OsWRKY22, a monocot WRKY gene, plays a role in the resistance response to blast

Abstract

With the aim of identifying novel regulators of host and nonhost resistance to fungi in rice, we carried out a systematic mutant screen of mutagenized lines. Two mutant wrky22 knockout lines revealed clear-cut enhanced susceptibility to both virulent and avirulent Magnaporthe oryzae strains and altered cellular responses to nonhost Magnaporthe grisea and Blumeria graminis fungi. In addition, the analysis of the pathogen responses of 24 overexpressor OsWRKY22 lines revealed enhanced resistance phenotypes on infection with virulent M. oryzae strain, confirming that OsWRKY22 is involved in rice resistance to blast. Bioinformatic analyses determined that the OsWRKY22 gene belongs to a well-defined cluster of monocot-specific WRKYs. The co-regulatory analysis revealed no significant co-regulation of OsWRKY22 with a representative panel of OsWRKYs, supporting its unique role in a series of transcriptional responses. In contrast, inquiring a subset of biotic stress-related Affymetrix data, a large number of resistance and defence-related genes were found to be putatively co-expressed with OsWRKY22. Taken together, all gathered experimental evidence places the monocot-specific OsWRKY22 gene at the convergence point of signal transduction circuits in response to both host and nonhost fungi encountering rice plants.

The Coiled-Coil and Nucleotide Binding Domains of BROWN PLANTHOPPER RESISTANCE14 Function in Signaling and Resistance against Planthopper in Rice

“…Previous data imply that WRKY46 and WRKY72 function in disease resistance signaling. WRKY46 transcript levels were significantly repressed following plant inoculation with avirulent M. oryzae strain CL3.6.7 (Abbruscato et al, 2012), while WRKY72 transcript levels were highly upregulated in 9804 (a japonica rice variety, which was used as the recipient of the maize Rxo1 gene) after inoculation with the bacterial The BPH14 monomers are assembled into a homodimer, which is capable of interacting with WRKY46 and WRKY72. Coexpression of BPH14 is considered to protect WRKY46 and WRKY72 from degradation by the ubiquitin proteasome system.…”

Tomato WRKY transcriptional factor SlDRW1 is required for disease resistance against Botrytis cinerea and tolerance to oxidative stress

“…Similarly, at least 10 rice WRKYs, i.e. OsWRKY03 [30], OsWRKY71 [31], OsWRKY13 [32], OsWRKY45 [33,34], OsWRK89 [35], OsWRKY31 [36], OsWRKY22 [37], OsWRKY30 [38], OsWRKY28 [39], OsWRKY76 [40] and OsWRKY62 [41], have been implicated in immune responses against fungal and bacterial pathogens. Alternatively, some of the WRKY proteins have also been shown to play important roles in regulating abiotic stress tolerance (for review see [42]), such as Arabidopsis WRKY6 and WRKY75 in low phosphorus stress [43,44], WRKY25 and WRKY39 in heat stress [45,46], WRKY63 (ABO3) and WRKY57 in drought stress [47,48], WRKY34 in cold stress [49]), WRKY18, WRKY40, WRKY70 and WRKY54 in osmotic stress [50,51], WRKY30 in oxidative stress [52] and WRKY46 in aluminum toxicity [53], and rice OsWRKY30 in drought stress [54].…”

Molecular breeding of rice for improved disease resistance, a review

“…That increased resistance in both cases was also associated with activated expression of both salicylic acid (SA) and JA-related defense genes. Abbruscato et al (2012) found over-expression of OsWRKY22 lead to enhanced disease resistance to M. oryzae. Singh et al (2013) identified an elevated expression of native rice gene Osmyb4 (also coding for TFs) in disease resistant cultivars indicating its possible role in disease resistant regulating mechanism.…”