Search Result

Select

Linking atmospheric emission and deposition to accumulation of soil cadmium in the Middle-Lower Yangtze Plain, China

TANG Li-li, FU Bo-min, WU Yang, CAI Fu-chen, MA Yi-bing

2023, 22 (10): 3170-3181. DOI: 10.1016/j.jia.2023.05.016

Abstract （190） PDF in ScienceDirect

Cadmium (Cd) is one of the most toxic heavy metals in the environment. Atmospheric deposition has been found to be the main source of Cd pollution of soil on a large scale in China, and identification of the relationships between anthropogenic emission, atmospheric deposition, and Cd accumulation in soil is important for developing ways to mitigate Cd non-point pollution. In this study, the relationship between atmospheric emission, atmospheric deposition, and soil Cd accumulation in the Middle-Lower Yangtze Plain in China was investigated using datasets of atmospheric emission, deposition, and soil accumulation from the literatures published between 2000 and 2020. The results showed that the soil Cd accumulation rate in the study area exceeded the national average (4.0 μg kg^–1 yr^–1) and continued to accumulate in recent decades, although the average accumulation rate decreased from 9.45 μg kg^–1 yr^–1 (2000–2010 period) to 8.86 μg kg^–1 yr^–1 (2010–2020 period). The contribution of atmospheric deposition flux to Cd increment in the soil was in the range of 22–29%, with the atmospheric deposition flux decreasing from 0.54 mg m^–2 yr^–1 (2000–2010) to 0.48 mg m^–2 yr^–1 (2010–2020), both values being greater than the national average. Atmospheric Cd deposition and emission were highly correlated in a provincial administrative region, which is close to a ratio of 1.0. Emission factors may be in a state of dynamic change due to the influences of new Cd emission control technologies and environmental policies. As the main sources of Cd emissions, dust, and smoke emissions per ton of non-ferrous metal production decreased by 64.7% between the 2000–2010 and 2010–2020 periods. Although new environmental policies have been instigated, atmospheric emission of Cd is still excessive. It was hoped that the findings of this work would provide a scientific basis for the rational control of atmospheric emissions and Cd pollution of soil.

Reference | Related Articles | Metrics

Select

A transferred regulator that contributes to Xanthomonas oryzae pv. oryzicola oxidative stress adaptation and virulence by regulating the expression of cytochrome bd oxidase genes

WANG Pei-hong, WANG Sai, NIE Wen-han, WU Yan, Iftikhar AHMAD, Ayizekeranmu YIMING, HUANG Jin, CHEN Gong-you, ZHU Bo

2022, 21 (6): 1673-1682. DOI: 10.1016/S2095-3119(21)63801-7

Abstract （392） PDF in ScienceDirect

Horizontal gene transfer (HGT) has been well documented as a driving force in the evolution of bacteria. It has been shown that a horizontally acquired gene, xoc_2868, involved in the global response against oxidative stress and pathogenicity of Xanthomonas oryzae pv. oryzicola strain BLS256. However, as a transcriptional factor (TF), the regulatory mechanism of XOC_2868 has not yet been revealed. Here, evolutionary analysis suggested XOC_2868 might be co-transferred with its physically proximate downstream genes from a Burkholderiaceae ancestor. Interestingly, RNA-seq data of wild-type (BLS256) and Δxoc_2868 strains under oxidative stress showed that XOC_2868 did not regulate the expression of its adjacent genes, but remarkably influenced the expression of several genes involved in the extracellular polysaccharide (EPS) production and xanthan biosynthesis. Chromatin immunoprecipitation-sequence (ChIP-seq) combined with transcriptome analysis revealed that XOC_2868 directly regulates a cydAB operon, encoding two subunits of cytochrome bd oxidase and involved in redox balance. Consistent with Δxoc_2868 strain, cydA- and cydAB-knockout mutants also showed a higher sensitivity to H₂O₂ along with a reduced bacterial virulence compared with the wild-type strain. Overall, our findings raise the possibility of regulatory circuit evolution shaped by HGT and driven by selection and reveal a novel regulatory pathway that regulates the expression of cytochrome bd oxidase and thus contributes to the virulence of BLS256.

