OsPDCD5 negatively regulates plant architecture and grain yield in rice.

Plant architecture is an important agronomic trait that affects crop yield. Here, we report that a gene involved in programmed cell death, OsPDCD5, negatively regulates plant architecture and grain yield in rice. We used the CRISPR/Cas9 system to introduce loss-of-function mutations into OsPDCD5 in 11 rice cultivars. Targeted mutagenesis of OsPDCD5 enhanced grain yield and improved plant architecture by increasing plant height and optimizing panicle type and grain shape. Transcriptome analysis showed that OsPDCD5 knockout affected auxin biosynthesis, as well as the gibberellin and cytokinin biosynthesis and signaling pathways. OsPDCD5 interacted directly with OsAGAP, and OsAGAP positively regulated plant architecture and grain yield in rice. Collectively, these findings demonstrate that OsPDCD5 is a promising candidate gene for breeding super rice cultivars with increased yield potential and superior quality.

Titer and distribution of little cherry virus 2 in Prunus avium.

Little cherry virus 2 (LChV-2) is a causal agent of little cherry disease, which produces small, misshapen fruit with poor color and taste. As LChV-2 symptoms are only present near harvest, molecular detection is essential for effective control. Therefore, we determined the titer and distribution of this virus in infected trees over time. While initial infections were found to be basipetal, in field trees, early-stage infection was characterized by uneven distribution and low titer, concentrated in woody stems. In contrast, established infections were systemic, and detection was consistent across tissues. These data provide improved sampling recommendations for the detection of LChV-2.

Assessing the effects of elevated ozone on physiology, growth, yield and quality of soybean in the past 40 years: A meta-analysis.

Soybean (Glycine max) production is seriously threatened by ground-level ozone (O3) pollution. The goal of our study is to summarize the impacts of O3 on physiology, growth, yield, and quality of soybean, as well as root parameters. We performed meta-analysis on the collated 48 peer-reviewed papers published between 1980 and 2019 to quantitatively summarize the response of soybean to elevated O3 concentrations ([O3]). Relative to charcoal-filtered air (CF), elevated [O3] significantly accelerated chlorophyll degradation, enhanced foliar injury, and inhibited growth of soybean, evidenced by great reductions in leaf area (-20.8%), biomass of leaves (-13.8%), shoot (-22.8%), and root (-16.9%). Shoot of soybean was more sensitive to O3 than root in case of biomass. Chronic ozone exposure of about 75.5 ppb posed pronounced decrease in seed yield of soybean (-28.3%). In addition, root environment in pot contributes to higher reduction in shoot biomass and yield of soybean. Negative linear relationships were observed between yield loss and intensity of O3 treatment, AOT40. The larger loss in seed yield was significantly associated with higher reduction in shoot biomass and other yield component. This meta-analysis demonstrates the effects of elevated O3 on soybean were pronounced, suggesting that O3 pollution is still a soaring threat to the productivity of soybean in regions with high ozone levels.

Association of fruit, pericarp, and epidermis traits with surface autofluorescence in green peppers.

We investigated the association of blue fluorescence (excitation at 365 nm) with the traits of the fruit, pericarp, and epidermis in green peppers. The fruits were manually classified into two groups based on fluorescence brightness. The dark fluorescence group showed the accumulation of blue-absorbing pigments and a thicker cuticular structure, suggesting epidermal development.

Analysis of the MIR160 gene family and the role of MIR160a_A05 in regulating fiber length in cotton.

