Improvement of leaf photosynthesis is an important strategy for greater crop productivity. Here we show that the quantitative trait locus GPS (GREEN FOR PHOTOSYNTHESIS) in rice (Oryza sativa L.) ...controls photosynthesis rate by regulating carboxylation efficiency. Map-based cloning revealed that GPS is identical to NAL1 (NARROW LEAF1), a gene previously reported to control lateral leaf growth. The high-photosynthesis allele of GPS was found to be a partial loss-of-function allele of NAL1. This allele increased mesophyll cell number between vascular bundles, which led to thickened leaves, and it pleiotropically enhanced photosynthesis rate without the detrimental side effects observed in previously identified nal1 mutants, such as dwarf plant stature. Furthermore, pedigree analysis suggested that rice breeders have repeatedly selected the high-photosynthesis allele in high-yield breeding programs. The identification and utilization of NAL1 (GPS) can enhance future high-yield breeding and provides a new strategy for increasing rice productivity.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Several reliable QTLs for leaf photosynthesis were detected using reciprocal mapping populations derived from japonica and indica rice varieties with different photosynthetic capacities.
Abstract
...The improvement of leaf net photosynthetic rate (An) is a major challenge in enhancing crop productivity. However, the genetic control of An among natural genetic accessions is still poorly understood. The high-yielding indica cultivar Takanari has the highest An of all rice cultivars, 20–30% higher than that of the high-quality japonica cultivar Koshihikari. By using reciprocal backcross inbred lines and chromosome segment substitution lines derived from a cross between Takanari and Koshihikari, we identified three quantitative trait loci (QTLs) where the Takanari alleles enhanced An in plants with a Koshihikari genetic background and five QTLs where the Koshihikari alleles enhanced An in plants with a Takanari genetic background. Two QTLs were expressed in plants with both backgrounds (type I QTL). The expression of other QTLs depended strongly on genetic background (type II QTL). These beneficial alleles increased stomatal conductance, the initial slope of An versus intercellular CO2 concentration, or An at CO2 saturation. Pyramiding of these alleles consistently increased An. Some alleles positively affected biomass production and grain yield. These alleles associated with photosynthesis and yield can be a valuable tool in rice breeding programs via DNA marker-assisted selection.
Introduction: Continuous glucose monitoring is essential for the management of patients with metabolic syndromes in their daily lives. However, how metabolic risks are accessed using time-series ...glucose excursion data for healthy individuals remains unclear. Methods: Thus, this study aimed to present a method for evaluating the risks of glucose dysregulation by analyzing glucose responses under reduced glycemic load using a phytochemical alpha-glucosidase inhibitor. A 14-day pilot trial with healthy adult participants was conducted to demonstrate the validity of the method. Results and Discussion: The results showed that ultradian glucose spike packets with lower heights dominantly appeared under reduced glycemic load, replacing postprandial single-lobe glucose spikes with higher heights. Furthermore, the frequency dominance of ultradian spike packets contributed to the reduction of overall mean glucose excursions during the test period under reduced glycemic load. Based on the time-delay model, it was indicated that glycemic load reduction recovers regular glucose–insulin coupling accompanying ultradian oscillations, thereby contributing to the maintenance of glucose homeostasis. The findings of this study indicate that the frequency ratio between pulsatile spike packets and single-lobe spikes could be a marker for evaluating glucose regulation/dysregulation in healthy adults.
Utilizing phosphate more efficiently is crucial for sustainable crop production. Highly efficient rice (Oryza sativa) cultivars have been identified and this study aims to identify metabolic markers ...associated with P utilization efficiency (PUE). P deficiency generally reduced leaf P concentrations and CO2 assimilation rates but efficient cultivars were reducing leaf P concentrations further than inefficient ones while maintaining similar CO2 assimilation rates. Adaptive changes in carbon metabolism were detected but equally in efficient and inefficient cultivar groups. Groups furthermore did not differ with respect to partial substitutions of phospholipids by sulfo‐ and galactolipids. Metabolites significantly more abundant in the efficient group, such as sinapate, benzoate and glucoronate, were related to antioxidant defence and may help alleviating oxidative stress caused by P deficiency. Sugar alcohols ribitol and threitol were another marker metabolite for higher phosphate efficiency as were several amino acids, especially threonine. Since these metabolites are not known to be associated with P deficiency, they may provide novel clues for the selection of more P efficient genotypes. In conclusion, metabolite signatures detected here were not related to phosphate metabolism but rather helped P efficient lines to keep vital processes functional under the adverse conditions of P starvation.
