Assessment of the changes in growth, photosynthetic traits and gene expression in Cynodon dactylon against drought stress.

Drought stress considered a key restrictive factor for a warm-season bermudagrass growth during summers in China. Genotypic variation against drought stress exists among bermudagrass (Cynodon sp.), but the selection of highly drought-tolerant germplasm is important for its growth in limited water regions and for future breeding. Our study aimed to investigate the most tolerant bermudagrass germplasm among thirteen, along latitude and longitudinal gradient under a well-watered and drought stress condition. Current study included high drought-resistant germplasm, "Tianshui" and "Linxiang", and drought-sensitive cultivars; "Zhengzhou" and "Cixian" under drought treatments along longitude and latitudinal gradients, respectively. Under water deficit conditions, the tolerant genotypes showed over-expression of a dehydrin gene cdDHN4, antioxidant genes Cu/ZnSOD and APX which leads to higher antioxidant activities to scavenge the excessive reactive oxygen species and minimizing the membrane damage. It helps in maintenance of cell membrane permeability and osmotic adjustment by producing organic osmolytes. Proline an osmolyte has the ability to keep osmotic water potential and water use efficiency high via stomatal conductance and maintain transpiration rate. It leads to optimum CO2 assimilation rate, high chlorophyll contents for photosynthesis and elongation of leaf mesophyll, palisade and thick spongy cells. Consequently, it results in elongation of leaf length, stolon and internode length; plant height and deep rooting system. The CdDHN4 gene highly expressed in "Tianshui" and "Youxian", Cu/ZnSOD gene in "Tianshui" and "Linxiang" and APX gene in "Shanxian" and "Linxiang". The genotypes "Zhongshan" and "Xiaochang" showed no gene expression under water deficit conditions. Our results indicate that turfgrass show morphological modifications firstly when subjected to drought stress; however the gene expression is directly associated and crucial for drought tolerance in bermudagrass. Hence, current research has provided excellent germplasm of drought tolerant bermudagrass for physiological and molecular study and future breeding.

H2O2 promotes trimming-induced tillering by regulating energy supply and redox status in bermudagrass.

Tillering/branching pattern plays a significant role in determining the structure and diversity of grass, and trimming has been found to induce tillering in turfgrass. Recently, it has been reported that hydrogen peroxide (H2O2) regulates axillary bud development. However, the role of H2O2 in trimming-induced tillering in bermudagrass, a kind of turfgrass, remains unclear. Our study unveils the significant impact of trimming on promoting the sprouting and growth of tiller buds in stolon nodes, along with an increase in the number of tillers in the main stem. This effect is accompanied by spatial-temporal changes in cytokinin and sucrose content, as well as relevant gene expression in axillary buds. In addition, the partial trimming of new-born tillers results in an increase in sucrose and starch reserves in their leaves, which can be attributed to the enhanced photosynthesis capacity. Importantly, trimming promotes a rapid H2O2 burst in the leaves of new-born tillers and axillary stolon buds. Furthermore, exogenous application of H2O2 significantly increases the number of tillers after trimming by affecting the expression of cytokinin-related genes, bolstering photosynthesis potential, energy reserves and antioxidant enzyme activity. Taken together, these results indicate that both endogenous production and exogenous addition of H2O2 enhance the inductive effects of trimming on the tillering process in bermudagrass, thus helping boost energy supply and maintain the redox state in newly formed tillers.

Enhancing systematic tolerance in Bermuda grass (Cynodon dactylon L.) through amplified alkB gene expression and bacterial-driven hydrocarbon degradation.

