Commelina Communis Research Articles

The chloroplast genome sequence of Commelina communis (Commelinaceae)

Commelina communis is a hyperaccumulator on heavy metal with high drought resistance and endurance. Using Illumina next-generation sequencing data, its chloroplast genome is assembled and characterized. The complete chloroplast genome is 159,664 bp in length, consisting of a pair of inverted repeats (IRs) of 26,146 bp each, an 88,854 bp large single-copy (LSC) region and an 18,518 bp small single-copy (SSC) region. It has 137 genes in total, comprising 81 unique protein-coding genes, 32 unique tRNA genes, and 7 rRNA genes. Phylogenetic analysis based on the complete chloroplast genome sequences indicates that C. communis is sister to Belosynapsis ciliata among species with available chloroplast genome sequences.

Development of microsatellite markers for the annual andromonoecious herb Commelina communis f. ciliata (Commelinaceae).

Commelina communis f. ciliata (Commelinaceae), a newly distinguished taxon, is an annual andromonoecious herb exhibiting a mixed mating system, the details of which remain unclear. We developed microsatellite markers for use in exploring the evolution of andromonoecy and mixed mating in the species. Fifteen microsatellite loci were developed using next-generation sequencing. The primer sets were used to evaluate 65 C. communis f. ciliata individuals from three populations in Japan; we found 1-13 alleles per locus and the expected heterozygosity ranged from 0.00 to 0.76. The markers are potentially useful to examine intra- and interspecies genetic structure and the mixed mating strategy of Commelina species via paternity analysis.

Test results of the new herbicide Flex in soybean crops in Primorsky Territory

The biological and economic efficiency of the new herbicide Flex in post-emergence application to soybean crops of the variety Sphera was studied. The tests were carried out incompliance with the standard methods in the form of the plot experiment in 2017, 2018 on brown meadow podzolized soils in the south of the Far East. The preparation was tested in the consumption rates of 1.25 and 1.5 l/ha when the crop reached the development phase of two triple leaves as opposed to the standard herbicide Galaxy Top in the rate of 1.7 l/ha. It was found that Flex has a high herbicidal activity against all dicotyledonous annual and perennial species of weeds. Common ragweed (Ambrosia artemisiifolia L.) and Asian copperleaf (Acalypha australis L.) were highly sensitive to the preparation even in the minimum consumption rate. Especially strong toxic effect of Flex was produced on such weeds in the rosette phase as Asiatic dayflower (Commelina communis L.), lamb’s quarters (Chenopodium album L.), field milk thistle (Sonchus arvensis L.), creeping thistle (Cirsium setosum (Willd.) Bieb.) and common mugwort (Artemisia vulgaris L.). Consistent application of graminicide Fuzilade Forte in the rate of 1.5 l/ha after treatment of soybean crops with herbicide Flex contributed to an almost complete elimination of annual grass weeds. The high biological efficiency of the experimental preparation contributed to a significant increase in crop yield. In 2018, when it was applied in the minimum rate of 1.25 l/ha, the yield achieved was 0.94 t/ha, exceeding the control value by 3.3 times. The highest yield increase of soybean seeds (1.12 t/ha on average for 2 years) was obtained with the use of herbicide Flex in the maximum consumption rate of 1.5 l/ha. Application of herbicide Flex to soybean crops in the rates of 1.25 and 1.5 l/ha alongside with the preparation Trend 90 in the rate of 0.2 l/ha proved to be highly effective in eliminating annual and perennial dicotyledonous weeds (in early stages of development) from soybean crops.

