通讯机构：
[Li, LZ ] H;Hunan Agr Univ, Coll Plant Protect, Hunan Engn & Technol Res Ctr Agr Big Data Anal & D, Changsha 410128, Peoples R China.
关键词：
rice;genome-wide association study;epistasis;gene pleiotropy;maker-associated selection;genome selection
摘要：
Marker-assisted selection (MAS) and genomic selection (GS) breeding have greatly improved the efficiency of rice breeding. Due to the influences of epistasis and gene pleiotropy, ensuring the actual breeding effect of MAS and GS is still a difficult challenge to overcome. In this study, 113 indica rice varieties (V) and their 565 testcross hybrids (TC) were used as the materials to investigate the genetic basis of 12 quality traits and nine agronomic traits. The original traits and general combining ability of the parents, as well as the original traits and mid-parent heterosis of TC, were subjected to genome-wide association analysis. In total, 381 primary significantly associated loci (SAL) and 1,759 secondary SALs that had epistatic interactions with these primary SALs were detected. Among these loci, 322 candidate genes located within or nearby the SALs were screened, 204 of which were cloned genes. A total of 39 MAS molecular modules that are beneficial for trait improvement were identified by pyramiding the superior haplotypes of candidate genes and desirable epistatic alleles of the secondary SALs. All the SALs were used to construct genetic networks, in which 91 pleiotropic loci were investigated. Additionally, we estimated the accuracy of genomic prediction in the parent V and TC by incorporating either no SALs, primary SALs, secondary SALs or epistatic effect SALs as covariates. Although the prediction accuracies of the four models were generally not significantly different in the TC dataset, the incorporation of primary SALs, secondary SALs, and epistatic effect SALs significantly improved the prediction accuracies of 5 (26%), 3 (16%), and 11 (58%) traits in the V dataset, respectively. These results suggested that SALs and epistatic effect SALs identified based on an additive genotype can provide considerable predictive power for the parental lines. They also provide insights into the genetic basis of complex traits and valuable information for molecular breeding in rice.
Marker-assisted selection (MAS) and genomic selection (GS) breeding have greatly improved the efficiency of rice breeding. Due to the influences of epistasis and gene pleiotropy, ensuring the actual breeding effect of MAS and GS is still a difficult challenge to overcome. In this study, 113 indica rice varieties (V) and their 565 testcross hybrids (TC) were used as the materials to investigate the genetic basis of 12 quality traits and nine agronomic traits. The original traits and general combining ability of the parents, as well as the original traits and mid-parent heterosis of TC, were subjected to genome-wide association analysis. In total, 381 primary significantly associated loci (SAL) and 1,759 secondary SALs that had epistatic interactions with these primary SALs were detected. Among these loci, 322 candidate genes located within or nearby the SALs were screened, 204 of which were cloned genes. A total of 39 MAS molecular modules that are beneficial for trait improvement were identified by pyramiding the superior haplotypes of candidate genes and desirable epistatic alleles of the secondary SALs. All the SALs were used to construct genetic networks, in which 91 pleiotropic loci were investigated. Additionally, we estimated the accuracy of genomic prediction in the parent V and TC by incorporating either no SALs, primary SALs, secondary SALs or epistatic effect SALs as covariates. Although the prediction accuracies of the four models were generally not significantly different in the TC dataset, the incorporation of primary SALs, secondary SALs, and epistatic effect SALs significantly improved the prediction accuracies of 5 (26%), 3 (16%), and 11 (58%) traits in the V dataset, respectively. These results suggested that SALs and epistatic effect SALs identified based on an additive genotype can provide considerable predictive power for the parental lines. They also provide insights into the genetic basis of complex traits and valuable information for molecular breeding in rice.
作者：
Jie Liu;Jie Zhang;Huijuan Yan;Tuyong Yi;Won Bo Shim;...
