Chlorophyll content is one of the most important physiological traits as it is closely related to leaf photosynthesis and crop yield potential. So far, few genes have been reported to be involved in natural variation of chlorophyll content in rice (Oryza sativa) and the extent of variations explored is very limited. We conducted a genome-wide association study (GWAS) using a diverse worldwide collection of 529 O. sativa accessions. A total of 46 significant association loci were identified. Three F2 mapping populations with parents selected from the association panel were tested for validation of GWAS signals. We clearly demonstrated that Grain number, plant height, and heading date7 (Ghd7) was a major locus for natural variation of chlorophyll content at the heading stage by combining evidence from near-isogenic lines and transgenic plants. The enhanced expression of Ghd7 decreased the chlorophyll content, mainly through down-regulating the expression of genes involved in the biosynthesis of chlorophyll and chloroplast. In addition, Narrow leaf1 (NAL1) corresponded to one significant association region repeatedly detected over two years. We revealed a high degree of polymorphism in the 5' UTR and four non-synonymous SNPs in the coding region of NAL1, and observed diverse effects of the major haplotypes. The loci or candidate genes identified would help to fine-tune and optimize the antenna size of canopies in rice breeding.
Glioblastoma (GBM) is one of the deadliest primary brain malignant tumors with a bleak prognosis. Craniotomy surgical resection followed by radiotherapy and chemotherapy was still the standard therapeutic strategy for GBM. As a target alkylating agent, temozolomide (TMZ) was utilized in the therapy of GBM for decades. However, effective treatment for GBM is stymied by rapid acquired resistance and bone marrow suppression. Here, we synthesize a tetrahedral framework nucleic acid (tFNA) nanoparticle that can carry TMZ to enhance the lethality on four GBM cell lines via activating the cell apoptosis and autophagy pathway. Our nanoparticle, namely, tFNA-TMZ, shows a more obvious efficacy in killing TMZ-sensitive cells (A172 and U87) than single-agent TMZ. Besides, tFNA-TMZ was able to attenuate drug resistance in TMZ-resistant cells (T98G and LN-18) via downregulating the expression of O6-methylguanine-DNA-methyltransferase. Furthermore, we modified the tFNA with GS24, a DNA aptamer that can specially bind to transferrin receptor in the cerebral vascular endothelial cell of mouse and enable the tFNA nanoparticle to cross the blood–brain barrier. In summary, our results demonstrated that tFNA-TMZ has a promising role as a nanoscale vehicle to deliver TMZ to enhance the efficacy of GBM.
The molecular mechanism of pollen germination and pollen tube growth has been revealed in detail during the last decade, while the mechanism that suspends pollen grains in a dormant state is largely unclear. Here, we identified the () gene by screening pollen-specific genes for those that are unnecessary for pollen germination. We showed that the pollen of the loss-of-function mutant exhibited hyperactive germination in sucrose-only medium and inside the anther, while this phenotype was rescued by the transgenic expression of in plants. JGB contains seven WD40 repeats and is highly conserved in flowering plants. Overexpression of inhibits pollen germination. These results indicate that JGB is a novel negative regulator of pollen germination. In addition, we found that jasmonic acid (JA) abundance was significantly elevated in pollen, while exogenous application of methyl jasmonate rescued the inhibition of pollen germination in plants overexpressing Based on the molecular features of JGB and on the finding that it interacts with a known JA biosynthesis-related transcription factor, TCP4, we propose that JGB, together with TCP4, forms a regulatory complex that controls pollen JA synthesis, ensuring pollination in moist environments.
Modulating microglial polarization is a potential strategy to assuage secondary brain injury caused by intracranial hemorrhage (ICH). However, despite decades of effort, effective therapies targeting microglia for ICH are still lacking. Here, a nanorobotic, tetrahedral framework nucleic acid (tFNA), is successfully synthesized and designed to carry C‐C chemokine receptor 2 (siCCR2) for use in in vitro hemin‐induced and in vivo collagenase‐induced ICH models. This nanoscale complex (tFNA‐siCCR2), which possesses biocompatibility, editability, and structural stability, exhibits a favorable effect in inhibiting the expression of CCR2. After treatment with tFNA‐siCCR2, hematoma absorption is accelerated, and neurological inflammation is mitigated by decreasing levels of proinflammatory cytokines, while increasing the release of anti‐inflammatory factors. Consequently, the neurological deficits of mice with ICH improve. These results indicate that inhibiting CCR2 expression during the acute phase of ICH polarizes microglia towards a therapeutic subtype, and restores neurological function, which demonstrates that tFNA has a promising ability to transfer siCCR2 for treating ICH.
Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also function as important signaling molecules that regulate biotic and abiotic stress responses as well as plant growth and development. Recent studies have implicated ROS in various aspects of plant reproduction. In male gametophytes, ROS are associated with germline development as well as the developmentally associated programmed cell death of tapetal cells necessary for microspore development. ROS have a role in regulation of female gametophyte patterning and maintenance of embryo sac polarity. During pollination, ROS play roles in the generation of self-incompatibility response during pollen-pistil interaction, pollen tube growth, pollen tube burst for sperm release and fertilization. In this mini review, we provide an overview of ROS production and signaling in the context of plant reproductive development, from female and male gametophyte development to fertilization.
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