Pollen Number and Ribosome Gene Expression Altered in a Genome-Editing Mutant of REDUCED POLLEN NUMBER1 Gene

The number of pollen grains varies within and between species. However, little is known about the molecular basis of this quantitative trait, in contrast with the many studies available on cell differentiation in the stamen. Recently, the first gene responsible for pollen number variation, REDUCED POLLEN NUMBER1 (RDP1), was isolated by genome-wide association studies of Arabidopsis thaliana and exhibited the signature of natural selection. This gene encodes a homolog of yeast Mrt4 (mRNA turnover4), which is an assembly factor of the large ribosomal subunit. However, no further data were available to link ribosome function to pollen development. Here, we characterized the RDP1 gene using the standard A. thaliana accession Col-0. The frameshift mutant, rdp1-3 generated by CRISPR/Cas9 revealed the pleiotropic effect of RDP1 in flowering, thus demonstrating that this gene is required for a broad range of processes other than pollen development. We found that the natural Col-0 allele conferred a reduced pollen number against the Bor-4 allele, as assessed using the quantitative complementation test, which is more sensitive than transgenic experiments. Together with a historical recombination event in Col-0, which was identified by sequence alignment, these results suggest that the coding sequence of RDP1 is the candidate region responsible for the natural phenotypic variation. To elucidate the biological processes in which RDP1 is involved, we conducted a transcriptome analysis. We found that genes responsible for ribosomal large subunit assembly/biogenesis were enriched among the differentially regulated genes, which supported the hypothesis that ribosome biogenesis is disturbed in the rdp1-3 mutant. Among the pollen-development genes, three key genes encoding basic helix-loop-helix (bHLH) transcription factors (ABORTED MICROSPORES (AMS), bHLH010, and bHLH089), as well as direct downstream genes of AMS, were downregulated in the rdp1-3 mutant. In summary, our results suggest a specialized function of ribosomes in pollen development through RDP1, which harbors natural variants under selection.

A 31-bp indel localised in the 5' untranslated region of OsSUT3 affects the gene expression and rice (Oryza sativa L.) pollen development

OsSUT genes have been demonstrated to be relevant for diverse biological processes in rice. In this study, we identified the close relationship between a 31-bp insertion in a 5' untranslated region (5' UTR) of the OsSUT3 gene and higher OsSUT3 expression in rice panicles by qRT-PCR and transgenic research. Statistically significant results (P < 0.01) were found for this 31-bp insertions/deletions (indels) in the rice pollen development and other panicle traits, such as the pollen number, pollen fertility, seeding rate, and grain length. An evolution analysis showed that the proportion of the 31-bp insertion significantly increases in rice domestication. Therefore, the 31-bp Indel could be considered as a convenient molecular marker to screen more pollen and better panicle traits in rice breeding.

Factors Affecting the Number of Pollen Grains per Male Strobilus in Japanese Cedar (Cryptomeria japonica)

Japanese cedar (Cryptomeria japonica) is the most important timber species in Japan; however, its pollen is the primary cause of pollinosis in Japan. The total number of pollen grains produced by a single tree is determined by the number of male strobili (male flowers) and the number of pollen grains per male strobilus. While the number of male strobili is a visible and well-investigated trait, little is known about the number of pollen grains per male strobilus. We hypothesized that genetic and environmental factors affect the pollen number per male strobilus and explored the factors that affect pollen production and genetic variation among clones. We counted pollen numbers of 523 male strobili from 26 clones using a cell counter method that we recently developed. Piecewise Structural Equation Modeling (pSEM) revealed that the pollen number is mostly affected by genetic variation, male strobilus weight, and pollen size. Although we collected samples from locations with different environmental conditions, statistical modeling succeeded in predicting pollen numbers for different clones sampled from branches facing different directions. Comparison of predicted pollen numbers revealed that they varied >3-fold among the 26 clones. The determination of the factors affecting pollen number and a precise evaluation of genetic variation will contribute to breeding strategies to counter pollinosis. Furthermore, the combination of our efficient counting method and statistical modeling will provide a powerful tool not only for Japanese cedar but also for other plant species.