期刊：
农业科学学报(英文),2024年 ISSN：2095-3119
作者机构：
[Jie Liu; Tuyong Yi; Zehua Zhou] Hunan Provincial Key Laboratory for Biology and Control of Plant Pests, Hunan Agricultural University, Changsha, 410128, China;[Jie Zhang] College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China;[Huijuan Yan] Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, CA 94143, USA;[Won Bo Shim] Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
关键词：
Fusarium verticillioides;FvVam6;fumonisin B 1;vacuolar morphology
摘要：
As the largest multifunctional and dynamic organelle in fungi, vacuoles are associated with different organelles through membrane contact sites and participate in various cellular processes. Vacuole and mitochondria patch (vCLAMP), the membrane contact site that tethers vacuoles and mitochondria, is indispensable for reciprocal interplay between these two organelles. The impairment of vacuoles and mitochondria significantly suppressed FB 1 production in Fusarium verticillioides . However, the understanding of how vCLAMP complex regulates fumonisin biosynthesis remained unknown. Herein, the biological functions of vCLAMP component Vam6 were investigated in F. verticillioides . Our results showed that FvVam6 deletion mutant ΔFvVam6 exhibited palpable defects in fungal development, stresses responses and pathogenicity. In addition, abnormal vacuolar morphology and significantly reduced FB 1 production were observed in ΔFvVam6. Furthermore, we demonstrated that two vacuolar sorting protein 39 (Vps39) domains and clathrin domain were critical for the biological functions of FvVam6, while clathrin and Vps39-2 domains played dominant roles in the regulation of virulence and FB 1 production. Taken together, our results advanced our understanding of vCLAMP in fumonisin biosynthesis in plant pathogenic fungus F. verticillioides .
As the largest multifunctional and dynamic organelle in fungi, vacuoles are associated with different organelles through membrane contact sites and participate in various cellular processes. Vacuole and mitochondria patch (vCLAMP), the membrane contact site that tethers vacuoles and mitochondria, is indispensable for reciprocal interplay between these two organelles. The impairment of vacuoles and mitochondria significantly suppressed FB 1 production in Fusarium verticillioides . However, the understanding of how vCLAMP complex regulates fumonisin biosynthesis remained unknown. Herein, the biological functions of vCLAMP component Vam6 were investigated in F. verticillioides . Our results showed that FvVam6 deletion mutant ΔFvVam6 exhibited palpable defects in fungal development, stresses responses and pathogenicity. In addition, abnormal vacuolar morphology and significantly reduced FB 1 production were observed in ΔFvVam6. Furthermore, we demonstrated that two vacuolar sorting protein 39 (Vps39) domains and clathrin domain were critical for the biological functions of FvVam6, while clathrin and Vps39-2 domains played dominant roles in the regulation of virulence and FB 1 production. Taken together, our results advanced our understanding of vCLAMP in fumonisin biosynthesis in plant pathogenic fungus F. verticillioides .
通讯机构：
[Meng, DL ] C;[Liu, TB ] T;Cent South Univ, Sch Minerals Proc & Bioengn, Changsha 410083, Peoples R China.;Tobacco Res Inst Hunan Prov, Changsha 410004, Peoples R China.
关键词：
Antibiotic resistance genes (ARGs);Bioagents;Environmental pollution;Integrative and conjugative elements (ICEs);Metagenomics;Rhizosphere soil
摘要：
Antibiotic resistance genes (ARGs) have been identified as emerging contaminants, raising concerns around the world. As environmentally friendly bioagents (BA), plant growth-promoting rhizobacteria (PGPR) have been used in agricultural systems. The introduction of BA will lead to the turnover of the microbial communities structure. Nevertheless, it is still unclear how the colonization of the invaded microorganisms could affects the rhizosphere resistome. Consequently, 190 ARGs and 25 integrative and conjugative elements (ICEs) were annotated using the metagenomic approach in 18 samples from the Solanaceae crop rhizosphere soil under BA and conventional treatment (CK) groups. Our study found that, after 90 days of treatment, ARG abundance was lower in the CK group than in the BA group. The results showed that aminoglycoside antibiotic resistance (OprZ), phenicol antibiotic resistance (OprN), aminoglycoside antibiotic resistance (ceoA/B), aminocoumarin antibiotic resistance (mdtB) and phenicol antibiotic resistance (MexW) syntenic with ICEs. Moreover, in 11 sequences, OprN (phenicol antibiotic resistance) was observed to have synteny with ICEPaeLESB58-1, indicating that the ICEs could contribute to the spread of ARGs. Additionally, the binning result showed that the potential bacterial hosts of the ARGs were beneficial bacteria which could promote the nutrition cycle, such as Haliangium, Nitrospira, Sideroxydans, Burkholderia, etc, suggesting that bacterial hosts have a great influence on ARG profiles. According to the findings, considering the dissemination of ARGs, BA should be applied with caution, especially the use of beneficial bacteria in BA. In a nutshell, this study offers valuable insights into ARGs pollution control from the perspective of the development and application of BA, to make effective strategies for blocking pollution risk migration in the ecological environment.