MAIN CONCLUSION: The MIR160 family in Gossypium hirsutum and G. barbadense was characterized, and miR160a_A05 was found to increase cotton-fiber length by downregulating its target gene (ARF17) and several GH3 genes. Cotton fiber is the most important raw material for the textile industry. MicroRNAs are involved in regulating cotton-fiber development, but a role in fiber elongation has not been demonstrated. In this study, miR160a was found to be differentially expressed in elongating fibers between two interspecific (between Gossypium hirsutum and G. barbadense) backcross inbred lines (BILs) with different fiber lengths. The gene MIR160 colocalized with a previously mapped fiber-length quantitative trait locus. Its target gene ARF17 was differentially expressed between the two BILs during fiber elongation, but in the inverse fashion. Bioinformatics was used to analyze the MIR160 family in both G. hirsutum and G. barbadense. Moreover, qRT-PCR analysis identified MIR160a as the functional MIR160 gene encoding the miR160a precursor during fiber elongation. Using virus-induced gene silencing and overexpression, overexpressed MIR160a_A05 resulted in significantly longer fibers compared with wild type, whereas suppression of miR160 resulted in significantly shorter fibers. Expression levels of the target gene auxin-response factor 17 (ARF17) and related genes GH3 in the two BILs and/or the virus-infected plants demonstrated similar changes in response to modulation of miR160a level. Finally, overexpression or suppression of miR160 increased or decreased, respectively, the cellular level of indole-3-acetic acid, which is involved in fiber elongation. These results describe a specific regulatory mechanism for fiber elongation in cotton that can be utilized for future crop improvement.

Small-Molecule Screens Reveal Novel Haustorium Inhibitors in the Root Parasitic Plant Triphysaria versicolor.

Root parasitic weeds in Orobanchaceae pose a tremendous threat to agriculture worldwide. We used an in vitro assay to screen libraries of small molecules for those capable of inhibiting or enhancing haustorium development in the parasitic plant Triphysaria versicolor. Several redox-modifying molecules and one structural analog of 2,6-dimethoxybenzoquine (DMBQ) inhibited haustorium development in the presence of the haustorium-inducing factor DMBQ, some of these without apparent growth inhibition to the root. Triphysaria seedlings were able to acclimate to some of these redox inhibitors. Transcript levels of four early-stage haustorium genes were differentially influenced by inhibitors. These novel haustorium inhibitors highlight the importance of redox cycling for haustorium development and suggest the potential of controlling parasitic weeds by interrupting early-stage redox-signaling pathways.

A robust, high-throughput method for computing maize ear, cob, and kernel attributes automatically from images.

Grain yield of the maize plant depends on the sizes, shapes, and numbers of ears and the kernels they bear. An automated pipeline that can measure these components of yield from easily-obtained digital images is needed to advance our understanding of this globally important crop. Here we present three custom algorithms designed to compute such yield components automatically from digital images acquired by a low-cost platform. One algorithm determines the average space each kernel occupies along the cob axis using a sliding-window Fourier transform analysis of image intensity features. A second counts individual kernels removed from ears, including those in clusters. A third measures each kernel's major and minor axis after a Bayesian analysis of contour points identifies the kernel tip. Dimensionless ear and kernel shape traits that may interrelate yield components are measured by principal components analysis of contour point sets. Increased objectivity and speed compared to typical manual methods are achieved without loss of accuracy as evidenced by high correlations with ground truth measurements and simulated data. Millimeter-scale differences among ear, cob, and kernel traits that ranged more than 2.5-fold across a diverse group of inbred maize lines were resolved. This system for measuring maize ear, cob, and kernel attributes is being used by multiple research groups as an automated Web service running on community high-throughput computing and distributed data storage infrastructure. Users may create their own workflow using the source code that is staged for download on a public repository.

Developmental programmes in the evolution of Equisetum reproductive morphology: a hierarchical modularity hypothesis.

