Dissection of heterotic loci for grain yield using interconnected chromosome segment substitution lines in rice

Heterosis contributes greatly to crop production, but the genetic basis of heterosis is not fully understood.To identify heterotic loci(HLs) for grain yield, 12 yield traits were evaluated in four rice(Oryza sativa L.)mapping populations: one parental population of chromosome segment substitution lines derived from a cross between the japonica cultivar Nipponbare and indica cultivar 9311 and three connected test populations in either a homozygous 9311 genetic background or a heterozygous background. A total of 390 HLs were detected for the measured traits in two environments. The genetic bases of heterosis differed between the backcross and testcross populations. At least 10 HLs were confirmed in F1 hybrids between9311 and near-isogenic lines, each of which carried a heterotic locus of interest in the same 9311 background. All 10 showed overdominant or dominant effects on grain yield and yield components. Among them, three were verified as being associated with yield heterosis and colocalized in the same regions as those containing previously reported heterosis-associated genes. Five HLs were identified to be promising candidate loci that could be used to achieve more than 15% yield heterosis in several commercial rice hybrids. These findings suggest the potential of indica or japonica introgression for increasing yield in hybrid rice breeding programs.

Theoretical Derivation of Thermal Value Equations for Heating Furnaces

Based on thermal value theory, the aim of this paper is to deduce the theoretical formulas for evaluating the energy effective utilization degree in technological pyrological processes exemplified by metallurgical heating furnaces. Heat transfer models for continuous heating furnaces, batch-type heating furnaces, and regenerative heating furnaces are established, respectively. By analyzing the movement path of injected infinitesimal heat attached on steel or gas, thermal value equations of continuous, batch-type, and regenerative heating furnaces are derived. Then the influences of such factors as hot charging, gas preheating and intake time of heat on energy effective utilization degree are discussed by thermal value equations. The results show that thermal value rises with hot charging and air preheating for continuous heating furnaces, with shorter intake time when heat is attached on steel or longer intake time when heat is attached on gas for batch-type heating furnaces and that with more heat supply at early heating stage or less at late stage for regenerative heating furnaces.

Hairy Leaf 6, an AP2/ERF Transcription Factor, Interacts with OsWOX3B and Regulates Trichome Formation in Rice

Trichome formation has been extensively studied as a mechanistic model for epidermal cell differentiation and cell morphogenesis in plants. However, the genetic and molecular mechanisms underlying trichome formation （i.e., initiation and elongation） in rice remain largely unclear. Here, we report an AP2/ERF transcription factor, Hairy Leaf 6 （HL6）, which controls trichome formation in rice. Functional analyses revealed that HL6 transcriptionally regulates trichome elongation in rice, which is dependent on functional OsWOX3B, a homeodomain-containing protein that acts as a key regulator in trichome initiation. Biochemical and molecular genetic analyses demonstrated that HL6 physically interacts with OsWOX3B, and both of them regulate the expression of some auxin-related genes during trichome formation, in which OsWOX3B likely enhances the binding ability of HL6 with one of its direct target gene, OsYUCCA5. Popu- lation genetic analysis indicated that HL6 was under negative selection during rice domestication. Taken together, our findings provide new insights into the molecular regulatory network of trichome formation in rice.

The self-assembled nanoparticle-based trimeric RBD mRNA vaccine elicits robust and durable protective immunity against SARS-CoV-2 in mice

As COVID-19 continues to spread rapidly worldwide and variants continue to emerge,the development and deployment of safe and effective vaccines are urgently needed.Here,we developed an mRNA vaccine based on the trimeric receptor-binding domain(RBD)of the SARS-CoV-2 spike(S)protein fused to ferritin-formed nanoparticles(TF-RBD).Compared to the trimeric form of the RBD mRNA vaccine(T-RBD),TF-RBD delivered intramuscularly elicited robust and durable humoral immunity as well as a Th 1-biased cellular response.After further challenge with live SARS-CoV-2,immunization with a two-shot low-dose regimen of TF-RBD provided adequate protection in hACE2-transduced mice.In addition,the mRNA template of TF-RBD was easily and quickly engineered into a variant vaccine to address SARS-CoV-2 mutations.The TF-RBD multivalent vaccine produced broad-spectrum neutralizing antibodies against Alpha(B.1.1.7)and Beta(B.1.351)variants.This mRNA vaccine based on the encoded self-assembled nanoparticle-based trimer RBD provides a referenee for the design of mRNA vaccines targeting SARS-CoV-2.