摘要：
Clubroot is a soil-borne disease caused by infection with Plasmodiophora brassicae , the causal agent of clubroot, and clubroot can directly cause enormous economic losses in cruciferous crops. The latent spores of P. brassicae are highly active, have a high rate of infection, and are transmitted over a wide range of channels. The manifestation of P. brassicae in fields is often caused by the mixed infection of multiple physiological races, and such mixed infections often pose a substantial challenge to the breeding of plants that are resistant to P. brassicae . In this study, a set of multiple molecular markers for the identification of the main physiological race of P. brassicae was established by utilizing a system to detect the clubroot microspecies-specific primers SCL14 (UP/LP) , PBRA_000030-2 (F/R) , PBRA_000303-1 (F/R) , PBRA_009348-2 (F/R) , and Novel342-1 (F/R) . The molecular identification of clubroot physiological race resulted in identifying of five such races, including No. 1, 4, 7, 9, and 11. The primers used in this study were more specific, and some strains were not only identified as No. 4 but also as No. 7, such as strains P2, P3, and P4, or as No. 1, such as strain P60. The highest frequency and widest distribution of the small species No. 4 in the sampling site indicated that race No. 4 is the dominant race of P. brassicae . Based on the distribution of race in the sampling site, it was found that the isolated strains of P. brassicae were more differentiated and caused more types of disease. In this study, the primers obtained for the molecular identification of P. brassicae in previous studies were improved and combined to form a multi-molecular marker method to identify the physiological race isolates of P. brassicae , which will provide a theoretical basis to identify the isolates of P. brassicae using molecular markers.
Clubroot is a soil-borne disease caused by infection with Plasmodiophora brassicae , the causal agent of clubroot, and clubroot can directly cause enormous economic losses in cruciferous crops. The latent spores of P. brassicae are highly active, have a high rate of infection, and are transmitted over a wide range of channels. The manifestation of P. brassicae in fields is often caused by the mixed infection of multiple physiological races, and such mixed infections often pose a substantial challenge to the breeding of plants that are resistant to P. brassicae . In this study, a set of multiple molecular markers for the identification of the main physiological race of P. brassicae was established by utilizing a system to detect the clubroot microspecies-specific primers SCL14 (UP/LP) , PBRA_000030-2 (F/R) , PBRA_000303-1 (F/R) , PBRA_009348-2 (F/R) , and Novel342-1 (F/R) . The molecular identification of clubroot physiological race resulted in identifying of five such races, including No. 1, 4, 7, 9, and 11. The primers used in this study were more specific, and some strains were not only identified as No. 4 but also as No. 7, such as strains P2, P3, and P4, or as No. 1, such as strain P60. The highest frequency and widest distribution of the small species No. 4 in the sampling site indicated that race No. 4 is the dominant race of P. brassicae . Based on the distribution of race in the sampling site, it was found that the isolated strains of P. brassicae were more differentiated and caused more types of disease. In this study, the primers obtained for the molecular identification of P. brassicae in previous studies were improved and combined to form a multi-molecular marker method to identify the physiological race isolates of P. brassicae , which will provide a theoretical basis to identify the isolates of P. brassicae using molecular markers.
关键词：
Apoptosis;Colletotrichum fructicola;Hypovirulence;Mycovirus;β subunit of voltage-gated potassium channel
摘要：
Colletotrichum fructicola is a globally significant phytopathogenic fungus. Mycovirus-induced hypovirulence has great potential for biological control and study of fungal pathogenic mechanisms. We previously reported that the mycovirus Colletotrichum alienum partitivirus 1 (CaPV1) is associated with the hypovirulence of C. fructicola , and the present study aimed to further investigate a host factor and its roles in mycovirus-induced hypovirulence. A gene named CfKOB1 , which encodes putative protein homologous to the β-subunit of voltage-gated potassium channels and aldo–keto reductase, is downregulated upon CaPV1 infection and significantly upregulated during the early infection phase of Nicotiana benthamiana by C. fructicola . Deleting the CfKOB1 gene resulted in diminished vegetative growth, decreased production of asexual spores, hindered appressorium formation, reduced virulence, and altered tolerance to abiotic stresses. Transcriptome analysis revealed that CfKOB1 regulates many metabolic pathways as well as the cell cycle and apoptosis. Furthermore, enhanced apoptosis was observed in the Δ CfKOB1 mutants. Viral RNA accumulation was significantly increased in the CfKOB1 deletion mutant. Additionally, our findings demonstrated that CaPV1 infection in the WT strain also induced cell apoptosis. Collectively, these results highlight the diverse biological roles of the CfKOB1 gene in the fungus C. fructicola , while it also participates in mycovirus-induced hypovirulence by regulating apoptosis.
