Biology subjects

Lu, G.

Publications and source records attributed to Lu, G..

6 recordsLinked to original sources

bioRxiv2018

Relationship between ecological stoichiometry and community diversity of plant ecosystems in the upper reaches of the Tarim River, China

AimAlthough it is commonly proposed that nutrient cycling can impact plant community diversity, this relationship has not been fully examined in arid and semi-arid zones. Here, we expand on the framework for evaluating the relationship between biodiversity and ecological stoichiometry by scaling up from the level of the community.\n\nLocationThe upper reaches of the Tarim River (Northwest China, 80{degrees}10-84{degrees}36E, 0{degrees}25-41{degrees}10N).\n\nMethodsWe used multivariate analysis of variance to compare the stoichiometric characteristics and species diversity indices of sampled plant communities. We also measured carbon (C), nitrogen (N), and phosphorous (P) content of plants. We then assessed correlations between community stoichiometry and species diversity through structural equation models (SEM) and redundancy analysis (RDA).\n\nResultsWe found that the differences between stoichiometric characteristics and community diversity indices were highly significant. The Margalef index was strongly related to C and P content. The Simpsons index and Shannon-Weaner index were most strongly correlated with C content. Pielous index was closely related to C and N contents, and the C:N and C:P ratios were important at driving ecological dominance.\n\nMain ConclusionsOur study highlights the importance of ecological stoichiometry in driving community assembly and diversity within a desert ecosystems in northwestern China. The relationship between eclogical stoichiometry in the desert plant community had an effect on species diversity, and it was a good indicator of plant community diversity.

ecology↗

bioRxiv2018

Tenuivirus uses a molecular bridge strategy to overcome insect midgut barriers for virus persistent transmission

Many persistent transmitted plant viruses, including Rice stripe tenuivirus (RSV), cause serious damages to crop productions in China and worldwide. Although many reports have indicated that successful insect-mediated virus transmission depends on proper virus-insect vector interactions, the mechanism(s) controlling interactions between viruses and insect vectors for virus persistent transmission remained poorly understood. In this study, we used RSV and its small brown planthopper (SBPH) vector as a working model to elucidate the molecular mechanism controlling RSV virion entrance into SBPH midgut for persistent transmission. We have now demonstrated that this non-enveloped Tenuivirus uses its non-structural glycoprotein NSvc2 as a helper component to bridge the specific interaction between virion and SBPH midgut cells, leading to overcome SBPH midgut barriers for virus persistent transmission. In the absence of this glycoprotein, purified RSV virion is not capable of entering SBPH midgut cells. In RSV-infected cells, glycoprotein NSvc2 is processed into two mature proteins: an amino-terminal protein NSvc2-N and a carboxyl-terminal protein NSvc2-C. We determined that NSvc2-N interacted with RSV virion and bound directly to midgut lumen surface via its N-glycosylation sites. Upon recognition by midgut cells, the midgut cells underwent endocytosis followed by compartmentalizing RSV virion and NSvc2 into early and then late endosomes. The acidic condition inside the late endosome triggered conformation change of NSvc2-C and caused cell membrane fusion via its highly conserved fusion loop motifs, leading to the release of RSV virion from endosome into cytosol. In summary, our results showed for the first time that a rice Tenuivirus uses a molecular bridge strategy to ensure proper interactions between virus and insect midgut for successful persistent transmission.\n\nAuthor summaryOver 75% of the known plant viruses are insect transmitted. Understanding how plant viruses interacted with their insect vectors during virus transmission is one of the key steps to manage virus diseases worldwide. Both the direct and indirect virus-insect vector interaction models have been proposed for virus non-persistent and semi-persistent transmission. However, the indirect virus-vector interaction mechanism during virus persistent transmission has not been reported previously. In this study, we developed a new reverse genetics technology and demonstrated that the circulative and propagative transmitted Rice stripe tenuivirus utilizes a glycoprotein NSvc2 as a helper component to ensure a specific interaction between Tenuivirus virion and midgut cells of small brown planthopper (SBPH), leading to conquering the midgut barrier of SBPH. This is the first report of a helper component mediated-molecular bridge mechanism for virus persistent transmission. These new findings and our new model on persistent transmission expand our understanding of molecular mechanism(s) controlling virus-insect vector interactions during virus transmission in nature.

pathology↗

bioRxiv2018

UBE2G1 Governs the Destruction of Cereblon Neomorphic Substrates

The immunomodulatory drugs (IMiDs) thalidomide, lenalidomide, and pomalidomide as well as the novel cereblon modulating agents (CMs) including CC-122, CC-220 and cereblon-based proteolysis-targeting chimaeras (PROTACs) repurpose the Cul4-RBX1-DDB1-CRBN (CRL4CRBN) E3 ubiquitin ligase complex to induce the degradation of specific neomorphic substrates via polyubiquitination in conjunction with an E1 ubiquitin-activating enzyme and E2 ubiquitin-conjugating enzymes, which have until now remained elusive. Here we show that the ubiquitin-conjugating enzymes UBE2G1 and UBE2D3 cooperatively promote the polyubiquitination of CRL4CRBN neomorphic substrates in a cereblon- and CM-dependent manner via a sequential ubiquitination mechanism: UBE2D3 transforms the neomorphic substrates into mono-ubiquitinated forms, upon which UBE2G1 catalyzes K48-linked polyubiquitin chain extension. Blockade of UBE2G1 diminishes the ubiquitination and degradation of neomorphic substrates, and consequent antitumor activities elicited by all tested CMs. For example, UBE2G1 inactivation significantly attenuated the degradation of myeloma survival factors IKZF1 and IKZF3 induced by lenalidomide and pomalidomide, hence conferring drug resistance. UBE2G1-deficient myeloma cells, however, remained sensitive to a more potent IKZF1/3 degrader CC-220. Collectively, these findings suggest that loss of UBE2G1 activity might be a resistance mechanism to drugs that hijack the CRL4CRBN to eliminate disease-driving proteins, and that this resistance mechanism can be overcome by next-generation CMs that destroy the same targeted protein more effectively.