Background: The origin of the Equisetum strobilus has long been debated and the fossil record has played an important role in these discussions. The paradigm underlying these debates has been the perspective of the shoot as node-internode alternation, with sporangiophores attached at nodes. However, fossils historically excluded from these discussions (e.g. Cruciaetheca and Peltotheca ) exhibit reproductive morphologies that suggest attachment of sporangiophores along internodes, challenging traditional views. This has rekindled discussions around the evolution of the Equisetum strobilus, but lack of mechanistic explanations has led discussions to a stalemate. Scope: A shift of focus from the node-internode view to a perspective emphasizing the phytomer as a modular unit of the shoot, frees the debate of homology constraints on the nature of the sporangiophore and inspires a mechanism-based hypothesis for the evolution of the strobilus. The hypothesis, drawing on data from developmental anatomy, regulatory mechanisms and the fossil record, rests on two tenets: (1) the equisetalean shoot grows by combined activity of the apical meristem, laying down the phytomer pattern, and intercalary meristems responsible for internode elongation; and (2) activation of reproductive growth programmes in the intercalary meristem produces sporangiophore whorls along internodes. Conclusions: Hierarchical expression of regulatory modules responsible for (1) transition to reproductive growth; (2) determinacy of apical growth; and (3) node-internode differentiation within phytomers, can explain reproductive morphologies illustrated by Cruciaetheca (module 1 only), Peltotheca (modules 1 and 2) and Equisetum (all three modules). This model has implications - testable by studies of the fossil record, phylogeny and development - for directionality in the evolution of reproductive morphology ( Cruciaetheca - Peltotheca - Equisetum ) and for the homology of the Equisetum stobilus. Furthermore, this model implies that sporangiophore development is independent of node-internode identity, suggesting that the sporangiophore represents the expression of an ancestral euphyllophyte developmental module that pre-dates the evolution of leaves.

Reproducibility of the effects of homeopathically potentised Argentum nitricum on the growth of Lemna gibba L. in a randomised and blinded bioassay.

BACKGROUND: A previous study reported a significant statistical interaction between experiment date and treatment effect of Argentum nitricum 14x-30x on the growth rate of duckweed (Lemna gibba L.). The aim of the present study was to investigate the stability of the test system and intra-laboratory reproducibility of the effects found. METHODS: Duckweed was treated with A. nitricum potencies (14x-30x) as well as succussed and unsuccussed water controls. The outcome parameter area-related growth rate for day 0-7 was determined by a computerised image analysis system in two series of independent randomised and blinded experiments. Systematic negative control (SNC) experiments were carried out to investigate test system stability. Statistical analysis was performed with full two-way analysis of variance (ANOVA) and protected Fisher's Least Significant Difference (LSD) test. RESULTS: In the first repetition series we found a significant treatment effect (p = 0.016), while in the second series no effect was observed. The negative control experiments showed that the experimental system was stable. An a posteriori subgroup analysis concerning gibbosity revealed the importance of this growth state of L. gibba for successful reproduction of the statistically significant interaction in the original study; flat: no interaction (p = 0.762); slight gibbosity: no interaction (p = 0.356); medium gibbosity: significant interaction (p = 0.031), high gibbosity: highly significant interaction (p = 0.005). CONCLUSIONS: With the original study design (disregarding gibbosity status of L. gibba) results of the original study could not be reproduced sensu stricto. We conclude that the growth state gibbosity is crucial for successful reproduction of the original study. Different physiological states of the test organisms used for bioassays for homeopathic basic research must carefully be considered.

Water Transport Properties of the Grape Pedicel during Fruit Development: Insights into Xylem Anatomy and Function Using Microtomography.

Xylem flow of water into fruits declines during fruit development, and the literature indicates a corresponding increase in hydraulic resistance in the pedicel. However, it is unknown how pedicel hydraulics change developmentally in relation to xylem anatomy and function. In this study on grape (Vitis vinifera), we determined pedicel hydraulic conductivity (kh) from pressure-flow relationships using hydrostatic and osmotic forces and investigated xylem anatomy and function using fluorescent light microscopy and x-ray computed microtomography. Hydrostatic kh (xylem pathway) was consistently 4 orders of magnitude greater than osmotic kh (intracellular pathway), but both declined before veraison by approximately 40% and substantially over fruit development. Hydrostatic kh declined most gradually for low (less than 0.08 MPa) pressures and for water inflow and outflow conditions. Specific kh (per xylem area) decreased in a similar fashion to kh despite substantial increases in xylem area. X-ray computed microtomography images provided direct evidence that losses in pedicel kh were associated with blockages in vessel elements, whereas air embolisms were negligible. However, vessel elements were interconnected and some remained continuous postveraison, suggesting that across the grape pedicel, a xylem pathway of reduced kh remains functional late into berry ripening.