Colletotrichum fructicola is a globally significant phytopathogenic fungus. Mycovirus-induced hypovirulence has great potential for biological control and study of fungal pathogenic mechanisms. We previously reported that the mycovirus Colletotrichum alienum partitivirus 1 (CaPV1) is associated with the hypovirulence of C. fructicola , and the present study aimed to further investigate a host factor and its roles in mycovirus-induced hypovirulence. A gene named CfKOB1 , which encodes putative protein homologous to the β-subunit of voltage-gated potassium channels and aldo–keto reductase, is downregulated upon CaPV1 infection and significantly upregulated during the early infection phase of Nicotiana benthamiana by C. fructicola . Deleting the CfKOB1 gene resulted in diminished vegetative growth, decreased production of asexual spores, hindered appressorium formation, reduced virulence, and altered tolerance to abiotic stresses. Transcriptome analysis revealed that CfKOB1 regulates many metabolic pathways as well as the cell cycle and apoptosis. Furthermore, enhanced apoptosis was observed in the Δ CfKOB1 mutants. Viral RNA accumulation was significantly increased in the CfKOB1 deletion mutant. Additionally, our findings demonstrated that CaPV1 infection in the WT strain also induced cell apoptosis. Collectively, these results highlight the diverse biological roles of the CfKOB1 gene in the fungus C. fructicola , while it also participates in mycovirus-induced hypovirulence by regulating apoptosis.
作者机构：
[Jin, Tuo; Peng, Jianwei] Hunan Agr Univ, Coll Resources, Changsha 410128, Peoples R China.;[Jin, Tuo] Minist Agr & Rural Affairs, Rural Energy & Environm Agcy, Beijing 100125, Peoples R China.;[Li, Lin; Chen, Wu; Li, Wei; Peng, Kewei] Hunan Agr Univ, Coll Plant Protect, Changsha 410128, Peoples R China.;[Jin, Decai] Chinese Acad Sci, Res Ctr Ecoenvironm Sci, Beijing 100085, Peoples R China.
通讯机构：
[Jin, T ] H;Hunan Agr Univ, Coll Resources, Changsha 410128, Peoples R China.;Minist Agr & Rural Affairs, Rural Energy & Environm Agcy, Beijing 100125, Peoples R China.
关键词：
fully biodegradable mulches;pepper;soil properties;degradation rate;bacterial community
摘要：
Biodegradable mulch films (BMFs) are becoming increasingly popular in agricultural practices. However, research on the ecological impact of biodegradable mulch films on pepper-soil systems is still scarce. To compare the differential effects of BMFs and polyethylene (PE) mulch on soil chemical properties, soil bacterial community composition, and pepper cultivation, a study was conducted encompassing eight distinct treatments. These treatments included three varieties of polybutylene adipate terephthalate (PBAT) combined with polylactic acid (PLA) mulches: PP-JL, PP-SD, and PP-SH; a black polypropylene carbonate mulch (PPC-BK); a brown PPC mulch (PPC-BR); a polyethylene (PE) mulch; straw mulching (NCK); and an uncovered control (PCK). After applying mulches for 129 days, most PPC and PBAT + PLA films had reached the rupture phase, whereas the PE film was still in the induction phase. Pepper yield was obviously higher in all mulched treatments (4830 kg hm-1) than in the un-mulched control (3290 kg hm-1), especially the BMF PP-JL treatment, which showed the most notable improvements in yield. Although BMF treatments maintained a lower soil temperature than the PE film mulch, they were still higher than the un-mulched control. Furthermore, the soil bacterial community composition and ecological network were not markedly affected by different mulching conditions. However, the PP-SH treatment significantly increased the abundance of Pseudomonas, Nitrosomonas, and Streptomyces genera. Moreover, Lactobacillus and Gp16 were substantially more abundant in the PPC-black (BK) and PPC-brown (BR) treatments compared to the PE mulching treatment. This study could provide valuable insights into the ecological benefits of BMFs in pepper cultivation. However, as our experiments were conducted for only one season, it is imperative to undertake long-term experiments across consecutive seasons and years for a thorough understanding and comprehensive study.
期刊：
Plant Physiology and Biochemistry,2024年215:109083 ISSN：0981-9428
通讯作者：
Bai, Lianyang;Pan, L
作者机构：
[Pan, Lang; Ouyang, Yulan; Bai, Lianyang; Wang, Junzhi; Qi, Jiale; Pan, L] Hunan Agr Univ, Coll Plant Protect, Changsha 410128, Peoples R China.;[Wang, Junzhi; Bai, Lianyang] Hunan Acad Agr Sci, Hunan Agr Biotechnol Res Inst, Changsha 410125, Peoples R China.;[Zhang, Baiqing; Qin, Long; Zhou, Shuguang] Zhejiang Xinan Chem Ind Grp Co Ltd, Jiande, Peoples R China.
