Characterization of a Mitogen-Activated Protein Kinase Gene from Cucumber Required for Trichoderma-Conferred Plant Resistance

Abstract

The fungal biocontrol agent Trichoderma asperellum has been recently shown to induce systemic resistance in plants through a mechanism that employs jasmonic acid and ethylene signal transduction pathways. Mitogen-activated protein kinase (MAPK) proteins have been implicated in the signal transduction of a wide variety of plant stress responses. Here we report the identification and characterization of a Trichoderma-induced MAPK (TIPK) gene function in cucumber (Cucumis sativus). Similar to its homologs, wound-induced protein kinase, MPK3, and MPK3a, TIPK is also induced by wounding. Normally, preinoculation of roots with Trichoderma activates plant defense mechanisms, which result in resistance to the leaf pathogen Pseudomonas syringae pv lachrymans. We used a unique attenuated virus vector, Zucchini yellow mosaic virus (ZYMV-AGII), to overexpress TIPK protein and antisense (AS) RNA. Plants overexpressing TIPK were more resistant to pathogenic bacterial attack than control plants, even in the absence of Trichoderma preinoculation. On the other hand, plants expressing TIPK-AS revealed increased sensitivity to pathogen attack. Moreover, Trichoderma preinoculation could not protect these AS plants against subsequent pathogen attack. We therefore demonstrate that Trichoderma exerts its protective effect on plants through activation of the TIPK gene, a MAPK that is involved in signal transduction pathways of defense responses.

The Molecular Basis of Shoot Responses of Maize Seedlings to Trichoderma harzianum T22 Inoculation of the Root: A Proteomic Approach

“…One of these, GSTF8, showed particularly dynamic responses to pathogen challenge (Jones et al, 2004) and was also induced by H 2 O 2 through the activation of MPK3/MPK6 (Kovtun et al, 2000). The homolog of MPK3 from cucumber was shown to be crucial for plant response to Trichoderma inoculation (Shoresh et al, 2006). It will be interesting, therefore, to determine whether the GST up-regulation in maize post Trichoderma colonization is via this MPK3 homolog.…”

“…This sensitization is apparent from both the reduction in disease symptoms and the systemic potentiation of the expression of defense-related genes (Yedidia et al, 2003;Shoresh et al, 2005). A mitogenactivated protein kinase, necessary for the process, was also potentiated similarly (Shoresh et al, 2006). Recent proteomic studies also demonstrate the involvement of defense-related proteins in plants inter-acting with Trichoderma (Chen et al, 2005;Marra et al, 2006;Djonovic et al, 2007).…”

Mitogen-Activated Protein Kinases 3 and 6 Are Required for Full Priming of Stress Responses inArabidopsis thaliana

“…Overexpression of the TIPK gene in cucumber plants enhanced their resistance to Ps pv lachrymans even in the absence of Trichoderma preinoculation, while TIPK antisense plants displayed increased susceptibility to pathogen attack (Shoresh et al, 2006). Thus, the systemic expression of TIPK upon Trichoderma infection of cucumber roots seems to be responsible for systemic immunity to Ps pv lachrymans (Shoresh et al, 2006). Similarly, transformation of rice (Oryza sativa) plants with MK1, the pepper (Capsicum annuum) ortholog of Arabidopsis MPK3, resulted in constitutive expression of the transgene, constitutive accumulation of the MK1 protein, as well as enhanced resistance to rice blast disease (Lee et al, 2004).…”

“…For example, preinoculation of cucumber (Cucumis sativus) roots with the fungal biocontrol agent Trichoderma asperellum systemically activates the gene for Trichoderma-induced protein kinase (TIPK), which is orthologous to Arabidopsis MPK3 and induces resistance to the leaf pathogen Ps pv lachrymans (Shoresh et al, 2006). Overexpression of the TIPK gene in cucumber plants enhanced their resistance to Ps pv lachrymans even in the absence of Trichoderma preinoculation, while TIPK antisense plants displayed increased susceptibility to pathogen attack (Shoresh et al, 2006). Thus, the systemic expression of TIPK upon Trichoderma infection of cucumber roots seems to be responsible for systemic immunity to Ps pv lachrymans (Shoresh et al, 2006).…”

Functional analysis of non-ribosomal peptide synthetases (NRPSs) in Trichoderma virens reveals a polyketide synthase (PKS)/NRPS hybrid enzyme involved in the induced systemic resistance response in maize

“…Even though the details of signalling events are not known, a mitogen-activated protein kinase from Trichoderma virens and one from cucumber have been identified to be involved in ISR responses (Viterbo et al, 2005;Shoresh et al, 2006). The strong induction of pal in response to Trichoderma inoculation of roots is universal, and pal is considered to be activated by the JA/ET signalling (Shoresh et al, 2010).…”