This study aimed to access the impact of soil polluted with petroleum (5, 10 g petroleum kg-1 soil) on Bermuda grass (Cynodon dactylon L.) with and without applied bacterial inoculants (Arthrobacter oxydans ITRH49 and Pseudomonas sp. MixRI75). Both soil and seed were given bacterial inoculation. The evaluated morphological parameters of Bermuda grass were fresh and dry weight. The results demonstrated that applied bacterial inoculants enhanced 5.4%, 20%, 28% and 6.4%, 21%, and 29% shoot and root fresh/dry weights in Bermuda grass under controlled environment. The biochemical analysis of shoot and root was affected deleteriously by the 10 g petroleum kg-1 soil pollution. Microbial inoculants enhanced the activities of enzymatic (catalase, peroxidase, glutathione reductase, ascorbate peroxidase, superoxide dismutase) and non-enzymatic (ɑ-tocopherols, proline, reduced glutathione, ascorbic acid) antioxidant to mitigate the toxic effects of ROS (H2O2) under hydrocarbon stressed condition. The maximum hydrocarbon degradation (75%) was recorded by Bermuda grass at 5 g petroleum kg-1 soil contamination. Moreover, bacterial persistence and alkane hydroxylase gene (alkB) abundance and expression were observed more in the root interior than in the rhizosphere and shoot interior of Bermuda grass. Subsequently, the microbe used a biological tool to propose that the application of plant growth-promoting bacteria would be the most favorable choice in petroleum hydrocarbon polluted soil to conquer the abiotic stress in plants and the effective removal of polyaromatic hydrocarbons in polluted soil.

First Report of Metadelphax propinqua (Fieber) (Hemiptera: Delphacidae) Feeding on Bermudagrass in Brazil.

Bermudagrass (Cynodon dactylon (L.) Pers., Poaceae) is one of the most important pasture grasses used in milk production systems in southern Brazil, with an increasing expansion of cultivated areas in recent years. Here, we report the first occurrence of the planthopper Metadelphax propinqua (Fieber) (Hemiptera: Delphacidae) feeding on bermudagrass in Brazil. Population outbreaks of this species were observed in January/February 2023 in a commercial hay production farm in the municipality of Chapecó, Santa Catarina State, southern Brazil. Metadelphax propinqua was found in association with three cultivars of C. dactylon (Tifton 85, Jiggs, and Vaquero). The infested plants showed leaf chlorosis and a reduced plant growth rate due to sap sucking and toxin injection as well as honeydew deposition on the leaves, which led to the development of sooty mold. In addition, this delphacid species has been reported as a vector of important pathogens to bermudagrass species and other row crops. Thus, M. propinqua is a potential pest of bermudagrass in Brazil and should be monitored to assess its establishment and behavior in Brazilian pasturelands.

Environmental and Edaphic Factors that Influence Spring Dead Spot Epidemics.

Spring dead spot (SDS) (Ophiosphaerella spp.) is a soilborne disease of warm-season turfgrasses grown where winter dormancy occurs. The edaphic factors that influence where SDS epidemics occur are not well defined. A study was conducted during the spring of 2020 and repeated in the spring of 2021 on four 'TifSport' hybrid bermudagrass (Cynodon dactylon × transvaalensis) golf course fairways expressing SDS symptoms in Cape Charles, VA, U.S.A. SDS within each fairway was mapped from aerial imagery collected in the spring of 2019 with a 20 MP CMOS 4k true color sensor mounted on a DJI Phantom 4 Pro drone. Three disease intensity zones were designated from the maps (low, moderate, high) based on the density of SDS patches in an area. Disease incidence and severity, soil samples, surface firmness, thatch depth, and organic matter measurements were taken from 10 plots within each disease intensity zone from each of the four fairways (n = 120). Multivariate pairwise correlation analyses (P < 0.1) and best subset stepwise regression analyses were conducted to determine which edaphic factors most influenced the SDS epidemic within each fairway and each year. Edaphic factors that correlated with an increase in SDS or were selected for the best fitting model varied across holes and years. However, in certain cases, soil pH and thatch depth were predictors for an increase in SDS. No factors were consistently associated with SDS occurrence, but results from this foundational study of SDS epidemics can guide future research to relate edaphic factors to SDS disease development.

Cover crops terminated with roller-crimper to manage Cynodon dactylon and other weeds in vineyards.