通讯机构：
[Bai, LY; Pan, L ] H;Hunan Agr Univ, Coll Plant Protect, Changsha 410128, Peoples R China.
关键词：
ALS-Inhibitors;Beckmannia syzigachne;Mesosulfuron-methyl;Target site resistance
摘要：
Understanding the mechanisms by which weeds develop herbicide resistance is crucial for managing resistance effectively and optimizing herbicide use. Beckmannia syzigachne, a harmful grass weed prevalent in wheat and rice-wheat rotation areas, poses a significant threat to crop productivity. A field herbicide resistance survey identified a resistant population with a new ALS mutation (Asp-376-Glu). The Glu-376-Asp population displayed varying resistance levels to seven ALS herbicides, verified using the dCAPS method. qRT-PCR analysis showed that no significant difference existed in the ALS gene expression between the Asp-376-Glu and S populations. P450 and GST inhibitors failed to reverse resistance to mesosulfuron-methyl, suggesting no involvement of P450- and GST-based metabolic resistance. Molecular docking indicated that the Asp-376-Glu mutation reduces the binding affinity between ALS-inhibitors and BsALS. The findings provide valuable insights into herbicide resistance mechanisms for weed resistance control.
Understanding the mechanisms by which weeds develop herbicide resistance is crucial for managing resistance effectively and optimizing herbicide use. Beckmannia syzigachne, a harmful grass weed prevalent in wheat and rice-wheat rotation areas, poses a significant threat to crop productivity. A field herbicide resistance survey identified a resistant population with a new ALS mutation (Asp-376-Glu). The Glu-376-Asp population displayed varying resistance levels to seven ALS herbicides, verified using the dCAPS method. qRT-PCR analysis showed that no significant difference existed in the ALS gene expression between the Asp-376-Glu and S populations. P450 and GST inhibitors failed to reverse resistance to mesosulfuron-methyl, suggesting no involvement of P450- and GST-based metabolic resistance. Molecular docking indicated that the Asp-376-Glu mutation reduces the binding affinity between ALS-inhibitors and BsALS. The findings provide valuable insights into herbicide resistance mechanisms for weed resistance control.
作者机构：
[Long, Qingshan; Liu, Qingshu; Tang, Ying] Hunan Inst Microbiol, Hunan Prov Engn Res Ctr Agr Microbiol Applicat, Changsha 410009, Peoples R China.;[Zhou, Wen] Chinese Acad Agr Sci, Shanghai Vet Res Inst, Key Lab Vet Chem Drugs & Pharmaceut, Minist Agr & Rural Affairs, Shanghai 200241, Peoples R China.;[Zhou, Haibo; Bian, Xiaoying] Shandong Univ, State Key Lab Microbial Technol, Helmholtz Inst Biotechnol, Helmholtz Int Lab Antiinfect, Qingdao 266237, Peoples R China.;[Chen, Wu; Chen, W] Hunan Agr Univ, Coll Plant Protect, Changsha 410128, Peoples R China.
通讯机构：
[Liu, QS ; Chen, W ] H;[Bian, XY ] S;Hunan Inst Microbiol, Hunan Prov Engn Res Ctr Agr Microbiol Applicat, Changsha 410009, Peoples R China.;Shandong Univ, State Key Lab Microbial Technol, Helmholtz Inst Biotechnol, Helmholtz Int Lab Antiinfect, Qingdao 266237, Peoples R China.;Hunan Agr Univ, Coll Plant Protect, Changsha 410128, Peoples R China.
摘要：
Covering: 2005 to August, 2023
Covering: 2005 to August, 2023
Polyamine-containing natural products (NPs) have been isolated from a wide range of terrestrial and marine organisms and most of them exhibit remarkable and diverse activities, including antimicrobial, antiprotozoal, antiangiogenic, antitumor, antiviral, iron-chelating, anti-depressive, anti-inflammatory, insecticidal, antiobesity, and antioxidant properties. Their extraordinary activities and potential applications in human health and agriculture attract increasing numbers of studies on polyamine-containing NPs. In this review, we summarized the source, structure, classification, bioactivities and biosynthesis of polyamine-containing NPs, focusing on the biosynthetic mechanism of polyamine itself and representative polyamine alkaloids, polyamine-containing siderophores with catechol/hydroxamate/hydroxycarboxylate groups, nonribosomal peptide-(polyketide)-polyamine (NRP-(PK)-PA), and NRP-PK-long chain poly-fatty amine (lcPFAN) hybrid molecules.
