Salinity is one of the most significant risks to crop production and food security as it harms plant physiology and biochemistry.  The salt stress during the rice emergence stages severely hampers the seed germination and seedling growth of direct-seeded rice.  Recently, nanoparticles (NPs) have been reported to be effectively involved in many plant physiological processes, particularly under abiotic stresses.  To our knowledge, no comparative studies have been performed to study the efficiency of conventional, chemical, and seed nanopriming for better plant stress tolerance.  Therefore, we conducted growth chamber and field experiments with different salinity levels (0, 1.5, and 3‰), two rice varieties (CY1000 and LLY506), and different priming techniques such as hydropriming, chemical priming (ascorbic acid, salicylic acid, and γ-aminobutyric acid), and nanopriming (zinc oxide nanoparticles).  Salt stress inhibited rice seed germination, germination index, vigor index, and seedling growth.  Also, salt stress increased the over accumulation of reactive oxygen species (H₂O₂ and O₂^-·) and malondialdehyde (MDA) contents.  Furthermore, salt-stressed seedlings accumulated higher sodium (Na⁺) ions and significantly lower potassium (K⁺) ions.  Moreover, the findings of our study demonstrated that, among the different priming techniques, seed nanopriming with zinc oxide nanoparticles (NanoZnO) significantly contributed to rice salt tolerance.  ZnO nanopriming improved rice seed germination and seedling growth in the pot and field experiments under salt stress.  The possible mechanism behind ZnO nanopriming improved rice salt tolerance included higher contents of α-amylase, soluble sugar, and soluble protein and higher activities of antioxidant enzymes to sustain better seed germination and seedling growth.  Moreover, another mechanism of ZnO nanopriming induced rice salt tolerance was associated with better maintenance of K⁺ ions content.  Our research concluded that NanoZnO could promote plant salt tolerance and be adopted as a practical nanopriming technique, promoting global crop production in salt-affected agricultural lands.

Fusarium graminearum is an important plant pathogenic fungus that causes disease and yield reduction in many cereal crops, such as wheat and barley.  Gyp8 stimulates GTP hydrolysis on Ypt1 in yeast.  However, the functions of Gyp8 in plant pathogenic fungi are still unknown.  In this study, we investigated the roles of FgGyp8 in F. graminearum by genetic and pathological analyses.  Through gene knockout and phenotypic analyses, we found that FgGyp8 is required for vegetative growth in F. graminearum.  The conidiation, conidial size and number of septa per conidium of ΔFggyp8 mutant are significantly reduced when compared to the wild type PH-1.  Furthermore, FgGyp8 is crucial for pathogenicity on wheat coleoptiles and wheat heads.  FgGyp8 contains a conserved TBC domain.  Domain deletion analysis showed that the TBC domain, C- and N-terminal regions of FgGyp8 are all important for its biological functions in F. graminearum.  Moreover, we showed that FgGyp8 catalyzes the hydrolysis of the GTP on FgRab1 to GDP in vitro, indicating that FgGyp8 is a GTPase-activating protein (GAP) for FgRab1.  In addition, we demonstrated that FgGyp8 is required for FgSnc1-mediated fusion of secretory vesicles with the plasma membrane in F. graminearum.  Finally, we showed that FgGyp8 has functional redundancy with another FgRab1 GAP, FgGyp1, in F. graminearum.  Taken together, we conclude that FgGyp8 is required for vegetative growth, conidiogenesis, pathogenicity and acts as a GAP for FgRab1 in F. graminearum.

The fine-tuned expression dynamics of the effector genes are pivotal for the transition from vegetative growth to host colonization of pathogenic filamentous fungi.  However, mechanisms underlying the dynamic regulation of these genes remain largely unknown.  Here, through comparative transcriptome and chromatin immunoprecipitation sequencing (ChIP-seq) analyses of the methyltransferase PoKmt6 in rice blast fungus Pyricularia oryzae (syn. Magnaporthe oryzae), we found that PoKmt6-mediated H3K27me3 deposition was enriched mainly at fast-evolving regions and contributed to the silencing of a subset of secreted proteins (SP) and transposable element (TE) families during the vegetative growth of P. oryzae.  Intriguingly, we observed that a group of SP genes, which were depleted of H3K27me3 modification, could also be silenced via the H3K27me3-mediated repression of the nearby TEs.  In conclusion, our results indicate that H3K27me3 modification mediated by PoKmt6 regulates the expression of some SP genes in fast-evolving regions through the suppression of nearby TEs.