BACKGROUND: Using cover crops in organic vineyards can provide many advantages, including weed suppression. However, their effectiveness may depend on the weed community, the cover crop species and the termination method. The most common practice for cover crop termination is shredding, but rapid residue decomposition can allow noxious species like Cynodon dactylon to proliferate during summer and compete with the vines. The use of roller-crimpers as an alternative method can be effective in some cropping systems, but no studies have focused on their use in the inter-row of vineyards. The objective of this study was to evaluate the effectiveness of seven cover crops (spontaneous, Avena strigosa, Hordeum vulgare, Lolium multiflorum, Phacelia tanacetifolia, Sinapis alba and X Triticosecale) and two termination methods (shredding or roller-crimper) in managing C. dactylon during summer. RESULTS: In 2020, rolled A. strigosa, P. tanacetifolia and the spontaneous flora limited the coverage of C. dactylon more than shredding (increases of 3% and 18% in C. dactylon cover from July to September in rolled and shredded cover crops, respectively), while in 2021, rolling was better than shredding for all cover crop species in September (5% and 18% increases, respectively). CONCLUSION: Roller-crimping cover crops was an effective method to control C. dactylon in vineyard inter-rows but it did not consistently work for all cover crops in both years. Our study is one of the first to test the efficacy of roller-crimpers to manage summer weeds in vineyards. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Could Cratylia argentea replace Tifton 85 hay on growing and finishing lamb diets in tropical areas?

Legumes shrubs such as Cratylia argentea have an ability to thrive in environments with low water availability and poor soil. On the other hand, forage grasses such as Tifton 85 have a greater demand for inputs to be productive. The objective of this study was to evaluate the performance of growing and finishing Lacaune lambs fed Cratylia argentea hay as an alternative to Tifton 85 (Cynodon spp). Twenty-four Lacaune lambs aged between five and six months (average body weight [BW] 21.50 ± 3.38 kg) were arranged in a split-plot randomized block design. The plots consisted of different Cratylia to Tifton 85 hay proportions (0, 20%, 40%, or 100%, dry matter [DM] basis) as a roughage replacement in the total diet. The subplots represented two evaluation times, entitled "initial period" and "final period", which consisted of the early seven days of total feces and urine collection, and the last seven days of the experiment, respectively. The lambs were blocked by weight with six replicates per treatment. The results show that the level of Tifton 85 replacement for Cratylia hay in the roughage portion of the lamb diet did not influence (P > 0.05) weight gain (WG), dry matter intake or dry matter digestibility; feed conversion, feed efficiency; and the evaluated nitrogen balance variables. The digestibility coefficient of neutral detergent fiber decreased linearly as Tifton 85 replacement for Cratylia level was increased, which probably happened due to the presence of highly lignified material within the Cratylia hay. However, the alternative legume maintained animal performance of Tifton 85. In conclusion, Cratylia hay can be recommended as a potential substitute for Tifton 85 hay, which requires greater inputs for the production. Cratylia may be considered a feeding strategy for livestock production, especially for smallholder livestock systems and regions with unfavorable soil and climate.

Research on the mechanism of plant root protection for soil slope stability.

In order to investigate the impact of herbaceous root development on soil slope stability in expansive soil areas, the research was conducted in the soil slope experimental area of Yaoshi Town, Shangzhou District, Shangluo City. Three types of herbaceous plants, namely Lolium perenne, Medicago, and Cynodon dactylon, were planted to examine their influence on slope stability. The results indicated that Lolium perenne had significantly higher root length density and root surface area density compared to Cynodon dactylon and Medicago. However, the root weight density of Cynodon dactylon was found to be highest. The roots of Lolium perenne, Cynodon dactylon, and Medicago were predominantly observed in diameter ranges of 0 < L ≤ 1.0 mm, 0 < L ≤ 2.5 mm, and 2.5 < L ≤ 3.0 mm, respectively. The roots of herbaceous plants have the ability to enhance water retention in soil, resist hydraulic erosion of slope soil, and reduce soil shrinkage and swelling. During the initial phase of herbaceous planting, there is an accelerated process of organic carbon mineralization in the soil. The roots of herbaceous plants play a crucial role in soil consolidation and slope protection. They achieve this by dispersing large clastic particles, binding small particles together, altering soil porosity, enhancing soil water retention, and reducing soil water infiltration. It was found that Lolium perenne and Medicago, which have well-developed roots, exhibited superior slope protection effects. These findings contribute to the theoretical understanding for the implementation of green ecological protection technology on soil slopes.

