Opposite roles of MAPKKK17 and MAPKKK21 against Tetranychus urticae in Arabidopsis

Abstract

After recognizing a biotic stress, plants activate signalling pathways to fight against the attack. Typically, these signalling pathways involve the activation of phosphorylation cascades mediated by Mitogen-Activated Protein Kinases (MAPKs). In the Arabidopsis thaliana-Tetranychus urticae plant-herbivore model, several Arabidopsis MAP kinases are induced by the mite attack. In this study, we demonstrate the participation of the MEKK-like kinases MAPKKK17 and MAPKKK21. Leaf damage caused by the mite was assessed using T-DNA insertion lines. Differential levels of damage were found when the expression of MAPKKK17 was increased or reduced. In contrast, reduced expression of MAPKKK21 resulted in less damage caused by the mite. Whereas the expression of several genes associated with hormonal responses did not suffer significant variations in the T-DNA insertion lines, the expression of one of these kinases depends on the expression of the other one. In addition, MAPKKK17 and MAPKKK21 are coexpressed with different sets of genes and encode proteins with low similarity in the C-terminal region. Overall, our results demonstrate that MAPKKK17 and MAPKKK21 have opposite roles. MAPKKK17 and MAPKKK21 act as positive and negative regulators, respectively, on the plant response. The induction of MAPKKK17 and MAPKKK21 after mite infestation would be integrated into the bulk of signalling pathways activated to balance the response of the plant to a biotic stress.

Arabidopsis Transcriptomics Reveals the Role of Lipoxygenase2 (AtLOX2) in Wound-Induced Responses

“…In line with this, jasmonate-responsive genes were among the early responding genes including those that encode enzymes in volatile biosynthesis (i.e., AtTPS04/GES, AtCYP82G1 [ 49 , 50 ]), enzymes involved in sealing damaged tissue (i.e., AtPP2-A5 [ 51 ]), transcription factors (i.e., AtRRTF1, AtWRKY40, AtRAP2.6 [ 52 , 53 , 54 , 55 , 56 ]) and proteins involved in plant defense against pathogens or insects (i.e., AtTI6, AtMAPKKK21 [ 57 , 58 ]).…”

“…This likely reflects the expression of genes encoding enzymes in jasmonate biosynthesis (AtLOX2, At4CL8) and signaling (AtMYC2) that were more highly expressed in wounded WT compared with lox2 plants [ 4 ]. Jasmonate-responsive genes involved in plant resistance to insect herbivory, such as AtHPL/AtCYP74B2 , which encodes an enzyme involved in volatile biosynthesis [ 83 ], AtCLH1 , AtKTI3 , AtTI1 , AtARGAH2 and AtMAPKKK17 , reflect this pattern [ 58 , 84 , 85 , 86 ]. Genes involved in antioxidant pathways are upregulated in wounded WT plants, including those that encode proteins involved in the ascorbate/glutathione cycle (i.e., AtDHAR1 [ 87 ]) and anthocyanin biosynthesis (i.e., AtPAP1, AtTT8, AtGL3, AtTTG2, At4CL, AtTT7, AtDFR, AtLDOX, AtUF3GT, At1g14090, At3AT1, At3AT2, AtGSTF12, At5MAT [ 88 , 89 , 90 ]) ( Figure 6 ).…”

“…In this and other studies, AtMAPKKK17, induced late in response to wounding in WT plants (Pattern 5, Figure 5 E), activates the MKK3-MPK1/2/7 module [ 114 , 115 ]. In plants challenged with the two-spotted spider mite, Tetranchus urtica , plants with higher constitutive AtMAPKKK17 expression had higher resistance against mite herbivory, exhibiting less leaf damage with mites having lower fecundity [ 58 ]. AtMAPKKK21 is expressed early after wounding in both genotypes (Pattern 1, Figure 5 A).…”

The MKK3 MAPK cascade integrates temperature and after-ripening signals to modulate seed germination

“…Heynh.) Columbia-0 (Col-0) accession were obtained from the Arabidopsis Biological Resource Center [ mkk3-1 (SALK_051970; Takahashi et al ., 2007), mkk3-2 (SALK_208528C; Sözen et al ., 2020), mpk1-1 (SALK_063847C; Enders et al ., 2017), mpk2-2 (SALK_047422C; Lv et al ., 2021), mpk7-1 (SALK_113631), mpk14-1 (SALK_022928C; Lv et al ., 2021), mapkkk13-1 (GK-277E09), map3k14-1 (GK-653B01; Sözen et al ., 2020), mapkkk15-1 (SALK_084817), map3k16 (Choi et al ., 2017), mapkkk17-2 (SALK_080309C; Romero-Hernandez and Martinez, 2022), mkkk18-2 (GK-676E02; Mitula et al ., 2015) and mapkkk20-3 (GK-458D07)]. Ds-transposon insertion lines of Arabidopsis Nossen accession were obtained from RIKEN BioResource Research Center [ mapkkk19-1 (pst14411) and mapkkk21-3 (psh20310)].…”

Pinus thunbergii Parl. Somatic Plants’ Resistance to Bursaphelenchus xylophilus Depends on Pathogen-Induced Differential Transcriptomic Responses

“…This suggested that the ABA pathway was activated; however, at 3 dpi, the PYL did not change, and the repressor PP2C was up-expressed, which resulted in MAPKKK (17)(18) being repressed (Figure 4; Table S9). MAPKKK17 was induced in response to a mite a ack in Arabidopsis [36], while MAPKKK18 (an ABA-activated kinase) was regulated by PP2C, which inhibited the kinase activity of MAPKKK18 [37]. The reduced transcription of MAPKKK18 in Arabidopsis exhibited obviously delayed leaf senescence [38].…”