Background
Understanding late pollen development, including the maturation and pollination process, is a key component in maintaining crop yields. Transcriptome data obtained through microarray or ...RNA-seq technologies can provide useful insight into those developmental processes. Six series of microarray data from a public transcriptome database, the Gene Expression Omnibus of the National Center for Biotechnology Information, are related to anther and pollen development.
Results
We performed a systematic and functional study across the rice genome of genes that are preferentially expressed in the late stages of pollen development, including maturation and germination. By comparing the transcriptomes of sporophytes and male gametes over time, we identified 627 late pollen-preferred genes that are conserved among japonica and indica rice cultivars. Functional classification analysis with a MapMan tool kit revealed a significant association between cell wall organization/metabolism and mature pollen grains. Comparative analysis of rice and
Arabidopsis
demonstrated that genes involved in cell wall modifications and the metabolism of major carbohydrates are unique to rice. We used the
GUS
reporter system to monitor the expression of eight of those genes. In addition, we evaluated the significance of our candidate genes, using T-DNA insertional mutant population and the CRISPR/Cas9 system. Mutants from T-DNA insertion and CRISPR/Cas9 systems of a rice gene encoding glycerophosphoryl diester phosphodiesterase are defective in their male gamete transfer.
Conclusion
Through the global analyses of the late pollen-preferred genes from rice, we found several biological features of these genes. First, biological process related to cell wall organization and modification is over-represented in these genes to support rapid tube growth. Second, comparative analysis of late pollen preferred genes between rice and
Arabidopsis
provide a significant insight on the evolutional disparateness in cell wall biogenesis and storage reserves of pollen. In addition, these candidates might be useful targets for future examinations of late pollen development, and will be a valuable resource for accelerating the understanding of molecular mechanisms for pollen maturation and germination processes in rice.
We isolated a pollen-preferential gene, RICE IMMATURE POLLEN 1 (RIP1), from a T-DNA insertional population of japonica rice that was trapped by a promoterless beta-glucuronidase (GUS) gene. ...Semi-quantitative reverse transcription-PCR (RT-PCR) analyses confirmed that the RIP1 transcript was abundant at the late stages of pollen development. Transgenic plants carrying a T-DNA insertion in the RIP1 gene displayed the phenotype of segregation distortion of the mutated rip1 gene. Moreover, rip1/rip1 homozygous progeny were not present. Reciprocal crosses between Rip1/rip1 heterozygous plants and the wild type showed that the rip1 allele could not be transmitted through the male. Microscopic analysis demonstrated that development in the rip1 pollen was delayed, starting at the early vacuolated stage. Close examination of that pollen by transmission electron microscopy also showed delayed formation of starch granules and the intine layer. In addition, development of the mitochondria, Golgi apparatus, lipid bodies, plastids and endoplasmic reticulum was deferred in the mutant pollen. Under in vitro conditions, germination of this mutant pollen did not occur, whereas the rate for 'wild' type, pollen was 90%. These results indicate that RIP1 is necessary for pollen maturation and germination. This gene encodes a protein that shares significant homology with a group of proteins containing five WD40 repeat sequences. The green fluorescent protein (GFP)-RIP1 fusion protein is localized to the nucleus. Therefore, RIP1 is probably a nuclear protein that may form a functional complex with other proteins and carry out essential cellular and developmental roles during the late stage of pollen formation.