Prior selfing can mitigate the negative effects of mutual reproductive interference between coexisting congeners

Abstract When more than one closely related plant species share the same pollination niche, reproductive interference via interspecific pollen transfer should limit their coexistence. However, some studies have reported the sympatric coexistence of two native close relatives pollinated by the same pollinators under reproductive interference, even without niche partitioning. We examined the frequency dependency of reproductive interference between close relatives in natural conditions and the potential roles of autonomous selfing in mitigating the negative reproductive interference effects between congeneric species. We investigated sympatrically growing Commelina communis (Cc) and C. c. f. ciliata (Ccfc) populations. These species exhibit very large overlaps in habitat preference, flowering phenology and pollination niche, but seldom produce hybrids. First, we conducted a hand‐pollination experiment to examine the negative effects of heterospecific pollen deposition on seed production and the potential of self‐pollination to mitigate the effects in both species. Then, we examined the effects of reproductive interference on reproductive success and the potential for autonomous selfing in the field. We found significant negative effects of heterospecific pollen deposition on seed production and the mitigation effects of prior and competing self‐pollination, in both Cc and Ccfc. For both species in the field, intraspecific pollinator movements and reproductive success significantly decreased with an increase in the relative floral abundance of competing species, although the negative reproductive interference effect on reproductive success was lower in Cc than in Ccfc. We also found greater potential for prior autonomous selfing in Cc than in Ccfc. Our findings suggest that Cc flowers were less affected by reproductive interference from competing species, which was likely due to a higher prior selfing ability compared to Ccfc flowers. The asymmetry in susceptibility to reproductive interference may explain the Cc‐biased distribution in the study area. The study improves our understanding of how prior autonomous selfing can reduce the negative reproductive interference effect from competing species in mixed‐mating species with frequent pollinator visits. A plain language summary is available for this article.

Weed management effect to increase grain yield in dry direct-seeded rice

An experiment was conducted during Kharif 2016 and 2017 at Agricultural Research Station, Dhadesugur, University of Agricultural Sciences, Raichur, Karnataka, India, to study the bio-efficacy of weed control practices on weeds and grain yield of dry-seeded rice. The dominant grassy weeds in fields were Echinochloa sp. Panicum repens, Cynodon dactylon, Bracharia mutica, Digitarias sanguinalis, Commelina communis and Leptochloa chinensis. Broad-leaf weeds were Eclipta alba, and Ludwigia parviflora and Cyperus sp. as sedge. Results revealed that, pre-emergence application of pretilachlor + pyrazosulfuron-ethyl (600 + 15 g/ha) recorded significantly lower weed dry weight at 15, 30 and 45 DAS during Kharif 2016 and 2017, higher weed control efficiency at 15, 30 and 45 days after sowing (DAS) (82.6, 80.2 and 80.6% during Kharif 2016 and 82.1, 82.7 and 80.2%, respectively during Kharif 2017, respectively) and higher rice grain yield (4.92 and 4.98 t/ha during Kharif 2016 and 2017, respectively) and which was at a par with twice hand weeding at 20 and 40 DAS.

Confirmation of mesophyll signals controlling stomatal responses by a newly devised transplanting method

There are opposing views on whether the responses of stomata to environmental stimuli are all autonomous reactions of stomatal guard cells or whether mesophyll is involved in these responses. Transplanting isolated epidermis onto mesophyll is a potent methodology for examining the roles of mesophyll-derived signals in stomatal responses. Here we report on development of a new transplanting method. Leaf segments of Commelina communis L. were pretreated in the light or dark at 10, 39 or 70Pa ambient CO2 for 1h. Then the abaxial epidermises were removed and the epidermal strips prepared from the other leaves kept in the dark at 39Pa CO2, were transplanted onto the mesophyll. After illumination of the transplants for 1h at 39Pa CO2, stomatal apertures were measured. We also examined the molecular sizes of the mesophyll signals by inserting the dialysis membrane permeable to molecules smaller than 100-500Da or 500-1000Da between the epidermis and mesophyll. Mesophyll pretreatments in the light at low CO2 partial pressures accelerated stomatal opening in the transplanted epidermal strips, whereas pretreatments at 70Pa CO2 suppressed stomatal opening. Insertion of these dialysis membranes did not suppress stomatal opening significantly at 10Pa CO2 in the light, whereas insertion of the 100-500Da membrane decelerated stomatal closure at high CO2. It is probable that the mesophyll signals inducing stomatal opening at low CO2 in the light would permeate both membranes, and that those inducing stomatal closure at high CO2 would not permeate the 100-500Da membrane. Possible signal compounds are discussed.

