Evaluation of Pre-Emergence and Post-Emergence Herbicides for Weed Management in <i>Miscanthus sacchariflorus</i> and <i>Miscanthus sinensis</i>

Miscanthus, is a promising bioenergy crop, considered superior to other bioenergy crops because of its higher water and nutrient use efficiency, cold tolerance, and higher production of biomass. Broadleaf weeds and grass weeds, cause major problems in the Miscanthus field. A field experiment was conducted in 2018 and 2019, to assess the effects of pre-emergence (alachlor and napropamide) and post-emergence herbicides (nicosulfuron, dicamba, bentazon, and glufosinate ammonium) on broadleaf and grass weeds in M. sinensis and M. sacchariflorus fields. The weed control efficiency and phytotoxicity of pre- and post-emergence herbicides were evaluated at 30 days after treatment (DAT) and compared to those of the control plots. The results showed wide variations in the susceptibility of the weed species to the treated herbicides. Treatment with nicosulfuron 40 g.a.i.ha⁻¹ provided the most effective overall weed control (with 10% visual injury), without affecting the height and biomass of neither Miscanthus species in the field. Post-emergence herbicides such as glufosinate ammonium 400 g.a.i.ha⁻¹ and dicamba 482 g.a.i.ha⁻¹ were effective and inhibited the growth and density of the majority of weeds to a 100%; however, they showed significant phytotoxicity (toxicity scale of 1–10) to both species of Miscanthus. The application of glufosinate ammonium caused severe injuries to the foliar region (90% visual injury) of both Miscanthus sps. Comparatively, M. sinensis showed a slightly higher tolerance to the herbicides nicosulfuron, bentazon and napropamide with 10% visual injury at the recommended dose than M. sacchariflorus. The present study clearly showed that infestation of broadleaf and grass weeds in Miscanthus fields can cause significant damage to the growth and biomass of Miscanthus and applying pre-emergence and post-emergence herbicides effectively controls the high infestation of these weeds.     

Physiological and Biochemical Mechanisms of Salinity Tolerance in <i>Carex morrowii</i> Boott

Carex species are widely used in many parts of the world and contain a large number of ecologically diverse species. Among the Carex species, some of them are known to be glycophytes, while others are halophytes. Carex morrowii Boott (Cyperaceae) is resistant to trample through their root structure and has an essential ornamental value in the landscape with their leaves. However, no information was found about the level of salinity tolerance/ sensitivity of the Carex morrowii among these species. In the present study, changes in trace element contents (Na, K, Ca, Cu, Mn, Mg, Ni, Fe, P, Zn, and N) and their transport from roots to leaves, osmotic regulation, alterations in chlorophyll and carotenoid contents, nitrogen assimilation (nitrate reductase activity; NRA) and total soluble protein content in both roots and leaves of Carex morrowii under different salinity concentrations (50 mM, 100 mM, 200 mM and 300 mM NaCl) were examined in detail. Our study provides the first detailed data concerning the responses of leaves and roots and the determination of the level of salinity tolerance/sensitivity of the Carex morrowii. The K+ /Na+ ratio was preserved up to 200 mM NaCl, and accordingly, the element uptake and transport ratios showed that they could control moderate NaCl levels. Ca homeostasis that is maintained even in 200 mM NaCl concentration can be effective in maintaining the structural integrity and selective permeability of the cell membranes, while 300 mM NaCl concentration caused decreased photosynthetic pigments, and deterioration in element content and compartmentation. Moreover, these data suggest that plant parts of Carex morrowii respond differently against varied levels of salinity stress. Although the decrease in NR activity at 200 mM and 300 mM NaCl concentrations in the leaves, NR activity was maintained in the roots. Consequently, Carex morrowii is moderately tolerant to salinity and the carotenoid content and osmotic regulation of Carex morrowii appears to be instrumental in its survival at different salinity levels. Especially the roots of Carex morrowii have a remarkable role in salinity tolerance.     