Bermudagrass mite (Acari: Eriophyidae) infestation worsens in response to increasing nitrogen fertility and decreasing irrigation volume but not mowing height.

Severe bermudagrass mite (Aceria cynodoniensis Sayed) infestation stunts turfgrass growth and reduces the aesthetic and recreational value of managed bermudagrass. Management practices, such as fertilization, mowing, and irrigation, may impact bermudagrass mite infestation and damage, but empirical evidence is lacking. Two 20 wk experiments were conducted with potted bermudagrass in a greenhouse or nursery to evaluate the effect of varying nitrogen rates (0, 24.5, or 49 kg N/ha), mowing heights (1.3, 2.5, 3.8, or 5 cm), and irrigation rates (60%, 100%, or 140% evapotranspiration [ET] rate) on the densities of witch's brooms (i.e., stunted and deformed terminals symptomatic of infestation) and bermudagrass mites. Increasing nitrogen fertility from 0 to 49 kg N/ha increased witch's broom and bermudagrass mite densities by 292% and 339%, respectively. Bermudagrass fertilized with nitrogen maintained higher turf quality than unfertilized grass despite greater mite damage. Decreasing irrigation from 140% to 60% of the ET rate also increased witch's broom densities by 124%. Mowing height did not consistently affect witch's broom or mite densities. Witch's broom and mite densities were positively correlated and followed a general trend with greater densities in April-August and a decline in densities in August-October. These findings suggest that nitrogen fertilization and water stress influence bermudagrass mite damage. Thus, limiting nitrogen fertilization to a level necessary to maintain turfgrass health and quality (0.5 kg N/ha) and minimizing turfgrass water stress can complement current chemical control strategies as part of an integrated pest management program.

Application of Three Compounds Extracted from Cynodon dactylon against Streptococcus mutans Biofilm Formation to Prevent Oral Diseases.

Streptococcus mutans bacteria form a biofilm called plaque that causes oral diseases, including tooth decay. Therefore, inhibition of biofilm formation is essential to maintaining good oral health. The health and nutritional benefits of Cynodon dactylon are well documented, but very little is known about its use to treat against oral diseases. The aim of this study was to detect the adhesion strength of the S. mutans bacterial biofilm in 100 cases in the Rajshahi region and evaluate the inhibitory activity of different compound extracts of C. dactylon on the S. mutans bacterial biofilm by determining the composition of isolated compounds using phytochemical analysis. Nuclear magnetic resonance (NMR) spectroscopy confirmed that three specific compounds from C. dactylon were discovered in this study: 3,7,11,15 tetramethyl hexadec-2-4dien 1-o1, compound 3,7,11,15 tetramethylhexadec-2-en-1-o1 from phytol derivatives, and stigmasterol. Results indicated that the compound of 3,7,11,15-tetramethyl-hexadec-2-en-1-ol exhibited higher antibiofilm activities on S. mutans than those of the other compound extracts. A lower level of minimum inhibitory concentration was exposed by 3, 7, 11,15 tetramethyl hexadeca-2-en-1-o1 (T2) on S. mutans at 12.5 mL. In this case, the compound of 3,7,11,15 tetramethyl hexadec 2en-1-o1 was used, and patients showed a mean value and standard error reduced from 3.42 ± 0.21 to 0.33 ± 0.06 nm. The maximum inhibition was (80.10%) in the case of patient no. 17, with a value of p < 0.05 found for S. mutans to which 12.5 µL/mL ethyl acetate extract was applied. From these findings, it may be concluded that C. dactylon extracts can be incorporated into various oral preparations to prevent tooth decay.

