pathogen attack
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2021 ◽  
Vol 12 ◽  
Author(s):  
Jian Sun ◽  
Youzheng Ning ◽  
Limin Wang ◽  
Katie A. Wilkins ◽  
Julia M. Davies

Extracellular ATP (eATP) is now held to be a constitutive damage-associated molecular pattern (DAMP) that is released by wounding, herbivory or pathogen attack. The concentration of eATP must be tightly regulated as either depletion or overload leads to cell death. In Arabidopsis thaliana, sensing of eATP is by two plasma membrane legume-like lectin serine–threonine receptor kinases (P2K1 and P2K2), although other receptors are postulated. The transcriptional response to eATP is dominated by wound- and defense-response genes. Wounding and pathogen attack can involve the cyclic nucleotides cyclic AMP (cAMP) and cyclic GMP (cGMP) which, in common with eATP, can increase cytosolic-free Ca2+ as a second messenger. This perspective on DAMP signaling by eATP considers the possibility that the eATP pathway involves production of cyclic nucleotides to promote opening of cyclic nucleotide-gated channels and so elevates cytosolic-free Ca2+. In silico analysis of P2K1 and P2K2 reveals putative adenylyl and guanylyl kinase sequences that are the hallmarks of “moonlighting” receptors capable of cAMP and cGMP production. Further, an Arabidopsis loss of function cngc mutant was found to have an impaired increase in cytosolic-free Ca2+ in response to eATP. A link between eATP, cyclic nucleotides, and Ca2+ signaling therefore appears credible.


2021 ◽  
Author(s):  
Yi Ding ◽  
Donald M Gardiner ◽  
Jonathan J Powell ◽  
Michelle L Colgrave ◽  
Robert F Park ◽  
...  

Author(s):  
Alhagie K. Cham ◽  
Ma del Carmen Ojeda Zacarías ◽  
Héctor Lozoya Saldaña ◽  
Rigoberto E. Vázquez Alvarado ◽  
Emilio Olivares Sáenz ◽  
...  

Plants protect themselves, after pathogen attack, through the passive and active defense mechanisms. The treatment of plants with various agents, including cell wall fragments, plant extracts, and synthetic chemicals, can induce resistance to subsequent pathogen attack both locally and systemically. In view of the capability of phytochemicals compounds found in fruits and vegetables with different proven health benefits to consumers, there are different strategies to enhance the concentration of these compounds, among which the use of elicitors. Elicitation has been used to trigger different defense responses in plants, which lead to different mechanisms, such as activation of enzymes related with secondary metabolism. In this study we investigated the effects of elicitors (Activane®, Micobiol®, Stemicol® in doses of 1.8 g L⁻¹, 3 m L⁻¹ and 2.5 g·L⁻¹) on the activity of two enzymes (polyphenoloxydase and peroxidase) in leaves as well as on the bioactive content (DPPH scavenging activity, total phenol and total flavonoid content) in fruits of Solanum lycopersicumL. The elicitors studied affected the production of enzyme and antioxidant activities in tomato, though showed a variable influence on the production of total phenolic and flavonoid content in tomato fruits. In general, the elicitors are able to increase polyphenoloxydase activity in leaves and phytochemical properties in fruits, with a significant negative correlation between the DPPH scavenging activity, total phenolic and flavonoids. These findings provide positive directions for the possible use of these elicitors in tomato (‘Bola’ and ‘Saladette’) production in greenhouse. Highlights - Elicitors increase the enzymatic activity of PPO in tomato leaves. - The production of total phenolic contents and flavonoids depends on type of elicitors. - No effects on the peroxidase content of the tomato leaves. - The antioxidant capacity of the aqueous fruits extract showed a significant difference (P = 0.05) between the treatments in the Saladette variety. - Positive relationship between total phenolic contents and flavonoids.


2021 ◽  
Author(s):  
Anne Cortleven ◽  
Venja M. Roeber ◽  
Manuel Frank ◽  
Jonas Bertels ◽  
Vivien Lortzing ◽  
...  

ABSTRACTPlants are exposed to regular diurnal rhythms of light and dark. Changes in the photoperiod by the prolongation of the light period cause photoperiod stress in short day-adapted Arabidopsis thaliana. Here we report on the transcriptional response to photoperiod stress of wild-type A. thaliana and photoperiod stress-sensitive cytokinin signalling and clock mutants. Transcriptomic changes induced by photoperiod stress included numerous changes in reactive oxygen (ROS)-related transcripts and showed a strong overlap with changes occurring in response to ozone stress and pathogen attack, which have in common the induction of an apoplastic oxidative burst. A core set of photoperiod stress-responsive genes has been identified, including salicylic acid (SA) biosynthesis and signalling genes. Genetic analysis revealed a central role for NPR1 in the photoperiod stress response as npr1-1 mutants were stress-insensitive. Photoperiod stress treatment led to a strong increase in camalexin levels which is consistent with shared photoperiod stress and pathogen response pathways. Photoperiod stress induced resistance of Arabidopsis plants to a subsequent infection by Pseudomonas syringae cv. tomato DC3000 indicating priming of the defence response. Together, photoperiod stress causes transcriptional reprogramming resembling plant pathogen defence responses and induces systemic acquired resistance in the absence of a pathogen.One sentence summaryPhotoperiod stress results in significant dynamic transcriptomic changes related to oxidative stress similar to those caused by pathogen attack and primes the defence response against a subsequent pathogen infection.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tong Huo ◽  
Chang-Tao Wang ◽  
Tai-Fei Yu ◽  
Da-Ming Wang ◽  
Meng Li ◽  
...  

