scholarly journals Overexpression of Brassica napus MPK4 Enhances Resistance to Sclerotinia sclerotiorum in Oilseed Rape

2009 ◽  
Vol 22 (3) ◽  
pp. 235-244 ◽  
Author(s):  
Zheng Wang ◽  
Han Mao ◽  
Caihua Dong ◽  
Ruiqin Ji ◽  
Li Cai ◽  
...  

Sclerotinia sclerotiorum causes a highly destructive disease in oilseed rape (Brassica napus) resulting in significant economic losses. Studies on the Arabidopsis thaliana MPK4 loss-of-function mutant have implicated that AtMPK4 is involved in plant defense regulation, and its effect on disease resistance varies in different plant–pathogen interactions. In this study, we isolated a B. napus mitogen-activated protein kinase, BnMPK4, and found that BnMPK4 along with PDF1.2 are inducible in resistant line Zhongshuang9 but both are consistently suppressed in susceptible line 84039 after inoculation with S. sclerotiorum. Transgenic oilseed rape overexpressing BnMPK4 markedly enhances resistance to S. sclerotiorum and Botrytis cinerea. Further experiments showed that transgenic plants inhibited growth of S. sclerotiorum and constitutively activated PDF1.2 but decreased H2O2 production and constitutively suppressed PR-1 expression. Treatment of roots of the transgenic plants with H2O2 solution resulted in enhanced susceptibility to the two pathogens. Our results support the idea that MPK4 positively regulates jasmonic acid-mediated defense response, which might play an important role in resistance to S. sclerotiorum in oilseed rape.

1993 ◽  
Vol 2 (6) ◽  
pp. 356-364 ◽  
Author(s):  
Jodi A. Scheffler ◽  
Russell Parkinson ◽  
Philip J. Dale

2013 ◽  
Vol 68 (3-4) ◽  
pp. 148-154 ◽  
Author(s):  
Hui Yang ◽  
Shu Yuan ◽  
Yi Luo ◽  
Ji Huang ◽  
Yang-Er Chen ◽  
...  

Plant hormones play pivotal roles as signals of plant-pathogen interactions. Here, we report that exogenous application of salicylic acid (SA), jasmonic acid (JA), ethephon (ETH), and abscisic acid (ABA) can reduce Turnip crinkle virus (TCV) accumulation in systemic leaves of Arabidopsis thaliana during early infection. SA and ABA are more efficient and confer a longer-lasting resistance against TCV than JA and ETH, and the plant hormones interact in effecting the plant defence. Synergistic actions of SA and JA, and SA and ET, and an antagonistic action of SA and ABA have been observed in the Arabidopsis-TCV interaction. ABA can down-regulate the expression of the pathogenesis-related genes PR1 and PDF1.2, and compared to the wild type, it drastically reduces TCV accumulation in NahG transgenic plants and the eds5-p1 mutant, both of which do not accumulate SA. This indicates that SA signaling negatively regulates the ABA-mediated defence. ABA-induced resistance against TCV is independent of SA. We also found that mitogen-activated protein kinase 5 (MPK5) may be involved in ABA-mediated defence. These results indicate that Arabidopsis can activate distinct signals to inhibit virus accumulation. Cooperative or antagonistic crosstalk between them is pivotal for establishing disease resistance. These results show potential to enhance the plant defence against viruses by manipulating diverse hormones.


Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1382 ◽  
Author(s):  
Mohamed Aashiq ◽  
Deborah A. Silverman ◽  
Shorook Na’ara ◽  
Hideaki Takahashi ◽  
Moran Amit

Recurrent, metastatic disease represents the most frequent cause of death for patients with thyroid cancer, and radioactive iodine (RAI) remains a mainstay of therapy for these patients. Unfortunately, many thyroid cancer patients have tumors that no longer trap iodine, and hence are refractory to RAI, heralding a poor prognosis. RAI-refractory (RAI-R) cancer cells result from the loss of thyroid differentiation features, such as iodide uptake and organification. This loss of differentiation features correlates with the degree of mitogen-activated protein kinase (MAPK) activation, which is higher in tumors with BRAF (B-Raf proto-oncogene) mutations than in those with RTK (receptor tyrosine kinase) or RAS (rat sarcoma) mutations. Hence, inhibition of the mitogen-activated protein kinase kinase-1 and -2 (MEK-1 and -2) downstream of RAF (rapidly accelerated fibrosarcoma) could sensitize RAI refractivity in thyroid cancer. However, a significant hurdle is the development of secondary tumor resistance (escape mechanisms) to these drugs through upregulation of tyrosine kinase receptors or another alternative signaling pathway. The sodium iodide symporter (NIS) is a plasma membrane glycoprotein, a member of solute carrier family 5A (SLC5A5), located on the basolateral surfaces of the thyroid follicular epithelial cells, which mediates active iodide transport into thyroid follicular cells. The mechanisms responsible for NIS loss of function in RAI-R thyroid cancer remains unclear. In a study of patients with recurrent thyroid cancer, expression levels of specific ribosomal machinery—namely PIGU (phosphatidylinositol glycan anchor biosynthesis class U), a subunit of the GPI (glycosylphosphatidylinositol transamidase complex—correlated with RAI avidity in radioiodine scanning, NIS levels, and biochemical response to RAI treatment. Here, we review the proposed mechanisms for RAI refractivity and the management of RAI-refractive metastatic, recurrent thyroid cancer. We also describe novel targeted systemic agents that are in use or under investigation for RAI-refractory disease, their mechanisms of action, and their adverse events.


1999 ◽  
Vol 19 (8) ◽  
pp. 5523-5534 ◽  
Author(s):  
Scott Stewart ◽  
Meera Sundaram ◽  
Yanping Zhang ◽  
Jeeyong Lee ◽  
Min Han ◽  
...  

ABSTRACT Genetic screens for modifiers of activated Ras phenotypes have identified a novel protein, kinase suppressor of Ras (KSR), which shares significant sequence homology with Raf family protein kinases. Studies using Drosophila melanogaster andCaenorhabditis elegans predict that KSR positively regulates Ras signaling; however, the function of mammalian KSR is not well understood. We show here that two predicted kinase-dead mutants of KSR retain the ability to complement ksr-1 loss-of-function alleles in C. elegans, suggesting that KSR may have physiological, kinase-independent functions. Furthermore, we observe that murine KSR forms a multimolecular signaling complex in human embryonic kidney 293T cells composed of HSP90, HSP70, HSP68, p50CDC37, MEK1, MEK2, 14-3-3, and several other, unidentified proteins. Treatment of cells with geldanamycin, an inhibitor of HSP90, decreases the half-life of KSR, suggesting that HSPs may serve to stabilize KSR. Both nematode and mammalian KSRs are capable of binding to MEKs, and three-point mutants of KSR, corresponding to C. elegans loss-of-function alleles, are specifically compromised in MEK binding. KSR did not alter MEK activity or activation. However, KSR-MEK binding shifts the apparent molecular mass of MEK from 44 to >700 kDa, and this results in the appearance of MEK in membrane-associated fractions. Together, these results suggest that KSR may act as a scaffolding protein for the Ras-mitogen-activated protein kinase pathway.


2013 ◽  
Vol 21 (2) ◽  
pp. 1455-1465 ◽  
Author(s):  
Mirco Hecht ◽  
Bernadette Oehen ◽  
Jürg Schulze ◽  
Peter Brodmann ◽  
Claudia Bagutti

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