Involvement of Potato (Solanum tuberosum L.) MKK6 in Response to Potato virus Y

Abstract

Mitogen-activated protein kinase (MAPK) cascades have crucial roles in the regulation of plant development and in plant responses to stress. Plant recognition of pathogen-associated molecular patterns or pathogen-derived effector proteins has been shown to trigger activation of several MAPKs. This then controls defence responses, including synthesis and/or signalling of defence hormones and activation of defence related genes. The MAPK cascade genes are highly complex and interconnected, and thus the precise signalling mechanisms in specific plant–pathogen interactions are still not known. Here we investigated the MAPK signalling network involved in immune responses of potato (Solanum tuberosum L.) to Potato virus Y, an important potato pathogen worldwide. Sequence analysis was performed to identify the complete MAPK kinase (MKK) family in potato, and to identify those regulated in the hypersensitive resistance response to Potato virus Y infection. Arabidopsis has 10 MKK family members, of which we identified five in potato and tomato (Solanum lycopersicum L.), and eight in Nicotiana benthamiana. Among these, StMKK6 is the most strongly regulated gene in response to Potato virus Y. The salicylic acid treatment revealed that StMKK6 is regulated by the hormone that is in agreement with the salicylic acid-regulated domains found in the StMKK6 promoter. The involvement of StMKK6 in potato defence response was confirmed by localisation studies, where StMKK6 accumulated strongly only in Potato-virus-Y-infected plants, and predominantly in the cell nucleus. Using a yeast two-hybrid method, we identified three StMKK6 targets downstream in the MAPK cascade: StMAPK4_2, StMAPK6 and StMAPK13. These data together provide further insight into the StMKK6 signalling module and its involvement in plant defence.

Plant Molecular Responses to Potato Virus Y: A Continuum of Outcomes from Sensitivity and Tolerance to Resistance

“…They are implicated in the signaling of plant developmental programes and response to multiple environmental stressors s and they are a core mediator for HR-associated PCD (reviewed by [60]). Specifically, the MAPK signaling network in HR-conferred resistance to PVY involves MAPK kinases 6 (MKK6) and the downstream targets MAPK4_2 (orthologue of AtMAPK4, -11 and -12), MAPK6 (orthologue of AtMAPK6), and MAPK13 (orthologue of AtMAPK13) [61]. Downregulation of MKK6 was shown to increase PVY concentrations in infected plants, confirming that this kinase is an important component of potato immunity against the virus [62].…”

Rule-Based Design of Plant Expression Vectors Using GenoCAD

“…Since plant promoter information is still scarce, so far the compilation of native promoter sequences in the plant GenoCAD library is based on identification and characterization of several Solanum tuberosum promoters performed in our research group (e.g. StMKK6 promoter [ 21 ]). However, the idea is that each user expands the library with new entries of experimentally characterized promoters of interest [ 22 ].…”

In silicoanalysis reveals widespread presence of three gene families, MAPK, MAPKK and MAPKKK, of the MAPK cascade from crop plants ofSolanaceaein comparison to the distantly-related syntenic species fromRubiaceae,coffee

“…Furthermore, 108 sequences from potato, 63 from eggplant, 79 from pepper, and 64 from coffee have been reported in this study based on perfectly conserved signature motifs belonging to the three major families of the MAPK cascade. Although, few members of some of these families were reported recently ( Daigle & Matton, 2015 ; Kong et al, 2012 ; Lazar et al, 2014 ; Liu et al, 2015 ; Mohanta et al, 2015 ; Wu et al, 2014 ), this articles reports the largest set of genes identified from all three of these gene families and their further subfamilies in the said species. Phylogenetic analysis of the reported sequences shows the conservation of the genes throughout the Solanaceae plant family and coffee, which is closely related to Solanaceae species in terms of its genetic make-up.…”

“…Identification of the three complete families of the MAPK cascade has not been done earlier in potato, eggplant, pepper, and coffee. However, being widely studied due to their vital functions, a few of these genes have recently been identified and reported as MPK, MKK, and MAPKKK in tomato ( Daigle & Matton, 2015 ; Kong et al, 2012 ; Lazar et al, 2014 ; Mohanta et al, 2015 ; Wu et al, 2014 ); as MPK, MKK, and MEKK-like from MAPKKK in potato ( Daigle & Matton, 2015 ; Lazar et al, 2014 ; Mohanta et al, 2015 ); and, as MPK and MKK in pepper ( Liu et al, 2015 ). However, genome identification of the three complete gene families hasn’t been reported for any one of them; thus, such an identification will be a huge step forward towards unraveling their functionality and importance.…”