Development of a New Cold-Tolerant Maize (<i>Zea mays</i> L.) Germplasm Using the <i>ICE1</i> Gene from <i>Arabidopsis thaliana</i>

To develop cold-tolerant maize germplasms and identify the activation of INDUCER OF CRT/DRE-BINDING FACTOR EXPRESSION (ICE1) expression in response to cold stress, RT-PCR was used to amplify the complete open reading frame sequence of the ICE1 gene and construct the plant expression vector pCAMBIA3301-ICE1-Bar. Immature maize embryos and calli were transformed with the recombinant vector using Agrobacterium tumefaciens-mediated transformations. From the regenerated plantlets, three T1 lines were screened and identified by PCR. A Southern blot analysis showed that a single copy of the ICE1 gene was integrated into the maize (Zea mays L.) genomes of the three T1 generations. Under low temperature-stress conditions (4°C), the relative conductivity levels decreased by 27.51%–31.44%, the proline concentrations increased by 12.50%–17.50%, the malondialdehyde concentrations decreased by 16.78%–18.37%, and the peroxidase activities increased by 19.60%–22.89% in the T1 lines compared with those of the control. A real-time quantitative PCR analysis showed that the ICE1 gene was ectopically expressed in the roots, stems, and leaves of the T1 lines. ICE1 positively regulates the expression of the CBF genes in response to cold stress. Thus, this study showed the successful transformation of maize with the ICE1 gene, resulting in the generation of a new maize germplasm that had increased tolerance to cold stress.     

Cloning and Characterization of <i>EuGID1</i> in <i>Eucommia ulmoides</i> Oliver

Gibberellic acid controlled the key developmental processes of the life cycle of landing plants, and regulated the growth and development of plants. In this study, a novel gibberellin receptor gene EuGID1 was obtained from Eucommia ulmoides Oliver. The cDNA of EuGID1 was 1556 bp, and the open reading frame was 1029 bp, which encoded 343 amino acids. EuGID1 had the homology sequence with the hormone-sensitive lipase family. Amino acid sequence alignment confirmed EuGID1 protein had the highest homology with the GID1 protein of Manihot esculenta. EuGID1 was located in the nucleus and cell membrane and had expression in four plant organs. Overexpression of EuGID1 in transgenic Arabidopsis plants promoted plant elongation and increased siliques yield.     

Genome-Wide Analysis of the <i>KANADI</i> Gene Family and Its Expression Patterns under Different Nitrogen Concentrations Treatments in <i>Populus trichocarpa</i>

KANADI (KAN) is a plant-specific gene that controlled the polarity development of lateral organs. It mainly acted on the abaxial characteristics of plants to make the lateral organs asymmetrical. However, it had been less identified in woody plants. In this study, the members of the KAN gene family in Populus trichocarpa were identified and analyzed using the bioinformatics method. The results showed that a total of 8 KAN family members were screened out, and each member contained the unique GARP domain and conserved region of the family proteins. Phylogenetic analysis and their gene structures revealed that all KAN genes from P. trichocarpa, Arabidopsis thaliana, and Nicotiana benthamiana could be divided into four subgroups, while the eight genes in P. trichocarpa were classified into three subgroups, respectively. The analysis of tissue-specific expression indicated that PtKAN1 was highly expressed in young leaves, PtKAN6 was highly expressed in young leaves and mature leaves, PtKAN2, PtKAN5, and PtKAN7 were highly expressed in nodes and internodes, PtKAN8 was highly expressed in roots, and PtKAN3 and PtKAN4 showed low expression levels in all tissues. Among them, PtKAN2 and PtKAN6, and PtKAN4 and PtKAN5 might have functional redundancy. Under high nitrogen concentrations, PtKAN2 and PtKAN8 were highly expressed in mature stems and leaves, respectively, while PtKAN4, PtKAN5, and PtKAN7 were highly expressed in roots. This study laid a theoretical foundation for further study of the KAN gene-mediated nitrogen effect on root development.     