Differential Regulations of Antioxidant Metabolism and Cold-Responsive Genes in Three Bermudagrass Genotypes under Chilling and Freezing Stress.

As a typical warm-season grass, bermudagrass growth and turf quality begin to decrease when the environmental temperature drops below 20 °C. The current study investigated the differential responses of three bermudagrass genotypes to chilling stress (8/4 °C) for 15 days and then freezing stress (2/-2 °C) for 2 days. The three genotypes exhibited significant variation in chilling and freezing tolerance, and Chuannong-3, common bermudagrass 001, and Tifdwarf were ranked as cold-tolerant, -intermediate, and -sensitive genotypes based on evaluations of chlorophyll content, the photochemical efficiency of photosystem II, oxidative damage, and cell membrane stability, respectively. Chuannong-3 achieved better tolerance through enhancing the antioxidant defense system to stabilize cell membrane and reactive oxygen species homeostasis after being subjected to chilling and freezing stresses. Chuannong-3 also downregulated the ethylene signaling pathway by improving CdCTR1 expression and suppressing the transcript levels of CdEIN3-1 and CdEIN3-2; however, it upregulated the hydrogen sulfide signaling pathway via an increase in CdISCS expression under cold stress. In addition, the molecular basis of cold tolerance could be associated with the mediation of key genes in the heat shock pathway (CdHSFA-2b, CdHSBP-1, CdHSP22, and CdHSP40) and the CdOSMOTIN in Chuannong-3 because the accumulation of stress-defensive proteins, including heat shock proteins and osmotin, plays a positive role in osmoprotection, osmotic adjustment, or the repair of denatured proteins as molecular chaperones under cold stress. The current findings give an insight into the physiological and molecular mechanisms of cold tolerance in the new cultivar Chuannong-3, which provides valuable information for turfgrass breeders and practitioners.

Evaluation of zinc tolerance and accumulation in eight cultivars of bermudagrass (Cynodon spp.): implications for zinc phytoremediation.

Zinc (Zn) is a vital element for plant growth and development, however, excessive Zn is toxic to plants. Common bermudagrass (Cynodon dactylon (L.) Pers.) and hybrid bermudagrass (C. dactylon (L.) Pers. × C. transvaalensis Burtt-Davy) are widely used turfgrass species with strong tolerance to diverse abiotic stresses, including excessive Zn2+ stress. However, the variation of zinc tolerance and accumulation in different bermudagrass cultivars remain unclear. In this study, we systematically analyzed the growth performance, physiological index and ion concentration in eight commercial cultivars of common and hybrid bermudagrass under different concentration of Zn2+ treatments using pot experiments. The results indicated that four cultivars of common bermudagrass could tolerate 20 mM Zn2+, whereas four cultivars of hybrid bermudagrass could only tolerate 10 mM Zn2+. Among the four common bermudagrass cultivars, cultivar Guanzhong and Common showed stronger Zn tolerance and accumulation abilities than other two cultivars. Further analyses of the expression of selected Zn homeostasis-related genes indicated that bermudagrass cultivars with stronger tolerance to excessive Zn have at least one expression-elevated gene involved in Zn homeostasis. These results not only expanded our understanding of Zn tolerance and accumulation in bermudagrass but also facilitated the application of commercial bermudagrass cultivars in phytoremediation of Zn pollution.

Production of MgFe2O4/activated carbons derived from a harmful grass Cynodon dactylon and their utilization for ciprofloxacin removal.

