Functional study of Csrbohs in defence response against Xanthomonas citri ssp. citri

2019 ◽  
Vol 46 (6) ◽  
pp. 543 ◽  
Author(s):  
Pengying Mei ◽  
Zhen Song ◽  
Zhong'an Li ◽  
Changyong Zhou
Keyword(s):  
Functional Study ◽  
H2o2 Production ◽  
Citrus Paradisi ◽  
Virus Induced Gene Silencing ◽  
Xanthomonas Citri ◽  
Resistant Genotype ◽  
Plant Pathogen Interaction ◽  
Ros Burst ◽  
Generate Superoxide Anion ◽  
Respiratory Burst Oxidase

NADPH oxidases, encoded by rbohs (respiratory burst oxidase homologues), transfer electrons from NADPH to molecular oxygen (O2) to generate superoxide anion (O2•–), which is the first step in the formation of hydrogen peroxide (H2O2) in the plant–pathogen interaction system. In the present work, six citrus rbohs (Csrbohs) genes were identified in citrus, and their possible involvement in resistance to Xanthomonas citri ssp. citri (Xcc) was examined. Inoculation with Xcc promoted the H2O2 production and induced expression of the Csrbohs, especially CsrbohD. Results showed that CsrbohD was markedly induced in the resistant genotype kumquat ‘Luofu’ [Fortunella margarita (Lour.) Swingle] compared with grapefruit ‘Duncan’ [Citrus paradisi (Linn.) Macf.]. Virus-induced gene silencing (VIGS) of CsrbohD resulted in reduced resistance to Xcc in grapefruit, but not in kumquat. Compared with non-silenced plants, canker-like symptoms were observed earlier, and they were more extensive in the CsrbohD-silenced grapefruit. Silencing of CsrbohD also suppressed the Xcc induced reactive oxygen species (ROS) burst, and resulted in accumulation of more Xcc bacterial colonies. Taken together, these data indicate that CsrbohD promotes resistance to Xcc, especially in grapefruit.

scholarly journals Genome-Wide Analysis of LRR-RLK Gene Family in Four Gossypium Species and Expression Analysis during Cotton Development and Stress Responses

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 592
Author(s):  
Ruibin Sun ◽  
Shaohui Wang ◽  
Dan Ma ◽  
Chuanliang Liu
Keyword(s):  
Gene Family ◽  
Stress Responses ◽  
Functional Divergence ◽  
Comprehensive Analysis ◽  
Functional Study ◽  
Gossypium Species ◽  
Genome Wide ◽  
Plant Pathogen Interaction ◽  
Gossypium Raimondii ◽  
Plant Hormone Signaling

Leucine-rich repeat receptor-like kinases (LRR-RLKs) have been reported to play important roles in plant growth, development, and stress responses. However, no comprehensive analysis of this family has been performed in cotton (Gossypium spp.), which is an important economic crop that suffers various stresses in growth and development. Here we conducted a comprehensive analysis of LRR-RLK family in four Gossypium species (Gossypium arboreum, Gossypium barbadense, Gossypium hirsutum, and Gossypium raimondii). A total of 1641 LRR-RLK genes were identified in the four Gossypium species involved in our study. The maximum-likelihood phylogenetic tree revealed that all the LRR-RLK genes were divided into 21 subgroups. Exon-intron organization structure of LRR-RLK genes kept relatively conserved within subfamilies and between Arabidopsis and Gossypium genomes. Notably, subfamilies XI and XII were found dramatically expanded in Gossypium species. Tandem duplication acted as an important mechanism in expansion of the Gossypium LRR-RLK gene family. Functional analysis suggested that Gossypium LRR-RLK genes were enriched for plant hormone signaling and plant-pathogen interaction pathways. Promoter analysis revealed that Gossypium LRR-RLK genes were extensively regulated by transcription factors (TFs), phytohormonal, and various environmental stimuli. Expression profiling showed that Gossypium LRR-RLK genes were widely involved in stress defense and diverse developmental processes including cotton fiber development and provides insight into potential functional divergence within and among subfamilies. Our study provided valuable information for further functional study of Gossypium LRR-RLK genes.