<i>DWARF</i> and <i>SMALL SEED1</i>, a Novel Allele of <i>OsDWARF</i>, Controls Rice Plant Architecture,Seed Size,and Chlorophyll Biosynthesis

Plant architecture is a vital agronomic trait to control yield in rice (Oryza sativa L.). A dwarf and small seed 1 (dss1) mutant were obtained from the ethyl methanesulfonate (EMS) mutagenized progeny of a Guizhou glutinous landrace cultivar, Lipingzabianhe. The dss1 mutant displayed phenotypes similar to those of brassinosteroid (BR) deficient mutants, such as dwarfing, dark green and rugose erect leaves, small seeds, and loner neck internode panicles with primary branching. In our previous study, the underlying DSS1 gene was isolated, a novel allele of OsDWARF (OsBR6ox) that encodes a cytochrome P450 protein involved in the BR biosynthetic pathway by MutMap technology. In this work, we confirmed that a Thr335Ile amino acid substitution residing in DSS1/OsDWARF was responsible for the dwarf, panicle architecture, and small seed phenotypes in the dss1 mutants by genetic transformation experiments. The overexpression of OsDWARF in the dss1 mutant background could not only recover dss1 to the normal plant height and panicle architecture but also rescued normal leaf angles, seed size, and leaf color. Thus, the specific mutation in DSS1/OsDWARF influenced plant architecture, seed size, and chlorophyll biosynthesis.     

Identification and Evaluation of Insect and Disease Resistance in Transgenic <i>Cry1Ab13-1</i> and <i>NPR1</i> Maize

PCR detection, quantitative real-time PCR (q-RTPCR), outdoor insect resistance, and disease resistance identification were carried out for the detection of genetic stability and disease resistance through generations (T₂, T₃, and T₄) in transgenic maize germplasms (S3002 and 349) containing the bivalent genes (insect resistance gene Cry1Ab13-1 and disease resistance gene NPR1) and their corresponding wild type. Results indicated that the target genes Cry1Ab13-1 and NPR1 were successfully transferred into both germplasms through tested generations; q-PCR confirmed the expression of Cry1Ab13-1 and NPR1 genes in roots, stems, and leaves of tested maize plants. In addition, S3002 and 349 bivalent gene-transformed lines exhibited resistance to large leaf spots and corn borer in the field evaluation compared to the wild type. Our study confirmed that Cry1Ab13-1 and NPR1 bivalent genes enhanced the resistance against maize borer and large leaf spot disease and can stably inherit. These findings could be exploited for improving other cultivated maize varieties.     

Effects of Different Geographical Aspects and Ontogenetic Variability on Total Hypericin Content of <i>Hypericum triquetrifolium</i> Turra. and <i>Hypericum scabrum</i> L.

The present study was conducted to determine the total hypericin contents of Hypericum triquetrifolium Turra. and Hypericum scabrum L. species which are naturally distributed in the flora of Siirt province, Turkey. Hypericin contents of Hypericum species grown in different geographical aspects (North, South, East, and West), and it was measured at different harvest times (full blooming and post blooming period). In the current study, it has been determined that total hypericin content varies considerably according to aspects, plant developmental stages (ontogenetic variance), and species. According to species x aspect interaction, the highest total hypericin content was recorded from the west aspect (3.13 mg/g) in Hypericum triquetrifolium, while, the lowest hypericin content was also obtained from the west aspect (1.22 mg/g) in Hypericum scabrum. When the highest total hypericin content was analyzed according to aspect x species x harvest time interaction, the highest total hypericin content was produced from Hypericum triquetrifolium at the harvest of west aspect with 5.28 mg/g, while the minimum amount of hypericin was obtained from the same aspect in Hypericum scabrum with 0.50 mg/g. In species x harvest time interaction, the highest total hypericin content was obtained from the full bloom (3.10 mg/g) harvest in Hypericum triquetrifolium, while the lowest hypericin was obtained from the full bloom (1.26 mg/g) harvest in Hypericum scabrum. The data suggest that the average total hypericin content was 2.26 mg/g in Hypericum triquetrifolium and 1.28 mg/g in Hypericum scabrum.     