Cynodon dactylon, an invasive species, exhibits its robust adaptability, reproduction and nutrient regime against the local species. Taking advantage of this harmful grass as a raw precursor to produce valuable materials for wastewater treatment has paid much attention. Herein, we report on the fabrication of Cynodom dactylon derived MgFe2O4@AC with a main goal of effective removal of ciprofloxacin antibiotic from water. Our findings showed that MgFe2O4@ACK1 composites attained mesoporous textures, high specific surface areas (884.3-991.6 m2 g-1), and MgFe2O4-20%@ACK1 was the most effective with a very high removal efficiency of 96.7%. The Elovich model was suitable for describing the kinetic of adsorption with (Radj)2 of 0.9988. Meanwhile, the isotherm data obeyed the Langmuir model corresponding to (Radj)2 of 0.9993. Qmax value of MgFe2O4-20%@ACK1 was determined at 211.67 mg g-1. The proposed adsorption mechanism primarily comprises five routes as follows, (i) pore-filling, (ii) π-π interaction, (iii) electrostatic interaction, (iv) hydrogen bonding, and (v) hydrophobic interaction. MgFe2O4-20%@ACK1 adsorbent could reuse with three cycles. We recommend that MgFe2O4/ACs derived from Cynodom dactylon could be high-efficiency adsorbents for the elimination of antibiotics.

Study on Cynodon dactylon root system affecting dry-wet cracking behavior and shear strength characteristics of expansive soil.

Expansive soil exhibits remarkable characteristics of water absorption expansion and water loss shrinkage, rendering it susceptible to cracking under the alternating dry-wet environments of nature. The generation and development of cracks in expansive soil can result in catastrophic engineering accidents such as landslides. Vegetation protection is an important approach to stabilizing expansive soil slopes and fulfilling ecological protection requirements. In this study, through indoor experiments and theoretical analysis methods, the effects of Cynodon dactylon roots on the crack development and shear strength of expansive soil subjected to dry-wet cycles were analyzed, and the relationship between the crack development and shear strength decay in root-doped expansive soil was explored. Furthermore, the mechanism of vegetative root system action was elucidated. The results show that the Cynodon dactylon root system exerts a significant inhibitory effect on crack development in expansive soil. The crack indexes of root-doped expansive soil exhibit significant phase characteristics during the process of dry-wet cycles. The crack-blocking and reinforcing effect of the root system becomes pronounced as the root-to-soil mass ratio increases and the root diameter decreased. Moreover, the process of crack development in expansive soil is accompanied by a decrease in soil shear strength. The quantitative relationship between crack development and shear strength decay can serve as a basis for predicting the stability of slope soil. Overall, the results highlight the potential of vegetation-based approaches in protecting slopes with expansive soils and have practical implications for ecological protection and engineering design in areas with expansive soils.

Dual metal ion (Fe3+ and As3+) sensing and cell bioimaging using fluorescent carbon quantum dots synthesised from Cynodon dactylon.

In this study, water dispersible fluorescent carbon quantum dot (CQD) has been synthesised, having an average size of 8.6 ± 0.4 nm using Cynodon dactylon (CD) following microwave assisted green synthetic one-step method. As-prepared CQD fluoresces strongly at 444 nm having a quantum yield of 1% in water when excited at 350 nm. This fluorescence of CQD is sensitive toward As3+ and Fe3+ metal ions. These CQD are utilized for dual metal ion fluorescence sensing; turn-on fluorescence sensing for As3+ and turn-off fluorescence sensing for Fe3+ ions. Limit of detection for As3+ and Fe3+ ions has been found to be 19 nM and 0.10 µM respectively, which is the lowest value reported for As3+ without any functionalization. The adsorption kinetics of As3+ and Fe3+ ions on CQD have been examined using pseudo-first-order-kinetic model revealing that physical adsorption is dominant over chemical processes in this work. For 0.41 g/L and 1.90 g/L dose of CQD, the equilibrium adsorption capacity was found to be 1.57 × 10-6 mg/g, 2.91 × 10-7 mg/g, and 1.01 × 10-5 mg/g, 1.69 × 10-6 mg/g respectively for As3+ and Fe3+ ions. Despite having low quantum yield in water, as-prepared CQD showed low cytotoxicity and good tolerance against photodegradation of biological cells at concentrations lower than 62.5 µg/mL and when the cells are illuminated up to 12 h. Owing to this, the synthesised CQD have been utilized as fluorescent probes for in itro cell imaging.