scholarly journals First Report of Xanthomonas citri pv. citri Pathotype A Causing Asiatic Citrus Canker on Grapefruit and Mexican Lime in Senegal

Plant Disease ◽  
2011 ◽  
Vol 95 (10) ◽  
pp. 1311-1311 ◽  
Author(s):  
A. Leduc ◽  
C. Vernière ◽  
C. Boyer ◽  
K. Vital ◽  
O. Pruvost ◽  
...  
Keyword(s):  
Insertion Sequence ◽  
Indian Subcontinent ◽  
Pcr Amplification ◽  
Citrus Canker ◽  
Pcr Analysis ◽  
Broad Host Range ◽  
Citrus Paradisi ◽  
Xanthomonas Citri ◽  
Mexican Lime ◽  
Dna Fragment

In February 2010, grapefruit (Citrus paradisi) and Mexican lime (C. aurantifolia) leaves with erumpent callus-like lesions were collected in Senegal in the Sebikotane area between Dakar and Thies. Similar symptoms have been observed by local farmers since 2008, and lesions were morphologically similar to those of citrus canker caused by Xanthomonas citri pv. citri (Asiatic canker) and X. citri pv. aurantifolii (South American canker). Lesions were primarily reported from grapefruit (cv. Shambar), which is the most frequent citrus species produced in this area, and Mexican lime, which is also commonly grown. Both species are very susceptible to X. citri pv. citri pathotype A, and Mexican lime is susceptible to X. citri pv. citri pathotype A* and X. citri pv. aurantifolii (4). Fifteen Xanthomonas-like strains were isolated from disease samples using KC semiselective medium (3). PCR with primer pair 4/7 (2) revealed that all the Senegalese strains and the X. citri pv. citri strain CFBP 2525 from New Zealand, used as a positive control, generated the expected DNA fragment, whereas no fragment was observed for negative controls (distilled water instead of the template). Insertion sequence ligation-mediated (IS-LM)-PCR analysis (1) of X. citri pv. citri strains from Senegal and reference strains of X. citri pv. citri pathotypes A and A* (1), with MspI and four primer pairs (unlabelled MspI primer and four 5′-labelled insertion sequence-specific primers targeting three IS elements), indicated that the strains from Senegal were related to X. citri pv. citri but not to pv. aurantifolii. They were closely related to X. citri pv. citri pathotype A strains, with a broad host range, present in the Indian subcontinent and Mali (C. Vernière, unpublished data). Multilocus sequence analysis of four partial housekeeping gene sequences (atpD, dnaK, efp, and gyrB) confirmed that four Senegalese strains were not related to X. citri pv. aurantifolii and showed a full sequence identity to X. citri pv. citri sequence type ST3 (2), fully consistent with IS-LM-PCR. Using a detached leaf assay (4), Duncan grapefruit, Pineapple sweet orange, and Mexican lime leaves inoculated with all strains from Senegal developed typical erumpent, callus-like tissue at wound sites 2 weeks after the inoculations. Xanthomonas-like colonies were reisolated and PCR amplification with the primer pair 4/7 produced the same 468-nt DNA fragment. This represents the fourth outbreak of citrus canker reported from Africa within the last 5 years, the other documented reports were from Ethiopia (2007) and Mali and Somalia (2008). High disease prevalence was observed in Senegal with incidence exceeding 90% in the orchards where lime and grapefruit were infected for 3 years, indicating the suitability of environmental conditions in this region for the development of Asiatic citrus canker. The origin of the inoculum associated with the reported canker outbreak in Senegal is currently unknown and the precise distribution of the pathogen needs to be thoroughly assessed. To our knowledge, this is the first documented report of the presence of Asiatic citrus canker in Senegal and this occurrence increases the threat to citriculture in West Africa. References: (1) L. Bui Thi Ngoc et al. FEMS Microbiol. Lett. 288:33, 2008. (2) L. Bui Thi Ngoc et al. Int. J. Syst. Evol. Microbiol. 60:515, 2010. (3) O. Pruvost et al. J. Appl. Microbiol. 99:803, 2005. (4) C. Vernière et al. Eur. J. Plant Pathol. 104:477, 1998.

