Search

NRL3 is essential for the growth and development of rice leaves. In this study, we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions. The yeast two-hybrid and the bimolecular fluorescence complementation proved that NRL3 interacts with OsK4, a Snf1-related kinase. OsK4 localized to the nucleus and expressed in various rice tissues. The rhythmic expression pattern of OsK4 was similar to NRL3 under long daylight and short daylight conditions. Knock-out mutants of OsK4 exhibited early heading under long daylight conditions, indicating that it acts as a negative regulator of heading date in rice. Interestingly, the OsK4 mutant under the nrl3 mutant background rescued the late heading phenotype of nrl3 under long daylight conditions, suggesting that OsK4 functions downstream of NRL3. Moreover, both NRL3 and OsK4 controlled heading date through regulating the expression of Hd3a and RFT1 genes. These findings shed light on the heading date regulation in rice and provide a sound theoretical base to improve regional adaptability of rice.

Understanding the response of biomass allocation in current-year twigs is crucial for elucidating the plant life-history strategies under heterogeneous volcanic habitats. We aimed to test whether twig biomass allocation, within-leaf biomass allocation, and the size-number trade-off of Betula platyphylla would be influenced. We measured twig traits of B. platyphylla in Wudalianchi volcanic kipuka, the lava platform, and Shankou lake in northeastern China using standardized major axis analyses. The results showed that the leaf number, total lamina mass (TLAM), stem mass (SM), and twig mass (TM) were significantly different between the three habitats and were greatest in kipuka with abundant soil nutrients. TLAM and SM scaled allometrically with respect to TM, while the normalization constants of the lava platform differ significantly between kipuka and Shankou lake, which showed that under certain TM, leaves gain more biomass in the lava platform. However, within the leaf, individual lamina mass (ILM) scaled isometrically with respect to individual petiole mass (IPM) in kipuka and the lava platform, but ILM scaled allometrically to IPM in Shankou lake. Our results indicated that inhabitats influenced the twig traits and biomass allocation and within-leaf biomass allocation are strategies for plants to adapt to volcanic heterogeneous habitats.

A mechanized direct seeding of rice with less labor and water usage, has been widely adopted. However, this approach requires varieties that exhibit uniform seedling emergence. Mesocotyl elongation (ME) offers the main drive of fast emergence of rice seedlings from soils; nevertheless, its genetic basis remains unknown. Here, we identify a major rice quantitative trait locus Mesocotyl Elongation1 (qME1), an allele of the Green Revolution gene Semi‐Dwarf1 (SD1), encoding GA20‐oxidase for gibberellin (GA) biosynthesis. ME1 expression is strongly induced by soil depth and ethylene. When rice grains are direct‐seeded in soils, the ethylene core signaling factor OsEIL1 directly promotes ME1 transcription, accelerating bioactive GA biosynthesis. The GAs further degrade the DELLA protein SLENDER RICE 1 (SLR1), alleviating its inhibition of rice PHYTOCHROME‐INTERACTING FACTOR‐LIKE13 (OsPIL13) to activate the downstream expansion gene OsEXPA4 and ultimately promote rice seedling ME and emergence. The ancient traits of long mesocotyl and strong emergence ability in wild rice and landrace were gradually lost in company with the Green Revolution dwarf breeding process, and an elite ME1‐R allele (D349H) is found in some modern Geng varieties (long mesocotyl lengths) in northern China, which can be used in the direct seeding and dwarf breeding of Geng varieties. Furthermore, the ectopic and high expression of ME1 driven by mesocotyl‐specific promoters resulted in rice plants that could be direct‐seeded without obvious plant architecture or yield penalties. Collectively, we reveal the molecular mechanism of rice ME, and provide useful information for breeding new Green Revolution varieties with long mesocotyl suitable for direct‐seeding practice. [ABSTRACT FROM AUTHOR]

Summary: Head rice yield (HRY) measures rice milling quality and determines final grain yield and commercial value. Here, we report that two major quantitative trait loci for milling quality in rice, qMq‐1 and qMq‐2, represent allelic variants of Waxylv/Waxyb (hereafter Wx) encoding Granule‐Bound Starch Synthase I (GBSSI) and Alkali Spreading Value ALKc/ALKb encoding Soluble Starch Synthase IIa (SSIIa), respectively. Complementation and overexpression transgenic lines in indica and japonica backgrounds confirmed that Wx and ALK coordinately regulate HRY by affecting amylose content, the number of amylopectin branches, amyloplast size, and thus grain filling and hardness. The transcription factor OsDOF18 acts upstream of Wx and ALK by activating their transcription. Furthermore, rice accessions with Wxb and ALKb alleles showed improved HRY over those with Wxlv and ALKc. Our study not only reveals the novel molecular mechanism underlying the formation of HRY but also provides a strategy for breeding rice cultivars with improved HRY. [ABSTRACT FROM AUTHOR]

Objective To investigate the antitumor efficacy of near-infrared photothermal therapy (NIPT) at different doses of gold nanorods (GNRs) and near-infrared light on gastric cancer SGC-7901 cells in vitro. Methods GNRs were prepared by seed-mediated growth method, and their morphology, particle size and light absorption were detected. The inhibitory rates of GNRs on the proliferation of SGC-7901 cells were measured by CCK-8. The inhibitory rates of GNRs at different concentrations and NIPT at different powers on the proliferation of SGC-7901 cells were calculated. Meanwhile, the apoptosis of gastric cancer cells was detected by Annexin V-FITC/PI fluorescence method, and the Caspase-3 and Caspase-9 enzyme activities were detected by spectrophotometry. Results The synthesized GNRs had a longitudinal plasmon resonance absorption peak at around 790nm. The cytotoxicity of pure GNRs was really low. However, NIPT had obvious antitumor effects on gastric cancer cells. With the increase of GNRs dose and near-infrared light power, the cell growth inhibition rate increased significantly. After administration of 40μg/ml GNRs for 1h and 3.0W/cm2 near-infrared radiation for 2min, the cell growth inhibition rate reached 93.4%. One hour after treatment, part of the cells were in early apoptotic stage; while three hours after treatment, the cells were in advanced apoptosis or death state, and the Caspase-3, Caspase-9 enzyme activity increased about one fold, compared with those of control group. Conclusion GNRs-mediated NIPT has obvious antitumor and apoptosis induction effects on gastric cancer cells.

Mullite-type AMn2O5 materials represent a group of promising candidates to substitute noble metal catalysts for the catalytic removal of volatile organic compounds (VOCs). When applied to catalytic oxidation of aromatic hydrocarbons such as toluene, AMn2O5 exhibits undesirable performance due to its poor intrinsic activity of oxygen species, leading to a light-off temperature above 250 °C. In this work, we have developed a synthesis route combining a two-step calcination and cation-exchange process to prepare a nanoporous CeO2-decorated Cu-SmMn2O5 composite mullite oxide catalyst applied in toluene oxidation. The best performing sample reached 90% toluene conversion at 190 °C, surpassing other transition metal oxide catalysts. Comprehensive characterizations reveal that Cu ion doping into the crystal lattice of the mullite phase is achieved via the cation-exchange process. In this catalyst design, surface CeO2 decoration and Cu doping promote the reduction ability and improve oxygen species activity to accelerate toluene oxidation. Overall, this work provides a strategy to prepare composite mullite oxide catalysts with high performance in the removal of VOCs, broadening the industrial application prospects of mullite-type materials. [ABSTRACT FROM AUTHOR]