Reference | Related Articles | Metrics

Select

Neopestalotiopsis eucalypti, a causal agent of grapevine shoot rot in cutting nurseries in China

MA Xuan-yan, JIAO Wei-qi, LI Heng, ZHANG Wei, REN Wei-chao, WU Yan, ZHANG Zhi-chang, LI Bao-hua, ZHOU Shan-yue

2022, 21 (12): 3684-3691. DOI: 10.1016/j.jia.2022.08.123

Abstract （385） PDF in ScienceDirect

Grapevine (Vitis vinifera L.) is an economically important fruit crop in the world, and China ranks first in the production of grapes with approximately 15% of the world’s total yield. However, diseases that cause the death of grapevine shoots pose a severe threat to the production of grapes. In this study, the fungus Neopestalotiopsis eucalypti was identified as a causal pathogen of grapevine shoot rot based on the morphology of conidia and a phylogenetic analysis. The phylogenetic analysis was performed with three isolates based on the combined sequence of internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (Tef) and the β-tubulin (Tub2) genes. The three isolates were all identified as N. eucalypti. Pathogenicity tests of the three fungal isolates were conducted on grapevines shoots in vitro and in vivo. The results showed that all three fungal isolates caused severe rot lesions on the inoculated grapevine shoots, and N. eucalypti was re-isolated from the inoculated grapevine shoots. Therefore, N. eucalypti was confirmed as a causal agent of the grapevine shoot rot. This is the first report of N. eucalypti causing grapevine shoot disease in China.

Reference | Related Articles | Metrics

Select

Horizontal gene transfer of a syp homolog contributes to the virulence of Burkholderia glumae

WANG Sai, WANG Pei-hong, NIE Wen-han, CUI Zhou-qi, LI Hong-yu, WU Yan, Ayizekeranmu YIMING, FU Luo-yi, Iftikhar AHMAD, CHEN Gong-you, ZHU Bo

2021, 20 (12): 3222-3229. DOI: 10.1016/S2095-3119(20)63553-5

Abstract （176） PDF in ScienceDirect

Horizontal gene transfer (HGT) has been proved a major driving force in prokaryotic evolution. However, the molecular functions of these transferred genes in pathogenic bacteria especially plant pathogenic bacteria are still not fully investigated. In this study, the whole-genome in silico analysis was performed and found a syringopeptin synthetase (syp) homolog in Burkholderia glumae, which can cause bacterial panicle blight in rice, was predicted to be horizontally transferred from Pseudomonas ancestor with solid confidence by phylogenetic analysis. The comprehensive molecular experiments were performed to study the potential role of this gene in B. glumae. Inoculation of rice panicles with the syp mutant resulted in 60% lower disease index compared with the wild type (WT) parent strain, suggesting the requirement of syp for the full virulence of B. glumae. Chromatography analysis of exudates from B. glumae showed suppression of synthesis of metabolites analogous to syringopeptin in the mutants. All these data raise the possibility of HGT phenomenon in shaping the virulence and adaptation of B. glumae over evolutionary time.

Reference | Related Articles | Metrics

Select

Drip irrigation incorporating water conservation measures: Effects on soil water–nitrogen utilization, root traits and grain production of spring maize in semi-arid areas

WU Yang, BIAN Shao-feng, LIU Zhi-ming, WANG Li-chun, WANG Yong-jun, XU Wen-hua, ZHOU Yu