molecular biology↗

bioRxiv2018

Comparative genomic analysis revealed rapid differentiation in the pathogenicity-related gene repertoires between Pyricularia oryzae and Pyricularia penniseti isolated from a Pennisetum grass

BackgroundsPyricularia is a multispecies complex that could infect and cause severe blast disease on diverse hosts, including rice, wheat and many other grasses. Although the genome size of this fungal complex is small [~40 Mbp for Pyricularia oryzae (syn. Magnaporthe oryzae), and ~45 Mbp for P. grisea], the genome plasticity allows the fungus to jump and adapt to new hosts. Therefore, deciphering the genome basis of individual species could facilitate the evolutionary and genetic study of this fungus. However, except for the P. oryzae subgroup, many other species isolated from diverse hosts, such as the Pennisetum grasses, remain largely uncovered genetically.\n\nResultsHere, we report the genome sequence of a pyriform-shaped fungal strain P. penniseti P1609 isolated from a Pennisetum grass (JUJUNCAO) using PacBio SMRT sequencing technology. We performed a phylogenomic analysis of 28 Magnaporthales species and 5 non-Magnaporthales species and addressed P1609 into a Pyricularia subclade that is distant from P. oryzae. Comparative genomic analysis revealed that the pathogenicity-related gene repertoires were fairly different between P1609 and the P. oryzae strain 70-15, including the cloned avirulence genes, other putative secreted proteins, as well as some other predicted Pathogen-Host Interaction (PHI) genes. Genomic sequence comparison also identified many genomic rearrangements.\n\nConclusionTaken together, our results suggested that the genomic sequence of the P. penniseti P1609 could be a useful resource for the genetic study of the Pennisetum-infecting Pyricularia species.

genomics↗

bioRxiv2018

Categorized analysis of forest ecological values in the China’s conversion cropland to forest program

Background\n\nThe Chinas Conversion Cropland to Forest Program (CCFP) is one of the large state ecological construction programs. Up to now, the program has effectively improved the ecological environment and produced large ecological benefit. However, there were also some problems in its implementation process, the program has been sometimes less effective than the expected.\n\nMethods\n\nBased on the data and the methods of State report on monitoring ecological effects in CCFP and the Chinese Forest Ecosystem Research Network (CFERN) in 2013, we analyzed the categorized forest ecological benefit value (B-V) s in the three forest restoration ways in different regions in China to provide references for CCFP construction.\n\nResults\n\nThe unit area B-Vs in CCFP varied between 35 000 RMBs.hm-2.a-1 and 100 000 RMBs.hm-2.a-1. Water conservation B-V and species conservation B-V were the two largest constituents, nutrient accumulation B-V was the least in all the categorized B-Vs on regional and unit area scale. The rank of restoration ways on average unit area total B-Vs was-- hillside forest conservation > returning cropland to forest > afforestation on suitable barren hills and wasteland in CCFP. Among the categorized B-Vs, some pairs were positively correlated with each other and some were negatively correlative. The correlation coefficients and some regression equations were given in the text and the attached Fig.s.\n\nConclusions\n\nWater conservation B-V was the highest and nutrient accumulation B-V was the lowest whether on regional or unit area scale in CCFP.\n\nForest ecological B-Vs varied in different forest restoration ways and different regions in CCFP. The hillside forest conservation restoration way and the water conservation B-V should be paid more attention in Chinas future forest restoration. We suggest that suitable forest restoration ways should be selective according to the regional specific and ecological targets.\n\nThere were correlations among the categorized B-Vs, and the correlations varied with different forest restoration ways in CCFP. Knowing about the correlations could clarify the targeted restoration ways according to the goal of ecological benefit.

ecology↗

bioRxiv2018

Localization and protein-protein interaction of protein kinase CK2 suggest a chaperone-like activity is integral to its function in M. oryzae.

Magnaporthe oryzae (Mo) is a model pathogen causing rice blast resulting in yield and economic losses world-wide. CK2 is a constitutively active, serine/threonine kinase in eukaryotes, having a wide array of known substrates and involved in many cellular processes. We investigated the localization and role of MoCK2 during growth and infection. BLAST search for MoCK2 components and targeted deletion of subunits was combined with protein-GFP fusions to investigate localization. We found one CKa and two CKb subunits of the CK2 holoenzyme. Deletion of the catalytic subunit CKa was not possible and might indicate that such deletions are lethal. The CKb subunits could be deleted but they were both necessary for normal growth and pathogenicity. Localization studies showed that the CK2 holoenzyme needed to be intact for normal localization at septal pores and at appressorium penetration pores. Nuclear localization of CKa was however not dependent on the intact CK2 holoenzyme. In appressoria, CK2 formed a large ring perpendicular to the penetration pore and the ring formation was dependent on the presence of all CK2 subunits. The effects on growth and pathogenicity of deletion of the b subunits combined with the localization indicate that CK2 can have important regulatory functions not only in the nucleus/nucleolus but also at fungal specific structures as septa and appressorial pores.

cell biology↗