Salicylic Acid and Calcium Treatments Improves Wheat Vigor, Lipids and Phenolics Under High Salinity.

Seed vigor is a complex physiological trait required to ensure the rapid and uniform emergence of plants in the field under different environmental conditions. Therefore, salicylic acid (SA, 0.5 mM) and calcium (Ca2+, 50 mM) priming were used as exogenous growth enhancers to stimulate wheat (Triticum durum Desf. cv. Yelken) seed vigor under high salinity. The main aim was to address whether priming of wheat with SA, Ca2+ and SA+Ca (SA, 0.5 mM + Ca2+, 50 mM; their combination) could bring about supplementary agronomic benefits particularly under stressful environments such as salinity. Exogenous application of SA or Ca2+ alone improved plant behavior in the presence of salinity stress. Nevertheless, the best results in terms of growth, seed vigor and total phenolic - flavonoids, chlorophyll - carotenoids contents and phenylalanine ammonia-lyase (PAL), ascorbic acide oxidase (AAO) activities and lipid peroxidation levels (LPO) were obtained in response to the combined SA+Ca treatment.

Developmental and evolutionary diversity of plant MADS-domain factors: insights from recent studies.

Members of the MADS-box transcription factor family play essential roles in almost every developmental process in plants. Many MADS-box genes have conserved functions across the flowering plants, but some have acquired novel functions in specific species during evolution. The analyses of MADS-domain protein interactions and target genes have provided new insights into their molecular functions. Here, we review recent findings on MADS-box gene functions in Arabidopsis and discuss the evolutionary history and functional diversification of this gene family in plants. We also discuss possible mechanisms of action of MADS-domain proteins based on their interactions with chromatin-associated factors and other transcriptional regulators.

Graphene quantum dots as enhanced plant growth regulators: effects on coriander and garlic plants.

BACKGROUND: We report investigations on the use of graphene quantum dots for growth enhancement in coriander (Coriandrum sativam L.) and garlic (Allium sativum) plants. The as-received seeds of coriander and garlic were treated with 0.2 mg mL(-1) of graphene quantum dots for 3 h before planting. RESULTS: Graphene quantum dots enhanced the growth rate in coriander and garlic plants, including leaves, roots, shoots, flowers and fruits, when the seeds were treated with graphene quantum dots. CONCLUSION: Our investigations open up the opportunity to use graphene quantum dots as plant growth regulators that can be used in a variety of other food plants for high yield.

Molecular control of normal and acrocona mutant seed cone development in Norway spruce (Picea abies) and the evolution of conifer ovule-bearing organs.

Reproductive organs in seed plants are morphologically divergent and their evolutionary history is often unclear. The mechanisms controlling their development have been extensively studied in angiosperms but are poorly understood in conifers and other gymnosperms. Here, we address the molecular control of seed cone development in Norway spruce, Picea abies. We present expression analyses of five novel MADS-box genes in comparison with previously identified MADS and LEAFY genes at distinct developmental stages. In addition, we have characterized the homeotic transformation from vegetative shoot to female cone and associated changes in regulatory gene expression patterns occurring in the acrocona mutant. The analyses identified genes active at the onset of ovuliferous and ovule development and identified expression patterns marking distinct domains of the ovuliferous scale. The reproductive transformation in acrocona involves the activation of all tested genes normally active in early cone development, except for an AGAMOUS-LIKE6/SEPALLATA (AGL6/SEP) homologue. This absence may be functionally associated with the nondeterminate development of the acrocona ovule-bearing scales. Our morphological and gene expression analyses give support to the hypothesis that the modern cone is a complex structure, and the ovuliferous scale the result of reductions and compactions of an ovule-bearing axillary short shoot in cones of Paleozoic conifers.

