Nucleotides and nucleotide derivatives as signal molecules in plantsWitte, Claus-Peter; Herde, Marco
doi: 10.1093/jxb/erae377pmid: 39252595
In reaction to a stimulus, signaling molecules are made, generate a response, and are then degraded. Nucleotides are classically associated with central metabolism and nucleic acid biosynthesis, but there are a number of nucleotides and nucleotide derivatives in plants to which this simple definition of a signaling molecule applies in whole or at least in part. These include cytokinins and chloroplast guanosine tetraposphate (ppGpp), as well as extracellular canonical nucleotides such as extracellular ATP (eATP) and NAD+ (eNAD+). In addition, there is a whole series of compounds derived from NAD+ such as ADP ribose (ADPR), and ATP–ADPR dinucleotides and their hydrolysis products (e.g. pRib-AMP) together with different variants of cyclic ADPR (cADPR, 2´-cADPR, 3´-cADPR), and also cyclic nucleotides such as 3´,5´-cAMP and 2´,3´-cyclic nucleoside monophosphates. Interestingly, some of these compounds have recently been shown to play a central role in pathogen defense. In this review, we highlight these exciting new developments. We also review nucleotide derivatives that are considered as candidates for signaling molecules, for example purine deoxynucleosides, and discuss more controversial cases.
Sex determination in bryophytes: current state of the artBožović, Djordje; Li, Mingai; Sabovljević, Aneta D; Sabovljević, Marko S; Varotto, Claudio
doi: 10.1093/jxb/erae347pmid: 39129663
With the advent of genomic and other omics technologies, the last decades have witnessed a series of steady and important breakthroughs in the understanding of genetic determinants of different reproductive systems in vascular plants and especially on how sexual reproduction shaped their evolution. In contrast, the molecular mechanisms of these fundamental aspects of the biology of bryophytes, a group of non-vascular embryophyte plants sister to all tracheophytes, are still largely obscure. The recent characterization of the sex chromosomes and genetic switches determining sex in bryophytes and emerging approaches for molecular sexing of gametophytes hold great promise for elucidation of the evolutionary history as well as the conservation of this species-rich but understudied group of land plants.
Post-translational modifications control the signal at the crossroads of plant–pathogen interactionsSoni, Kamlesh Kumar; Gurjar, Kishan; Ranjan, Aastha; Sinha, Shashank; Srivastava, Moumita; Verma, Vivek
doi: 10.1093/jxb/erae358pmid: 39177255
The co-evolution of plants and pathogens has enabled them to ‘outsmart’ each other by promoting their own defence responses and suppressing those of the other. While plants are reliant on their sophisticated immune signalling pathways, pathogens make use of effector proteins to achieve the objective. This entails rapid regulation of underlying molecular mechanisms for prompt induction of associated signalling events in both plants as well as pathogens. The past decade has witnessed the emergence of post-translational modification (PTM) of proteins as a key a factor in modulating cellular responses. The ability of PTMs to expand the functional diversity of the proteome and induce rapid changes at the appropriate time enables them to play crucial roles in the regulation of plant–pathogen interactions. Therefore, this review will delve into the intricate interplay of five major PTMs involved in plant defence and pathogen countermeasures. We discuss how plants employ PTMs to fortify their immune networks, and how pathogen effectors utilize/target host modification systems to gain entry into plants and cause disease. We also emphasize the need for identification of novel PTMs and propose the use of PTM pathways as potential targets for genome editing approaches.
Imaging the spatial distribution of structurally diverse plant hormonesChen, Lulu; Zhang, Yue; Bu, Yufen; Zhou, Junhui; Man, Yi; Wu, Xinyuan; Yang, Haobo; Lin, Jinxing; Wang, Xiaodong; Jing, Yanping
doi: 10.1093/jxb/erae384pmid: 39269320
Plant hormones are essential and structurally diverse molecules that regulate various aspects of plant growth, development, and stress responses. However, the precise analysis of plant hormones in complex biological samples poses a challenge due to their low concentrations, dynamic levels, and intricate spatial distribution. Moreover, the complexity and interconnectedness of hormone signaling networks make it difficult to simultaneously trace multiple hormone spatial distributions. In this review, we provide an overview of currently recognized small-molecule plant hormones, signal peptide hormones, and plant growth regulators, along with the analytical methods employed for their analysis. We delve into the latest advancements in mass spectrometry imaging and in situ fluorescence techniques, which enable the examination of the spatial distribution of plant hormones. The advantages and disadvantages of these imaging techniques are further discussed. Finally, we propose potential avenues in imaging techniques to further enhance our understanding of plant hormone biology.
CNGC15 and DMI1 ion channel gating in nuclear calcium signaling: opening new questions and closing controversiesJacott, Catherine N; del Cerro, Pablo
doi: 10.1093/jxb/erae352pmid: 39140702
Nuclear calcium (Ca2+) signaling is crucial for symbiotic interactions between legumes and beneficial microbes, such as rhizobia and arbuscular mycorrhizal fungi. The ion channels DMI1 and CNGC15 are key to generating repetitive nuclear Ca2+ oscillations. Despite more than 20 years of research on symbiotic nuclear Ca2+ spiking, important questions remain, including the exact function of the DMI1 channel. This review highlights recent developments that have filled knowledge gaps regarding the regulation of CNGC15 and its interplay with DMI1. We also explore new insights into the evolutionary conservation of DMI1-induced symbiotic nuclear Ca2+ oscillations and the roles of CNGC15 and DMI1 beyond symbiosis, such as in nitrate signaling, and discuss new questions this raises. As we delve deeper into the regulatory mechanisms and evolutionary history of these ion channels, we move closer to fully understanding the roles of nuclear Ca2+ signaling in plant life.