Polyamine-containing natural products (NPs) have been isolated from a wide range of terrestrial and marine organisms and most of them exhibit remarkable and diverse activities, including antimicrobial, antiprotozoal, antiangiogenic, antitumor, antiviral, iron-chelating, anti-depressive, anti-inflammatory, insecticidal, antiobesity, and antioxidant properties. Their extraordinary activities and potential applications in human health and agriculture attract increasing numbers of studies on polyamine-containing NPs. In this review, we summarized the source, structure, classification, bioactivities and biosynthesis of polyamine-containing NPs, focusing on the biosynthetic mechanism of polyamine itself and representative polyamine alkaloids, polyamine-containing siderophores with catechol/hydroxamate/hydroxycarboxylate groups, nonribosomal peptide-(polyketide)-polyamine (NRP-(PK)-PA), and NRP-PK-long chain poly-fatty amine (lcPFAN) hybrid molecules.
摘要：
Root rot is an important disease of tea plants owing to its unobvious early symptoms and permanent damage (Huu et al. 2016). In 2019, 5% of tea plants displayed symptoms consistent with root rot in a tea plantation (28°09'N, 113°13'E) located in Changsha city, Hunan province of China. The symptoms of the diseased tea plants ranged from wilting leaves to entirely dead. The roots had black lesions and rot typical of this disease. Symptomatic roots were collected, washed with water and disinfected with 75% ethanol, then cut into pieces and sterilized with 0.1% mercuric chloride for 30 s, 75% ethanol for 1 min, and rinsed with sterile water five times. After drying on sterilized filter paper, root tissues were cultured on potato dextrose agar (PDA) medium at 25 oC for 7 days in the dark. Four isolates, CAGF1, CAGF2, CAGF3, and CAGF4 were purified by selecting single spores. All isolates were subjected to a pathogenicity test. A conidial suspension of each strain was collected at a concentration of 2×106 conidia/mL. For the pathogenicity test, two-year-old field grown tea plants were transplanted in plastic pots containing 240 g of the rice grain-bran mixture (inoculated with 4 mL of conidial suspension and cultured for 14 days) and 960 g of sterilized soil (Huu et al. 2016). The pots without inoculated mixture served as control group. All the pots were kept in illumination incubators at 25 (o)C and a 12L:12D photoperiod. The pathogenicity test for each strain was repeated three times with three repetitions. Only strain CAGF1 exhibited pathogenicity to tea plants. Symptoms appeared on the third day post inoculation (dpi) and gradually worsened by the 7 dpi. On the 14 dpi, most leaves had died and the roots were black and partially rotten, similar to field symptoms. The reisolated fungus from potted roots was identified as CAGF1 based on ITS region and colony morphology, while isolation was attempted, CAGF1 was not isolated from the control plants, which fulfilled Koch's postulates. On PDA, the colony center of CAGF1 was purple with white margin, while on carnation leaf agar (CLA) medium was white. On CLA medium, macroconidia have 0 to 3 septa, measured 19.1 μm to 41.2 μm × 4.2 μm to 5.4 μm (mean= 31.2 μm × 4.8 μm, n=30). The microconidia were measured as 6.7 μm to 12.8 μm × 2.4 μm to 4.9 μm (mean= 10.1 μm × 3.3 μm, n=30), with 0 to 1 septa. And the chlamydospores were measured as 6.0 to 9.7μm (mean= 7.7μm, n=30). Morphologically, strain CAGF1 was identified as Fusarium oxysporum (Leslie and Summerell 2006). Additionally, the genomic DNA of strain CAGF1 was extracted by cetyltrimethylammonium bromide (CTAB) method, the internal transcribed spacer (ITS), elongation factor 1 alpha (EF-1α) and second largest subunit of RNA polymerase II (RPB2) were amplified using the primers ITS1/ITS4 (White et al. 1990), EF-1/EF-2 (Geiser et al. 2004) and fRPB2-5F/fRPB2-7cR (Liu et al. 1999), respectively. Sequences were deposited in GenBank (ITS, OK178562.1; EF-1α, OK598121.1; RPB2, OP381476.1). BLASTn searches revealed that strain CAGF1 was 100% (ON075522.1 for ITS and JX885464.1 for RPB2) and 99.6% (JQ965440.1 for EF-1α) identical to Fusarium oxysporum species complex (FOSC). Based on phylogenetic analysis, the strain CAGF1 was identified as Fusarium cugenangense, belonging to FOSC. To our knowledge, this is the first report of F. cugenangense causing root rot of tea plants in China. The findings are important for the management of this root rot and the improvement of economic benefits of tea cultivation.