How do 'housekeeping' genes control organogenesis?--Unexpected new findings on the role of housekeeping genes in cell and organ differentiation.

In recent years, an increasing number of mutations in what would appear to be 'housekeeping genes' have been identified as having unexpectedly specific defects in multicellular organogenesis. This is also the case for organogenesis in seed plants. Although it is not surprising that loss-of-function mutations in 'housekeeping' genes result in lethality or growth retardation, it is surprising when (1) the mutant phenotype results from the loss of function of a 'housekeeping' gene and (2) the mutant phenotype is specific. In this review, by defining housekeeping genes as those encoding proteins that work in basic metabolic and cellular functions, we discuss unexpected links between housekeeping genes and specific developmental processes. In a surprising number of cases housekeeping genes coding for enzymes or proteins with functions in basic cellular processes such as transcription, post-transcriptional modification, and translation affect plant development.

GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome branching through gibberellic acid signaling in Arabidopsis.

Cell differentiation generally corresponds to the cell cycle, typically forming a non-dividing cell with a unique differentiated morphology, and Arabidopsis trichome is an excellent model system to study all aspects of cell differentiation. Although gibberellic acid is reported to be involved in trichome branching in Arabidopsis, the mechanism for such signaling is unclear. Here, we demonstrated that GLABROUS INFLORESCENCE STEMS (GIS) is required for the control of trichome branching through gibberellic acid signaling. The phenotypes of a loss-of-function gis mutant and an overexpressor showed that GIS acted as a repressor to control trichome branching. Our results also show that GIS is not required for cell endoreduplication, and our molecular and genetic study results have shown that GIS functions downstream of the key regulator of trichome branching, STICHEL (STI), to control trichome branching through the endoreduplication-independent pathway. Furthermore, our results also suggest that GIS controls trichome branching in Arabidopsis through two different pathways and acts either upstream or downstream of the negative regulator of gibbellic acid signaling SPINDLY (SPY).

Proteomic analysis revealed nitrogen-mediated metabolic, developmental, and hormonal regulation of maize (Zea mays L.) ear growth.

Optimal nitrogen (N) supply is critical for achieving high grain yield of maize. It is well established that N deficiency significantly reduces grain yield and N oversupply reduces N use efficiency without significant yield increase. However, the underlying proteomic mechanism remains poorly understood. The present field study showed that N deficiency significantly reduced ear size and dry matter accumulation in the cob and grain, directly resulting in a significant decrease in grain yield. The N content, biomass accumulation, and proteomic variations were further analysed in young ears at the silking stage under different N regimes. N deficiency significantly reduced N content and biomass accumulation in young ears of maize plants. Proteomic analysis identified 47 proteins with significant differential accumulation in young ears under different N treatments. Eighteen proteins also responded to other abiotic and biotic stresses, suggesting that N nutritional imbalance triggered a general stress response. Importantly, 24 proteins are involved in regulation of hormonal metabolism and functions, ear development, and C/N metabolism in young ears, indicating profound impacts of N nutrition on ear growth and grain yield at the proteomic level.

Control of cell proliferation, organ growth, and DNA damage response operate independently of dephosphorylation of the Arabidopsis Cdk1 homolog CDKA;1.

Entry into mitosis is universally controlled by cyclin-dependent kinases (CDKs). A key regulatory event in metazoans and fission yeast is CDK activation by the removal of inhibitory phosphate groups in the ATP binding pocket catalyzed by Cdc25 phosphatases. In contrast with other multicellular organisms, we show here that in the flowering plant Arabidopsis thaliana, cell cycle control does not depend on sudden changes in the phosphorylation pattern of the PSTAIRE-containing Cdk1 homolog CDKA;1. Consistently, we found that neither mutants in a previously identified CDC25 candidate gene nor plants in which it is overexpressed display cell cycle defects. Inhibitory phosphorylation of CDKs is also the key event in metazoans to arrest cell cycle progression upon DNA damage. However, we show here that the DNA damage checkpoint in Arabidopsis can also operate independently of the phosphorylation of CDKA;1. These observations reveal a surprising degree of divergence in the circuitry of highly conserved core cell cycle regulators in multicellular organisms. Based on biomathematical simulations, we propose a plant-specific model of how progression through the cell cycle could be wired in Arabidopsis.