A set of marker metabolites predictive of high PUE in contrasting groups of efficient and inefficient rice genotypes was identified. These metabolites were not related to carbon, lipid or P metabolism but linked to ROS defence or were sugar alcohols of unknown relation to P.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Increasing rice yield potential is a major objective in rice breeding programs, given the need for meeting the demands of population growth, especially in Asia. Genetic analysis using genomic ...information and high-yielding cultivars can facilitate understanding of the genetic mechanisms underlying rice yield potential. Chromosome segment substitution lines (CSSLs) are a powerful tool for the detection and precise mapping of quantitative trait loci (QTLs) that have both large and small effects. In addition, reciprocal CSSLs developed in both parental cultivar backgrounds may be appropriate for evaluating gene activity, as a single factor or in epistatic interactions.
We developed reciprocal CSSLs derived from a cross between Takanari (one of the most productive indica cultivars) and a leading japonica cultivar, Koshihikari; both the cultivars were developed in Japan. Forty-one CSSLs covered most of the Takanari genome in the Koshihikari background and 39 CSSLs covered the Koshihikari genome in the Takanari background. Using the reciprocal CSSLs, we conducted yield trials under canopy conditions in paddy fields. While no CSSLs significantly exceeded the recurrent parent cultivar in yield, genetic analysis detected 48 and 47 QTLs for yield and its components in the Koshihikari and Takanari backgrounds, respectively. A number of QTLs showed a trade-off, in which the allele with increased sink-size traits (spikelet number per panicle or per square meter) was associated with decreased ripening percentage or 1000-grain weight. These results indicate that increased sink size is not sufficient to increase rice yield in both backgrounds. In addition, most QTLs were detected in either one of the two genetic backgrounds, suggesting that these loci may be under epistatic control with other gene(s).
We demonstrated that the reciprocal CSSLs are a useful tool for understanding the genetic mechanisms underlying yield potential in the high-yielding rice cultivar Takanari. Our results suggest that sink-size QTLs in combination with QTLs for source strength or translocation capacity, as well as careful attention to epistatic interactions, are necessary for increasing rice yield. Thus, our findings provide a foundation for developing rice cultivars with higher yield potential in future breeding programs.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Depletion of non-renewable rock phosphate reserves and phosphorus (P) fertilizer price increases has renewed interest in breeding P-efficient varieties. Internal P utilization efficiency (PUE) is of ...prime interest because there has been no progress to date in breeding for high PUE. We characterized the genotypic variation for PUE present within the rice gene pool by using a hydroponic system that assured equal plant P uptake, followed by mapping of loci controlling PUE via Genome-Wide Association Studies (GWAS). Loci associated with PUE were mapped on chromosomes 1, 4, 11 and 12. The highest PUE was associated with a minor indica-specific haplotype on chromosome 1 and a rare aus-specific haplotype on chromosome 11. Comparative variant and expression analysis for genes contained within the chromosome 1 haplotype identified high priority candidate genes. Differences in coding regions and expression patterns between genotypes of contrasting haplotypes, suggested functional alterations for two predicted nucleic acid-interacting proteins that are likely causative for the observed differences in PUE. The loci reported here are the first identified for PUE in any crop that is not confounded by differential P uptake among genotypes. Importantly, modern rice varieties lacked haplotypes associated with superior PUE, and would thus benefit from targeted introgressions of these loci from traditional donors to improve plant growth in phosphorus-limited cropping systems.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The global atmospheric CO2 concentration has been increasing annually. To determine the trait that effectively increases rice (Oryza sativa L.) grain yield under increased atmospheric CO2 ...concentrations, as predicted in the near future, we grew a chromosome segment substitution line (CSSL) and a near-isogenic line (NIL) producing high spikelet numbers per panicle (CSSL-GN1 and NIL-APO1, respectively) under free-air CO2 enrichment (FACE) conditions and examined the effects of a large sink capacity on grain yield, its components, and growth-related traits under increased atmospheric CO2 concentrations. Under ambient conditions, CSSL-GN1 and NIL-APO1 exhibited a similar grain yield to Koshihikari, as a result of the trade-off between increased spikelet number and reduced grain filling. However, under FACE conditions, CSSL-GN1 and NIL-APO1 had an equal or a higher grain yield than Koshihikari because of the higher number of spikelets and lower reduction in grain filling. Thus, the improvement of source activity by increased atmospheric CO2 concentrations can lead to enhanced grain yield in rice lines that have a large sink capacity. Therefore, introducing alleles that increase sink capacity into conventional varieties represents a strategy that can be used to develop high-yielding varieties under increased atmospheric CO2 concentrations, such as those predicted in the near future.