scholarly journals Genomic and Transcriptomic Analysis Provide Insights Into Root Rot Resistance in Panax notoginseng

2021 ◽  
Vol 12 ◽  
Author(s):  
Kang Ning ◽  
Mengzhi Li ◽  
Guangfei Wei ◽  
Yuxin Zhou ◽  
Guozhuang Zhang ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Defense Response ◽  
Root Rot ◽  
Panax Notoginseng ◽  
Rna Seq ◽  
Resistant Genotype ◽  
Hub Gene ◽  
Medicinal Value ◽  
Resistant Varieties ◽  
Plant Pathogen Interaction

Panax notoginseng (Panax notoginseng (Burk.) F.H. Chen), a plant of high medicinal value, is severely affected by root rot during cultivation. Here, we generated a reference genome of P. notoginseng, with a contig N50 size of 241.268 kb, and identified 66 disease-resistance genes (R-genes) as candidate genes for breeding disease-resistant varieties. We then investigated the molecular mechanism underlying the responses of resistant and susceptible P. notoginseng genotypes to Fusarium oxysporum infection at six time points by RNA-seq. Functional analysis of the genes differentially expressed between the two genotypes indicated that genes involved in the defense response biological process like hormone transduction and plant-pathogen interaction are continuously and highly expressed in resistant genotype during infection. Moreover, salicylic acid and jasmonic acid levels gradually increased during infection in the resistant genotype. Coexpression analysis showed that PnWRKY22 acts as a hub gene in the defense response of the resistant genotype. Finally, transiently overexpressing PnWRKY22 increased salicylic acid levels in P. notoginseng leaves. Our findings provide a theoretical basis for studying root rot resistance in P. notoginseng.

scholarly journals A stress recovery signaling network for enhanced flooding tolerance inArabidopsis thaliana

2018 ◽  
Vol 115 (26) ◽  
pp. E6085-E6094 ◽  
Author(s):  
Elaine Yeung ◽  
Hans van Veen ◽  
Divya Vashisht ◽  
Ana Luiza Sobral Paiva ◽  
Maureen Hummel ◽  
...  
Keyword(s):  
Recovery Phase ◽  
Signaling Network ◽  
Oxygen Species ◽  
Recovery Processes ◽  
Genome Wide ◽  
Regulatory Module ◽  
Ros Homeostasis ◽  
A Genome ◽  
Ros Burst ◽  
Respiratory Burst Oxidase

Abiotic stresses in plants are often transient, and the recovery phase following stress removal is critical. Flooding, a major abiotic stress that negatively impacts plant biodiversity and agriculture, is a sequential stress where tolerance is strongly dependent on viability underwater and during the postflooding period. Here we show that inArabidopsis thalianaaccessions (Bay-0 and Lp2-6), different rates of submergence recovery correlate with submergence tolerance and fecundity. A genome-wide assessment of ribosome-associated transcripts in Bay-0 and Lp2-6 revealed a signaling network regulating recovery processes. Differential recovery between the accessions was related to the activity of three genes:RESPIRATORY BURST OXIDASE HOMOLOG D,SENESCENCE-ASSOCIATED GENE113, andORESARA1, which function in a regulatory network involving a reactive oxygen species (ROS) burst upon desubmergence and the hormones abscisic acid and ethylene. This regulatory module controls ROS homeostasis, stomatal aperture, and chlorophyll degradation during submergence recovery. This work uncovers a signaling network that regulates recovery processes following flooding to hasten the return to prestress homeostasis.

scholarly journals First report of Xanthomonas citri Subsp. Citri causing citrus canker on grape fruit (Citrus paradisi), washington naval (Citrus sinensis), kaghzi limon (Citrus aurantifolia Swingle), lemon (Citrus lim

2021 ◽  
Vol 58 (04) ◽  
pp. 1373-1377
Author(s):  
Muhammad Shah Nawaz ul Rehman
Keyword(s):  
Citrus Sinensis ◽  
Sequence Similarity ◽  
Citrus Canker ◽  
Citrus Limon ◽  
Evolutionary Analysis ◽  
Citrus Paradisi ◽  
Xanthomonas Citri ◽  
Citrus Aurantifolia ◽  
Grape Fruit ◽  
Citrus Maxima

