scholarly journals Overexpression of (At)NPR1 in Rice Leads to a BTH- and Environment-Induced Lesion-Mimic/Cell Death Phenotype

2004 ◽  
Vol 17 (2) ◽  
pp. 140-151 ◽  
Author(s):  
Heather A. Fitzgerald ◽  
Maw-Sheng Chern ◽  
Roy Navarre ◽  
Pamela C. Ronald

Systemic acquired resistance (SAR) is an inducible defense response that protects plants against a broad spectrum of pathogens. A central regulator of SAR in Arabidopsis is NPR1 (nonexpresser of pathogenesis-related genes). In rice, overexpression of Arabidopsis NPR1 enhances plant resistance to the bacterial pathogen Xanthomonas oryzae pv. oryzae. This report demonstrates that overexpression of (At)NPR1 in rice also triggers a lesion-mimic/cell death (LMD) phenotype. The LMD phenotype is environmentally regulated and heritable. In addition, the development of lesions and death correlates with the expression of rice defense genes and the accumulation of hydrogen peroxide. Application of the salicylic acid (SA) analog, benzo(1,2,3) thiadiazole-7-carbothioc acid S-methyl ester (BTH), potentiates this phenotype. Endogenous SA levels are reduced in rice overexpressing (At)NPR1 when compared with wild-type plants, supporting the idea that (At)NPR1 may perceive and modulate the accumulation of SA. The association of (At)NPR1 expression in rice with the development of an LMD phenotype suggests that (At)NPR1 has multiple roles in plant stress responses that may affect its efficacy as a transgenic tool for engineering broad-spectrum resistance.

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12617
Author(s):  
Yarui Wei ◽  
Shuliang Zhao ◽  
Na Liu ◽  
Yuxing Zhang

The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1) plays a master regulatory role in the salicylic acid (SA) signal transduction pathway and plant systemic acquired resistance (SAR). Members of the NPR1-like gene family have been reported to the associated with biotic/abiotic stress in many plants, however the genome-wide characterization of NPR1-like genes has not been carried out in Chinese pear (Pyrus bretschneideri Reld). In this study, a systematic analysis was conducted on the characteristics of the NPR1-like genes in P. bretschneideri Reld at the whole-genome level. A total nine NPR1-like genes were detected which eight genes were located on six chromosomes and one gene was mapped to scaffold. Based on the phylogenetic analysis, the nine PbrNPR1-like proteins were divided into three clades (Clades I–III) had similar gene structure, domain and conserved motifs. We sorted the cis-acting elements into three clades, including plant growth and development, stress responses, and hormone responses in the promoter regions of PbrNPR1-like genes. The result of qPCR analysis showed that expression diversity of PbrNPR1-like genes in various tissues. All the genes were up-regulated after SA treatment in leaves except for Pbrgene8896. PbrNPR1-like genes showed circadian rhythm and significantly different expression levels after inoculation with Alternaria alternata. These findings provide a solid insight for understanding the functions and evolution of PbrNPR1-like genes in Chinese pear.


2018 ◽  
Author(s):  
Yun Chu Chen ◽  
Eric C. Holmes ◽  
Jakub Rajniak ◽  
Jung-Gun Kim ◽  
Sandy Tang ◽  
...  

AbstractSystemic acquired resistance (SAR) is a global response in plants induced at the site of infection that leads to long-lasting and broad-spectrum disease resistance at distal, uninfected tissues. Despite the importance of this priming mechanism, the identity of the mobile defense signal that moves systemically throughout plants to initiate SAR has remained elusive. In this paper, we describe a new metabolite, N-hydroxy-pipecolic acid (N-OH-Pip), and provide evidence that this molecule is a mobile signal that plays a central role in initiating SAR signal transduction in Arabidopsis thaliana. We demonstrate that FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1), a key regulator of SAR-associated defense priming, can synthesize N-OH-Pip from pipecolic acid in planta, and exogenously applied N-OH-PIP moves systemically in Arabidopsis and can rescue the SAR-deficiency of fmo1 mutants. We also demonstrate that N-OH-Pip treatment causes systemic changes in the expression of pathogenesis-related genes and metabolic pathways throughout the plant, and enhances resistance to a bacterial pathogen. This work provides new insight into the chemical nature of a mobile signal for SAR and also suggests that the N-OH-Pip pathway is a promising target for metabolic engineering to enhance disease resistance.


BioEssays ◽  
2006 ◽  
Vol 28 (11) ◽  
pp. 1091-1101 ◽  
Author(s):  
Tsanko S. Gechev ◽  
Frank Van Breusegem ◽  
Julie M. Stone ◽  
Iliya Denev ◽  
Christophe Laloi

2018 ◽  
Vol 115 (21) ◽  
pp. E4920-E4929 ◽  
Author(s):  
Yun-Chu Chen ◽  
Eric C. Holmes ◽  
Jakub Rajniak ◽  
Jung-Gun Kim ◽  
Sandy Tang ◽  
...  