Antibacterial Activity and Mechanisms of Ethanol Extracts from <i>Scutellaria baicalensis</i> Georgi and <i>Magnolia officinalis</i> against <i>Phytophthora nicotianae</i>

Phytophthora nicotianae causes substantial economic losses in most countries where tobacco is produced. At present, the control of P. nicotianae mainly depends on chemical methods, with considerable environmental and health issues. We investigated the effects of ethanol extracts from Scutellaria baicalensis Georgi (SBG) and Magnolia officinalis (MO). On mycelial growth, sporangium formation, and zoospore release of P. nicotianae. Both extracts inhibited the growth of P. nicotianae, with mycelial growth inhibition rates of 88.92% and 93.92%, respectively, at 40 mg/mL, and EC50 values of 5.39 and 5.74 mg/mL, respectively. The underlying mechanisms were the inhibition of sporangium formation, the reduction of zoospore number, and the destruction of the mycelium structure. At an SBG extract concentration of 16.17 mg/mL, the inhibition rates for sporangia and zoospores were 98.66% and 99.39%, respectively. At an MO extract concentration of 2.87 mg/mL, the production of sporangia and zoospores was completely inhibited. The hyphae treated with the two plant extracts showed different degrees of deformation and damage. Hyphae treated with SBG extract showed adhesion and local swelling, whereas treatment with MO extract resulted in broken hyphae. Mixture of the extracts resulted in a good synergistic effect.     

DDG1 and G Protein α Subunit RGA1 Interaction Regulates Plant Height and Senescence in Rice (<i>Oryza sativa</i>)

Many studies have already shown that dwarfism and moderate delayed leaf senescence positively impact rice yield, but the underlying molecular mechanism of dwarfism and leaf senescence remains largely unknown. Here, using map-based cloning, we identified an allele of DEP2, DDG1, which controls plant height and leaf senescence in rice. The ddg1 mutant displayed dwarfism, short panicles, and delayed leaf senescence. Compared with the wild-type, ddg1 was insensitive to exogenous gibberellins (GA) and brassinolide (BR). DDG1 is expressed in various organs, especially in stems and panicles. Yeast two-hybrid assay, bimolecular fluorescent complementation and luciferase complementation image assay showed that DDG1 interacts with the α-subunit of the heterotrimeric G protein. Disruption of RGA1 resulted in dwarfism, short panicles, and darker-green leaves. Furthermore, we found that ddg1 and the RGA1 mutant was more sensitive to salt treatment, suggesting that DDG1 and RGA1 are involved in regulating salt stress response in rice. Our results show that DDG1/DEP2 regulates plant height and leaf senescence through interacting with RGA1.     

Germination and Photosynthetic Responses to Salinity and Alkalinity in <i>Avicenna marina</i> Propagules

Avicenna marina (Forssk.) Vierh is a halophytic mangrove. The reproductive unit is green and has photosynthetic propagules. Mangroves are naturally exposed to fluctuations in some abiotic factors at the soil surface, including salinity and alkalinity. The objective of this study was to determine the effects of two salts including NaCl and NaHCO₃ on germination processes and discuss the relationships between cotyledon photosynthesis and embryo axis growth in A. marina propagules. These propagules came from Al Birk, located on the shoreline of the Saudi Red Sea. The results showed that the studied salts did not affect neither the final germination percentage nor the embryo axis growth. However, rooting and root growth were delayed by both salts at 300 mM and were strongly inhibited by 600 mM NaHCO₃. Both NaCl and NaHCO₃ reduced the photosynthetic activity. These two salts did not affect the other photosynthetic parameters, including stomatal conductance, net transpiration, and intercellular CO₂. Thereafter, the reduction in net photosynthesis was not related to any limitation of stomatal conductance. The early germination phase was independent of cotyledon photosynthesis, whereas rooting and root growth may be limited by reduced photosynthesis under NaCl and NaHCO₃.     

Genome-Wide Identification,Evolution and Expression Analyses of <i>GA2ox</i> Gene Family in <i>Brassica napus</i> L.