Rice SPL10 positively regulates trichome development through expression of HL6 and auxin-related genes

Trichomes function in plant defenses against biotic and abiotic stresses;examination of glabrous lines,which lack trichomes,has revealed key aspects of trichome development and function.Tests of allelism in 51 glabrous rice(Oryza sativa)accessions collected worldwide identified OsSPL10 and OsWOX3B as regulators of trichome development in rice.Here,we report that OsSPL10 acts as a transcriptional regulator controlling trichome development.Haplotype and transient expression analyses revealed that variation in the approximately 700-bp OsSPL10 promoter region is the primary cause of the glabrous phenotype in the indica cultivar WD-17993.Disruption of OsSPL10 by genome editing decreased leaf trichome density and length in the NIL-HL6 background.Plants with genotype OsSPL10^(WD-17993)/HL6 generated by crossing WD-17993 with NIL-HL6 also had fewer trichomes in the glumes.HAIRY LEAF6(HL6)encodes another transcription factor that regulates trichome initiation and elongation,and OsSPL10 directly binds to the HL6 promoter to regulate its expression.Moreover,the transcript levels of auxin-related genes,such as OsYUCCA5 and OsPIN-FORMED1b,were altered in OsSPL10 overexpression and RNAi transgenic lines.Feeding tests using locusts(Locusta migratoria)demonstrated that non-glandular trichomes affect feeding by this herbivore.Our findings provide a molecular framework for trichome development and an ecological perspective on trichome functions.

A recombinant receptor-binding domain in trimeric form generates protective immunity against SARSCoV-2 infection in nonhuman primates

A safe and effective vaccine is critical to combat the COVID-19 pandemic.Here,we developed a trimeric SARS-CoV-2 receptor-binding domain(RBD)subunit vaccine candidate that simulates the natural structure of the spike(S)trimer glycoprotein.Immunization with the RBD trimer-induced robust humoral and cellular immune responses,and a high level of neutralizing antibodies was maintained for at least 4.5 months.Moreover,the antibodies that were produced in response to the vaccine effectively cross-neutralized the SARS-CoV-2501Y.V2 variant(B.1.351).Of note,when the vaccine-induced antibodies dropped to a sufficiently low level,only one boost quickly activated the anamnestic immune response,conferring full protection against a SARSCoV-2 challenge in rhesus macaques without typical histopathological changes in the lung tissues.These results demonstrated that the SARS-CoV-2 RBD trimer vaccine candidate is highly immunogenic and safe,providing long-lasting,broad,and significant immunity protection in nonhuman primates,thereby offering an optimal vaccination strategy against COVID-19.

A multiple-target mRNA-LNP vaccine induces protective immunity against experimental multi-serotype DENV in mice

Dengue virus(DENV)is a mosquito-borne virus with a rapid spread to humans,causing mild to potentially fatal illness in hundreds of millions of people each year.Due to the large number of serotypes of the virus,there remains an unmet need to develop protective vaccines for a broad spectrum of the virus.Here,we constructed a modified mRNA vaccine containing envelope domain III(E-DIII)and non-structural protein 1(NS1)coated with lipid nanoparticles.This multi-target vaccine induced a robust antiviral immune response and increased neutralizing antibody titers that blocked all four types of DENV infection in vitro without significant antibodydependent enhancement(ADE).In addition,there was more bias for Th1 than Th2 in the exact E-DIII and NS1-specific T cell responses after a single injection.Importantly,intramuscular immunization limited DENV transmission in vivo and eliminated vascular leakage.Our findings highlight that chimeric allogeneic structural and non-structural proteins can be effective targets for DENV vaccine and that they can prevent the further development of congenital DENV syndrome.