Ring signatures allow a user to sign messages as a member of a set of users, which is called the ring. This primitive ensures that nobody can detect which member in the ring signs the message. ...Libert, Peters, and Qian (2018) 24 proposed the first tightly secure ring signature scheme with O(logn) signature size in the random oracle model, where n is the size of a ring. To our knowledge, a tightly secure ring signature scheme has never been reported without depending on the random oracle methodology. In this paper, we propose two generic constructions of tightly secure ring signatures in the standard model. Our first (resp., second) construction is secure in the common reference string model (resp., the plain model). Both of our constructions are secure under the decisional linear assumption over the pairing groups. Our first generic construction has a more efficient instantiation than our second one. While our second generic construction does not have an efficient instantiation, its signature size achieves O(logn) asymptotically, which is the same as one of the Libert et al.'s scheme.
At the transition from vegetative to reproductive growth in rice (Oryza sativa), a developmental program change occurs, resulting in panicle (rice inflorescence) formation. The initial event of the ...transition is the change of the shoot apical meristem to an inflorescence meristem (IM), accompanied by a rapid increase in the meristem size. Suppression of leaf growth also occurs, resulting in the formation of bracts. The IM generates branch meristems (BMs), indeterminate meristems that reiteratively generate next-order meristems. All meristems eventually acquire a determinate spikelet meristem identity and terminate after producing a floret. ABERRANT PANICLE ORGANIZATION2 (APO2) is the rice ortholog of Arabidopsis (Arabidopsis thaliana) LEAFY (LFY), a plant-specific transcription factor (TF). APO2 is a positive regulator of panicle branch formation. Here, we show that APO2 is also required to increase the meristem size of the IM and suppress bract outgrowth. We identified genes directly and indirectly regulated by APO2 and identified APO2-binding sites. These analyses showed that APO2 directly controls known regulators of panicle development, including SQUAMOSA PROMOTER BINDING PROTEIN LIKE14 and NECK LEAF1. Furthermore, we revealed that a set of genes act as downstream regulators of APO2 in controlling meristem cell proliferation during reproductive transition, bract suppression, and panicle branch formation. Our findings indicate that APO2 acts as a master regulator of rice panicle development by regulating multiple steps in the reproductive transition through directly controlling a set of genes.
Intracellular delivery of oligonucleotides is important for their use as therapeutic drugs. The conjugation of molecules interacting with cell membrane proteins to enhance their internalization into ...cells is an effective strategy for delivering oligonucleotides. In the present study, we focused on creating aptamers, which are single-stranded oligonucleotides that bind target molecules with high affinity and specificity, as membrane protein-binding molecules. With an evolutionary selection approach using a random DNA library containing a uracil derivative with a hydrophobic functional group at the 5 position, we successfully obtained aptamers that are efficiently internalized into A549 cells. The efficacies of the aptamers were tested by further conjugation with MALAT1-targeting antisense oligonucleotides (ASOs), and the expression levels of MALAT1 RNA were examined. The aptamer-ASO conjugates were taken up by A549 cells, although there was no observable reduction in MALAT1 RNA levels. In contrast, the activity of the aptamer-ASO conjugate was potentiated when endosomal/lysosomal escape was enhanced by the addition of chloroquine. Thus, we showed that the hydrophobic modification of the nucleobase moiety is useful for developing highly internalizing aptamers and that endosomal/lysosomal escape is important for the intracellular delivery of ASOs by aptamers.
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With the hydrophobic modification of nucleobase, we successfully developed cell-internalizing aptamers. The aptamers had higher cell-internalizing ability than did those developed without the modification. Although the aptamers could deliver antisense oligonucleotide into cells, endosomal/lysosomal escape was a bottleneck to increase target RNA degradation by the delivered antisense oligonucleotide.