2021, 20 (12): 3127-3142. DOI: 10.1016/S2095-3119(20)63314-7

Abstract （252） PDF in ScienceDirect

The Northeast Plain is the largest maize production area in China, and drip irrigation has recently been proposed to cope with the effects of frequent droughts and to improve water use efficiency (WUE). In order to develop an efficient and environmentally friendly irrigation system, drip irrigation experiments were conducted in 2016–2018 incorporating different soil water conservation measures as follows: (1) drip irrigation under plastic film mulch (PI), (2) drip irrigation under biodegradable film mulch (BI), (3) drip irrigation incorporating straw returning (SI), and (4) drip irrigation with the tape buried at a shallow soil depth (OI); with furrow irrigation (FI) used as the control. The results showed that PI and BI gave the highest maize yield, as well as the highest WUE and nitrogen use efficiency (NUE) because of the higher root length density (RLD) and better heat conditions during the vegetative stage. But compared with BI, PI consumed more soil water in the 20–60 and 60–100 cm soil layers, and accelerated the progress of root and leaf senescence due to a larger root system in the top 0–20 cm soil layer and a higher soil temperature during the reproductive stage. SI was effective in improving soil water and nitrate contents, and promoted RLD in deeper soil layers, thereby maintaining higher physiological activity during the reproductive stage. FI resulted in higher nitrate levels in the deep 60–100 cm soil layer, which increased the risk of nitrogen losses by leaching compared with the drip irrigation treatments. RLD in the 0–20 cm soil layer was highly positively correlated with yield, WUE and NUE (P<0.001), but it was negatively correlated with root nitrogen use efficiency (NRE) (P<0.05), and the correlation was weaker in deeper soil layers. We concluded that BI had advantages in water–nitrogen utilization and yield stability response to drought stress, and thus is recommended for environmentally friendly and sustainable maize production in Northeast China.

Reference | Related Articles | Metrics

Select

Comparative analysis of flower-meristem-identity gene APETALA2 (AP2) codon in different plant species

WU Yan-qing, LI Zhi-yuan, ZHAO Da-qiu, TAO Jun

2018, 17 (04): 867-877. DOI: 10.1016/S2095-3119(17)61732-5

Abstract （625） PDF in ScienceDirect

The flower-meristem-identity gene APETALA2 (AP2), one of class-A genes, is involved in the establishment of the floral meristem and the forming of sepals and petals. Codon usage bias (CUB) identifies differences among species, meanwhile dynamic analysis of base composition can identify the molecular mechanisms and evolutionary relationships of a specific gene. In this study, eight coding sequences (CDS) of AP2 gene were selected from different plant species using the GenBank database. Their nucleotide composition (GC content), genetic index, relative synonymous codon usage (RSCU) and relative codon usage bias (RCUB) were calculated with R Software to compare codon bias and base composition dynamics of AP2 gene codon usage patterns in different plant species. The results showed that the usage of AP2 gene codons from different plant species were influened by GC bias, especially GC3s. Overall, base composition analysis indicated that the usage frequency of codon AT in the gene coding sequence was higher than GC among AP2 gene CDS from different plant species. Furthermore, most AP2 gene CDSs ended with AT; AGA, GCU and UGU had relatively high RSCU values as the most dominant codon; the usage characteristic of the AP2 gene codon in Malus domestica was similar to that of Vitis vinifera; Paeonia lactiflora was similar to Paeonia suffruticosa and Solanum lycopersicum was similar to Petunia×hybrida. There was a moderate preference in the usage of AP2 gene codon among different plant species from relatively low frequency of optimal codon (Fop) values and high effective number of codons (ENC) value. This study has revealed the usage characteristics of the AP2 gene codon from the comparision of AP2 gene codon preference and base dynamics in different plant species and provide a platform for further study towards transgenic engineering and codon optimization.

Reference | Related Articles | Metrics

Select

Molecular characterization of chalcone isomerase (CHI) regulating flower color in herbaceous peony (Paeonia lactiflora Pall.)

WU Yan-qing, ZHU Meng-yuan, JIANG Yu, ZHAO Da-qiu, TAO Jun

2018, 17 (01): 122-129. DOI: 10.1016/S2095-3119(16)61628-3

Abstract （667） PDF in ScienceDirect

Chalcone isomerase (CHI) is a key enzyme that converts yellow chalcone to colorless naringenin, playing an important regulatory role in color formation of ornamental flowers. We determined the coding sequence of CHI in herbaceous peony using rapid-amplification of cDNA ends (RACE) technology, and subsequently detected the expression pattern of CHI in the inner and outer petals at different developmental stages using qRT-PCR. We cloned the upstream promoter sequences of CHI using genome walking technology and predicted the location of CpG islands and 5´ truncation. In addition, we constructed five dual-luciferase reporter gene carriers and detected the promoter activities of different fragments. Our results showed that the full-length cDNA sequence of CHI was 898 bp, and the 5´-upstream core promoter was located at –1 651 to –2 050 bp region, where contained one CpG island (–1 897 to –2 010 bp) and several important binding sites of transcription factor, such as Sp1, serum response factor (SRF), activating protein (AP)-2alpha and CCAAT/enhancer binding protein (C/EBP)alpha. Expression results showed that the expression of CHI at different developmental stages was generally higher in inner petals than those in outer petals, and the maximum at the bud stage (S1). Thus, this study will provide theoretical basis for an in-depth study of CHI gene function and expression regulation.