NH
4
+
is an important nitrogen resource for rice plants in paddy soil. Therefore, it is likely that NH
4
+
-triggered plant growth interacts with phytohormone-mediated developmental mechanisms. Our ...previous transcriptomic analysis revealed that many genes involved in auxin signaling and efflux are sensitive to NH
4
+
. In the current study, we found that NH
4
+
treatment causes a delayed gravity response in rice roots. To further elucidate the interlocking relationship between NH
4
+
and auxin signaling during root development, we utilized mutants and overexpressors of a key NH
4
+
signaling transcription factor
INDETERMINATE DOMAIN 10
(
IDD10
), encoding a transcription factor that regulates the expression of NH
4
+
uptake and N-assimilation genes. We obtained several lines of evidence that auxin affects NH
4
+
-mediated gene expression and root development in rice plants via IDD10. First, the gravity response was delayed in
idd10
roots and accelerated in
IDD10
overexpressor (
IDD10 OX
) roots in the absence and (especially) presence of NH
4
+
. Second, idd10 plants showed strong root coiling only in the presence of NH
4
+
. However, treatment of 1-N-naphthylphthalamic acid (NPA), a polar auxin transport inhibitor suppressed the NH
4
+
-specific root phenotype of
idd10
. Third, the expression of NH
4
+
-responsive auxin-related genes was affected in
idd10
and
IDD10
overexpressors. Finally,
IDD10
expression was induced by IAA and suppressed by NPA. These findings suggest that the gene expression patterns and phenotypes triggered by NH
4
+
are influenced by the actions of auxin during root development, pointing to a regulatory circuit between NH
4
+
and auxin signaling that functions in root development in rice.
Importin β1 interacts with nuclear transport factors and mediates the import of nuclear proteins. We isolated a pollen-expressed gene, rice
Importin β1 (OsImpβ1)
, from a T-DNA insertional population ...that was trapped by a promoterless
β-glucuronidase (GUS)
gene. The GUS reporter was expressed in the anthers and ovaries from early through mature developmental stages. Its expression was also observed in all floral organs. However, these patterns changed as the spikelet developed. T-DNA was inserted into the
OsImpβ1
gene at 339 bp downstream from the translation initiation site. We obtained another T-DNA insertional allele by searching the flanking sequence tag database. In both lines, the wild-type and T-DNA-carrying progeny segregated at a ratio close to 1:1. The latter genotype was heterozygous (
OsImpβ1/osimpβ1
). Reciprocal crosses between WT and heterozygous plants demonstrated that the mutant alleles could not be transmitted through the male gametophyte. Close examination of the heterozygous anthers revealed that the mutant pollen matured normally. However,
in vitro
assays showed that tube elongation was hampered in the mutant grains. These results indicate that
OsImpβ1
is specifically required for pollen tube elongation.
This study empirically investigates the revenue return to differential seat pricing in the Korean movie theater market and how it is affected by competition. In March 2016, one of three major ...multiplex chains in the market divided the seats in most of its screening auditoria into prime (high-quality), standard (medium-quality), and economy (low-quality) zones, and started charging different prices for each seating zone. For the analysis, we construct a unique dataset that contains ticket prices and the number of tickets that are sold at the show level. We find that differential seat pricing increases revenue on average by 10.6%, but does not affect the number of tickets sold. Based on the results, we suggest that in a situation in which a large number of seats remain unsold, the pricing scheme involves encouraging the sale of the prime zone seats by increasing their price only slightly. By measuring the degree of competition as the number of showings of the same movie that are played by neighboring theaters at a similar time, we also find that competition has a small negative effect on the revenue gain from differential seat pricing. This finding may be explained by switching costs that are due to moviegoers’ being away from preferred theater locations and showtimes.
This study was carried out to evaluate the expression of yellow endosperm color in the progeny of Psy-2A-CrtI (β-carotene gene, PAC) transgenic plants crossed with IR36. The selected 25 lines of F2 ...progeny exhibited stable expression of yellow endosperm color and high agronomic characteristics. IR36 and PAC transgenic plant of the grain length, width and ratio showed the same tendency of normal distribution. For progeny selection, colorimeters were as employed to distinguish differing visible colors. Correlation analysis was conducted to investigate the relationship between b* value and the expression of specific genes. b* value was associated with the relative expression of the PAC-Rev and MAR product by real-time PCR and t-test revealed significant difference. Based on this study, correlation between colorimetric values and real-time PCR was effective to detect gene expression. Yellow endosperm progenies represent a new genetic pool that might be useful to increase the genetic diversity of yellow endosperm rice.