The 24-nucleotides (nt) phased secondary small interfering RNA (phasiRNA) is a unique class of plant small RNAs abundantly expressed in monocot anthers at early meiosis. Previously, 44 intergenic ...regions were identified as the loci for longer precursor RNAs of 24-nt phasiRNAs (24-PHASs) in the rice genome. However, the regulatory mechanism that determines spatiotemporal expression of these RNAs has remained elusive. ETERNAL TAPETUM1 (EAT1) is a basic-helix-loop-helix (bHLH) transcription factor indispensable for induction of programmed cell death (PCD) in postmeiotic anther tapetum, the somatic nursery for pollen production. In this study, EAT1-dependent non-cell-autonomous regulation of male meiosis was evidenced from microscopic observation of the eat1 mutant, in which meiosis with aberrantly decondensed chromosomes was retarded but accomplished somehow, eventually resulting in abortive microspores due to an aberrant tapetal PCD. EAT1 protein accumulated in tapetal-cell nuclei at early meiosis and postmeiotic microspore stages. Meiotic EAT1 promoted transcription of 24-PHAS RNAs at 101 loci, and importantly, also activated DICER-LIKE5 (DCL5, previous DCL3b in rice) mRNA transcription that is required for processing of double-stranded 24-PHASs into 24-nt lengths. From the results of the chromatin-immunoprecipitation and transient expression analyses, another tapetum-expressing bHLH protein, TDR INTERACTING PROTEIN2 (TIP2), was suggested to be involved in meiotic small-RNA biogenesis. The transient assay also demonstrated that UNDEVELOPED TAPETUM1 (UDT1)/bHLH164 is a potential interacting partner of both EAT1 and TIP2 during early meiosis. This study indicates that EAT1 is one of key regulators triggering meiotic phasiRNA biogenesis in anther tapetum, and that other bHLH proteins, TIP2 and UDT1, also play some important roles in this process. Spatiotemporal expression control of these bHLH proteins is a clue to orchestrate precise meiosis progression and subsequent pollen production non-cell-autonomously.
Root-associated microbial communities are very important in the adaptation of halophytes to coastal environments. However, little has been reported on microbial community structures related to ...halophytes, or on comparisons of their compositions among halophytic plant species. Here, we studied the diversity and community structure of both rhizosphere and root endosphere bacteria in two halophytic plants:
and
. We sampled the rhizosphere, the root endosphere, and bulk control soil samples, and performed bacterial 16S rRNA sequencing using the Illumina MiSeq platform to characterize the bacterial community diversities in the rhizosphere and root endosphere of both halophytes. Among the
.
samples, the richness and diversity of bacteria in the rhizosphere were higher than those in the root endosphere but were lower than those of the bulk soil. In contrast for
.
, the bulk soil, the rhizosphere, and the root endosphere all had similar bacterial richness and diversity. The number of unique operational taxonomic units within the root endosphere, the rhizosphere, and the bulk soil were 181, 366, and 924 in
.
and 126, 416, and 596 in
.
, respectively, implying habitat-specific patterns for each halophyte. In total, 35 phyla and 566 genera were identified. The dominant phyla across all samples were
and
.
was extremely abundant in the root endosphere from
.
. Beneficial bacterial genera were enriched in the root endosphere and rhizosphere in both halophytes.
,
, and
were highly abundant in
.
, whereas
and
were highly abundant in
.
A principal coordinate analysis demonstrated significant differences in the microbiota composition associated with the plant species and type of sample. These results strongly indicate that there are clear differences in bacterial community structure and diversity between
.
and
.
. This is the first report to characterize the root microbiome of
.
, and to compare the diversity and community structure of rhizosphere and root endosphere bacteria between
.
and
.
.
Although spinach is predominantly dioecious, monoecious plants with varying proportions of female and male flowers are also present. Recently, monoecious inbred lines with highly female and male ...conditions have been preferentially used as parents for F1-hybrids, rather than dioecious lines. Accordingly, identifying the loci for monoecism is an important issue for spinach breeding. We here used long-read sequencing and Hi-C technology to construct SOL_r2.0_pseudomolecule, a set of six pseudomolecules of spinach chromosomes (total length: 879.2 Mb; BUSCO complete 97.0%) that are longer and more genetically complete than our previous version of pseudomolecules (688.0 Mb; 81.5%). Three QTLs, qFem2.1, qFem3.1, and qFem6.1, responsible for monoecism were mapped to SOL_r2.0_pseudomolecule. qFem3.1 had the highest LOD score and corresponded to the M locus, which was previously identified as a determinant of monoecious expression, by genetic analysis of progeny from female and monoecious plants. The other QTLs were shown to modulate the ratio of female to male flowers in monoecious plants harboring a dominant allele of the M gene. Our findings will enable breeders to efficiently produce highly female- and male-monoecious parental lines for F1-hybrids by pyramiding the three QTLs. Through fine-mapping, we narrowed the candidate region for the M locus to a 19.5 kb interval containing three protein-coding genes and one long non-coding RNA gene. Among them, only RADIALIS-like-2a showed a higher expression in the reproductive organs, suggesting that it might play a role in reproductive organogenesis. However, there is no evidence that it is involved in the regulation of stamen and pistil initiation, which are directly related to the floral sex differentiation system in spinach. Given that auxin is involved in reproductive organ formation in many plant species, genes related to auxin transport/response, in addition to floral organ formation, were identified as candidates for regulators of floral sex-differentiation from qFem2.1 and qFem6.1.
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