Chinese cabbage(Brassica rapa subsp.pekinensis)suffers from soft rot disease caused by Pectobacterium carotovorum(Pc).To uncover the mechanisms underlying the defense response of Chinese cabbage to Pc,we constructed a...Chinese cabbage(Brassica rapa subsp.pekinensis)suffers from soft rot disease caused by Pectobacterium carotovorum(Pc).To uncover the mechanisms underlying the defense response of Chinese cabbage to Pc,we constructed a suppression subtractive hybridization(SSH)library from Pc-infected cabbage and obtained 1919 non-redundant expressed sequence tags(ESTs),which were used for cDNA microarray.We detected 800 differentially expressed genes(DEGs)in cabbage at different time points post-Pc inoculation,which were further confirmed by quantitative real-time PCR.One quarter of these DEGs were involved in the biotic stress pathways visualized by MapMan.Among them,8,8,1,3,and 2 DEGs were related to jasmonic acid(JA),ethylene(ET),JA+ET,auxin,and abscisic acid(ABA)signaling pathways,respectively,while no DEG was detected for salicylic acid(SA)signaling.Assessment of phytohormone production in the Pc-infected leaves showed that JA and ET production was increased,while SA production was decreased.Treatment with JA,methyl jasmonate(MeJA),the ET precursor 1-aminocyclopropane-1-carboxylate(ACC),or combinations thereof,reduced the disease severity,and the JA and JA+ACC treatments were superior and performed equally well.Our findings suggest that JA and ET may act synergistically against Pc infection in Chinese cabbage,and JA-mediated signaling might be the most significant.展开更多
Various bacterial species are known to be agents causing soft rot of potatoes. The results of this study showed that potato soft rot is widely spread in different potato planting areas in Jordan. A survey was conducte...Various bacterial species are known to be agents causing soft rot of potatoes. The results of this study showed that potato soft rot is widely spread in different potato planting areas in Jordan. A survey was conducted through the years 2013-2015 to detect potato soft rot disease in Jordan, two hundred and four rotted potato samples were collected from different potato growing areas through different potato growing seasons. One hundred and thirty one bacterial isolates were isolated, purified on selective media and identified as Pectobacterium carotovorum subspecies carotovorum (Pcc) by different biochemical and physiological tests. Furthermore, 131 Pcc Jordanian (Jo) isolates were identified by PCR analysis of total DNA extracted from isolates that were biochemically identified as Pcc using universal primer Fd1/Rd1. Cloning and sequencing of representative PCR products, amplifying the 16S rDNA region were done. Phylogenetic analysis of the Pcc Jo-isolates revealed other than 90% similarity with different reference Pcc strains available at the GenBank. Different rot causal agents also were detected by PCR amplification and further sequences. The sequencing data revealed similarities to Pseudomonas fluorescence, Enterobacteriaceae genera such as Enterobacter spp., Serratia spp. and Klebsiella spp., in addition to Pectobacterium carotovorum subsp. carotovorum. This study indicated that using molecular techniques such as amplification of 16S rDNA region is a sensitive and specific method for detecting Pcc as potato soft rot causal agent. So far this is the first study where Pcc has been identified by using PCR and sequencing approaches in Jordan.展开更多
Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production.This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of...Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production.This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused by Pectobacterium carotovorum.Eleven bacteriophages isolated from soil and water samples collected in Wuhan,China,were used to infect P.carotovorum host strains isolated from potato tubers showing soft rot symptoms in Nakuru county,Kenya.The efficacy of the phages in controlling soft rot disease was evaluated by applying individual phage strains or a phage cocktail on potato slices and tubers at different time points before or after inoculation with a P.carotovorum strain.The phages could lyse 20 strains of P.carotovorum,but not Pseudomonas fluorescens control strains.Among the 11 phages,Pectobacterium phage Wc5r,interestingly showed cross-activity against Pectobacterium atrosepticum and two phage-resistant P.carotovorum strains.Potato slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot control.Phage cocktail applied at a concentration of 1×10^9 plaque-forming units per milliliter before or within an hour after bacterial inoculation on potato slices,resulted in>90%reduction of soft rot symptoms.This study provides a basis for the development and application of phages to reduce the impact of potato soft rot disease.展开更多