Pengaruh Desain Kotak Terhadap Produktivitas Lebah Trigona sp

One of the factors that effect the productivity of honey bees is the factor of temperature and humidity of the nest or stup where the bees live. A nest or stup with a maintened temperature and humidity will provide the bee comfort for live. This study discusses the effect of stup size design on the productivity honey bee of Trigona sp. This study used a Complete Random Design (CRD) with 3 stup design, namely: Horizontal, Vertical and Medium. Each design size consists of 4 replications, and each replication consists of 2 stup. Data were analyzed using by analysis of variance (ANOVA) and Duncan's test at 95% confidence level. The parameters observed were number of egg cells and pollen, weight pollen, number of honey pots and volume of honey. The results of the analysis showed that production of the medium design for number of egg cells, pollen, weight pollen, number of honey pots and the volume of honey of Trigona sp was significantly higher than vertical and horizontal design. The conclusion of this study showed that the medium stup is better used in farming system of Trigona sp.

Lidar Depolarization Ratio of Atmospheric Pollen at Multiple Wavelengths

Lidar observations during the pollen season 2019 at the European Aerosol Research Lidar Network (EARLINET) station in Kuopio, Finland were analyzed in order to optically characterize atmospheric pollen. Previous studies showed the detectability of non-spherical pollen using depolarization ratio measurements. We present lidar depolarization ratio measurements at three wavelengths of atmospheric pollen in ambient conditions. In addition to the depolarization ratio detected with the multiwavelength Raman polarization lidar PollyXT at 355 and 532 nm, depolarization measurements of a co-located HALO Photonics Streamline Doppler lidar at 1565 nm were utilized. During a four days period of high birch (Betula) and spruce (Picea abies) pollen concentrations, unusually high depolarization ratios were observed within the boundary layer. Detected layers were investigated regarding the share of spruce pollen to the total pollen number concentration. Daily mean particle depolarization ratios of the pollen layers on the day with the highest spruce pollen share are 0.10 ± 0.02, 0.38 ± 0.23 and 0.29 ± 0.10 at 355, 532 and 1565 nm, respectively. Whereas on days with lower spruce pollen share, depolarization ratios are lower with less wavelength dependence. This spectral dependence of the depolarization ratios could be indicative of big, non-spherical spruce pollen. The depolarization ratio of pollen particles was investigated by applying a newly developed method and assuming a backscatter-related Ångström exponent of zero. Depolarization ratios of 0.44 and 0.16 at 532 and 355 nm for the birch and spruce pollen mixture were determined.

An improved pollen number counting method using a cell counter and mesh columns

Background The determination of pollen number is important in evolutionary, agricultural, and medical studies. Tree species of the Cupressaceae family cause serious pollinosis worldwide. Although Japanese cedar (Cryptomeria japonica) is the most important forestry species in Japan, it is also the biggest cause of pollinosis in the country. Japanese cedar trees have been selected for growth speed and superior morphological traits and then cloned. These clones may vary in their pollen production, but there has been little research on how many pollen grains are produced by a single male strobilus (flower). A recently reported method for counting pollen number with a cell counter was applicable to Arabidopsis species and wheat, but was not suitable for Japanese cedar because the strobilus does not open with heating (e.g. 60 °C, overnight). Results Here, we report an improved pollen counting method for Japanese cedar using a precise and rapid cell counter in combination with home-made mesh columns. The male strobilus was gently crushed using a pestle. Large and small debris were then removed using 100- and 20-μm mesh columns, respectively. We successfully detected pollen sizes and numbers that differed between two clones using this method. Conclusions This improved method is not only suitable for counting pollen from Japanese cedar, but could also be applied to other species of the Cupressaceae family with hard scale tissue covering the pollen. Moreover, this method could be applied to a broader range of plant species, such as wheat, because there is no need to wait for anthesis and debris can be removed efficiently.