摘要：
Pre-parasitic second-stage juveniles (pre-J2s) of Meloidogyne graminicola are non-feeding in soil, and their migration, localization and successful invasion of host roots are essential for survival. Chemotaxis is thought to play a central role in host localization, but the mechanisms of chemotaxis are poorly understood. In this study, we cloned and evaluated the molecular characteristics and functions of four chemosensory genes, including Mg-odr-3, Mg-odr-1, Mg-tax-4, and Mg-osm-9. Quantitative real-time PCR (qRT-PCR) analysis revealed that Mg-odr-3 and Mg-osm-9 tended to be expressed in pre-J2s and parasitic J2s (par-J2s), while Mg-odr-1 and Mg-tax-4 were expressed in par-J2s, consistent with their functions during the host-seeking period and establishment of suitable feeding sites in root tips. Root signals from eight plant root extracts, namely, rice, barnyard grass (Echinochloa crus-galli), wheat, soybean, pepper, tomato, eggplant, and marigold, were repulsive to J2s of M. graminicola. Moreover, RNAi silencing of Mg-odr-3, Mg-odr-1, Mg-tax-4, and Mg-osm-9 in J2s attenuated their repulsion to the rice root extract. Furthermore, we found that the response of J2s to root exudates was concentration-dependent, with high concentrations of root exudates repelling J2s. Silenced J2s also showed reduced repulsion in response to high concentrations of rice root exudates. Conversely, M. graminicola J2s were attracted to the root tips of the eight plants, while RNAi-J2s showed defective attraction to root tips. In conclusion, our results showed that chemosensory genes are crucial for the chemotactic host-seeking behaviour of M. graminicola.
摘要：
Background Shortawn foxtail (Alopecurus aequalis Sobol.) is a noxious weed in China. The resistance of A. aequalis developed rapidly due to the long-term application of acetolactate synthase (ALS)-inhibiting herbicides. Here, a suspected mesosulfuron-methyl-resistant A. aequalis population, Aa-R, was collected from a wheat field in China.
Shortawn foxtail (Alopecurus aequalis Sobol.) is a noxious weed in China. The resistance of A. aequalis developed rapidly due to the long-term application of acetolactate synthase (ALS)-inhibiting herbicides. Here, a suspected mesosulfuron-methyl-resistant A. aequalis population, Aa-R, was collected from a wheat field in China.
Results A dose‒response test showed that the Aa-R population has evolved a high level of resistance to mesosulfuron-methyl, and its growth was suppressed by imazamox, pyroxsulam and bispyribac-sodium. ALS gene sequence analysis revealed that a known resistance-related mutation (Pro-197-Thr) was present in the Aa-R population. Moreover, ALS gene overexpression was detected in the Aa-R population. The mesosulfuron-methyl resistance could be reversed by cytochrome P450 monooxygenase (CYP450) and glutathione S-transferase (GST) inhibitors. In addition, enhanced metabolism of mesosulfuron-methyl was detected in the Aa-R population compared with the susceptible population. NADPH-cytochrome P450 reductase and GST activities were strongly inducible in the Aa-R population. One CYP450 gene, CYP74A2, and one GST gene, GST4, were constitutively upregulated in the Aa-R population. Molecular docking results showed the binding affinity of CYP74A2 and GST4 for the tested ALS-inhibiting herbicides, respectively.
A dose‒response test showed that the Aa-R population has evolved a high level of resistance to mesosulfuron-methyl, and its growth was suppressed by imazamox, pyroxsulam and bispyribac-sodium. ALS gene sequence analysis revealed that a known resistance-related mutation (Pro-197-Thr) was present in the Aa-R population. Moreover, ALS gene overexpression was detected in the Aa-R population. The mesosulfuron-methyl resistance could be reversed by cytochrome P450 monooxygenase (CYP450) and glutathione S-transferase (GST) inhibitors. In addition, enhanced metabolism of mesosulfuron-methyl was detected in the Aa-R population compared with the susceptible population. NADPH-cytochrome P450 reductase and GST activities were strongly inducible in the Aa-R population. One CYP450 gene, CYP74A2, and one GST gene, GST4, were constitutively upregulated in the Aa-R population. Molecular docking results showed the binding affinity of CYP74A2 and GST4 for the tested ALS-inhibiting herbicides, respectively.
Conclusion This study confirmed that target-site resistance and non-target-site resistance involving CYP450 and GST were the main mechanisms involved in resistance in the mesosulfuron-methyl-resistant A. aequalis population.