为明确高压脉冲电场(High plused electric fields,HPEF)对果胶杆菌的最优杀菌参数并对其潜在机制进行初步探索,本研究首先通过测定高压脉冲电场不同处理条件下果胶杆菌的存活率,明确影响杀菌效果的主要因素;然后研究不同电场强度和脉...为明确高压脉冲电场(High plused electric fields,HPEF)对果胶杆菌的最优杀菌参数并对其潜在机制进行初步探索,本研究首先通过测定高压脉冲电场不同处理条件下果胶杆菌的存活率,明确影响杀菌效果的主要因素;然后研究不同电场强度和脉冲占空比对果胶杆菌生长曲线、细胞膜脂肪酸含量变化、细胞膜渗透率以及核酸和蛋白质泄漏量的影响,以及果胶杆菌在不同生长期对高压脉冲电场敏感度的差异。结果表明:电场强度和脉冲占空比是影响高压脉冲电场杀灭果胶杆菌的主要因素。当电场强度为28 kV/cm,脉冲占空比为36.5%时,抑菌作用最强,果胶杆菌活菌对数减少值达1.60;在高压脉冲电场作用下,果胶杆菌延滞期延长,生长受到抑制,同时细胞膜结构被破坏,渗透性增大,胞内核酸和蛋白质发生严重泄漏。此外,不同生长期的果胶杆菌对高压脉冲电场敏感度不同,其中对数生长期最为敏感。最后,建立了果胶杆菌活菌对数减少值lnS与电场强度和脉冲占空比的动力学方程(y=-0.1067x+0.1166和y=-0.0895x+0.3249)。该方程符合一级动力学模型,较好地反映了高压脉冲电场处理后果胶杆菌生长的关系,为选择合适的处理条件提供了理论依据。本研究确定了高压脉冲电场杀灭果胶杆菌的最佳参数,为进一步实现高压脉冲电场杀菌保鲜在采后和鲜切行业的产业化应用奠定了基础。展开更多
The morphological characteristics, pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB...The morphological characteristics, pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB medium at 28℃ for48 h, the colonies were light yellow, circular or amorphous, translucent, with smooth and slightly concaved surface and neat edge. Observation under electron microscope showed that the isolates was red-shaped, decapsulated and gram-nega- tive in the size of （0.5 - 1.0） μm × （2.2 -3.0） μm, with 2 -8 flagella. After cultivation on CVP medium at 28 ℃ for 48 h, the colonies were sunken like a cup. The pathogen was able to grow in 5% NaCl medium at 37 ℃, and produced acid through glucose fermentation; it was facuhative anaerobic, and could use citrates, but could not produce indole. It was preliminarily confirmed that the pathogen causing Wufeng Maryland tobacco hollow stalk was Pectobacterium carotovorum subsp. carotovorum.展开更多
基金the Beijing Leafy Vegetables Innovation Team of Modern Agro-industry Technology Research System,China(BAIC07)the Beijing Natural Science Foundation,China(5051002)。
文摘Chinese cabbage(Brassica rapa subsp.pekinensis)suffers from soft rot disease caused by Pectobacterium carotovorum(Pc).To uncover the mechanisms underlying the defense response of Chinese cabbage to Pc,we constructed a suppression subtractive hybridization(SSH)library from Pc-infected cabbage and obtained 1919 non-redundant expressed sequence tags(ESTs),which were used for cDNA microarray.We detected 800 differentially expressed genes(DEGs)in cabbage at different time points post-Pc inoculation,which were further confirmed by quantitative real-time PCR.One quarter of these DEGs were involved in the biotic stress pathways visualized by MapMan.Among them,8,8,1,3,and 2 DEGs were related to jasmonic acid(JA),ethylene(ET),JA+ET,auxin,and abscisic acid(ABA)signaling pathways,respectively,while no DEG was detected for salicylic acid(SA)signaling.Assessment of phytohormone production in the Pc-infected leaves showed that JA and ET production was increased,while SA production was decreased.Treatment with JA,methyl jasmonate(MeJA),the ET precursor 1-aminocyclopropane-1-carboxylate(ACC),or combinations thereof,reduced the disease severity,and the JA and JA+ACC treatments were superior and performed equally well.Our findings suggest that JA and ET may act synergistically against Pc infection in Chinese cabbage,and JA-mediated signaling might be the most significant.
文摘Various bacterial species are known to be agents causing soft rot of potatoes. The results of this study showed that potato soft rot is widely spread in different potato planting areas in Jordan. A survey was conducted through the years 2013-2015 to detect potato soft rot disease in Jordan, two hundred and four rotted potato samples were collected from different potato growing areas through different potato growing seasons. One hundred and thirty one bacterial isolates were isolated, purified on selective media and identified as Pectobacterium carotovorum subspecies carotovorum (Pcc) by different biochemical and physiological tests. Furthermore, 131 Pcc Jordanian (Jo) isolates were identified by PCR analysis of total DNA extracted from isolates that were biochemically identified as Pcc using universal primer Fd1/Rd1. Cloning and sequencing of representative PCR products, amplifying the 16S rDNA region were done. Phylogenetic analysis of the Pcc Jo-isolates revealed other than 90% similarity with different reference Pcc strains available at the GenBank. Different rot causal agents also were detected by PCR amplification and further sequences. The sequencing data revealed similarities to Pseudomonas fluorescence, Enterobacteriaceae genera such as Enterobacter spp., Serratia spp. and Klebsiella spp., in addition to Pectobacterium carotovorum subsp. carotovorum. This study indicated that using molecular techniques such as amplification of 16S rDNA region is a sensitive and specific method for detecting Pcc as potato soft rot causal agent. So far this is the first study where Pcc has been identified by using PCR and sequencing approaches in Jordan.