Reference | Related Articles | Metrics

Select

Identification of suitable reference genes in leaves and roots of rapeseed (Brassica napus L.) under different nutrient deficiencies

HAN Pei-pei, QIN Lu, LI Yin-shui, LIAO Xiang-sheng, XU Zi-xian, HU Xiao-jia, XIE Li-hua, YU Chang-bing, WU Yan-feng, LIAO Xing

2017, 16 (04): 809-819. DOI: 10.1016/S2095-3119(16)61436-3

Abstract （760） PDF in ScienceDirect

Nutrient deficiency stresses often occur simultaneously in soil. Thus, it’s necessary to investigate the mechanisms underlying plant responses to multiple stresses through identification of some key stress-responsive genes. Quantitative real-time PCR (qRT-PCR) is essential for detecting the expression of the interested genes, of which the selection of suitable reference genes is a crucial step before qRT-PCR. To date, reliable reference genes to normalize qRT-PCR data under different nutrient deficiencies have not been reported in plants. In this study, expression of ten candidate reference genes was detected in leaves and roots of rapeseed (Brassica napus L.) after implementing different nutrient deficiencies for 14 days. These candidate genes, included two traditionally used reference genes and eight genes selected from an RNA-Seq dataset. Two software packages (GeNorm, NormFinder) were employed to evaluate candidate gene stability. Results showed that VHA-E1 was the highest-ranked gene in leaves of nutrient-deficient rapeseed, while VHA-G1 and UBC21 were most stable in nutrient-deficient roots. When rapeseed leaves and roots were combined, UBC21, HTB1, VHA-G1 and ACT7 were most stable among all samples. To evaluate the stabilities of the highest-ranked genes, the relative expression of two target genes, BnTrx1;1 and BnPht1;3 were further determined. The results showed that the relative expression of BnTrx1;1 depended on reference gene selection, suggesting that it’s necessary to evaluate the stability of reference gene prior to qRT-PCR. This study provides suitable reference genes for gene expression analysis of rapeseed responses to different nutrient deficiencies, which is essential for elucidation of mechanisms underlying rapeseed responses to multiple nutrient deficiency stresses.

Reference | Related Articles | Metrics

Select

Flavonoid content and expression analysis of flavonoid biosynthetic genes in herbaceous peony (Paeonia lactiflora Pall.) with double colors

WU Yan-qing, WEI Meng-ran, ZHAO Da-qiu, TAO Jun

2016, 15 (9): 2023-2031. DOI: 10.1016/S2095-3119(15)61318-1

Abstract （1316） PDF in ScienceDirect

Herbaceous peony (Paeonia lactiflora Pall.) is a famous flower with medicinal values, and its flowers have a number of medicinal constituents, especially flavonoids. In this study, a P. lactiflora cultivar with double colors including white outer-petal and yellow inner-petal was used as the experimental materials to perform the qualitative and quantitative analysis of flavonoids by high-performance liquid chromatograph-electrospray ionization-mass spectrometry (HPLC-ESI-MSⁿ) and investigate the expression patterns of flavonoid biosynthetic genes using real-time quantitative polymerase chain reaction (Q-PCR). The results showed that the colors of both petals gradually weakened with flower development. Moreover, one main anthocyanin composition (peonidin 3,5-di-O-glucoside) and five main anthoxanthin compositions (kaempferol di-hexoside, kaempferol-3-O-malonylglucoside-7-O-glucoside, quercetin-3-O-galactoside, luteolin-7-O-glucoside and isorhamnetin-3-O-glucoside) were found in the both, differing significantly in their peak areas only. Total anthocyanin, anthoxanthin and flavonoid contents in white outer-petal and yellow inner-petal gradually decreased during flower development, and were consistently higher in white outer-petal. Furthermore, the expression patterns of nine structural genes in P. lactiflora flavonoid biosynthetic pathway showed that the expression levels of phenylalanine ammonialyase gene (PlPAL), chalcone synthase gene (PlCHS), flavanone 3-hydroxylase gene (PlF3H), anthocyanidin synthase gene (PlANS) and UDP-glucoside: flavonoid 5-O-glucosyltransferase gene (PlF5GT) in two petals basically presented declined tendencies, and transcription levels of PlPAL, PlCHS, PlANS, PlF3GT and PlF5GT also tended to be higher in white outer-petal, which was correlated with their flavonoid contents. These results would lay a solid foundation for the exploration and utilization of flavonoid resources in P. lactiflora flowers.