Systemic acquired resistance (SAR) is a global response in plants induced at the site of infection that leads to long-lasting and broad-spectrum disease resistance at distal, uninfected tissues. Despite the importance of this priming mechanism, the identity and complexity of defense signals that are required to initiate SAR signaling is not well understood. In this paper, we describe a metabolite, N-hydroxy-pipecolic acid (N-OH-Pip) and provide evidence that this mobile molecule plays a role in initiating SAR signal transduction in Arabidopsis thaliana. We demonstrate that FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1), a key regulator of SAR-associated defense priming, can synthesize N-OH-Pip from pipecolic acid in planta, and exogenously applied N-OH-Pip moves systemically in Arabidopsis and can rescue the SAR-deficiency of fmo1 mutants. We also demonstrate that N-OH-Pip treatment causes systemic changes in the expression of pathogenesis-related genes and metabolic pathways throughout the plant and enhances resistance to a bacterial pathogen. This work provides insight into the chemical nature of a signal for SAR and also suggests that the N-OH-Pip pathway is a promising target for metabolic engineering to enhance disease resistance.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 697
Author(s):  
Juan Mao ◽  
Wenxin Li ◽  
Jing Liu ◽  
Jianming Li

The plant glycogen synthase kinase 3 (GSK3)-like kinases are highly conserved protein serine/threonine kinases that are grouped into four subfamilies. Similar to their mammalian homologs, these kinases are constitutively active under normal growth conditions but become inactivated in response to diverse developmental and environmental signals. Since their initial discoveries in the early 1990s, many biochemical and genetic studies were performed to investigate their physiological functions in various plant species. These studies have demonstrated that the plant GSK3-like kinases are multifunctional kinases involved not only in a wide variety of plant growth and developmental processes but also in diverse plant stress responses. Here we summarize our current understanding of the versatile physiological functions of the plant GSK3-like kinases along with their confirmed and potential substrates.


Rice ◽  
2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiang Zhang ◽  
Yan Long ◽  
Jingjing Huang ◽  
Jixing Xia

Abstract Background Salt stress threatens crop yields all over the world. Many NAC transcription factors have been reported to be involved in different abiotic stress responses, but it remains unclear how loss of these transcription factors alters the transcriptomes of plants. Previous reports have demonstrated that overexpression of OsNAC45 enhances salt and drought tolerance in rice, and that OsNAC45 may regulate the expression of two specific genes, OsPM1 and OsLEA3–1. Results Here, we found that ABA repressed, and NaCl promoted, the expression of OsNAC45 in roots. Immunostaining showed that OsNAC45 was localized in all root cells and was mainly expressed in the stele. Loss of OsNAC45 decreased the sensitivity of rice plants to ABA and over-expressing this gene had the opposite effect, which demonstrated that OsNAC45 played an important role during ABA signal responses. Knockout of OsNAC45 also resulted in more ROS accumulation in roots and increased sensitivity of rice to salt stress. Transcriptome sequencing assay found that thousands of genes were differently expressed in OsNAC45-knockout plants. Most of the down-regulated genes participated in plant stress responses. Quantitative real time RT-PCR suggested that seven genes may be regulated by OsNAC45 including OsCYP89G1, OsDREB1F, OsEREBP2, OsERF104, OsPM1, OsSAMDC2, and OsSIK1. Conclusions These results indicate that OsNAC45 plays vital roles in ABA signal responses and salt tolerance in rice. Further characterization of this gene may help us understand ABA signal pathway and breed rice plants that are more tolerant to salt stress.


2007 ◽  
Vol 97 (7) ◽  
pp. 794-802 ◽  
Author(s):  
Shobha D. Potlakayala ◽  
Darwin W. Reed ◽  
Patrick S. Covello ◽  
Pierre R. Fobert

Systemic acquired resistance (SAR) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. Here we show that treatment of Brassica napus plants with the SAR-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) significantly enhanced resistance against virulent strains of the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Leptosphaeria maculans. Localized preinoculation of plants with an avirulent strain of P. syringae pv. maculicola also enhanced resistance to these pathogens but was not as effective as BTH treatment. Single applications of either SAR-inducing pretreatment were effective against P. syringae pv. maculicola, even when given more than 3 weeks prior to the secondary challenge. The pretreatments also led to the accumulation of pathogenesis-related (PR) genes, including BnPR-1 and BnPR-2, with higher levels of transcripts observed in the BTH-treatment material. B. napus plants expressing a bacterial salicylate hydroxylase transgene (NahG) that metabolizes salicylic acid to catechol were substantially compromised in SAR and accumulated reduced levels of PR gene transcripts when compared with untransformed controls. Thus, SAR in B. napus displays many of the hallmarks of classical SAR including long lasting and broad host range resistance, association with PR gene activation, and a requirement for salicylic acid.


2001 ◽  
Vol 13 (6) ◽  
pp. 451-456 ◽  
Author(s):  
Takeshi Kinpara ◽  
Yuji Murakami ◽  
Kenji Yokoyama ◽  
Eiichi Tamiya

2019 ◽  
Vol 46 (3) ◽  
pp. 197 ◽  
Author(s):  
Xiaxia Yu ◽  
Wenjin Zhang ◽  
Yu Zhang ◽  
Xiaojia Zhang ◽  
Duoyong Lang ◽  
...  

Plants are constantly exposed to various stresses, which can degrade their health. The stresses can be alleviated by the application of methyl jasmonate (MeJA), which is a hormone involved in plant signalling. MeJA induces synthesis of defensive compounds and initiates the expression of pathogenesis-related genes involved in systemic acquired resistance and local resistance. Thus, MeJA may be used against pathogens, salt stress, drought stress, low temperature, heavy metal stress and toxicities of other elements. The application of MeJA improves growth, induces the accumulation of active compounds, and affects endogenous hormones levels, and other physiological and biochemical characteristics in stressed plants. Furthermore, MeJA antagonises the adverse effects of osmotic stress by regulating inorganic penetrating ions or organic penetrants to suppress the absorption of toxic ions. MeJA also mitigates oxidative stress by activating antioxidant systems to scavenge reactive oxygen species (ROS) in stressed plants. For these reasons, we reviewed the use of exogenous MeJA in alleviating biotic (pathogens and insects) and abiotic stresses in plants.


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