This study confirmed that target-site resistance and non-target-site resistance involving CYP450 and GST were the main mechanisms involved in resistance in the mesosulfuron-methyl-resistant A. aequalis population.
摘要：
The Clearfield® technology is an useful tool for controlling weedy rice due to the effectiveness of imazamox and the cultivation of rice varieties resistant to imidazolines. However, residual imazamox in the soil probably causes phytotoxicity to subsequent non-resistant rice crops. We previously found that pyrroloquinoline quinone (PQQ), a bioactive elicitor, can enhance rice tolerance to imazamox. In this study, we explored the molecular mechanism of PQQ-mediated rice tolerance to imazamox by RNA-seq analysis, real-time quantitative PCR (RT-qPCR) assay, and enzyme activity assay. The results indicated that compared to imazamox at 66.7 mg a.i./L (IMA) alone, rice plants treated with imazamox at 66.7 mg a.i./L and PQQ at 0.66 mg a.i./L (IMA + PQQ) exhibited significantly reduced sensitivity to imazamox. Seven days post-treatment, IMA + PQQ-treated rice plants showed partial chlorosis and leaf curling, but IMA-treated rice plants had severe wilting and died. The fresh weight inhibition rate was 29.3% in the IMA + PQQ group, significantly lower than that of 56.6% in the IMA group alone. RNA-seq analysis showed differentially expressed genes were mainly involved in phenylpropanoid biosynthesis, diterpenoid biosynthesis, and MAPK signaling pathways in response to IMA + PQQ treatment. Both RNA-seq analysis and RT-qPCR assay showed that the expression of OsCATB gene in the catalase (CAT) gene family was upregulated at 12 h, the expression of OsGSTU1 gene was upregulated at 12, 24, and 48 h, while the expressions of OsABCB2, OsABCB11, and OsABCG11 genes were upregulated at 24 and 48 h. Enzyme activity assays revealed that the activity of superoxide dismutase in the IMA + PQQ group was increased by 47.45~120.31% during 12~72 h, compared to that in the IMA group. CAT activity in the IMA + PQQ group was increased by 123.72 and 59.04% at 12 and 48 h, respectively. Moreover, malondialdehyde levels indicative of oxidative damage were consistently lower in IMA + PQQ-treated plants, with a reduction of 46.29, 11.37, and 14.50% at 12, 36, and 72 h, respectively. Overall, these findings discover that PQQ has potential in reducing imazamox phytotoxicity in rice by enhancing antioxidant enzyme activities and regulating oxidative stress responses. They will provide valuable strategies for improving imazamox tolerance in crops.
摘要：
Using biochar to absorb organic pollutants in water and soil is a simple and efficient method. However, most biochar is typically prepared at high temperatures (>500 ℃), resulting in low yield and high production costs and hence limiting its practical applications. This study aimed to prepare biochar (P-BC) through low-temperature (280 ℃) phosphoric acid assisted pyrolysis of cotton stalks. P-BC possessed a large specific surface area (389.96 m2·g−1) and contained abundant oxygen functional groups as well as phosphorous and nitrogen nutrient elements. This study applied P-BC to remove paclobutrazol (PBZ) from water and remediate PBZ-polluted soil. The water adsorption capacity of P-BC was 192.89 mg·g−1. The adsorption mechanisms of P-BC included pore filling, hydrogen bonding, weak electrostatic effects, and π-π interactions. Adding 1 % P-BC to soil contaminated with 10 mg·kg−1 PBZ could alleviate PBZ induced phytotoxicity in mung bean seedlings, ensuring the normal growth of roots and plants.
Using biochar to absorb organic pollutants in water and soil is a simple and efficient method. However, most biochar is typically prepared at high temperatures (>500 ℃), resulting in low yield and high production costs and hence limiting its practical applications. This study aimed to prepare biochar (P-BC) through low-temperature (280 ℃) phosphoric acid assisted pyrolysis of cotton stalks. P-BC possessed a large specific surface area (389.96 m2·g−1) and contained abundant oxygen functional groups as well as phosphorous and nitrogen nutrient elements. This study applied P-BC to remove paclobutrazol (PBZ) from water and remediate PBZ-polluted soil. The water adsorption capacity of P-BC was 192.89 mg·g−1. The adsorption mechanisms of P-BC included pore filling, hydrogen bonding, weak electrostatic effects, and π-π interactions. Adding 1 % P-BC to soil contaminated with 10 mg·kg−1 PBZ could alleviate PBZ induced phytotoxicity in mung bean seedlings, ensuring the normal growth of roots and plants.