AbstractPlant-specific WRKY transcription factors play important roles in regulating the expression of defense-responsive genes against pathogen attack. A multiple stress-responsive WRKY gene, ZmWRKY65, was identified in maize by screening salicylic acid (SA)-induced de novo transcriptomic sequences. The ZmWRKY65 protein was localized in the nucleus of mesophyll protoplasts. The analysis of the ZmWRKY65 promoter sequence indicated that it contains several stress-related transcriptional regulatory elements. Many environmental factors affecting the transcription of ZmWRKY65 gene, such as drought, salinity, high temperature and low temperature stress. Moreover, the transcription of ZmWRKY65 gene was also affected by the induction of defense related plant hormones such as SA and exogenous ABA. The results of seed germination and stomatal aperture assays indicated that transgenic Arabidopsis plants exhibit enhanced sensitivity to ABA and high concentrations of SA. Overexpression of ZmWRKY65 improved tolerance to both pathogen attack and abiotic stress in transgenic Arabidopsis plants and activated several stress-related genes such as RD29A, ERD10, and STZ as well as pathogenesis-related (PR) genes such as PR1, PR2 and PR5; these genes are involved in resistance to abiotic and biotic stresses in Arabidopsis. Together, this evidence implies that the ZmWRKY65 gene is involved in multiple stress signal transduction pathways.


2021 ◽  
Vol 12 ◽  
Author(s):  
Diego Alberto Mengarelli ◽  
Lara Roldán Tewes ◽  
Salma Balazadeh ◽  
María Inés Zanor

Plants, as sessile organisms, are continuously threatened by multiple factors and therefore their profitable production depends on how they can defend themselves. We have previously reported on the characterization of fitness mutants which are more tolerant to environmental stresses due to the activation of defense mechanisms. Here, we demonstrate that in fitness mutants, which accumulate moderate levels of salicylic acid (SA) and have SA signaling activated, pathogen infection is restricted. Also, we demonstrate that NPR1 is essential in fitness mutants for SA storage and defense activation but not for SA synthesis after Pseudomonas syringae (Pst) infection. Additionally, these mutants do not appear to be metabolically impared, resulting in a higher seed set even after pathogen attack. The FITNESS transcriptional network includes defense-related transcription factors (TFs) such as ANAC072, ORA59, and ERF1 as well as jasmonic acid (JA) related genes including LIPOXYGENASE2 (LOX2), CORONATINE INSENSITIVE1 (COI1), JASMONATE ZIM-domain3 (JAZ3) and JAZ10. Induction of FITNESS expression leads to COI1 downregulation, and to JAZ3 and JAZ10 upregulation. As COI1 is an essential component of the bioactive JA perception apparatus and is required for most JA-signaling processes, elevated FITNESS expression leads to modulated JA-related responses. Taken together, FITNESS plays a crucial role during pathogen attack and allows a cost-efficient way to prevent undesirable developmental effects.


2021 ◽  
Author(s):  
Marta Markiewicz ◽  
Piotr Lewandowski ◽  
Maciej Spychalski ◽  
Rafal Kukawka ◽  
Joanna Feder-Kubis ◽  
...  

Systemic acquired resistance (SAR) is a natural mechanism that is triggered in plants as a response to pathogen attack and results in systemic increased resistance. SAR inducers are therefore an...


2020 ◽  
Vol 22 (1) ◽  
pp. 3-18
Author(s):  
Zhi‐Qin Liu ◽  
Lan‐Ping Shi ◽  
Sheng Yang ◽  
Shan‐Shan Qiu ◽  
Xiao‐Ling Ma ◽  
...  
Keyword(s):  

2020 ◽  
Vol 21 (7) ◽  
pp. 491-503
Author(s):  
Indrani Baruah ◽  
Gajendra Mohan Baldodiya ◽  
Jagajjit Sahu ◽  
Geetanjali Baruah

Plants inherently show resistance to pathogen attack but are susceptible to multiple bacteria, viruses, fungi, and phytoplasmas. Diseases as a result of such infection leads to the deterioration of crop yield. Several pathogen-sensitive gene activities, promoters of such genes, associated transcription factors, and promoter elements responsible for crosstalk between the defense signaling pathways are involved in plant resistance towards a pathogen. Still, only a handful of genes and their promoters related to plant resistance have been identified to date. Such pathogen-sensitive promoters are accountable for elevating the transcriptional activity of certain genes in response to infection. Also, a suitable promoter is a key to devising successful crop improvement strategies as it ensures the optimum expression of the required transgene. The study of the promoters also helps in mining more details about the transcription factors controlling their activities and helps to unveil the involvement of new genes in the pathogen response. Therefore, the only way out to formulate new solutions is by analyzing the molecular aspects of these promoters in detail. In this review, we provided an overview of the promoter motifs and cis-regulatory elements having specific roles in pathogen attack response. To elaborate on the importance and get a vivid picture of the pathogen-sensitive promoter sequences, the key motifs and promoter elements were analyzed with the help of PlantCare and interpreted with available literature. This review intends to provide useful information for reconstructing the gene networks underlying the resistance of plants against pathogens.


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