THE EFFECIENCY OF LEAF EFFECT HERBICIDES FOR CORN CROPS

The efficiency of leaf effect herbicides in corn crops was studied. The study was carried out in 2001–2016 in the experimental fields of Primorye on brown meadow podzolized soils containing 3-4% of humus in the arable horizon. In 2001–2010 corn of hybrid population Slavyanka was sown and in 2015–2016 – ZPTK196, with a seeding rate of 70.000 seeds/ha. Herbicides Milagro (1.0 and 1.5 l/ha), Titus (0.04 kg/ha), Cordus (0.04 kg/ ha) and Doublon Gold (0.07 kg/ha) in tank mixture with Luvaram (0.82 l/ha) or Dianatom (0.4 l/ ha) enhanced the effect of preparations on weed plants, especially on common ragweed (Ambrosia artemisiifolia). Biological efficiency increased to 74–90%, and yield – by 0.43–1.80 t/ha. The use of herbicide Basis (0.02 and 0.025 kg/ha) led to the increase in corn grain yield to 1.43–2.06 t/ ha. Resistant to this herbicide was dayflower (Commelina communis), which, due to the lack of other weeds, increased the above-ground mass to 1.3 kg / m2.. The application of herbicide MaisTer provided the yield increase up to 2.09–2.41 t/ha. It was observed that for more reliable suppression of common ragweed, herbicide MaisTer (0.125 and 0.15 kg/ha) should be used no later than the phase of three pairs of leaves when the air temperature does not exceed 200C. The herbicides Titus Plus (0.34 and 0.38 kg/ha) and Stellar (1.5l/ ha) almost completely purified the corn from weeds, which contributed to the preservation of 2.07–3.59 t/ha of corn.

EVALUATION OF TANK MIXTURES OF HERBICIDES PROPONIT AND PLEDGE WHEN APPLIED BEFORE EMERGENCE OF SOYBEANS

The work presents the results of testing tank mixtures of herbicides Proponit and Pledge applied in different doses to soybean crops during preemergence Treatment. The tests were carried out in Primorsky territory by standard methods in the form of the plot experiment in the trial field with brown meadow podzolized soils (by mechanical composition characterized as medium clay, content of humus 3.8%, labile phosphorus and exchange potassium in the soil 16 and 120 mg/kg respectively, PH 5.3). Hydrothermal conditions during the experiment were favorable for the implementation of the herbicidal potential of soil preparations. Trial tank mixtures showed high herbicidal activity against annual grass weeds (Echinochloa crusgalli, Setaria spp), annual dicotyledonous species (Ambrosia artemisiifolia, Acalypha australis, Abutilon theophrasti, Elsholtzia pseudocristata, Chenopodium album), Commelina communis and certain perennial dicotyledonous weeds. The use of mixtures of Proponit and Pledge in higher doses contributed to an increase in protective action and increase in the total herbicidal activity of preparations. The highest yield of soybean in the experiment, 2.41 t/ha, which exceeded the control value by 3.5 times, was achieved in the variant of the soil treatment with a mixture of herbicides in the maximum recommended rates (Proponit 3.0 l/ ha + Pledge 0.12 kg/ha). The economic efficiency of chemical weeding amounted to 39.0 thousand rubles/ha. Thus, in the conditions of soya crops contamination mainly by sensitive annual weed species and with optimal soil moisture, preemergence use of Proponit + Pledge tank mixtures was sufficient for reliable protection of soybean crops and eliminated the need for foliar herbicides.

