Transcriptional responses to cantharidin, a protein phosphatase inhibitor, in Arabidopsis thaliana reveal the involvement of multiple signal transduction pathways

Abstract

Cantharidin is a natural compound isolated from the blister beetle (Epicauta spp.). It is a potent inhibitor of protein serine/threonine phosphatases (PPPs), especially PP2A and PP4. Protein phosphatases and kinases maintain a sensitive balance between dephosphorylated and phosphorylated forms of appropriate proteins, thereby playing important roles in signal transduction pathways and regulation of gene expression, cellular proliferation, cell differentiation, apoptosis and other processes. The foliage of 12-day-old Arabidopsis thaliana seedlings was treated with 200 µM (IC(30) ) of the PPP inhibitor cantharidin, and the entire transcriptome profile was determined by microarray analysis at 2, 10 and 24 h after treatment. The transcription of approximately 10% (2577) of the 24 000 genes of Arabidopsis changed significantly (P≤ 0.05 and signal log ratios: ≥1 or ≤-1) after treatment. Inhibition of PPPs significantly reduced transcription of genes associated with auxin and light signaling and induced expression of genes involved in the hypersensitive response and in flagellin and abscisic acid signaling. The great variety of up- and downregulated genes in this microarray experiment implied that cantharidin interfered with the activities of PPPs that interact directly or indirectly with receptors or are located near the beginning of signal transduction pathways. In many cases, PPPs interact with protein complexes of various receptors such as ethylene or light sensors localized in different cell compartments. They function as negative regulators modifying receptor functions, thus altering signaling that influences transcriptional responses.

Serine/threonine protein phosphatases: Multi-purpose enzymes in control of defense mechanisms

“…The expression of the very commonly used SA signal marker gene PR1 (Pathogenesis Related gene 1), as well as other members of PathogenesisRelated family (such as PR2), were downregulated and only one (PR5) upregulated at the 24 h time point. 12 Taken together, these data suggest that cantharidin treatment might favor both JA-dependent and -independent wound responses. This hypothesis will need additional empirical confirmation.…”

“…Several such genes were affected by cantharidin treatment. 12 For example, gene NPR1 (Nonexpressor of PR genes 1) slightly increased expression at the 2-h time point (1.3) ( Table 1). NPR1 functions as a sensor of redox status and controls SA and JA signal transduction pathways by negatively regulating SA signaling, and positively modulating the expression of JA-dependent genes during herbivore attack.…”

“…27 In our experiment, GRX480 was strongly induced by cantharidin (2.4 at 10 h time point and 1.3 at 24 h time point) while the transcript level of WRKY70 decreased (-1.3 at 10 h and -1.2 at 24 h). 12 The role of this transcription factor in regulation of SA-dependent signaling was described in a study where its accumulation caused a decrease of MeJA-dependent PDF1.2 expression. 28 This indirectly agreed with our data: downregulation of WRKY70 and upregulation of PDF1.2.…”

“…[6][7][8][9][10][11] However, until the publication of our recent paper on the effects of cantharidin on the entire transcriptome of Arabidopsis, 12 there were no studies demonstrating the full capacity of a PPP inhibitor to impact gene transcription. The microarray experiment described in this paper revealed the breadth of the role of PPP in responses to biotic and abiotic stresses.…”

Status and Perspective of Bioherbicde Development for Organic Weed Management

“…Endothall은 1950년에 처음 개발된 제초제이며, cantharidin의 구조적 유 사화합물이다. Cantharidin과 endothall은 serine/threonine 단백질 인산가수분해 효소를 저해하는 기작을 갖고 있다 (Bajas et al, 2011). (Table 4), 옥수수 글루텐 가루의 50-100%를 포함한 제품이 판매되고 있다 (Christians, 1990;McDade and Christians, 2000).…”