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Linnaeoideae is a small subfamily of erect or creeping shrubs to small trees in Caprifoliaceae that exhibits a wide disjunct distribution in Eurasia, North America and Mexico. Most taxa of the ...subfamily occur in eastern Asia and Mexico but the monospecific genus Linnaea has a circumboreal to north temperate distribution. In this study, we conducted phylogenetic and biogeographic analyses for Linnaeoideae and its close relatives based on sequences of the nuclear ribosomal ITS and nine plastid (rbcL, trnS-G, matK, trnL-F, ndhA, trnD-psbM, petB-D, trnL-rpl32 and trnH-psbA) markers. Our results support that Linnaeoideae is monophyletic, consisting of four eastern Asian lineages (Abelia, Diabelia, Dipelta and Kolkwitzia), the Mexican Vesalea, and Linnaea. The Mexican Vesalea was formerly placed in Abelia, but it did not form a clade with the eastern Asian Abelia; instead Vesalea and Linnaea are sisters. The divergence time between the eastern Asian lineages and the Mexican Vesalea plus the Linnaea clade was dated to be 50.86 Ma, with a 95% highest posterior density of 42.8 Ma (middle Eocene) to 60.19 Ma (early Paleocene) using the Bayesian relaxed clock estimation. Reconstructed ancestral areas indicated that the common ancestor of Linnaea plus Vesalea may have been widespread in eastern Asia and Mexico or originated in eastern Asia during the Eocene and likely migrated across continents in the Northern Hemisphere via the North Atlantic Land Bridges or the Bering Land Bridge. The Qinling Mountains of eastern Asia are the modern-day center of diversity of Kolkwitzia-Dipelta-Diabelia clade. The Diabeliaclade became highly diversified in Japan and eastern China. Populations of Diabelia serrata in Japan and eastern China were found to be genetically identical in this study, suggesting a recent disjunction across the East China Sea, following the last glacial event.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Interspecific reproductive barriers are poorly understood, but are central to the biological species concept. The pre‐zygotic barriers between red‐ and green‐fruited species in the tomato clade of ...the genus Solanum provide a model to better understand these barriers in plants. Compatibility usually follows the SI x SC rule: pollen from self‐compatible (SC) red‐fruited species is rejected on pistils of the predominantly self‐incompatible (SI) green‐fruited species, but the reciprocal crosses are compatible. This suggests that the interspecific reproductive barrier may be linked to the intraspecific SI mechanism. However, pollen from the SC red‐fruited species is also rejected by SC accessions of green‐fruited species that lack S‐RNase, a key protein expressed in pistils of SI Solanum species. Thus, multiple mechanisms may contribute to the barrier between red‐ and green‐fruited species. We tested whether an S‐RNase‐dependent barrier is sufficient for rejection of pollen from red‐fruited species by introducing functional S‐RNase, HT‐A and HT‐B genes from SI species into Solanum lycopersicum (cultivated tomato). We found that expressing S‐RNase in combination with either HT‐A or HT‐B in the pistil is sufficient to cause rejection of pollen from all four red‐fruited species. Thus, redundant mechanisms must operate side by side to prevent crosses between red‐ and green‐fruited species in the clade, underlining the complexity of interspecific pollination barriers. Our results also have implications for mating system transitions. We suggest that these transitions must occur in a specific sequence, and that the transition from SI to SC also affects interspecific compatibility.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Canopy temperature can be a good indicator of stomatal conductance. To understand the genetic basis of phenotypic differences in stomatal conductance between average and high-yielding rice (Oryza ...sativa L.) cultivars, we conducted a quantitative trait locus (QTL) analysis of canopy temperature. We developed reciprocal series of backcross inbred lines (BC1F6) derived from a cross between the average-yielding japonica cultivar ‘Koshihikari’ and the high-yielding indica cultivar ‘Takanari’. A stable QTL, qCTd11 (QTL for canopy temperature difference on chromosome 11) on the short arm of chromosome 11, accounted for 10.4 and 19.8% of the total phenotypic variance in the two lines; the ‘Takanari’ allele decreased the canopy temperature difference value. A chromosome segment substitution line carrying the Takanari qCTd11 showed a greater reduction in canopy temperature than ‘Koshihikari’, and had higher stomatal conductance and photosynthetic rate. These results suggest that qCTd11 is not only involved in canopy temperature, but is also involved in both stomatal conductance and photosynthetic rate.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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