of Botany,Chinese Academy Of Sciences
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Mutual upregulation of HY5 and TZP in mediating phytochrome A signaling
No full textPhytochrome A (phyA) is the far-red (FR) light photoreceptor in plants that is essential for seedling de-etiolation under FR-rich environments, such as canopy shade. TANDEM ZINC-FINGER/PLUS3 (TZP) was recently identified as a key component of phyA signal transduction in Arabidopsis thaliana; however, how TZP is integrated into the phyA signaling networks remains largely obscure. Here, we demonstrate that ELONGATED HYPOCOTYL5 (HY5), a well-characterized transcription factor promoting photomorphogenesis, mediates FR light induction of TZP expression by directly binding to a G-box motif in the TZP promoter. Furthermore, TZP physically interacts with CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1), an E3 ubiquitin ligase targeting HY5 for 26S proteasome-mediated degradation, and this interaction inhibits COP1 interaction with HY5. Consistent with those results, TZP post-translationally promotes HY5 protein stability in FR light, and in turn, TZP protein itself is destabilized by COP1 in both dark and FR light conditions. Moreover, tzp hy5 double mutants display an additive phenotype relative to their respective single mutants under high FR light intensities, indicating that TZP and HY5 also function in largely independent pathways. Together, our data demonstrate that HY5 and TZP mutually upregulate each other in transmitting the FR light signal, thus providing insights into the complicated but delicate control of phyA signaling networks
Innovatively treat rural food waste through producing organic grains
No full textFood waste (FW) in a whole country contains a large amount of nitrogen which could be used to replace chemical fertilizers to produce organic grains, thus mitigating environmental pollution from the source. A 2-year field experiment was carried out using rural FW to grow organic grains in Shandong Province, China. Different proportions of FW and cattle manure were designed: FM0, 100% cattle manure compost (CMC); FM1, 75% CMC + 25% FW; FM2, 50% CMC + 50% FW; FM3, 25% CMC + 75% FW; FM4, 100% FW; CF, 100% chemical fertilizer; CK, without any fertilizers. Compared with CK and FM0, the application of FW significantly increased the total nitrogen, total phosphorus, and total potassium content of the soil. Simultaneously, all the three indicators increased with the increase of the proportion of FW. FW did not cause increase of contents of heavy metals such as cuprum, zinc, and chromium in the soils, nor did it increase the heavy metals in the grains. Using FW to replace all cattle manure, the total organic yield of grains reached to an average of 18,163 kg ha(-1). We found that 1 kg dry FW could produce 1.64 kg organic grains under organic conditions, with the average net income being 5.42 times that of chemical mode. Our findings may provide an innovative solution for treating rural food wastes, ensuring food safety, and conservating the agriculture ecosystem
OsGLYI3, a glyoxalase gene expressed in rice seed, contributes to seed longevity and salt stress tolerance
No full textThe glyoxalase pathway plays a vital role in the chemical detoxification of methylglyoxal (MG) in biological systems. Our previous study suggested that OsGLYI3 may be effective in seed natural aging. In this study, the rice OsGLYI3 gene was cloned and characterized as specifically expressed in the seed. The accelerated aging (AA) treatment results indicated significant roles of OsGLYI3 in seed longevity and vigor, as the seeds of the transgenic lines with overexpressed and knocked-out OsGLYI3 exhibited higher and lower germination, respectively. The AA treatment also increased the superoxide dismutase (SOD) activity in the overexpressed transgenic seeds compared to the wild-type seeds yet lowered the SOD activity in the CRISPR/Cas9-derived transgenic rice lines. Rice OsGLYI3 was markedly upregulated in response to NaCl induced stress conditions. Compared to wild-type plants, overexpressed transgenic rice lines exhibited increased GLYI activity, decreased MG levels and improved salt stress tolerance, while CRISPR/Cas9 knockout transgenic rice lines showed decreased glyoxalase I activity, increased MG levels, and greater sensitivity to stress treatments with NaCl. Collectively, our results confirmed for the first time that OsGLYI3 is specifically expressed in rice seeds and contributes to seed longevity and salt stress tolerance
Terrestrial carbon sinks in China and around the world and their contribution to carbon neutrality
No full textEnhancing the terrestrial ecosystem carbon sink (referred to as terrestrial C sink) is an important way to slow down the continuous increase in atmospheric carbon dioxide (CO2) concentration and to achieve carbon neutrality target. To better understand the characteristics of terrestrial C sinks and their contribution to carbon neutrality, this review summarizes major progress in terrestrial C budget researches during the past decades, clarifies spatial patterns and drivers of terrestrial C sources and sinks in China and around the world, and examines the role of terrestrial C sinks in achieving carbon neutrality target. According to recent studies, the global terrestrial C sink has been increasing from a source of (-0.2 +/- 0.9) Pg C yr(-1) (1 Pg=10(15) g) in the 1960s to a sink of (1.9 +/- 1.1) Pg C yr(-1) in the 2010s. By synthesizing the published data, we estimate terrestrial C sink of 0.20-0.25 Pg C yr(-1) in China during the