Citrus fruit production is largely affected by different bacterial and fungal pathogens. In Pakistan bacterial diseases like citrus bacterial canker (CBC) pose severe risk to citrus economy. Diagnoses of such diseases could be helpful to avoid the epidemics in nurseries or orchids. In 2011-12, citrus canker symptoms i.e., callus-like outgrowths on leaves and fruits of grape fruit (Citrus paradisi), Washington naval (Citrus sinensis), Kaghzi Limon (Citrus aurantifolia swingle), lemon (Citrus Limon) and pomelo (Citrus maxima) were noticed in Sargodha district of Punjab, Pakistan. Bacteria i.e., yellow mucoid, Xanthomonas- like isolates, were isolated from these lesions. Bacteria isolated from these lesions were cultured and total DNA was isolated. A diagnostic fragment of 581 bp based on rpf genes of Xanthomonas citri pv. citri was amplified, cloned and completely sequenced. BLAST and evolutionary analysis revealed that these isolates show 100% sequence similarity and group with Xanthomonas citri subsp. citri from Argentina (CP023285) and Reunion (CP018858), (CP018854). To our knowledge, this is the first formal report of X. campestris pv. citri pathotypes A on Citrus paradise, Citrus sinensis, Citrus maxima, Citrus Limon and Citrus aurantifolia swingle in Pakistan

Overexpression of HvAKT1 improves drought tolerance in barley by regulating root ion homeostasis and ROS and NO signaling

2020 ◽  
Vol 71 (20) ◽  
pp. 6587-6600
Author(s):  
Xue Feng ◽  
Wenxing Liu ◽  
Fangbin Cao ◽  
Yizhou Wang ◽  
Guoping Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Molecular Mechanisms ◽  
Ion Homeostasis ◽  
Enzyme Activation ◽  
K Channel ◽  
H2o2 Production ◽  
Virus Induced Gene Silencing ◽  
K Uptake ◽  
Drought Treatment

Abstract Potassium (K+) is the major cationic inorganic nutrient utilized for osmotic regulation, cell growth, and enzyme activation in plants. Inwardly rectifying K+ channel 1 (AKT1) is the primary channel for root K+ uptake in plants, but the function of HvAKT1 in barley plants under drought stress has not been fully elucidated. In this study, we conducted evolutionary bioinformatics, biotechnological, electrophysiological, and biochemical assays to explore molecular mechanisms of HvAKT1 in response to drought in barley. The expression of HvAKT1 was significantly up-regulated by drought stress in the roots of XZ5—a drought-tolerant wild barley genotype. We isolated and functionally characterized the plasma membrane-localized HvAKT1 using Agrobacterium-mediated plant transformation and Barley stripe mosaic virus-induced gene silencing of HvAKT1 in barley. Evolutionary bioinformatics indicated that the K+ selective filter in AKT1 originated from streptophyte algae and is evolutionarily conserved in land plants. Silencing of HvAKT1 resulted in significantly decreased biomass and suppressed K+ uptake in root epidermal cells under drought treatment. Disruption of HvAKT1 decreased root H+ efflux, H+-ATPase activity, and nitric oxide (NO) synthesis, but increased hydrogen peroxide (H2O2) production in the roots under drought stress. Furthermore, we observed that overexpression of HvAKT1 improves K+ uptake and increases drought resistance in barley. Our results highlight the importance of HvAKT1 for root K+ uptake and its pleiotropic effects on root H+-ATPase, and H2O2 and NO in response to drought stress, providing new insights into the genetic basis of drought tolerance and K+ nutrition in barley.

scholarly journals Focal Accumulation of ROS Can Block Pyricularia oryzae Effector BAS4-Expression and Prevent Infection in Rice