Genetic diversity and population structure of Commelina communis in China based on simple sequence repeat markers

Commelina communis (Asiatic dayflower) is a troublesome weed in China. Genetic variation of 46 C. communis populations from different collection sites in our country was investigated using 12 simple sequence repeat (SSR) primer pairs. Polymorphism analysis results showed high level of genetic diversity among these populations. The alleles (bands) were amplified by these primer pairs. The polymorphic proportion was 18.25%, and the average polymorphism information content was 0.1330. The highest effective number of alleles was 1.9915 at locus YP33, and the lowest value was 1.0000 at both loci YP25 and YP31. C. communis showed major average observed heterozygosity value (0.8655) than that of average expected heterozygosity (0.1330). C. communis populations were divided into three groups on the basis of unweighted pair-group method with arithmetic mean cluster analysis (Dice genetic similarity coefficient=0.772) and genetic structure analysis (K=3), and a principal coordinate analysis. The results of this study further illustrated that C. communis populations contained abundant genetic information, and the 12 SSR markers could detect the microsatellite loci of C. communis genomic DNA. These results might indicate that C. communis maintains high genetic diversity among different populations.

Comparative Analysis of Genetic Variation of Cucumber Mosaic Virus from Commelina communis in Korea

Three isolates of Cucumber mosaic virus isolated from Commelina communis plants showing chlorosis and mosaic were collected in Chungju and Chuncheon, Korea. To confirm genetic variation of these three isolates (CMV-Co, CMV-Co2, and CMV-Co3), we performed PCR-RFLP and sequence analysis. Sequences of coat protein genes of CMV-C0, -Co2 and -Co3 were compared with CMV-Fny and showed 96.3%, 96.3%, and 95.9% similarities, respectively. In host reactions, three CMV-Co isolates induced systemic necrosis in Cucurbita pepo unlike CMV-Fny and CMV-Co, CMV-Co2 and CMV-Co3 observed differential symptoms responses in Physalis angulata and Nicotiana rustica. These results indicated that three isolates of CMV isolated from C. communis have genetic and biological variation.

Study on weed flora in Major Kharif crops of ashoknagar district

A servey of weed flora studies in kharif season was conducted during year of 2017 major kharif crops were soybean blackgram, maize and rice crops of Ashok Nagar district. On the basis of result it was found that the Commelina bengalensis, Celosia argentia, Digra arvensis, Uphorbia jeniculata and Pathenium hysterophorus were the major weeds of soybean crops. Digra arvensis, Cynodon dactylon, Commelina bengalensis, Celosia argentia and Pathenium hysterophorus were the major weed of blackgram crops. Eichnoacloa crusgulli, Commelina communis, Cyprus Rotundus, Eichnoacloa, Colonum, and Eshemum, Rugosum were the major weeds of rice crop. Dactylectimium egyptium, Cynodon dectylon, Cyprus rotundus, Eclipta alba and Uhorbia hirta were the major weeds of maize crop in Ashoknagar district.

Simultaneous Qualitative and Quantitative Study of Main Compounds in Commelina communis Linn. by UHPLC-Q-TOF-MS-MS and HPLC-ESI-MS-MS.

This study reported the identification and determination of the main components of Commelina communis Linn. A total of 62 compounds were identified in C. communis Linn. extract, which included 29 flavonoids and flavonoid glycosides, 17 phenolic acids, 4 alkaloids, 1 pyrimidine alkaloids, 3 sterols and 8 fatty acids and others by ultra high performance liquid chromatography coupled with hybrid triple quadrupole time-of-flight mass spectrometry. Moreover, a specific, simple, rapid and sensitive high performance liquid chromatography with tandem mass spectrometry method was developed and validated for determination of 13 components of C. communis Linn., which included orientin, iso-orientin, vitexin, isovitexin, rutin, apigenin, protocatechuate, vanillic acid, caffeic acid, ferulic acid, luteolin, quercetin and isorhamnetin. All calibration curves showed good linearity (r ≥ 0.9991) within the test range. The intra- and inter-day precisions (relative standard deviation%, RSD%) were within 1.04 and 0.92%, and the recoveries ranged from 98.64 to 100.8%. These results may contribute to the further study and quality control for C. communis Linn.

Suppression of Fatty Acid and Triglyceride Synthesis by the Flavonoid Orientin through Decrease of C/EBPδ Expression and Inhibition of PI3K/Akt-FOXO1 Signaling in Adipocytes.

