Discovery and structure-activity relationship studies of novel tetrahydro-β-carboline derivatives as apoptosis initiators for treating bacterial infections
Targeted mutations of BnPAP2 lead to a yellow seed coat in Brassica napus L.
Brown planthopper E78 regulates moulting and ovarian development by interacting with E93
The brown planthopper (Nilaparvata lugens) is the main migratory pest in many rice growing areas in Asia. E78 is a member of the nuclear hormone receptor superfamily which plays an important role in egg development and maternal regulation of early embryogenesis. In this study, brown planthopper E78 (NlE78) was cloned, and the predicted amino acid sequence showed that it contains two conserved domains: NR-LBD and DBD. qRT-PCR showed that the expression of NlE78 is high in the fifth instar nymphs and the ovaries of females. After downregulation of NlE78, the rate of moulting failure (33.2%) increased significantly, and ovarian development was delayed. However, when NlE78 was downregulated together with NlE93, the emergence rate increased significantly (78.79%), and ovarian development was similar to that when NlE78 was downregulated but not delayed. A co-immunoprecipitation experiment showed that NlE78 interacts with NlE93, a crucial downstream transcription factor of the ecdysone signalling pathway. Cellular localization by immunofluorescence revealed that NlE78 and NlE93 are expressed in the nucleus. This study indicates that NlE78 regulates ovarian development and moulting, possibly through its interaction with NlE93. This study is of great significance for the development of new pesticides and control methods based on newly discovered targets.
Cassava MeRS40 is required for the regulation of plant salt tolerance
Soil salinity affects the expression of serine/arginine-rich (SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress. We previously identified the cassava spliceosomal component 35 like (SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses. However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich (RS) subfamily in response to salt stress remains to be explored. In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions. Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses. Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes. However, overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA. Moreover, the MeRS40 protein interacted with MeU1-70Ks (MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively. Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants.
Cylas formicarius is one of the most important pests of sweet potato worldwide, causing considerable ecological and economic damage. This study improved the effect of comprehensive management and understanding of genetic mechanisms by examining the functional genomics of C. formicarius. Using Illumina and PacBio sequencing, this study obtained a chromosome-level genome assembly of adult weevils from lines inbred for 15 generations. The high-quality assembly obtained was 338.84 Mb, with contig and scaffold N50 values of 14.97 and 34.23 Mb, respectively. In total, 157.51 Mb of repeat sequences and 11 907 protein-coding genes were predicted. A total of 337.06 Mb of genomic sequences was located on the 11 chromosomes, accounting for 99.03% of the total length of the associated chromosome. Comparative genomic analysis showed that C. formicarius was sister to Dendroctonus ponderosae, and C. formicarius diverged from D. ponderosae approximately 138.89 million years ago (Mya). Many important gene families expanded in the C. formicarius genome were involved in the detoxification of pesticides, tolerance to cold stress and chemosensory system. To further study the role of odorant-binding proteins (OBPs) in olfactory recognition of C. formicarius, the binding assay results indicated that CforOBP4–6 had strong binding affinities for sex pheromones and other ligands. The high-quality C. formicarius genome provides a valuable resource to reveal the molecular ecological basis, genetic mechanism, and evolutionary process of major agricultural pests; it also offers new ideas and new technologies for ecologically sustainable pest control.
Meloidogyne incognita is a devastating plant-parasitic nematode. Effectors play important roles during the stages of nematodes infection and parasitism, but their molecular functions remain largely unknown. In this study, we characterized a new effector, Minc03329, which contains signal peptide for secretion and a C-type lectin domain. The yeast signal sequence trap experiments indicated that the signal peptide of Minc03329 is functional. In situ hybridization showed that Minc03329 was specifically expressed in the subventral esophageal gland. Real-time qPCR confirmed that the expression level of Minc03329 transcript was significantly increased in pre-parasitic and parasitic second-stage juveniles (pre-J2s and par-J2s). Tobacco rattle virus (TRV)-mediated gene silencing of Minc03329 in host plants largely reduced the pathogenicity of nematodes. On the contrary, ectopic expression of Minc03329 in Arabidopsis thaliana significantly increased plant susceptibility to nematodes. Transient expression of Minc03329 in Nicotiana benthamiana leaves suppressed the programmed cell death triggered by the pro-apoptotic protein BAX. Moreover, the transcriptome analysis of Minc03329-transgenic Arabidopsis and wild type revealed that many defense-related genes were significantly down-regulated. Interestingly, some different expressed genes were involved in the formation of nematode feeding sites. These results revealed that Minc03329 is an important effector for M. incognita, suppressing host defense response and promoting pathogenicity.