基金supported financially by the Sino-Africa Joint Research Centre (SAJC201605)the Chinese Academy of Sciences (ZDRW-ZS-2016-4)
文摘Soft rot is an economically significant disease in potato and one of the major threats to sustainable potato production.This study aimed at isolating lytic bacteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused by Pectobacterium carotovorum.Eleven bacteriophages isolated from soil and water samples collected in Wuhan,China,were used to infect P.carotovorum host strains isolated from potato tubers showing soft rot symptoms in Nakuru county,Kenya.The efficacy of the phages in controlling soft rot disease was evaluated by applying individual phage strains or a phage cocktail on potato slices and tubers at different time points before or after inoculation with a P.carotovorum strain.The phages could lyse 20 strains of P.carotovorum,but not Pseudomonas fluorescens control strains.Among the 11 phages,Pectobacterium phage Wc5r,interestingly showed cross-activity against Pectobacterium atrosepticum and two phage-resistant P.carotovorum strains.Potato slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot control.Phage cocktail applied at a concentration of 1×10^9 plaque-forming units per milliliter before or within an hour after bacterial inoculation on potato slices,resulted in>90%reduction of soft rot symptoms.This study provides a basis for the development and application of phages to reduce the impact of potato soft rot disease.
文摘为明确高压脉冲电场(High plused electric fields,HPEF)对果胶杆菌的最优杀菌参数并对其潜在机制进行初步探索,本研究首先通过测定高压脉冲电场不同处理条件下果胶杆菌的存活率,明确影响杀菌效果的主要因素;然后研究不同电场强度和脉冲占空比对果胶杆菌生长曲线、细胞膜脂肪酸含量变化、细胞膜渗透率以及核酸和蛋白质泄漏量的影响,以及果胶杆菌在不同生长期对高压脉冲电场敏感度的差异。结果表明:电场强度和脉冲占空比是影响高压脉冲电场杀灭果胶杆菌的主要因素。当电场强度为28 kV/cm,脉冲占空比为36.5%时,抑菌作用最强,果胶杆菌活菌对数减少值达1.60;在高压脉冲电场作用下,果胶杆菌延滞期延长,生长受到抑制,同时细胞膜结构被破坏,渗透性增大,胞内核酸和蛋白质发生严重泄漏。此外,不同生长期的果胶杆菌对高压脉冲电场敏感度不同,其中对数生长期最为敏感。最后,建立了果胶杆菌活菌对数减少值lnS与电场强度和脉冲占空比的动力学方程(y=-0.1067x+0.1166和y=-0.0895x+0.3249)。该方程符合一级动力学模型,较好地反映了高压脉冲电场处理后果胶杆菌生长的关系,为选择合适的处理条件提供了理论依据。本研究确定了高压脉冲电场杀灭果胶杆菌的最佳参数,为进一步实现高压脉冲电场杀菌保鲜在采后和鲜切行业的产业化应用奠定了基础。
基金Supported by Tobacco Research Project of Hubei Tobacco Company(2011-13)Scientific and Technological Project of Yichang City(A2011-201)
文摘The morphological characteristics, pathogenicity and biological characteristics of the pathogen isolated from Maryland tobacco in Wufeng County of Hubei Province were studied in the laboratory. After cultivation on LB medium at 28℃ for48 h, the colonies were light yellow, circular or amorphous, translucent, with smooth and slightly concaved surface and neat edge. Observation under electron microscope showed that the isolates was red-shaped, decapsulated and gram-nega- tive in the size of （0.5 - 1.0） μm × （2.2 -3.0） μm, with 2 -8 flagella. After cultivation on CVP medium at 28 ℃ for 48 h, the colonies were sunken like a cup. The pathogen was able to grow in 5% NaCl medium at 37 ℃, and produced acid through glucose fermentation; it was facuhative anaerobic, and could use citrates, but could not produce indole. It was preliminarily confirmed that the pathogen causing Wufeng Maryland tobacco hollow stalk was Pectobacterium carotovorum subsp. carotovorum.