Plant flavonoids have a variety of biological properties. In a previous study, we found that the tea of the Asian dayflower, Commelina communis L., decreased the body weight gain in high-fat diet-fed mice. In this study, we studied the anti-adipogenic ability of a flavonoid orientin that is found in abundance in C. communis. Orientin repressed the accumulation of intracellular triglyceride (TG) in mouse adipocyte 3T3-L1 cells. The treatment with orientin also decreased the mRNA levels of the genes involved in adipogenesis, lipogenesis, lipolysis, and TG synthesis, and reduced the release of glycerol. Orientin lowered the expression of CCAAT/enhancer binding protein (C/EBP) δ in the early stage of adipogenesis, leading to a decrease in the expression of the adipogenic master transcription factors such as peroxisome proliferator-activated receptor (PPAR) γ and C/EBPα. Moreover, the anti-adipogenic effect of orientin repressed the phosphorylation of Akt and subsequent phosphorylation of forkhead box protein O1 (FOXO1), which inhibits the transcription of the Ppar gene. These results indicate that a plant flavonoid orientin suppressed the expression of the Pparγ gene through repression of C/ebpδ expression and inhibition of the phosphoinositide 3-kinase /Akt-FOXO1 signaling in adipocytes.

A comparative study on the efficiency of biodegradable EDDS and micro-electric field on the promotion of the phytoextraction by Commelina communis L. in Cu-contaminated soils

Phytoextraction has been considered as an attractive option technique for the remediation of heavy metals contaminated soils. In this study, Commelina communis L. (Control), and plant with EDDS (5mmolkg−1) or micro-electric field (0.5Vcm−1) was performed to treat Cu-contaminated soils spiked by Cu content of 0, 100, 200, 400, 600mgL−1. Compared with the Control system, when biodegradable chelant of EDDS or micro-electric field were applied into treatments, the concentration of accumulated Cu, increased by 15%–47%, and 65%–79%, respectively, in the shoots of plants. While it increased by 16%–86% and 28%–38%, respectively, in the roots of plants. Highest Cu accumulation in shoot and root of plant under micro-electric field was 78.7 and 2068.9mgkg−1. In addition, copper was strongly inhibited the growth and metabolism under a higher Cu concentration (>200mgL−1) due to the disorder of water and nutrients acquisition and use. Hence, the enzyme activities (MDA and POD) of leaves and the concentrations of soluble carbohydrate significantly increased with the application of EDDS or micro-electric filed compared with the Control system. These results indicate that the use of micro-electric field is more effective treatment for the remediate the Cu-contaminated soils compared with the biodegradable chelant of EDDS.

Detecting nutrient deficiency in plant systems using synchrotron Fourier-transform infrared microspectroscopy

By 2050, it is estimated that the global population will have surpassed 9 billion people, presenting a significant challenge with regards to food security. In order to provide sufficient quantities of nutritious food in the future, it is necessary to improve agricultural productivity by up to 70%. Nutrient deficiencies are one particular threat to food security that can have a negative impact on crop yield and quality. Currently the standard agricultural approach to prevention is to supply an excess of macronutrient fertiliser, such as nitrate or phosphate, during crop production. However, the efficiency of this approach is poor as deficiencies of specific nutrients, such as Ca, are not prevented in this circumstance, and fertiliser use is associated with a host of adverse environmental impacts. Herein, we describe a novel method to detect Ca deficiency using synchrotron radiation-based Fourier-transform infrared (FTIR) microspectroscopy in live and fixed tissue of the model plant Commelina communis, as a precursor to targeted nutrient remediation in the field.

식물에서 기공 형태에 대한 오해와 진실

The walls of guard cells have many different specialized features. Guard cells are present in leaves of bryophytes, ferns and almost all of the vascular plants. Guard cells show considerable morphological diversities. It is understood that the stomata show two types in terms of morphological characterizations of guard cells. The first type is only found in a few monocots including Poaceae and Cyperaceae. In rice and corn, guard cells have the morphological characteristics of dumbbell shape. The morphological characteristics of dumbbell shape always have subsidiary cells. The other type is found in every dicots and many monocots and they are kidney-shaped guard cells. The plants of kidney-shaped guard cells rarely have subsidiary cells except Commelina communis L. Therefore, it could be concluded that two types of the morphological characteristics of guard cells cannot divide according to monocots or dicots. Every plants in which stomatal characteristic features were all different, most of them belong to kidney-shaped guard cells. However in case of Sedum sarmentosum, guard cells were shown to be long and narrow lips type. In Tradescantia virginiana, the shape of guard cells could be called perfectly to half-moon type. Therefore, it could be concluded that kidney-shaped types are all different in some way, but dumbbell-shaped types are almost constant.