Enhanced Escherichia coli removal from stormwater with bermudagrass-derived activated biochar filtration systems.

Stormwater treatment and reuse can alleviate water pollution and scarcity while current sand filtration systems showed low treatment performance for stormwater. For enhancing E. coli removal in stormwater, this study applied the bermudagrass-derived activated biochars (BCs) in the BC-sand filtration systems for E. coli removal. Compared with the pristine BC (without activation), the FeCl3 and NaOH activations increased the BC carbon content from 68.02% to 71.60% and 81.22% while E. coli removal efficiency increased from 77.60% to 81.16% and 98.68%, respectively. In all BCs, the BC carbon content showed a highly positive correlation with E. coli removal efficiency. The FeCl3 and NaOH activations also led to the enhancement of roughness of BC surface for enhancing E. coli removal by straining (physical entrapment). The main mechanisms for E. coli removal by BC-amended sand column were found to be hydrophobic attraction and straining. Additionally, under 105-107 CFU/mL of E. coli, final E. coli concentration in NaOH activated BC (NaOH-BC) column was one order of magnitude lower than those in pristine BC and FeCl3 activated BC (Fe-BC) columns. The presence of humic acid remarkably lowered the E. coli removal efficiency from 77.60% to 45.38% in pristine BC-amended sand column while slightly lowering the E. coli removal efficiencies from 81.16% and 98.68% to 68.65% and 92.57% in Fe-BC and NaOH-BC-amended sand columns, respectively. Moreover, compared to pristine BC, the activated BCs (Fe-BC and NaOH-BC) also resulted in the lower antibiotics (tetracycline and sulfamethoxazole) concentrations in the effluents from the BC-amended sand columns. Therefore, for the first time, this study indicated NaOH-BC showed high potential for effective treatment of E. coli from stormwater by the BC-amended sand filtration system compared with pristine BC and Fe-BC.

Overexpression of CdtCIPK21 from triploid bermudagrass reduces salt and drought tolerance but increases chilling tolerance in transgenic rice.

Calcineurin B-like-interacting protein kinase (CIPK) is a serine/threonine kinase, which transmits the Ca2+ signal sensed by CBL proteins. A CdtCIPK21 showing highly identical to OsCIPK21 in rice was isolated from triploid bermudagrass (Cynodon dactylon × Cynodon transvaalensis). CdtCIPK21 transcript could be detected in roots, rhizomes, stems, stolons, and leaves, with highest level in roots. It was induced by salinity, dehydration and chilling, but reduced by ABA treatment. Transgenic rice plants overexpressing CdtCIPK21 had decreased salt and drought tolerance as well as ABA sensitivity but increased chilling tolerance. Lower SOD and CAT activities was observed in transgenic lines under salinity and drought stress conditions, but higher levels under chilling stress. Similarly, lower levels of proline concentration and P5CS1 and P5CS2 transcripts were maintained in transgenic lines under salinity and drought stresses, and higher levels were maintained under chilling. In addition, transgenic lines had lower transcript levels of ABA-independent genes (OsDREB1A, OsDREB1B, and OsDREB2A) and ABA responsive genes (OsLEA3, OsLIP9, and OsRAB16A) under salinity and drought but higher levels under chilling compared with WT. The results suggest that CdtCIPK21 regulates salt and drought tolerance negatively and chilling tolerance positively, which are associated with the altered ABA sensitivity, antioxidants, proline accumulation and expression of ABA-dependent and ABA-independent stress responsive genes.

Leaf Cuticular Waxes of Bermudagrass Response to Environment-Driven Adaptations of Climate Effect Inferred from Latitude and Longitude Gradient in China.