Reference | Related Articles | Metrics

Select

Effects of CO₂ enrichment and spikelet removal on rice quality under open-air field conditions

JING Li-quan, WU Yan-zhen, ZHUANG Shi-teng, WANG Yun-xia, ZHU Jian-guo, WANG Yu-long, YANG Lian-xin

2016, 15 (9): 2012-2022. DOI: 10.1016/S2095-3119(15)61245-X

Abstract （1368） PDF in ScienceDirect

The increase of atmospheric carbon dioxide (CO₂) concentration adversely affect several quality traits of rice grains, but the biochemical mechanism remains unclear. The objectives of this study were to determine how changes in the source-sink relationship affected rice quality. Source-sink manipulation was achieved by free-air CO₂ enrichment from tillering to maturity and partial removal of spikelet at anthesis using a japonica rice cultivar Wuyunjing 23. Enrichment with CO₂ decreased the head rice percentage and protein concentration of milled rice, but increased the grain chalkiness. In contrast, spikelet removal resulted in a dramatic increase in the head rice percentage and protein concentration, and much less grain chalkiness. Neither CO₂ enrichment nor spikelet removal affected the starch content, but the distribution of starch granule size showed distinct treatment effects. On average, spikelet removal decreased the percentage of starch granules of diameter >10 and 5–10 μm by 23.6 and 5.6%, respectively, and increased those with a diameter of 2–5 and <2 μm by 4.6 and 3.3%, respectively. In contrast, CO₂ elevation showed an opposite response: increasing the proportion of large starch granules (>5 μm) and decreasing that of <5 μm. The starch pasting properties were affected by spikelet removal much more than by CO₂ elevation. These results indicated that the protein concentration and starch granule size played a role in chalkiness formation under these experimental conditions.

Reference | Related Articles | Metrics

Select

ASimpleMethod for the Isolation andPurification of 2,4-Dihydroxy-7-Methoxy- 2H-1,4-Benzoxazin-3(4H)-One (DIMBOA) from Maize (Zea mays L.) Seedlings

LI Jing, LIU Xin-gang, DONG Feng-shou, XU Jun, GUO Li-qun, KONG Zhi-qiang, TIAN Ying-ying, WU Yan-bin , ZHENG Yong-quan

2013, 12 (1): 95-102. DOI: 10.1016/S2095-3119(13)60209-9

Abstract （1590） PDF in ScienceDirect

2,4-Dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one (DIMBOA), the dominant benzoxazinoid hydroxamic acid in maize (Zea Mays L.), serves as important factors of resistance against insects and microbial diseases, allelochemicals used in competition with other plants. In this paper, a novel and simple method for the isolation and purification of DIMBOA from maize seedlings was developed. Frozen shoots from 7-d-old maize seedlings (1 000×g) were firstly defrosted and then were directly homogenized and extracted with ethyl acetate. The macerate was allowed to stand at room temperature (25±2)°C for 1 h to allow enzymatic release of DIMBOA from DIMBOA-glucoside. Then the ethyl acetate phase was filtered, dried and evaporated to dryness. The resulting light-tan, semicrystalline residue was stored at -20°C for 24 h. Upon recrystallization from acetone-hexane, a relative higher yield (0.58 g) of pure DIMBOA crystals was obtained compared with the yield afforded by Woodward methodology (0.26 g).

Reference | Related Articles | Metrics

About JIA

Editorial board

For authors