An improved pollen number counting method using a cell counter and mesh columns

BackgroundThe determination of pollen number is important in evolutionary, agricultural, and medical studies. Tree species of the Cupressaceae family cause serious pollinosis worldwide. Although Japanese cedar (Cryptomeria japonica) is the most important forestry species in Japan, it is also the biggest cause of pollinosis in the country. Japanese cedar trees have been selected for growth speed and superior morphological traits and then cloned. These clones may vary in their pollen production, but there has been little research on how many pollen grains are produced by a single male strobilus (flower). A recently reported method for counting pollen number with a cell counter was applicable to Arabidopsis species and wheat, but was not suitable for Japanese cedar because the strobilus does not open with heating (e.g. 60°C, overnight). ResultsHere, we report an improved pollen counting method for Japanese cedar using a precise and rapid cell counter in combination with home-made mesh columns. The male strobilus was gently crushed using a pestle. Large and small debris were then removed using 100- and 20-μm mesh columns. We successfully detected pollen sizes and numbers that differed between two clones using this method. ConclusionsThis improved method is not only suitable for counting pollen from Japanese cedar, but could also be applied to other species of the Cupressaceae family with hard scale tissue covering the pollen. Moreover, this method could be applied to a broader range of plant species, such as wheat, because there is no need to wait for anthesis and debris can be removed efficiently.

An improved pollen number counting method using a cell counter and mesh columns

Background The determination of pollen number is important in evolutionary, agricultural, and medical studies. Tree species of the Cupressaceae family cause serious pollinosis worldwide. Although Japanese cedar (Cryptomeria japonica) is the most important forestry species in Japan, it is also the biggest cause of pollinosis in the country. Japanese cedar trees have been selected for growth speed and superior morphological traits and then cloned. These clones may vary in their pollen production, but there has been little research on how many pollen grains are produced by a single male strobilus (flower). A recently reported method for counting pollen number with a cell counter was applicable to Arabidopsis species and wheat, but was not suitable for Japanese cedar because the strobilus does not open with heating. Results Here, we report an improved pollen counting method for Japanese cedar using a precise and rapid cell counter in combination with home-made mesh columns. The male strobilus was gently crushed using a pestle. Large and small debris were then removed using 100- and 20-µm mesh columns. We successfully detected pollen sizes and numbers that differed between two clones using this method. Conclusions This improved method is not only suitable for counting pollen from Japanese cedar, but could also be applied to other species of the Cupressaceae family with hard scale tissue covering the pollen. Moreover, this method could be applied to a broader range of plant species, such as wheat, because there is no need to wait for anthesis and debris can be removed efficiently.

Pollen number and vigor contribute to effective ovule numbers among contrasting nitrogen utilization efficiency oilseed rapes genotypes before heart stage

Background: While no significant differences in initial ovule number were found among oilseed rape genotypes, there was a large variation in effective ovule number (EON), which determines the final seeds per silique (SPS), a critical component of yield. Up to date, on study has been focused on unraveling the pre-flowering main factors to restrict EON and identifying the critical period of EON formation among contrasting nitrogen utilization efficiency (NUtE) oilseed rape genotypes.Results: In this study, we selected 18 oilseed rape genotypes with different NUtE to identify the main factors that contribute to EON, and determine if genotypes differed in the critical period of EON formation under both field and pot experiments from 2016-2018. Our results showed the high NUtE genotypes also showed 14.3% higher NUtE, accompanied with 29.4% higher yield per plant and 21.1% higher SPS. The greater productivity of the high NUtE oilseed rape genotypes was associated with 44.1% greater pollen number, 23.5% higher pollen vigor, and 39.3% lower ovule abortion rate, compared to the low NUtE genotypes. In addition, at the heart stage, the high NUtE genotypes displayed higher silique net photosynthetic rate, surface area, biomass, and RNA expression levels, compared to the low NUtE ones. Taken together, this study indicated the pollen number, pollen vigor and ovule abortion rate contributed to the final EON of diverse oilseed rape genotypes; the critical period of determining EON among contrasting NUtE genotypes was at the heart stage.Conclusion: Increasing pollen number and vigor, and decreasing ovule abortion rate before the heart stage should be the prerequisite for breeders to improve yield and NUtE of oilseed rape genotypes.