Potato is one of the staple food crops in North China. However, potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation. Increasing yield and water use efficiency (WUE) of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China. However, the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region. Based on meta-analysis of field experiments from the literature and model simulation, this study quantified the potential yields of potatoes without water and fertilizer limitation, and yield under irrigated and rainfed conditions, and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains (DH), the Foothills of Yanshan hilly (YH), the North foot of the Yinshan Mountains (YM), and the Loess Plateau (LP) in North China. Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha–1 for the YH region, 11.4 t ha–1 for the YM region, 11.2 t ha–1 for the DH region, and 10.7 t ha–1 for the LP region, respectively. Observed rainfed potato tuber dry weight yield accounted for 61, 30, 28 and 24% of the potential yield in the DH, YH, YM, and LP regions. The maximum WUE of 2.2 kg m–3 in the YH region, 2.1 kg m–3 in the DH region, 1.9 kg m–3 in the YM region and 1.9 kg m–3 in the LP region was achieved under the potential yield level. Ridge-furrow planting could boost yield by 8–49% and WUE by 2–36% while ridge-furrow planting with film mulching could boost yield by 35–89% and WUE by 7–57% across North China. Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.
Chromatin accessibility plays a vital role in gene transcriptional regulation. However, the regulatory mechanism of chromatin accessibility, as well as its role in regulating crucial gene expression and kernel development in maize (Zea mays) are poorly understood. In this study, we isolated a maize kernel mutant designated as defective kernel219 (dek219), which displays opaque endosperm and embryo abortion. Dek219 encodes the DICER-LIKE1 (DCL1) protein, an essential enzyme in miRNA biogenesis. Loss of function of Dek219 results in significant reductions in the expression levels of most miRNAs and histone genes. Further research showed that the Heat shock transcription factor17 (Hsf17)-Zm00001d016571 module may be one of the factors affecting the expression of histone genes. Assay results for transposase-accessible chromatin sequencing (ATAC-seq) indicated that the chromatin accessibility of dek219 is altered compared with that of wild type (WT), which may regulate the expression of crucial genes in kernel development. By analyzing differentially expressed genes (DEGs) and differentially accessible chromatin regions (ACRs) between WT and dek219, we identified 119 candidate genes that are regulated by chromatin accessibility, including some reported to be crucial genes for kernel development. Taken together, these results suggest that Dek219 affects chromatin accessibility and the expression of crucial genes that are required for maize kernel development
Some H5 viruses isolated in poultry or wild birds between 2020 and 2021 were found to be antigenically different from the vaccine strains (H5-Re11 and H5-Re12) used in China. In this study, we generated three new recombinant vaccine seed viruses by using reverse genetics and used them for vaccine production. The vaccine strain H5-Re13 contains the hemagglutinin (HA) and neuraminidase (NA) genes of an H5N6 virus that bears the clade 2.3.4.4h HA gene, H5-Re14 contains the HA and NA genes of an H5N8 virus that bears the clade 2.3.4.4b HA gene, and H7-Re4 contains the HA and NA genes of H7N9 virus detected in 2021. We evaluated the protective efficacy of the novel H5/H7 trivalent inactivated vaccine in chickens, ducks, and geese. The inactivated vaccine was immunogenic and induced substantial antibody responses in the birds tested. Three weeks after vaccination, chickens were challenged with five different viruses detected in 2020 and 2021: three viruses (an H5N1 virus, an H5N6 virus, and an H5N8 virus) bearing the clade 2.3.4.4b HA gene, an H5N6 virus bearing the clade 2.3.4.4h HA gene, and an H7N9 virus. All of the control birds shed high titers of virus and died within 4 days post-challenge, whereas the vaccinated chickens were completely protected from these viruses. Similar protective efficacy against H5 viruses bearing the clade 2.3.4.4h or 2.3.4.4b HA gene was observed in ducks and geese. Our study indicates that the newly updated H5/H7 vaccine can provide solid protection against the H5 and H7N9 viruses that are currently circulating in nature.