전남 장성지역 한국잔디 재배지 잡초발생 현황

본 연구는 전라남도 장성지역의 한국잔디 재배지의 발생 잡초를 확인하기 위하여 2014년 9월(1차 조사)과 2016년 5월(2차 조사)에 전남 장성군 삼서면 일대에서 한국잔디 재배포장을 밭 토양과 논 토양으로 구분하여 발생잡초 분포조사를 수행하였다. 잡초분포 조사결과 밭 토양에서는 27과 66종(일년생 49종, 다년생 17종)으로 일년생잡초 74.2%, 다년생잡초 25.8%의 발생을 확인하였다. 과별로 보면 국화과(Compositae)가 19.7%로 가장 많이 발생하였고, 그 다음으로 벼과(Gramineae) 13.6%, 콩과(Leguminosae) 10.6% 순이었다. 논 토양에서는 22과 69종(일년생 53종, 다년생 16종)으로 일년생잡초 76.8%, 다년생잡초 23.2% 비율의 발생을 확인하였다. 과별로 보면 국화과(Compositae)가 18.8%로 가장 많이 발생하였고, 그 다음으로 벼과(Gramineae) 14.5%, 사초과(Cyperaceae) 7.2% 순이었다. 밭 토양의 1차 조사에서는 벼과의 바랭이(8.49), 2차 조사에서는 괭이밥과의 괭이밥(7.26)이 가장 우점하였고, 논 토양의 1차 조사에서 국화과의 개망초(9.52), 2차 조사에서는 닭의장풀과의 닭의장풀(5.08)과 벼과의 뚝새풀(5.08)이 가장 우점하는 잡초종으로 확인되었다. 잡초발생 현황을 조사시기와 토양조건을 구분하여 비교한 결과 논 잡초와 밭 잡초가 혼생하는 것으로 확인되었다. 조사시기 또는 토양조건에 상관없이 공통적으로 발생하는 초종의 비율이 49.2%로 비교적 높게 나타났다. 따라서 한국잔디 재배지에서 제초제를 이용한 효율적인 방제효과를 위해서는 재배토양에 상관없이 논 잡초와 밭 잡초를 모두 잘 방제할 수 있는 약제를 선택해야 할 것으로 판단되었다. This study was conducted to provide basic information for weed control by surveying the occurrence of weed species in turf sod production areas. Surveys of weed species occurred in turf sod production areas were conducted in Jangsung-gun, Jeonnam province from September 2014 to May 2016. Total 50 sites of turf sod production areas in two soil conditions were investigated. On the upland soil condition in turf sod production areas, 66 weed species in 27 families were identified and classified to 49 annuals and 17 perennials and on the paddy soil condition, 69 weed species in 22 families were identified and classified to 53 annuals and 16 perennials. Based on the importance values, the most dominant weed species on the upland soil condition in the first survey (September 2014) was Digitaria ciliaris (8.49%), followed by Erigeron annuus (7.94%) and Rorippa indica (6.56%). In the second survey (May 2016) was Oxalis corniculata (7.26%), followed by Capsella bursa-pastoris (6.21%) and Conyza canadensis (6.21%). Whereas the most dominant weed species on the paddy soil condition in the first survey (September 2014) was Erigeron annuus (9.52%), followed by Mazus pumilus (7.41%) and Cyperus iria (6.82%). In the second survey (May 2016) was Commelina communis (5.08%), followed by Alopecurus aequalis (5.08%) and Erigeron annuus (4.79%). This information could be useful for estimation of future weed occurrence and effective weed control methods in turf sod production areas in Jangsung-gun, Jeonnam Province.