This paper investigates the effects of vertical integration on screening decisions using data from the Korean movie industry. We find that integrated theaters show their affiliated movies more than ...nonaffiliated movies, and more than nonintegrated theaters do. However, this gap reduces during the peak times of the day and after the opening week. Our evidence suggests that the integrated theaters’ screening decisions favorable to their own movies are better understood as the result of dealing with the incentive misalignment than as the result of foreclosing other movies.
•We examine the effects of vertical integration on screening decisions in the Korean movie industry.•We find that integrated theaters show their affiliated movies more than nonaffiliated movies.•However, this gap reduces during the peak times of the day and after the opening week.•Our evidence suggests that the integrated theaters’ screening decisions are consistent with treating the incentive misalignment.
A phosphate starvation-induced, purple, acid phosphatase cDNA was cloned from rice, Oryza sativa. The cDNA encoding the phosphatase (OsPAP2) has 1,893 bp with an open reading frame of 630 amino acid ...residues. The deduced amino acid sequence of OsPAP2 shows identities of 60-63% with other plant purple acid phosphatases and appears to have five conserved motifs containing the residues involved in metal binding. OsPAP2 expression is up-regulated in the rice plant and in cell cultures in the absence of phosphate (P i ). The induced expression of OsPAP2 is a specific response to P i starvation, and is not affected by the deprivation of other nutrients. OsPAP2 expression was responsive to the level of P i -supply, and transcripts of OsPAP2 were abundant in P i -deprived roots. The OsPAP2 cDNA was expressed as a 69 kDa polypeptide in baculovirus-infected insect Sf9 cells. In addition, the OsPAP2 gene was introduced into Arabidopsis via an Agrobacterium-mediated transformation. Functional expression of the OsPAP2 gene in the transgenic Arabidopsis line was confirmed by northern and western blot analyses, as well as by phosphatase activity assays. These results suggest that the OsPAP2 gene can be used to develop new transgenic dicotyledonous plants that are able to adapt to P i -deficient conditions.
Insertional mutagen-mediated gene tagging populations have been essential resources for analyzing the function of plant genes. In rice, maize transposable elements have been successfully utilized to ...produce transposant populations. However, many generations and substantial field space are required to obtain a sufficiently sized transposant population. In rice, the japonica and indica subspecies are phenotypically and genetically divergent. Here, callus cultures with seeds carrying Ac and Ds were used to produce 89,700 lines of Dongjin, a japonica cultivar, and 6,200 lines of MGRI079, whose genome is composed of a mixture of the genetic backgrounds of japonica and indica. Of the more than 3,000 lines examined, 67% had Ds elements. Among the Ds-carrying lines, 81% of Dongjin and 63% of MGRI079 contained transposed Ds, with an average of around 2.0 copies. By examining more than 15,000 lines, it was found that 12% expressed the reporter gene GUS during the early-seedling stage. GUS was expressed in root hairs and crown root initials at estimated frequencies of 0.78% and 0.34%, respectively. The 5,271 analyzed Ds loci were found to be randomly distributed over all of the rice chromosomes.
The concentration of nutrients in brown rice is mainly associated with embryo size. Various beneficial components have been purified from rice bran. Recently developed black waxy rice with a giant ...embryo (‘Milyang 263’, BGE), which is the
ge
t
mutant of the GE gene, was selected and analyzed to produce high quality nutritional components. γ-Aminobutyric acid (GABA) content in BGE rice bran, one of the most important nutritional compounds in rice, showed a 10.6-fold increase (2.66±0.48 mg/g) compared to that of BGE brown rice (0.25±0.01 mg/g). In addition, brown rice and BGE rice bran showed enriched amylopectin (94.5±0.5 and 97.0±0.0%) and bioactive anthocyanin Cy-3-G: 75.15±4.18 (brown rice), 82.97±0.81 (rice bran) and Pn-3-G: 1.52±0.50 (brown rice), 4.33±0.20 (rice bran); mg/100 g contents. These results suggest that BGE rice bran can be used as an excellent raw material to efficiently produce high quality essential amino acids, cyanidin-3 glycoside-enriched anthocyanins, and GABA.
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