Plants cannot move to escape environmental challenges. Biotic stresses result from a battery of potential pathogens: fungi, bacteria, nematodes and insects intercept the photosynthate produced by plants, and viruses use replication machinery at the host's expense. Plants, in turn, have evolved sophisticated mechanisms to perceive such attacks, and to translate that perception into an adaptive response. Here, we review the current knowledge of recognition-dependent disease resistance in plants. We include a few crucial concepts to compare and contrast plant innate immunity with that more commonly associated with animals. There are appreciable differences, but also surprising parallels.

Plant pathogens and integrated defence responses to infection.

Rapid generation of superoxide and accumulation of H2O2 is a characteristic early feature of the hypersensitive response following perception of pathogen avirulence signals. Emerging data indicate that the oxidative burst reflects activation of a membrane-bound NADPH oxidase closely resembling that operating in activated neutrophils. The oxidants are not only direct protective agents, but H2O2 also functions as a substrate for oxidative cross-linking in the cell wall, as a threshold trigger for hypersensitive cell death, and as a diffusible signal for induction of cellular protectant genes in surrounding cells. Activation of the oxidative burst is a central component of a highly amplified and integrated signal system, also involving salicylic acid and perturbations of cytosolic Ca2+, which underlies the expression of disease-resistance mechanisms.

The oxidative burst in plant disease resistance

Microbe-associated molecular patterns (MAMPs) are molecular signatures typical of whole classes of microbes, and their recognition plays a key role in innate immunity. Endogenous elicitors are similarly recognized as damage-associated molecular patterns (DAMPs). This review focuses on the diversity of MAMPs/DAMPs and on progress to identify the corresponding pattern recognition receptors (PRRs) in plants. The two best-characterized MAMP/PRR pairs, flagellin/FLS2 and EF-Tu/EFR, are discussed in detail and put into a phylogenetic perspective. Both FLS2 and EFR are leucine-rich repeat receptor kinases (LRR-RKs). Upon treatment with flagellin, FLS2 forms a heteromeric complex with BAK1, an LRR-RK that also acts as coreceptor for the brassinolide receptor BRI1. The importance of MAMP/PRR signaling for plant immunity is highlighted by the finding that plant pathogens use effectors to inhibit PRR complexes or downstream signaling events. Current evidence indicates that MAMPs, DAMPs, and effectors are all perceived as danger signals and induce a stereotypic defense response.

A Renaissance of Elicitors: Perception of Microbe-Associated Molecular Patterns and Danger Signals by Pattern-Recognition Receptors

Host-microbe interactions: Shaping the evolution of the plant immune response

FLS2: an LRR receptor-like kinase involved in the perception of the bacterial elicitor flagellin in Arabidopsis.

The rice Xa21 gene, which confers resistance to Xanthomonas oryzae pv. oryzae race 6, was isolated by positional cloning. Fifty transgenic rice plants carrying the cloned Xa21 gene display high levels of resistance to the pathogen. The sequence of the predicted protein, which carries both a leucine-rich repeat motif and a serine-threonine kinase-like domain, suggests a role in cell surface recognition of a pathogen ligand and subsequent activation of an intracellular defense response. Characterization of Xa21 should facilitate understanding of plant disease resistance and lead to engineered resistance in rice.

/pdf/a-receptor-kinase-like-protein-encoded-by-the-rice-disease-31w4l4ry4h.pdf

A receptor kinase-like protein encoded by the rice disease resistance gene, Xa21. - eScholarship

OBJECTIVE
Chemoresistance is one of the main obstacles in the clinical treatment of cancer. However, secondary resistance to paclitaxel poses new challenges for cancer treatment. Long noncoding RNAs regulate cellular functions at different levels and mechanisms and play an important role in the biological behavior of tumors.


MATERIALS AND METHODS
LncRNA microarrays were used to detect lncRNAs in Paclitaxel-resistant cells and corresponding parental cells. Cell counting kit 8 and Transwell analysis were used to test the effect of lncRNA on function.


RESULTS
The expression of lncRNA DBH-AS1 in TE-4 TAX-R cells was significantly higher than that in TE-4 cells. Transwell analysis showed that the overexpression of lncRNA DBH-AS1 increased the invasion of Eca cells. Cell scratches and Transwell analysis showed that the overexpression of lncRNA DBH-AS1 in Eca cell culture supernatants promoted the migration and invasion of HUVEC. In addition, lncRNA DBH-AS1 relies on miR-21 to regulate the expression of YOD1.


CONCLUSIONS
Paclitaxel-resistant lncRNA DBH-AS1 appears to promote ECa cell proliferation and invasion by acting as a ceRNA and regulating miR-21-5p /YOD1 signaling pathway.

Paclitaxel-resistant related lncRNA DBH-AS1 promotes the proliferation and invasion of esophageal cancer.

OBJECTIVE
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. Increasing evidence suggests that the dysregulation of RNA-binding proteins (RBPs) is involved in the development of various cancers. However, there is a paucity of studies investigating the roles of RBPs in HCC.


MATERIALS AND METHODS
Data on HCC samples were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases (available at: www.ncbi.nlm.nih.gov/geo), and data regarding human RBPs were integrated from SONAR, XRNAX, and CARIC results. We identified modules associated with prognosis using weighted gene co-expression network analysis (WGCNA) and performed functional enrichment analysis. Univariate and least absolute shrinkage and selection operator (LASSO) regression analyses were used to identify prognostic RBPs and establish a prediction model. According to the median risk score, we separated patients into high- and low-risk groups and investigated the differences in immune cell infiltration, somatic mutations, and gene set enrichment. Univariate and multivariate regression analyses were used to identify prognostic factors for HCC. A nomogram was constructed, and its performance was evaluated with calibration curves.


RESULTS
Sixteen RBPs (MEX3A, TTK, MRPL53, IQGAP3, PFN2, IMPDH1, TCOF1, DYNC1LI1, EIF2B4, NOL10, GNL2, EIF1B, PSMD1, AHSA1, SEC61A1, and YBX1) were identified as prognostic genes, and a prognostic model was established. Survival analysis indicated that the model had good predictive performance and that a high-risk score was significantly related to a poor prognosis. Additionally, there were significant differences in immune cell infiltration, somatic mutations, and gene set enrichment between the high- and low-risk groups. Univariate and multivariate regression analyses indicated that the RBP-based signature was an independent prognostic factor for HCC. The nomogram based on 16 RBPs performed well in predicting the overall survival of HCC patients.


CONCLUSIONS
The RBP-based signature is an independent prognostic factor for HCC, and this study could provide an innovative method for analyzing prognostic biomarkers and therapeutic targets for HCC.

L H Zhu

Papers

A receptor kinase-like protein encoded by the rice disease resistance gene, Xa21. - eScholarship

Paclitaxel-resistant related lncRNA DBH-AS1 promotes the proliferation and invasion of esophageal cancer.

Exploration and validation of the prognostic value of RNA-binding proteins in hepatocellular carcinoma.