past decades, and predict it to be 0.15-0.52 Pg C yr(-1) by 2060. The terrestrial C sinks are mainly located in the mid- and high latitudes of the Northern Hemisphere, while tropical regions act as a weak C sink or source. The C balance differs much among ecosystem types: forest is the major C sink; shrubland, wetland and farmland soil act as C sinks; and whether the grassland functions as C sink or source remains unclear. Desert might be a C sink, but the magnitude and the associated mechanisms are still controversial. Elevated atmospheric CO2 concentration, nitrogen deposition, climate change, and land cover change are the main drivers of terrestrial C sinks, while other factors such as fires and aerosols would also affect ecosystem C balance. The driving factors of terrestrial C sink differ among regions. Elevated CO2 concentration and climate change are major drivers of the C sinks in North America and Europe, while afforestation and ecological restoration are additionally important forcing factors of terrestrial C sinks in China. For future studies, we recommend the necessity for intensive and long term ecosystem C monitoring over broad geographic scale to improve terrestrial biosphere models for accurately evaluating terrestrial C budget and its dynamics under various climate change and policy scenarios
Molecular basis for turnover inefficiencies (misses) during water oxidation in photosystem II
No full textPhotosynthesis stores solar light as chemical energy and efficiency of this process isv highly important. The electrons required for CO2 reduction are extracted from water in a reaction driven by light-induced charge separations in the Photosystem II reaction center and catalyzed by the CaMn4O5-cluster. This cyclic process involves five redox intermediates known as the S-0-S-4 states. In this study, we quantify the flash-induced turnover efficiency of each S state by electron paramagnetic resonance spectroscopy. Measurements were performed in photosystem II membrane preparations from spinach in the presence of an exogenous electron acceptor at selected temperatures between -10 degrees C and +20 degrees C and at flash frequencies of 1.25, 5 and 10 Hz. The results show that at optimal conditions the turnover efficiencies are limited by reactions occurring in the water oxidizing complex, allowing the extraction of their S state dependence and correlating low efficiencies to structural changes and chemical events during the reaction cycle. At temperatures 10 degrees C and below, the highest efficiency (i.e. lowest miss parameter) was found for the S-1 -> S-2 transition, while the S-2 -> S-3 transition was least efficient (highest miss parameter) over the whole temperature range. These electron paramagnetic resonance results were confirmed by measurements of flash-induced oxygen release patterns in thylakoid membranes and are explained on the basis of S state dependent structural changes at the CaMn4O5-cluster that were determined recently by femtosecond X-ray crystallography. Thereby, possible molecular errors connected to the e(-) transfer, H+ transfer, H2O binding and O-2 release are identified
Integrative taxonomy recognized a new cryptic species within Stipa grandis from Loess Plateau of China
No full textStipa shanxiensis, a cryptic species within Stipa grandis that originated from central and western China, is described based on morphological, genomic, and ecological data from field and common garden experiments. Stipa shanxiensis morphologically resembles S. grandis, although phylogenetically it is closely related to the less morphologically similar Stipa baicalensis and Stipa krylovii. Of the eight significant morphological differences between S. shanxiensis and S. grandis, the two, cauline ligules longer than 2 cm with a filiform apex, and hairs shorter than 0.2 mm on the adaxial surface of the cauline uppermost leaves can be used to distinguish the species. Results from a common garden experiment verified that the two diagnostic characteristics were relatively stable and less morphologically plastic in response to environmental variation. Furthermore, a significant ecological divergence was found between S. shanxiensis and S. grandis, such that the former preferred warmer and more humid climates, and their predicted distribution was generally separated. Taken together, our results highlight that the integrative taxonomic approach was valuable for recognizing a new cryptic species in Stipa. In particular, we find that common garden experiments involving the effects of growth stage and characteristic position helped to morphologically diagnose cryptic species. These findings may also facilitate our understandings of ecological adaption and phenotypic plasticity in response to environmental change
Tree Species Classification Using Plant Functional Traits and Leaf Spectral Properties along the Vertical Canopy Position
