• The Plant Pathology Journal
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• 제31권2호
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• pp.192-194
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• 2015

Pathogen-associated molecular patterns (PAMPs) activate mitogen-activated protein kinases (MAPKs), essential components of plant defense signaling. Salicylic acid (SA) is also central to plant resistance responses, but its specific role in regulation of MAPK activation is not completely defined. We have investigated the role of SA in PAMP-triggered MAPKs pathways in Arabidopsis SA-related mutants, specifically in the flg22-triggered activation of MPK3 and MPK6. cim6, sid2, and npr1 mutants exhibited wild-type-like flg22-triggered MAPKs activation, suggesting that impairment of SA signaling has no effect on the flg22-triggered MAPKs activation. Pretreatment with low concentrations of SA enhanced flg22-induced MPK3 and MPK6 activation in all seedlings except npr1, indicating that NPR1 is involved in SA-mediated priming that enhanced flg22-induced MAPKs activation.

• Molecules and Cells
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• 제38권1호
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• pp.40-50
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• 2015

In the interaction between plants and pathogens, carbon (C) resources provide energy and C skeletons to maintain, among many functions, the plant immune system. However, variations in C availability on pathogen associated molecular pattern (PAMP) triggered immunity (PTI) have not been systematically examined. Here, three types of starch mutants with enhanced susceptibility to Pseudomonas syringae pv. tomato DC3000 hrcC were examined for PTI. In a dark period-dependent manner, the mutants showed compromised induction of a PTI marker, and callose accumulation in response to the bacterial PAMP flagellin, flg22. In combination with weakened PTI responses in wild type by inhibition of the TCA cycle, the experiments determined the necessity of C-derived energy in establishing PTI. Global gene expression analyses identified flg22 responsive genes displaying C supply-dependent patterns. Nutrient recycling-related genes were regulated similarly by C-limitation and flg22, indicating re-arrangements of expression programs to redirect resources that establish or strengthen PTI. Ethylene and NAC transcription factors appear to play roles in these processes. Under C-limitation, PTI appears compromised based on suppression of genes required for continued biosynthetic capacity and defenses through flg22. Our results provide a foundation for the intuitive perception of the interplay between plant nutrition status and pathogen defense.

• 생명과학회지
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• 제22권8호
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• pp.1018-1023
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• 2012

Snail은 E-cadherin 발현을 직접 억제하는 zinc finger transcription factor로서, 암세포의 invasion과 metastasis를 촉진시키는 epithelial-mesenchymal transition (EMT)를 유발한다. 또한 Snail은 세포사멸 자극과 세포 생존물질의 제거로 인한 세포사멸에 대해 저항성을 나타낸다. 그러나 이에 대한 분자기작은 잘 알려져 있지 않다. 본 연구에서는 가장 널리 사용되는 항암제 중의 하나인 5-fluorouracil (5-FU)에 의한 세포사멸에 대한 Snail의 저항성 기작에 대하여 조사하였다. MCF-7 #5 세포주에 doxycycline (DOX)을 처리하여 Snail을 과발현시킨 세포에서 5-FU에 의한 세포사멸이 억제되고 세포괴사가 일어남을 확인하였다. DOX 처리 및 Snail expression vectors인 pCR3.1-Snail-Flg와 phosphorylation-resistant mutant Snail vector인 pCR3.1-S104, 107A Snail-Flg을 이용하여 Snail을 과발현 시킨 경우 ERK1/2의 활성에는 영향을 주지 않는 반면 PTEN 발현억제 및 불활성화, 그리고 Akt/PKB 활성화가 유도됨을 관찰하였다. 또한, Snail은 5-FU에 의한 p53의 발현을 억제한다는 사실을 확인하였다. 따라서 Snail은 prosurvival kinase인 Akt/PKB의 활성화와 p53 억제를 통해 5-FU에 의한 세포사멸을 세포괴사로 전환하는 것으로 생각된다.