs, the lectin receptor-like kinases (LecRLKs) possess a characteristic extracellular carbohydrate-binding lectin domain and play important roles in plant development and innate immunity. There are 75 and 173 LecRLKs in Arabidopsis and rice, respectively. However, little is known about LecRLKs in perennial woody plants. RESULTS: Here we report the genome-wide analysis of classification, domain architecture and expression of LecRLKs in the perennial woody model plant Populus. We found that the LecRLK family has expanded in Populus to a total of 231, including 180 G-type, 50 L-type and 1 C-type LecRLKs. Expansion of the Populus LecRLKs (PtLecRLKs) occurred partially through tandem duplication. Based on domain architecture and orientation features, we classified PtLecRLKs into eight different classes. RNA-seq-based transcriptomics analysis revealed diverse expression patterns of PtLecRLK genes among leaves, stems, roots, buds and reproductive tissues and organs. CONCLUSIONS: This study offers a comprehensive view of LecRLKs in the perennial woody model plant Populus and provides a foundation for functional characterization of this important family of receptor-like kinases.