2020 ◽  
Vol 21 (17) ◽  
pp. 6196
Author(s):  
Yafei Chen ◽  
Sarmina Dangol ◽  
Juan Wang ◽  
Nam-Soo Jwa
Keyword(s):  
Plant Immunity ◽  
Pathogenic Fungus ◽  
Hyphal Growth ◽  
Infection Process ◽  
Pyricularia Oryzae ◽  
High Concentrations ◽  
Ros Burst ◽  
Immunity Mechanism ◽  
Respiratory Burst Oxidase

The reactive oxygen species (ROS) burst is the most common plant immunity mechanism to prevent pathogen infection, although the exact role of ROS in plant immunity has not been fully elucidated. We investigated the expression and translocation of Oryza sativa respiratory burst oxidase homologue B (OsRBOHB) during compatible and incompatible interactions between rice epidermal cells and the pathogenic fungus Pyricularia oryzae (syn. Magnaporthe oryzae). We characterized the functional role of ROS focal accumulation around invading hyphae during P. oryzae infection process using the OsRBOHB inhibitor diphenyleneiodonium (DPI) and the actin filament polymerization inhibitor cytochalasin (Cyt) A. OsRBOHB was strongly induced during incompatible rice–P. oryzae interactions, and newly synthesized OsRBOHB was focally distributed at infection sites. High concentrations of ROS focally accumulated at the infection sites and suppressed effector biotrophy-associated secreted (BAS) proteins BAS4 expression and invasive hyphal growth. DPI and Cyt A abolished ROS focal accumulation and restored P. oryzae effector BAS4 expression. These results suggest that ROS focal accumulation is able to function as an effective immune mechanism that blocks some effectors including BAS4-expression during P. oryzae infection. Disruption of ROS focal accumulation around invading hyphae enables successful P. oryzae colonization of rice cells and disease development.

scholarly journals Positive Interaction between H2O2 and Ca2+ Mediates Melatonin-Induced CBF Pathway and Cold Tolerance in Watermelon (Citrullus lanatus L.)

Antioxidants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1457
Author(s):  
Jingjing Chang ◽  
Yanliang Guo ◽  
Jiayue Li ◽  
Zhuangzhuang Su ◽  
Chunxia Wang ◽  
...  
Keyword(s):  
Cold Stress ◽  
Cold Tolerance ◽  
Citrullus Lanatus ◽  
Early Response ◽  
H2o2 Production ◽  
Plant Tolerance ◽  
Positive Interaction ◽  
H2o2 Accumulation ◽  
Regulatory Loop ◽  
Respiratory Burst Oxidase

Cold stress is a major environmental factor that detrimentally affects plant growth and development. Melatonin has been shown to confer plant tolerance to cold stress through activating the C-REPEAT BINDING FACTOR (CBF) pathway; however, the underlying modes that enable this function remain obscure. In this study, we investigated the role of H2O2 and Ca2+ signaling in the melatonin-induced CBF pathway and cold tolerance in watermelon (Citrullus lanatus L.) through pharmacological, physiological, and genetic approaches. According to the results, melatonin induced H2O2 accumulation, which was associated with the upregulation of respiratory burst oxidase homolog D (ClRBOHD) during the early response to cold stress in watermelon. Besides, melatonin and H2O2 induced the accumulation of cytoplasmic free Ca2+ ([Ca2+]cyt) in response to cold. This was associated with the upregulation of cyclic nucleotide-gated ion channel 2 (ClCNGC2) in watermelon. However, blocking of Ca2+ influx channels abolished melatonin- or H2O2-induced CBF pathway and cold tolerance. Ca2+ also induced ClRBOHD expression and H2O2 accumulation in early response to cold stress in watermelon. Inhibition of H2O2 production in watermelon by RBOH inhibitor or in Arabidopsis by AtRBOHD knockout compromised melatonin-induced [Ca2+]cyt accumulation and melatonin- or Ca2+-induced CBF pathway and cold tolerance. Overall, these findings indicate that melatonin induces RBOHD-dependent H2O2 generation in early response to cold stress. Increased H2O2 promotes [Ca2+]cyt accumulation, which in turn induces H2O2 accumulation via RBOHD, forming a reciprocal positive-regulatory loop that mediates melatonin-induced CBF pathway and subsequent cold tolerance.

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