Physiological response of Cu and Cu mine tailing remediation of Paulownia fortunei (Seem) Hemsl.

The physiological responses and Cu accumulation of Paulownia fortunei (Seem) Hemsl. were studied under 15.7-157 µmol L(-1) Cu treatments in liquid culture for 14 days; the impacts of Cu concentration in the seedlings were evaluated under Cu mine tailing culture with acetic acid and EDTA treatment for 60 days. Results showed that the concentrations of Chl-a, Chl-b and Carotenoids significantly increased (p < 0.05) at 15.7-78.7 µmol L(-1)Cu treatment and significantly decreased at 157 µmol L(-1) treatment after 14 days of Cu exposure. The activities of superoxide dismutase (SOD) and catalase (CAT) significantly increased as Cu levels were enhanced and the activities of both SOD and CAT under 157 µmol L(-1) Cu stress were 2.9 and 1.9 times higher than that of control, respectively. The concentrations of proline and soluble sugars in the leaves of P. fortunei significantly increased as the Cu concentrations were elevated. Cu concentrations in roots, stems and leaves of P. fortunei increased significantly as Cu levels increased and reached 1911, 101 and 93 µg g(-1) dry weights (DW) at 157 µmol L(-1) Cu treatment, respectively. The seedlings of P. fortunei cultivated in Cu tailing experienced unsuccessful growth and loss of leaves in all treatments due to poor nutrition of the Cu tailing. The dry weight of P. fortunei increased under all the treatments of acetic acid after 60 days exposure. However, dry weight significantly decreased under both levels of EDTA. The Cu concentrations increased significantly in roots and decreased in leaves when each was treated with both concentrations of acetic acid. The Cu concentrations in the roots, stems and leaves increased significantly, and the concentrations of Cu in the stems and leaves under the treatment of 2 µmol L(-1) EDTA reached 189.5 and 763.1 µg g(-1) DW, respectively. The result indicated that SOD, CAT, proline and soluble sugars played an important role in coping with the oxidative stress of copper. Acetic acid could promote growth and EDTA at the experimental levels, which could also enhance Cu absorption and translocation into the stems and leaves of P. fortune. Furthermore, acetic acid and EDTA could be rationally utilized in Cu-contaminated soil.

Genotypic differences in zinc efficiency of Chinese maize evaluated in a pot experiment.

BACKGROUND: Zinc (Zn) deficiency, a major problem limiting crop production worldwide, is common on calcareous soils of China. Using such a Zn-deficient soil supplied adequately with plant mineral nutrients, with or without Zn, 30 Chinese maize genotypes were grown for 30 days in a greenhouse pot experiment and assessed for Zn efficiency (ZE), measured as relative biomass under Zn-limiting compared with non-limiting conditions. RESULTS: Substantial variation in tolerance to low Zn nutritional status was observed within the maize genotypes. Tolerant genotypes did not show Zn deficiency symptoms at the studied early seedling growth, and there was a well-defined relationship between shoot dry matter and the ZE trait. ZE values ranged on average from 45 to 100% for shoot dry weight. Under low available soil Zn conditions, shoot and root dry weights, shoot Zn concentration and content, leaf superoxide dismutase (SOD) activity, leaf area and plant height were all correlated with ZE. Shoot Zn and phosphorus (P) concentrations were negatively correlated. CONCLUSION: Three genotypes (L55 × 178, L114 × 178 and Zhongnong 99) were identified as highly Zn-efficient and three (L53 × 178, L105 × 178 and L99 × 178) as very low in ZE. This selection allows further work to evaluate ZE based on grain yield and grain Zn concentration, including field experiments likely to benefit farmers producing maize on Chinese soils low in available Zn.