Biology subjects

Kwaaitaal, M.

Publications and source records attributed to Kwaaitaal, M..

4 recordsLinked to original sources

bioRxiv2024

A SUMO interacting motif in the Replication initiator protein of Tomato yellow leaf curl virus is required for viral replication

CRESS-DNA viruses form a diverse group of viruses that use rolling-circle replication to replicate their genomes. They infect organisms in almost all branches of the eukaryotic tree of life. All CRESS-DNA viruses have one protein in common, the Replication initiator protein (Rep), which orchestrates viral replication using the host DNA replication machinery. In the case of the plant-infecting Geminiviridae, this multifunctional protein both recruits the host DNA replication machinery and manipulates posttranslational modification including Small ubiquitin-like modifier (SUMO) conjugation. In fact, Rep from two different geminiviruses, Tomato yellow leaf curl virus (TYLCV) and Tomato golden mosaic virus (TGMV), was shown to interact with the SUMO conjugating enzyme SCE1. Here, we demonstrate that also TYLCV Rep interacts with Arabidopsis SUMO1 and report on a SUMO interacting motif (SIM) in the SF3 helicase domain of Rep. Remarkably, an intact SIM proved to be important for the interaction of Rep with both SUMO1 and SCE1. The same motif was also essential for viral replication and Rep ATPase activity. Our findings thus connect the interaction between Rep and the SUMO machinery with viral replication of TYLCV. ImportanceThe identification of a non-canonical SUMO-interacting motif (SIM) within the Rep protein of Tomato yellow leaf curl virus (TYLCV) reveals a connection between viral replication and a protein modification, SUMOylation. Importantly, the motif was found to be conserved between Rep proteins from different geminiviruses. Functionally, the motif was critical for the interaction of Rep with proteins of the SUMO machinery, viral DNA replication, and Rep ATPase acitvity. In particular, the third position of the motif was important for each of these activities. We thus uncover a novel mechanism on how geminiviruses recruit the SUMO machinery likely to their own need.

plant biology↗

bioRxiv2023

Whitefly effector G4 interacts with tomato proteins of which MIPDB141 affects whitefly performance

The phloem-feeding insect Bemisia tabaci is an important pest, responsible for the transmission of several crop-threatening virus species. While feeding, the insect secretes a cocktail of effectors to modulate defense responses. Here, we present a set of proteins that was identified in artificial diet on which B. tabaci was salivating. We studied whether these candidate effectors can play a role in plant immune suppression. Effector G4 was the most robust suppressor of the flg22-induced ROS response when transiently expressed in Nicotiana benthamiana. In addition, G4 was able to supress ROS in Solanum lycopersicum (tomato) and Capsicum annuum (pepper). Fused to a fluorescence tag, G4 localized in the cytoplasm in N. benthamiana. A yeast two-hybrid screen combined with a luciferase bimolecular complementation and co-localization assays resulted in the identification of two target proteins in tomato: REF-like stress related protein 1 (RSP1) and meloidogyne-induced giant cell protein DB141 (MIPDB141). Silencing of MIPDB141 in tomato, using virus-induced gene silencing, reduced whitefly fecundity up to 40% demonstrating that the protein is involved in susceptibility to B. tabaci. Together our data demonstrate that effector G4 impairs tomato immunity to whiteflies by interfering with the ROS production and via a direct interaction with tomato susceptibility protein MIPDB141.

plant biology↗

bioRxiv2021

The protein modifier SUMO is critical for Arabidopsis shoot meristem maintenance at warmer ambient temperatures

Short heat waves (>37{degrees}C) are extremely damaging to non-acclimated plants and their capacity to recover from heat stress is key for their survival. To acclimate, the HEAT SHOCK TRANSCRIPTION FACTOR A1 (HSFA1) subfamily activates a transcriptional response that resolves incurred damages. In contrast, little is known how plants acclimate to sustained non-detrimental warm periods at 27-28{degrees}C. Plants respond to this condition with a thermomorphogenesis response. In addition, HSFA1 is critical for plant survival during these warm periods. We find that SUMO, a protein modification whose conjugate levels rise sharply during acute heat stress in eukaryotes, is critical too for plant longevity during warm periods, in particular for normal shoot meristem development. The known SUMO ligases were not essential to endure these warm periods, alone or in combination. Thermo-lethality was also not seen when plants lacked certain SUMO proteases or when SUMO chain formation was blocked. The SUMO-dependent thermo-resilience was as well independent of the autoimmune phenotype of the SUMO mutants. As acquired thermotolerance was normal in the sumo1/2 knockdown mutant, our data thus reveal a role for SUMO in heat acclimation that differs from HSFA1 and SIZ1. We conclude that SUMO is critical for shoot meristem integrity during warm periods. HighlightThe protein modifier SUMO governs shoot meristem maintenance in Arabidopsis allowing sustained rosette development when plants endure a sustained warm non-detrimental period of 28 degrees Celsius.

plant biology↗

bioRxiv2018

The SUMO conjugation complex self-assembles into nuclear bodies independent of SIZ1 and COP1

One sentence SummarySUMO conjugation activity causes formation of SUMO nuclear bodies, which strongly overlap with COP1 bodies thanks to a substrate-binding (VP) motif in the E3 ligase SIZ1 that acts as bridge protein.\n\nAbstractAttachment of the small ubiquitin-like modifier SUMO to substrate proteins modulates their turnover, activity or interaction partners. An unresolved question is how this SUMO conjugation activity concentrates the enzymes involved and the substrates into uncharacterized nuclear bodies (NBs). We here define the requirements for the formation of SUMO NBs and for their subsequent co-localisation with the master regulator of growth, the E3 ubiquitin ligase COP1. COP1 activity results in degradation of transcription factors, which primes the transcriptional response that underlies elongation growth induced by night-time and high ambient temperatures (skoto- and thermomorphogenesis, respectively). SUMO conjugation activity itself is sufficient to target the SUMO machinery into NBs. Co-localization of these bodies with COP1 requires besides SUMO conjugation activity, a SUMO acceptor site in COP1 and the SUMO E3 ligase SIZ1. We find that SIZ1 docks in the substrate-binding pocket of COP1 via two VP motifs - a known peptide motif of COP1 substrates. The data reveal that SIZ1 physically connects COP1 and SUMO conjugation activity in the same NBs that can also contain the blue-light receptors CRY1 and CRY2. Our findings thus suggest that sumoylation apparently coordinates COP1 activity inside these NBs; a mechanism that potentially explains how SIZ1 and SUMO both control the timing and amplitude of the high-temperature growth response. The strong co-localization of COP1 and SUMO in these NBs might also explain why many COP1 substrates are sumoylated.\n\nFunding informationThe Netherlands Scientific Organisation (ALW-VIDI grant 864.10.004 to HvdB) and the Topsector T&U program Better Plants for Demands (grant 1409-036 to HvdB), including the partnering breeding companies, supported this work; FM is financially supported by Keygene N.V. (The Netherlands).

plant biology↗