BWMK1 Responds to Multiple Environmental Stresses and Plant Hormones

Abstract

Many plant mitogen-activated protein kinases (MAPKs) play an important role in regulating responses to both abiotic and biotic stresses. The first reported rice MAPK gene BWMK1 is induced by both rice blast (Magnaporthe grisea) infection and mechanical wounding. For further analysis of its response to other environmental cues and plant hormones, such as jasmonic acid (JA), salicylic acid (SA), and benzothiadiazole (BTH), the promoter of BWMK1 was fused with the coding region of the ß-glucuronidase (GUS) reporter gene. Two promoter-GUS constructs with a 1.0-and 2.5-kb promoter fragment, respectively, were generated and transformed into the japonica rice cultivars TP309 and Zhonghua 11. Expression of GUS was induced in the transgenic lines by cold, drought, dark, and JA. However, light, SA, and BTH treatments suppressed GUS expression. These results demonstrate that BWMK1 is responsive to multiple abiotic stresses and plant hormones and may play a role in cross-talk between different signaling pathways.Key words: abiotic stresses; BWMK1; disease resistance; mitogen-activated protein kinase; Oryza sativa; promoter.Hong WF, He C, Wang L, Wang DJ, Joseph LM, Jantasuriyarat C, Dai L, Wang GL (2007). BWMK1 responds to multiple environmental stresses and plant hormones. J. Integr. Plant Biol. 49(6), 843−851. Available online at www.blackwell-synergy.com/links/toc/jipb, www.jipb.net Because plants have been exposed to a wide range of environmental signals, they have developed sophisticated mechanisms to recognize those signals and integrate them into specific signaling pathways that moderate their output. The series of signal transductions that lead to modification of gene expression patterns allow plants to adapt to changes in their environment throughout their life cycle. Mitogen-activated protein kinase (MAPK) pathways have been reported to be central components of such signal transduction pathways (Hirt 1997;Stratmann and Ryan 1997;Seo et al. 1999; Ichimura et al. 2002). MAPKs are known to respond to a wide variety of different stimuli and to enable transmission of the signal from the receptors/sensors into the cytosol and nucleus (Ligterink et al. 1997; Lenormand et al. 1998; Kyriakis and Avruch 2001;Whitehurst et al. 2002). These signaling pathways generally direct cellular activities ranging from gene expression, mitosis, cell division, cellular differentiation, development, and metabolism to defense responses.All eukaryotic cells possess a set of MAPK cascades. Each of these is preferentially recruited by distinct sets of stimuli, 844 Journal of Integrative Plant Biology Vol. 49 No. 6 2007 thereby allowing cells to respond coordinately to multiple and divergent inputs. Typically, MAPK cascades consist of three kinase modules: (i) MAPK kinase kinase (MEKK); (ii) MAPK kinase (MAPKK); and (iii) MAPK. The MAPKKK enzyme activates an MAPKK by phosphorylating two serine/threonine residues on its activation loop, which, in turn, is responsible for activating both threonine and tyrosine by phosphorylation o...

Genome-Wide Identification of MAPKK and MAPKKK Gene Families in Tomato and Transcriptional Profiling Analysis during Development and Stress Response

“…These data imply that most SlMAPKKK genes may be involved in plant hormone signaling during plant development and defense response. In rice, a MAPK gene, BWMK1 , responds to other plant hormones, such as JA, SA, and benzothiadiazole [58] . Using the Arabidopsis leaf protoplast transient expression system, Kovtun et al proved that an oxidative stress MAPK cascade can negatively regulate early auxin response [59] .…”

The transcriptional regulation and cell-specific expression of the MAPK-activated protein kinase MK5

“…However, the transcript levels of some MAPK are inducible. The expressions of the rice MAPK genes OsBIMK1 and BWMK1 are affected by abiotic and biotic stresses [4,5], while cold stress and high salt stress increase the transcript levels of OsMAPK2, and sugar starvation increases those of OsMAPK4 [6,7]. Transcript profiling of the tissues derived from untreated and stress-exposed Arabidopsis thalania revealed 2,715 differentially expressed genes, including the MAPKs MKK9 and MAPKKK14 [8].…”