1-Deoxynojirimycin: Occurrence, Extraction, Chemistry, Oral Pharmacokinetics, Biological Activities and In Silico Target Fishing.

1-Deoxynojirimycin (DNJ, C6H13NO4, 163.17 g/mol), an alkaloid azasugar or iminosugar, is a biologically active natural compound that exists in mulberry leaves and Commelina communis (dayflower) as well as from several bacterial strains such as Bacillus and Streptomyces species. Deoxynojirimycin possesses antihyperglycemic, anti-obesity, and antiviral features. Therefore, the aim of this detailed review article is to summarize the existing knowledge on occurrence, extraction, purification, determination, chemistry, and bioactivities of DNJ, so that researchers may use it to explore future perspectives of research on DNJ. Moreover, possible molecular targets of DNJ will also be investigated using suitable in silico approach.

Geography Plays a More Important Role than Soil Composition on Structuring Genetic Variation of Pseudometallophyte Commelina communis.

Pseudometallophytes are excellent models to study microevolution and local adaptation to soil pollution, as they can grow both on metalliferous and contrasting non-metalliferous soils. Although, there has been accumulating evidence for the effects of edaphic conditions and geographical isolation on the genetic structure of pesudometallophytes, it is still a difficult problem in evolutionary biology to assess their relative importance. In this study, we investigated the spatial patterns of genetic variability, population differentiation and genetic groups in pseudometallophyte Commelina communis with 12 microsatellite loci. Eight metallicolous and six non-metallicolous populations of C. communis were sampled from cupriferous sites and surrounding non-contaminated areas in China. Neither significant reduction in genetic diversity nor apparent founder and bottleneck effects were observed in metallicolous populations of C. communis. Based on Bayesian and Neighbor-Joining clustering analyses and a principal coordinates analysis, all sampled populations were found to be mainly separated into three genetic groups, corresponding well to their geographical locations rather than edaphic origins. Moreover, a significant and strong correlation between population genetic divergence and geographical distance were detected by Mantel test (r = 0.33; P < 0.05) and multiple matrix regression with randomization (MMRR; βD = 0.57, P < 0.01). However, the effect of copper concentration on genetic patterns of C. communis was not significant (MMRR; βE = -0.17, P = 0.12). Our study clearly demonstrated that the extreme edaphic conditions in metalliferous areas had limited effects on the genetic variability in C. communis. Geographic distance played a more important role in affecting the genetic structure of C. communis than soil composition did. In C. communis, the geographically disjunctive populations on metalliferous soils had multiple origins and evolved independently from nearby non-metallicolous populations.

Effect of copper tolerant Elsholtzia splendens on bacterial community associated with Commelina communis on a copper mine spoil

Facilitation, or positive plant–plant interaction, has received increasing concern from ecologists over the last two decades. Facilitation may occur through direct mitigation of severe environments or indirect mediation by a third participant from the same or different trophic levels. The copper (Cu) tolerant species Elsholtzia splendens facilitates the establishment and growth of co-occurring Commelina communis through indirect enrichment of microbial activity. However, whether and how E. splendens impacts the microbial community that is associated with C. communis is less known. We characterized the soil bacterial community in the rhizosphere of C. communis in the absence and presence of E. splendens using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) and sequencing. The result showed that the richness of the bacterial community increased, but diversity and evenness remained similar, in the presence of E. splendens. Chloroflexi, Acidobacteria and Proteobacteria were the most dominant bacteria. The relative abundance of dominant and minor bacterial groups showed distinctly different responses to E. splendens. Principal component analysis and redundancy analysis indicated that variation of the bacterial community was determined by multiple factors and might be driven by the tested soil parameters collectively, or alternatively changed through plant root exudates or other microorganisms. Our results enhance the understanding of how the bacterial community associated with a beneficiary plant responds to a benefactor plant and suggests that the changes of bacterial community composition may have far-reaching influence on plant–soil feedback and the aboveground plant community in the long run.