MicroRNAs (miRNAs) play important roles in rice response to Magnaporthe oryzae, the causative agent of rice blast disease. Studying the roles of rice miRNAs is of great significance for the disease ...control. Osa‐miR167d belongs to a conserved miRNA family targeting auxin responsive factor (ARF) genes that act in developmental and stress‐induced responses. Here, we show that Osa‐miR167d plays a negative role in rice immunity against M. oryzae by suppressing its target gene. The expression of Osa‐miR167d was significantly suppressed in a resistant accession at and after 24 h post inoculation (hpi), however, its expression was significantly increased at 24 hpi in the susceptible accession upon M. oryzae infection. Transgenic rice lines over‐expressing Osa‐miR167d were highly susceptible to multiple blast fungal strains. By contrast, transgenic lines expressing a target mimicry to block Osa‐miR167d enhanced resistance to rice blast disease. In addition, knocking out the target gene ARF12 led to hyper‐susceptibility to multiple blast fungal strains. Taken together, our results indicate that Osa‐miR167d negatively regulate rice immunity to facilitate the infection of M. oryzae by downregulating ARF12. Thus, Osa‐miR167d‐ARF12 regulatory module could be valuable in improvement of blast‐disease resistance.
Rice blast caused by Magnaporthe oryzae is one of the most destructive diseases. Here we demonstrated that rice Osa‐miR167d facilitates the infection of M. oryzae by suppressing ARF12, and ARF12 is required for resistance to the blast disease. Our findings suggest that the Osa‐miR167d‐ARF12 regulatory module is valuable in blast‐disease breeding programs.
The development of natural gas in China has entered a golden and leap-forward stage, which is a necessary bridge to clean energy. This in-depth study on the status quo, theory, technology and ...prospect of natural gas development shows: (1) The global remaining proven recoverable reserves of natural gas are 186×1012 m3 and the reserves-production ratio is 52.4, indicating a solid resource base for long-term and rapid development. (2) Ten formation and distribution laws of conventional and unconventional natural gas reservoirs have been proposed. In terms of exploration geology, the theory of conventional “monolithic” giant gas fields with different gas sources, and an unconventional gas accumulation theory with continuous distribution of “sweet areas” in different lithologic reservoirs have been established; in terms of development geology, a development theory of conventional structural gas reservoirs is oriented to “controlling water intrusion”, while a development theory of unconventional gas is concentrated on man-made gas reservoirs. (3) With the geological resources (excluding hydrates) of 210×1012 m3 and the total proven rate of the resources less than 2% at present, the natural gas in China will see a constant increase in reserve and production; by 2030, the proven geological reserves of natural gas are expected to reach about (6 000− 7000)×108 m3 the production of conventional and unconventional natural gas each will reach about 1 000×108 m3 and the gas consumption will reach 5500×108 m3. The dependence on imported natural gas may be 64% by 2030, and 70% by 2050. (4) Ten measures for future development of natural gas have been proposed, including strengthening exploration in large-scale resource areas, increasing the development benefits of unconventional gas, and enhancing the peak adjusting capacity of gas storage and scale construction of liquified natural gas.
miRNAs contribute to plant resistance against pathogens. Previously, we found that the function of miR398b in immunity in rice differs from that in Arabidopsis. However, the underlying mechanisms are ...unclear.
In this study, we characterized the mutants of miR398b target genes and demonstrated that multiple superoxide dismutase genes contribute to miR398b-regulated rice immunity against the blast fungus Magnaporthe oryzae.
Out of the four target genes of miR398b, mutations in Cu/Zn-Superoxidase Dismutase1 (CSD1), CSD2 and Os11g09780 (Superoxide DismutaseX, SODX) led to enhanced resistance to M. oryzae and increased hydrogen peroxide (H₂O₂) accumulation. By contrast, mutations in Copper Chaperone for Superoxide Dismutase (CCSD) resulted in enhanced susceptibility. Biochemical studies revealed that csd1, csd2 and sodx displayed altered expression of CSDs and other superoxide dismutase (SOD) family members, leading to increased total SOD enzyme activity that positively contributed to higher H₂O₂ production. By contrast, the ccsd mutant showed CSD protein deletion, resulting in decreased CSD and total SOD enzyme activity.
Our results demonstrate the roles of different SODs in miR398b-regulated resistance to rice blast disease, and uncover an integrative regulatory network in which miR398b boosts total SOD activity to upregulate H₂O₂ concentration and thereby improve disease resistance.
Summary
The Arabidopsis RESISTANCE TO POWDERY MILDEW 8.1 (RPW8.1) activates confined cell death and defense against different pathogens. However, the underlying regulatory mechanisms still remain ...elusive.
Here, we show that RPW8.1 activates ethylene signaling that, in turn, negatively regulates RPW8.1 expression. RPW8.1 binds and stabilizes 1‐aminocyclopropane‐1‐carboxylate oxidase 4 (ACO4), which may in part explain increased ethylene production and signaling in RPW8.1‐expressing plants. In return, ACO4 and other key components of ethylene signaling negatively regulate RPW8.1‐mediated cell death and disease resistance via suppressing RPW8.1 expression.
Loss of function in ACO4, EIN2, EIN3 EIL1, ERF6, ERF016 or ORA59 increases RPW8.1‐mediated cell death and defense response. By contrast, overexpression of EIN3 abolishes or significantly compromises RPW8.1‐mediated cell death and disease resistance. Furthermore, ERF6, ERF016 and ORA59 appear to act as trans‐repressors of RPW8.1, with OAR59 being able to directly bind to the RPW8.1 promoter.