Gibberellin 2-oxidases (GA2ox) are important enzymes that maintain the balance of bioactive GAs in plants. GA2ox genes have been identified and characterized in many plants, but these genes were not investigated in Brassica napus. Here, we identified 31 GA2ox genes in B. napus and 15 of these BnaGA2ox genes were distributed in the A and C subgenomes. Subcellular localization predictions suggested that all BnaGA2ox proteins were localized in the cytoplasm, and gene structure analysis showed that the BnaGA2ox genes contained 2–4 exons. Phylogenetic analysis indicated that BnGA2ox family proteins in monocotyledons and dicotyledons can be divided into four groups, including two C₁₉-GA2ox and two C₂₀-GA2ox clades. Group 4 is a C₂₀-GA2ox Class discovered recently. Most BnaGA2ox genes had a syntenic relationship with AtGA2ox genes. BnaGA2ox genes in the C subgenome had experienced stronger selection pressure than genes in the A subgenome. BnaGA2ox genes were highly expressed in specific tissues such as those involved in growth and development, and most of them were mainly involved in abiotic responses, regulation of phytohormones and growth and development. Our study provided a valuable evolutionary analysis of GA2ox genes in monocotyledons and dicotyledons, as well as an insight into the biological functions of GA2ox family genes in B. napus.     

<i>VvAGAMOUS</i> Affect Development of Four Different Grape Species Ovary

Grape pistil has an important influence on fruit size and quality. However, there were few studies on grape ovary, and the development process of the ovary is still unclear. Therefore, in this paper, four different grape varieties with different lengths of small inflorescences, namely ‘Musct Hambourg’ grape (Vitis vinifera), ‘Concord’ grape (Vitis labrusca), ‘ShanPuTao’ grape (Vitis amurensis) and ‘GongNiang2Hao’ grape (Vitis amurensis × Vitis vinifera) were used as test materials. Four varieties ovary were significant differences by means of stereomicroscope, paraffin section. The expression of ovary determining gene VvAGAMOUS (VvAG) and its development related genes VvCRABS CLAW (VvCRC) andVvAGAMOUS-LIKE 11 (VvAGL11) with similar functions during the development of different grape varieties were preliminarily explored using fluorescence quantitative test. The relationship between VvAG and VvCRC, VvAG and VvAGL11 were analyzed using Y1H assay. Our results showed that there were obvious abdominal sutures on the surface of expect for ‘Musct Hambourg’ grape, and existing poly carpels. The ovary development of ‘ShanPuTao’ and ‘GongNiang2Hao’ grape was completed when the inflorescence length was less than 1 cm, while the ‘Concord’ and ‘Musct Hambourg’ grape were fully developed when the length of inflorescence was 3–4 and 4–5 cm, respectively. VvAG and VvCRC began to express in large quantities after the formation of stamen primordia, while VvAGL11 during the forming of ovule primordia. Therefore, VvAG and VvCRC mainly regulated the development of stamens and carpels and also promote the development of ovules, while VvAGL11 major regulated the development of ovules. The promoters of VvCRC and VvAGL11 were bound by VvAG. This study provides an important theoretical basis for further research on the molecular mechanism of grape ovary development.     

Participation of Auxin Transport in the Early Response of the <i>Arabidopsis</i> Root System to Inoculation with <i>Azospirillum brasilense</i>

The potential of Plant Growth Promoting Rhizobacteria (PGPR) has been demonstrated in the case of plant inoculation with bacteria of the genus Azospirillum which improves yield. A. brasilense produces a wide variety of molecules, including the natural auxin indole-3-acetic acid (IAA), as well as other phytoregulators. However, several studies have suggested that auxin induces changes in plant development during their interaction with the bacteria. The effects of A. brasilense Sp245 on the development of Arabidopsis thaliana root were investigated to help explain the molecular basis of the interaction. The results obtained showed a decrease in primary root length from the first day and remained so throughout the exposure, accompanied by a stimulation of initiation and maturation of lateral root primordia and an increase of lateral roots. An enhanced auxin response was evident in the vascular tissue and lateral root meristems of inoculated plants. However, after five days of bacterization, the response disappeared in the primary root meristems. The role of polar auxin transport (PAT) in auxins relocation involved the PGP1, AXR4-1, and BEN2 proteins, which apparently mediated A. brasilense-induced root branching of Arabidopsis seedlings.