scholarly journals The Induction of Tomato Leucine Aminopeptidase Genes (LapA) After Pseudomonas syringae pv. tomato Infection Is Primarily a Wound Response Triggered by Coronatine

2001 ◽  
Vol 14 (2) ◽  
pp. 214-224 ◽  
Author(s):  
Véronique Pautot ◽  
Frances M. Holzer ◽  
Josette Chaufaux ◽  
Linda L. Walling

Tomato plants constitutively express a neutral leucine aminopeptidase (LAP-N) and an acidic LAP (LAP-A) during floral development and in leaves in response to insect infestation, wounding, and Pseudomonas syringae pv. tomato infection. To assess the physiological roles of LAP-A, a LapA-antisense construct (35S:asLapA1) was introduced into tomato. The 35S:asLapA1 plants had greatly reduced or showed undetectable levels of LAP-A and LAP-N proteins in healthy and wounded leaves and during floral development. Despite the loss of these aminopeptidases, no global changes in protein profiles were noted. The 35S:asLapA1 plants also exhibited no significant alteration in floral development and did not impact the growth and development of Manduca sexta and P. syringae pv. tomato growth rates during compatible or incompatible infections. To investigate the mechanism underlying the strong induction of LapA upon P. syringae pv. tomato infection, LapA expression was monitored after infection with coronatine-producing and -deficient P. syringae pv. tomato strains. LapA RNA and activity were detected only with the coronatine-producing P. syringae pv. tomato strain. Coronatine treatment of excised shoots caused increases in RNAs for jasmonic acid (JA)-regulated wound-response genes (LapA and pin2) but did not influence expression of a JA-regulated pathogenesis-related protein gene (PR-1). These results indicated that coronatine mimicked the wound response but was insufficient to activate JA-regulated PR genes.

Author(s):  
Mara Quaglia ◽  
Marika Bocchini ◽  
Benedetta Orfei ◽  
Roberto D’Amato ◽  
Franco Famiani ◽  
...  

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses.


Plant Disease ◽  
2012 ◽  
Vol 96 (8) ◽  
pp. 1204-1209 ◽  
Author(s):  
Hardian S. Addy ◽  
Ahmed Askora ◽  
Takeru Kawasaki ◽  
Makoto Fujie ◽  
Takashi Yamada

The wide host range of Ralstonia solanacearum, causal agent of bacterial wilt, and its ability to survive for long periods in the environment restrict the effectiveness of cultural and chemical control measures. The use of phages for disease control is a fast-expanding trend of plant protection with great potential to replace chemical measures. The filamentous phage ϕRSM3 that infects R. solanacearum strains and inactivates virulence on plants is a potential agent for controlling bacterial wilt in tomato. We demonstrated that inoculation of ϕRSM3-infected cells into tomato plants did not cause bacterial wilt. Instead, ϕRSM3-infected cells enhanced the expression of pathogenesis-related (PR) genes, including PR-1a, PR-2b, and PR7, in tomato plants. Moreover, pretreatment with ϕRSM-infected cells protect tomato plants from infection by virulent R. solanacearum strains. The effective dose of ϕRSM3-infected cells for disease prevention was determined to be approximately 105 CFU/ml. Because the ϕRSM3-infected cells can grow and continue to produce infectious phage particles under appropriate conditions, ϕRSM phages may serve as an efficient tool to control bacterial wilt in crops.


2016 ◽  
Vol 29 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Eva-Maria Disch ◽  
Meixuezi Tong ◽  
Tanja Kotur ◽  
Gerald Koch ◽  
Carl-Asmus Wolf ◽  
...  

Plants have evolved elaborate mechanisms to regulate pathogen defense. Imbalances in this regulation may result in autoimmune responses that are affecting plant growth and development. In Arabidopsis, SAUL1 encodes a plant U-box ubiquitin ligase and regulates senescence and cell death. Here, we show that saul1-1 plants exhibit characteristics of an autoimmune mutant. A decrease in relative humidity or temperature resulted in reduced growth and systemic lesioning of saul1-1 rosettes. These physiological changes are associated with increased expression of salicylic acid–dependent and pathogenesis-related (PR) genes. Consistently, resistance of saul1-1 plants against Pseudomonas syringae pv. maculicola ES4326, P. syringae pv. tomato DC3000, or Hyaloperonospora arabidopsidis Noco2 was enhanced. Transmission electron microscopy revealed alterations in saul1-1 chloroplast ultrastructure and cell-wall depositions. Confocal analysis on aniline blue–stained leaf sections and cellular universal micro spectrophotometry further showed that these cell-wall depositions contain callose and lignin. To analyze signaling downstream of SAUL1, we performed epistasis analyses between saul1-1 and mutants in the EDS1/PAD4/SAG101 hub. All phenotypes observed in saul1-1 plants at low temperature were dependent on EDS1 and PAD4 but not SAG101. Taken together, SAUL1 negatively regulates immunity upstream of EDS1/PAD4, likely through the degradation of an unknown activator of the pathway.