No full textPlant functional traits are rarely used in tree species classification, and the impact of vertical canopy positions on collecting samples for classification also remains unclear. We aim to explore the feasibility and effectiveness of leaf traits in classification, as well as to detect the effect of vertical position on classification accuracy. This work will deepen our understanding of the ecological mechanism of natural forest structure and succession from new perspectives. In this study, we collected foliar samples from three canopy layers (upper, middle and lower) and measured their spectra, as well as eight well-known leaf traits. We used a leaf hyperspectral reflectance (LHR) dataset, leaf functional traits (LFT) dataset and LFT + LHR dataset to classify six dominant tree species in a subtropical evergreen broad-leaved forest. Our results showed that the LFT + LHR dataset achieved the highest classification results (overall accuracy (OA) = 77.65% and Kappa = 0.73), followed by the LFT dataset (OA = 74.26% and Kappa = 0.69) and the LHR dataset (OA = 69.06% and Kappa = 0.63). Along the vertical canopy, the OA and Kappa increased from the lower to the upper layers, and the combination data of the three canopy layers achieved the highest accuracy. For the individual tree species, the shade-tolerant species (including Machilus chinensis, Cryptocarya chinensis and Cryptocarya concinna) produced higher accuracies than the light-demanding species (including Schima superba and Castanopsis chinensis). Our results provide an approach for enhancing tree species recognition from the plant physiology and biochemistry perspective and emphasize the importance of vertical direction in forest community research
Palynological Study of Weed Flora from Potohar Plateau
No full textThe pollen morphology of weeds was investigated by scanning electron microscopy (SEM). A morpho-palynological investigation of 18 species of weeds that belongs to 16 angiosperms families was performed using SEM to document distinguishable microscopic features. The main objective of the present study was to provide basic knowledge about morpho-palynological features of weed species that helps delimit the weed flora of the Potohar Plateau. The results show diversity among the qualitative and quantitative characteristics of pollen shape, equatorial and polar axis diameter, the exine's thickness, and the exine's surface ornamentation. The pollen grains were spherical, prolate-spheroidal, oblate-spheroidal, and sub-oblate. The exine ornamentation in most species was reticulate, scarbate, aerolate, faveolate, reticulate-perforate, and reticulate-scabrate. All the species described possessed tricolpate pollen. The variations found in the thickness of the exine and other characters were helpful at the genus and species-specific levels. In accordance with these variations, a taxonomic key was prepared using these characteristics to identify and differentiate weed plant species. SEM images of pollen grains can help delimit the taxa to the species level. This study provides baseline information to distinguish the species of weeds
OsMADS58 Stabilizes Gene Regulatory Circuits during Rice Stamen Development
No full textRice (Oryza sativa) OsMADS58 is a C-class MADS box protein, and characterization of a transposon insertion mutant osmads58 suggested that OsMADS58 plays a role in stamen development. However, as no null mutation has been obtained, its role has remained unclear. Here, we report that the CRISPR knockout mutant osmads58 exhibits complex altered phenotypes, including anomalous diploid germ cells, aberrant meiosis, and delayed tapetum degeneration. This CRISPR mutant line exhibited stronger changes in expression of OsMADS58 target genes compared with the osmads58 dSpm (transposon insertion) line, along with changes in multiple pathways related to early stamen development. Notably, transcriptional regulatory circuits in young panicles covering the stamen at stages 4-6 were substantially altered in the CRISPR line compared to the dSpm line. These findings strongly suggest that the pleiotropic effects of OsMADS58 on stamen development derive from a potential role in stabilizing gene regulatory circuits during early stamen development. Thus, this work opens new avenues for viewing and deciphering the regulatory mechanisms of early stamen development from a network perspective
Responding time scales of vegetation production to extreme droughts over China
No full textExtreme drought events have caused extensive and severe impacts on terrestrial ecosystem in last decades in China. Given droughts may be more intense and frequent under future climate change, accurate assessment of the drought impact on vegetation primary production can provide reliably scientific supports for the carbon sink potential. Numerous existing studies have used Standardized Precipitation Evapotranspiration Index (SPEI) to discover the drought-production relationships, however, most of them just considered the strongest correlation between production and different time scales (i.e. correlation-based method), which may underestimate the production loss because of the asymmetric responses under dry and wet conditions. In this work, we proposed a new method which assumed that the dominant time scale should correspond to the lowest primary production during each drought year (extreme-based method). Based on six independent Gross Primary Productivity (GPP) products and SPEI dataset, it showed that the extreme-based method was more reasonable and robust (with a larger inter-consistency of 0.50 than that of 0.05 for correlation-based method) to determine at which time scale GPP predominantly responded to extreme droughts. And the GPP loss can be underestimated by 45 +/- 26% (mean +/- s.d.) if the time scale was randomly selected. Furthermore, spatial analysis suggested that vegetation type, water balance and soil textures mainly affected the spatial heterogeneity of the dominant time scales. In detail, forests, humid biomes, and vegetation planted in loam tended to be more sensitive to longer-term droughts. This study highlighted that optimal time-scale selection using extreme-based assumption can give more accurate estimation of the drought impacts on vegetation primary production