1.
NADPH Oxidases: The Vital Performers and Center Hubs during Plant Growth and Signaling.
Hu, CH, Wang, PQ, Zhang, PP, Nie, XM, Li, BB, Tai, L, Liu, WT, Li, WQ, Chen, KM
Cells. 2020;(2)
Abstract
NADPH oxidases (NOXs), mostly known as respiratory burst oxidase homologs (RBOHs), are the key producers of reactive oxygen species (ROS) in plants. A lot of literature has addressed ROS signaling in plant development regulation and stress responses as well as on the enzyme's structure, evolution, function, regulation and associated mechanisms, manifesting the role of NOXs/RBOHs as the vital performers and center hubs during plant growth and signaling. This review focuses on recent advances of NOXs/RBOHs on cell growth, hormone interaction, calcium signaling, abiotic stress responses, and immunity. Several primary particles, including Ca2+, CDPKs, BIK1, ROPs/RACs, CERK, FER, ANX, SnRK and SIK1-mediated regulatory mechanisms, are fully summarized to illustrate the signaling behavior of NOXs/RBOHs and their sophisticated and dexterous crosstalks. Diverse expression and activation regulation models endow NOXs/RBOHs powerful and versatile functions in plants to maintain innate immune homeostasis and development integrity. NOXs/RBOHs and their related regulatory items are the ideal targets for crop improvement in both yield and quality during agricultural practices.
2.
Properties and functions of calcium-dependent protein kinases and their relatives in Arabidopsis thaliana.
Yip Delormel, T, Boudsocq, M
The New phytologist. 2019;(2):585-604
Abstract
Calcium is a ubiquitous second messenger that mediates plant responses to developmental and environmental cues. Calcium-dependent protein kinases (CDPKs) are key actors of plant signaling that convey calcium signals into physiological responses by phosphorylating various substrates including ion channels, transcription factors and metabolic enzymes. This large diversity of targets confers pivotal roles of CDPKs in shoot and root development, pollen tube growth, stomatal movements, hormonal signaling, transcriptional reprogramming and stress tolerance. On the one hand, specificity in CDPK signaling is achieved by differential calcium sensitivities, expression patterns, subcellular localizations and substrates. On the other hand, CDPKs also target some common substrates to ensure key cellular processes indispensable for plant growth and survival in adverse environmental conditions. In addition, the CDPK-related protein kinases (CRKs) might be closer to some CDPKs than previously anticipated and could contribute to calcium signaling despite their inability to bind calcium. This review highlights the regulatory properties of Arabidopsis CDPKs and CRKs that coordinate their multifaceted functions in development, immunity and abiotic stress responses.
3.
Identification and validation of sugarcane streak mosaic virus-encoded microRNAs and their targets in sugarcane.
Viswanathan, C, Anburaj, J, Prabu, G
Plant cell reports. 2014;(2):265-76
Abstract
Plants have developed several defense mechanisms to cope with various pathogens (bacteria, fungi, virus, and phytoplasma). Among these, RNA interference (RNAi)-mediated defense against viral infection was found to be a major innate immune response. As a counter attack strategy against the host defense, viruses produce suppressors of host RNAi pathway. MicroRNAs (miRNAs) are an abundant class of short (~18-22 nucleotide) non-coding single-stranded RNAs involved in RNAi pathway leading to post-transcriptional regulation of gene expression. Sugarcane streak mosaic virus (SCSMV) is a distinct strain of Potyviridae family which has a single-stranded positive-sense RNA genome causing mosaic disease in sugarcane. In this study, we computationally predicted and experimentally validated the miRNA encoded by the SCSMV genome with detection efficiency of 99.9 % in stem-loop RT-qPCR and predicted their potential gene targets in sugarcane. These sugarcane target genes considerably broaden future investigation of the SCSMV-encoded miRNA function during viral pathogenesis and might be applied as a new strategy for controlling mosaic disease in sugarcane.
4.
RALFs: peptide regulators of plant growth.
Bedinger, PA, Pearce, G, Covey, PA
Plant signaling & behavior. 2010;(11):1342-6
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Abstract
Peptide signaling regulates a variety of developmental processes and environmental responses in plants. For example, the peptide systemin induces the systemic defense response in tomato and defensins are small cysteine-rich proteins that are involved in the innate immune system of plants. The CLAVATA3 peptide regulates meristem size and the SCR peptide is the pollen self-incompatibility recognition factor in the Brassicaceae. LURE peptides produced by synergid cells attract pollen tubes to the embryo sac. RALFs are a recently discovered family of plant peptides that play a role in plant cell growth.
5.
Priming of plant innate immunity by rhizobacteria and beta-aminobutyric acid: differences and similarities in regulation.
Van der Ent, S, Van Hulten, M, Pozo, MJ, Czechowski, T, Udvardi, MK, Pieterse, CMJ, Ton, J
The New phytologist. 2009;(2):419-431
Abstract
Pseudomonas fluorescens WCS417r bacteria and beta-aminobutyric acid can induce disease resistance in Arabidopsis, which is based on priming of defence. In this study, we examined the differences and similarities of WCS417r- and beta-aminobutyric acid-induced priming. Both WCS417r and beta-aminobutyric acid prime for enhanced deposition of callose-rich papillae after infection by the oomycete Hyaloperonospora arabidopsis. This priming is regulated by convergent pathways, which depend on phosphoinositide- and ABA-dependent signalling components. Conversely, induced resistance by WCS417r and beta-aminobutyric acid against the bacterial pathogen Pseudomonas syringae are controlled by distinct NPR1-dependent signalling pathways. As WCS417r and beta-aminobutyric acid prime jasmonate- and salicylate-inducible genes, respectively, we subsequently investigated the role of transcription factors. A quantitative PCR-based genome-wide screen for putative WCS417r- and beta-aminobutyric acid-responsive transcription factor genes revealed distinct sets of priming-responsive genes. Transcriptional analysis of a selection of these genes showed that they can serve as specific markers for priming. Promoter analysis of WRKY genes identified a putative cis-element that is strongly over-represented in promoters of 21 NPR1-dependent, beta-aminobutyric acid-inducible WRKY genes. Our study shows that priming of defence is regulated by different pathways, depending on the inducing agent and the challenging pathogen. Furthermore, we demonstrated that priming is associated with the enhanced expression of transcription factors.