2016 ◽  
Vol 29 (12) ◽  
pp. 977-989 ◽  
Author(s):  
Xiaodong Wang ◽  
Baoju Yang ◽  
Kun Li ◽  
Zhensheng Kang ◽  
Dario Cantu ◽  
...  

In Arabidopsis, NPR1 is a key transcriptional coregulator of systemic acquired resistance. Upon pathogen challenge, NPR1 translocates from the cytoplasm to the nucleus, in which it interacts with TGA-bZIP transcription factors to activate the expression of several pathogenesis-related (PR) genes. In a screen of a yeast two-hybrid library from wheat leaves infected with Puccinia striiformis f. sp. tritici, we identified a conserved rust protein that interacts with wheat NPR1 and named it PNPi (for Puccinia NPR1 interactor). PNPi interacts with the NPR1/NIM1-like domain of NPR1 via its C-terminal DPBB_1 domain. Using bimolecular fluorescence complementation assays, we detected the interaction between PNPi and wheat NPR1 in the nucleus of Nicotiana benthamiana protoplasts. A yeast three-hybrid assay showed that PNPi interaction with NPR1 competes with the interaction between wheat NPR1 and TGA2.2. In barley transgenic lines overexpressing PNPi, we observed reduced induction of multiple PR genes in the region adjacent to Pseudomonas syringae pv. tomato DC3000 infection. Based on these results, we hypothesize that PNPi has a role in manipulating wheat defense response via its interactions with NPR1.


Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2283
Author(s):  
Ameena A. Al-Surhanee ◽  
Muhammad Afzal ◽  
Nahla Alsayed Bouqellah ◽  
Salama A. Ouf ◽  
Sajid Muhammad ◽  
...  

Pathogenic infestations are significant threats to vegetable yield, and have become an urgent problem to be solved. Rhizoctonia solani is one of the worst fungi affecting tomato crops, reducing yield in some regions. It is a known fact that plants have their own defense against such infestations; however, it is unclear whether any exogenous material can help plants against infestation. Therefore, we performed greenhouse experiments to evaluate the impacts of R. solani on 15- and 30-day old tomato plants after fungal infestation, and estimated the antifungal activity of nanoparticles (NPs) against the pathogen. We observed severe pathogenic impacts on the above-ground tissues of tomato plants which would affect plant physiology and crop production. Pathogenic infection reduced total chlorophyll and anthocyanin contents, which subsequently disturbed plant physiology. Further, total phenolic contents (TPC), total flavonoid contents (TFC), and malondialdehyde (MDA) contents were significantly increased in pathogen treatments. Constitutively, enhanced activities were estimated for catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) in response to reactive oxygen species (ROS)in pathogen-treated plants. Moreover, pathogenesis-related genes, namely, chitinase, plant glutathione S-transferase (GST), phenylalanine ammonia-lyase (PAL1), pathogenesis-related protein (PR12), and pathogenesis-related protein (PR1) were evaluated, with significant differences between treated and control plants. In vitro and greenhouse antifungal activity of silver nanoparticles (Ag NPs), chitosan nanoparticles, and Ag NPs/CHI NPs composites and plant health was studied using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectrophotometry. We found astonishing results, namely, that Ag and CHI have antifungal activities against R. solani. Overall, plant health was much improved following treatment with Ag NPs/CHI NPs composites. In order to manage R. solani pathogenicity and improve tomato health, Ag/CHI NPs composites could be used infield as well as on commercial levels based on recommendations. However, there is an urgent need to first evaluate whether these NP composites have any secondary impacts on human health or the environment.


2010 ◽  
Vol 23 (3) ◽  
pp. 340-351 ◽  
Author(s):  
Madhumati Mukherjee ◽  
Katherine E. Larrimore ◽  
Naushin J. Ahmed ◽  
Tyler S. Bedick ◽  
Nadia T. Barghouthi ◽  
...  

The ascorbic acid (AA)-deficient Arabidopsis thaliana vtc1-1 mutant exhibits increased resistance to the virulent bacterial pathogen Pseudomonas syringae. This response correlates with heightened levels of salicylic acid (SA), which induces antimicrobial pathogenesis-related (PR) proteins. To determine if SA-mediated, enhanced disease resistance is a general phenomenon of AA deficiency, to elucidate the signal that stimulates SA synthesis, and to identify the biosynthetic pathway through which SA accumulates, we studied the four AA-deficient vtc1-1, vtc2-1, vtc3-1, and vtc4-1 mutants. We also studied double mutants defective in the AA-biosynthetic gene VTC1 and the SA signaling pathway genes PAD4, EDS5, and NPR1, respectively. All vtc mutants were more resistant to P. syringae than the wild type. With the exception of vtc4-1, this correlated with constitutively upregulated H2O2, SA, and messenger RNA levels of PR genes. Double mutants exhibited decreased SA levels and enhanced susceptibility to P. syringae compared with the wild type, suggesting that vtc1-1 requires functional PAD4, EDS5, and NPR1 for SA biosynthesis and pathogen resistance. We suggest that AA deficiency causes constitutive priming through a buildup of H2O2 that stimulates SA accumulation, conferring enhanced disease resistance in vtc1-1, vtc2-1, and vtc3-1, whereas vtc4-1 might be sensitized to H2O2 and SA production after infection.


Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 287
Author(s):  
Huub de Jong ◽  
Tony Reglinski ◽  
Philip A.G. Elmer ◽  
Kirstin Wurms ◽  
Joel L. Vanneste ◽  
...  

An isolate of Aureobasidium pullulans (strain = CG163) and the plant defence elicitor acibenzolar-S-methyl (ASM) were investigated for their ability to control leaf spot in kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 (Psa). Clonal Actinidia chinensis var. deliciosa plantlets (‘Hayward’) were treated with ASM, CG163 or ASM + CG163 at seven and one day before inoculation with Psa. ASM (0.2 g/L) was applied either as a root or foliar treatments and CG163 was applied as a foliar spray containing 2 × 107 CFU/mL. Leaf spot incidence was significantly reduced by all treatments compared with the control. The combination of ASM + CG163 had greater efficacy (75%) than either ASM (55%) or CG163 (40%) alone. Moreover, treatment efficacy correlated positively with the expression of defence-related genes: pathogenesis-related protein 1 (PR1), β-1,3-glucosidase, Glucan endo 1,3-β-glucosidase (Gluc_PrimerH) and Class IV chitinase (ClassIV_Chit), with greater gene upregulation in plants treated with ASM + CG163 than by the individual treatments. Pathogen population studies indicated that CG163 had significant suppressive activity against epiphytic populations of Psa. Endophytic populations were reduced by ASM + CG163 but not by the individual treatments, and by 96–144 h after inoculation were significantly lower than the control. Together these data suggest that ASM + CG163 have complementary modes of action that contribute to greater control of leaf spotting than either treatment alone.


2020 ◽  
Vol 110 (4) ◽  
pp. 873-880 ◽  
Author(s):  
Xinxin Hou ◽  
Jun Cui ◽  
Weiwei Liu ◽  
Ning Jiang ◽  
Xiaoxu Zhou ◽  
...  

Our previous study has indicated that a long noncoding RNA (lncRNA), lncRNA39026, can be responsive to Phytophthora infestans infection. However, the function and regulation mechanism of lncRNA39026 during tomato resistance to P. infestans are unknown. In this study, an lncRNA39026 sequence was cloned from tomato Zaofen No. 2, and this sequence contained an endogenous target mimicry for miR168a, which might suppress the expression of miR168a. LncRNA39026 was strongly downregulated at 3 h in the tomato plants infected with P. infestans, and its expression level displayed a negative correlation with the expression level of miR168a and a positive correlation with the expression levels of SlAGO1 genes (target gene of miR168a) upon P. infestans infection. Tomato plants in which lncRNA39026 was overexpressed displayed enhanced resistance to P. infestans, decreased level of miR168a, and increased level of SlAGO1, whereas the resistance was impaired, level of miR168a was increased, and level of SlAGO1 was decreased after lncRNA39026 silencing. In addition, lncRNA39026 could also induce the expression of pathogenesis-related (PR) genes, as shown by increased and decreased expression levels of PR genes in tomato plants with overexpressed and silenced lncRNA39026, respectively. The result demonstrated that lncRNA39026 might function to decoy miR168a and affect the expression of PR genes in tomato plants, increasing resistance to disease.


2019 ◽  
Vol 48 (6) ◽  
pp. 1425-1433 ◽  
Author(s):  
Hongying Cui ◽  
Yucheng Sun ◽  
Zihua Zhao ◽  
Youjun Zhang

Abstract Global change and biotic stress, such as tropospheric contamination and virus infection, can individually modify the quality of host plants, thereby altering the palatability of the plant for herbivorous insects. The bottom-up effects of elevated O3 and tomato yellow leaf curl virus (TYLCV) infection on tomato plants and the associated performance of Bemisia tabaci Mediterranean (MED) were determined in open-top chambers. Elevated O3 decreased eight amino acid levels and increased the salicylic acid (SA) and jasmonic acid (JA) content and the gene expression of pathogenesis-related protein (PR1) and proteinase inhibitor (PI1) in both wild-type (CM) and JA defense-deficient tomato genotype (spr2). TYLCV infection and the combination of elevated O3 and TYLCV infection increased eight amino acids levels, SA content and PR1 expression, and decreased JA content and PI1 expression in both tomato genotypes. In uninfected tomato, elevated O3 increased developmental time and decreased fecundity by 6.1 and 18.8% in the CM, respectively, and by 6.8 and 18.9% in the spr2, respectively. In TYLCV-infected tomato, elevated O3 decreased developmental time and increased fecundity by 4.6 and 14.2%, respectively, in the CM and by 4.3 and 16.8%, respectively, in the spr2. These results showed that the interactive effects of elevated O3 and TYLCV infection partially increased the amino acid content and weakened the JA-dependent defense, resulting in increased population fitness of MED on tomato plants. This study suggests that whiteflies would be more successful at TYLCV-infected plants than at uninfected plants in elevated O3 levels.


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