Bermudagrass (Cynodon dactylon) is a widely used warm season lawn grass. Cuticular wax covering the surface of plant leaves plays an important role in helping plants resist biotic and abiotic stresses. We analyzed the changes of cuticle wax in 25 bermudagrass populations from different longitude and latitude gradients, in order to verify how environmental conditions affect the structure and chemical composition of cuticle wax. Five wax components were identified, including alkanes, esters, alkenes, aldehydes and primary alcohols. The wax characteristics were divided into two principal components, explaining 58.2 % and 66.7 % of the total variability in latitude and longitude, even some populations had a certain correlation with each other. Pearson correlation analysis further showed that the total wax coverage, wax component content and antioxidant enzyme activity of bermudagrass populations on the latitudinal gradient had different responses to environmental factors. Finally, nineteen key genes involved in wax biosynthesis, redox and photosynthesis were identified and verified by RT-qPCR. The results showed that the responses of bermudagrass in different populations to climate change were quite different, which was of great significance for the evolution of bermudagrass populations.

Water deficits shape the microbiome of Bermudagrass roots to be Actinobacteria rich.

There is increasing evidence that microbes can help ameliorate plant growth under environmental stress. Still, it is largely unknown what microbes and potential functions are involved in sustaining turfgrass, the major component of urban/suburban landscapes, under drought. We examined microbial responses to water deficits in bulk soil, rhizosphere, and root endosphere of bermudagrass by applying evapotranspiration (ET)-based dynamic irrigation twice per week during the growing season to create six treatments (0%, 40%, 60%, 80%, 100%, and 120% ET) and respective drought-stressed soil conditions. Bacterial and fungal communities were analyzed via marker gene amplicon sequencing and thereafter drought-reshaped potential functions of the bacterial community were projected. Slight yet significant microbial responses to irrigation treatments were observed in all three microhabitats. The root endophytic bacterial community was most responsive to water stress. No-irrigation primarily increased the relative abundance of root endophytic Actinobacteria, especially the genus Streptomyces. Irrigation at ≤40% ET increased the relative abundances of PICRUSt2-predicted functional genes encoding 1-aminocyclopropane-1-carboxylic acid deaminase, superoxide dismutase, and chitinase in root endosphere. Our data suggest that the root endophytic Actinobacteria are likely the key players to improve bermudagrass fitness under drought by modulating phytohormone ethylene production, scavenging reactive oxygen species, or ameliorating nutrient acquisition.

Effects of mowing on Pb accumulation and transport in Cynodon dactylon (L.) Pers.

Bermudagrass is a perennial herb with the potential to remediate Pb pollution in soils, and it has mechanical resistance to shearing. However, the effects of mowing on Pb absorption and accumulation in bermudagrass are still unclear. In this study, we investigated the effects of different quantities (0, 1, 2, 4 applications) of mowing treatments under 200 mg L-1 Pb application on Pb accumulation and transport in bermudagrass and explored the related mechanisms. Compared to the Pb treatment, all of the mowing treatments greatly decreased root Pb concentration/accumulation, significantly enhanced Pb concentrations/accumulations in stubble stems and stubble leaves, and ultimately promoted Pb enrichment and transport. Of the treatments in this study, two applications of mowing best promoted Pb enrichment, and four applications of mowing best promoted Pb transport efficiency. Furthermore, mowing mediated the microdistribution and physiological patterns of Pb in bermudagrass and affected the Pb transport by changing the subcellar distribution patterns and chemical forms of Pb in various tissues. Additionally, mowing promoted the transport of all mineral elements and showed a synergistic relationship with Pb absorption and transport. The change in mineral element metabolism patterns may be an important reason why mowing promoted Pb accumulation in bermudagrass. Our study provides the first comprehensive evidence regarding mowing facilitating the absorption, accumulation and transport of Pb in bermudagrass. Moderate mowing may be an effective strategy to assist in soil Pb remediation using bermudagrass.