Taken together, our results have revealed a feedback regulatory circuit connecting RPW8.1 and the ethylene‐signaling pathway, in which RPW8.1 enhances ethylene signaling, and the latter, in return, negatively regulates RPW8.1‐mediated cell death and defense response via suppressing RPW8.1 expression to attenuate its defense activity.
Fitness cost is a common phenomenon in rice blast disease-resistance breeding. MiR396 is a highly conserved microRNA (miRNA) family targeting
Growth Regulating Factor
(
OsGRF
) genes. Mutation at the ...target site of miR396 in certain
OsGRF
gene or blocking miR396 expression leads to increased grain yield. Here we demonstrated that fitness cost can be trade-off in miR396-
OsGRF
s module via balancing growth and immunity against the blast fungus. The accumulation of miR396 isoforms was significantly increased in a susceptible accession, but fluctuated in a resistant accession upon infection of
Magnaporthe oryzae
. The transgenic lines over-expressing different miR396 isoforms were highly susceptible to
M. oryzae
. In contrast, overexpressing target mimicry of miR396 to block its function led to enhanced resistance to
M. oryzae
in addition to improved yield traits. Moreover, transgenic plants overexpressing
OsGRF6
,
OsGRF7
,
OsGRF8
, and
OsGRF9
exhibited enhanced resistance to
M. oryzae
, but showed different alteration of growth. While overexpression of
OsGRF7
led to defects in growth, overexpression of
OsGRF6
,
OsGRF8
, and
OsGRF9
resulted in better or no significant change of yield traits. Collectively, our results indicate that miR396 negatively regulates rice blast disease- resistance via suppressing multiple
OsGRF
s, which in turn differentially control growth and yield. Therefore, miR396-
OsGRFs
could be a potential module to demolish fitness cost in rice blast disease-resistance breeding.
miRNAs contribute to plant resistance against pathogens. Previously, we found that the function of miR398b in immunity in rice differs from that in Arabidopsis. However, the underlying mechanisms are ...unclear. In this study, we characterized the mutants of miR398b target genes and demonstrated that multiple superoxide dismutase genes contribute to miR398b-regulated rice immunity against the blast fungus Magnaporthe oryzae. Out of the four target genes of miR398b, mutations in Cu/Zn-Superoxidase Dismutase1 (CSD1), CSD2 and Os11g09780 (Superoxide DismutaseX, SODX) led to enhanced resistance to M. oryzae and increased hydrogen peroxide (H
O
) accumulation. By contrast, mutations in Copper Chaperone for Superoxide Dismutase (CCSD) resulted in enhanced susceptibility. Biochemical studies revealed that csd1, csd2 and sodx displayed altered expression of CSDs and other superoxide dismutase (SOD) family members, leading to increased total SOD enzyme activity that positively contributed to higher H
O
production. By contrast, the ccsd mutant showed CSD protein deletion, resulting in decreased CSD and total SOD enzyme activity. Our results demonstrate the roles of different SODs in miR398b-regulated resistance to rice blast disease, and uncover an integrative regulatory network in which miR398b boosts total SOD activity to upregulate H
O
concentration and thereby improve disease resistance.
Acute spinal cord injury (SCI) could cause mainly two types of pathological sequelae, the primary mechanical injury, and the secondary injury. The macrophage in SCI are skewed toward the M1 phenotype ...that might cause the failure to post-SCI repair.
SCI model was established in Balb/c mice, and the changes in macrophage phenotypes after SCI were monitored. Bioinformatic analyses were performed to select factors that might regulate macrophage polarization after SCI. Mouse bone marrow-derived macrophages (BMDMs) were isolated, identified, and induced for M1 or M2 polarization; the effects of lncRNA guanylate binding protein-9 (lncGBP9) and suppressor of cytokine signaling 3 (SOCS3) on macrophages polarization were examined in vitro and in vivo. The predicted miR-34a binding to lncGBP9 and SOCS3 was validated; the dynamic effects of lncGBP9 and miR-34a on SOCS3, signal transducer and activator of transcription 1 (STAT1)/STAT6 signaling, and macrophage polarization were examined. Finally, we investigated whether STAT6 could bind the miR-34a promoter to activate its transcription.
In SCI Balb/c mice, macrophage skewing toward M1 phenotypes was observed after SCI. In M1 macrophages, lncGBP9 silencing significantly decreased p-STAT1 and SOCS3 expression and protein levels, as well as the production of Interleukin (IL)-6 and IL-12; in M2 macrophages, lncGBP9 overexpression increased SOCS3 mRNA expression and protein levels while suppressed p-STAT6 levels and the production of IL-10 and transforming growth factor-beta 1 (TGF-β1), indicating that lncGBP9 overexpression promotes the M1 polarization of macrophages. In lncGBP9-silenced SCI mice, the M2 polarization was promoted on day 28 after the operation, further indicating that lncGBP9 silencing revised the predominance of M1 phenotype at the late stage of secondary injury after SCI, therefore improving the repair after SCI. IncGBP9 competed with SOCS3 for miR-34a binding to counteract miR-34a-mediated suppression on SOCS3 and then modulated STAT1/STAT6 signaling and the polarization of macrophages. STAT6 bound the promoter of miR-34a to activate its transcription.
In macrophages, lncGBP9 sponges miR-34a to rescue SOCS3 expression, therefore modulating macrophage polarization through STAT1/STAT6 signaling. STAT6 bound the promoter of miR-34a to activate its transcription, thus forming two different regulatory loops to modulate the phenotype of macrophages after SCI.
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