The Sw-5b NLR nucleotide-binding domain plays a role in oligomerization, and its self-association is important for activation of cell death signaling.

Plant and animal intracellular nucleotide-binding and leucine-rich repeat (NLR) receptors play important roles in sensing pathogens and activating defense signaling. However, the molecular mechanisms underlying the activation of host defense signaling by NLR proteins remain largely unknown. Many studies have determined that the coil-coil (CC) or Toll and interleukin-1 receptor/resistance protein (TIR) domain of NLR proteins and their dimerization/oligomerization are critical for activating downstream defense signaling.

Cytoplasmic and nuclear Sw-5b NLR act both independently and synergistically to confer full host defense against tospovirus infection.

Plant intracellular nucleotide-binding leucine-rich repeat (NLR) receptors play critical roles in mediating host immunity to pathogen attack. We use tomato Sw-5b::tospovirus as a model system to study the specific role of the compartmentalized plant NLR in dictating host defenses against the virus at different infection steps. We demonstrated here that tomato NLR Sw-5b distributes to the cytoplasm and nucleus, respectively, to play different roles in inducing host resistances against tomato spotted wilt orthotospovirus (TSWV) infection.

Development of a Mini-Replicon-Based Reverse-Genetics System for Rice Stripe Tenuivirus.

Negative-stranded RNA (NSR) viruses include both animal- and plant-infecting viruses that often cause serious diseases in humans and livestock and in agronomic crops. Rice stripe tenuivirus (RSV), a plant NSR virus with four negative-stranded/ambisense RNA segments, is one of the most destructive rice pathogens in many Asian countries. Due to the lack of a reliable reverse-genetics technology, molecular studies of RSV gene functions and its interaction with host plants are severely hampered.

Molecular Co-Chaperone SGT1 Is Critical for Cell-to-Cell Movement and Systemic Infection of Tomato Spotted Wild Virus in Nicotiana benthamiana.

Tospovirus is a tripartite negative stranded RNA virus and is considered as one of the most devastating plant viruses. Successful virus infection in plant requires many host factors. To date, very few host factors have been identified as important in infection in plants.

An Improved Silencing Vector: Greater Insert Stability and More Extensive VIGS.

Virus-induced gene silencing (VIGS) is used extensively for gene function studies in plants. VIGS is inexpensive and rapid compared with silencing conducted through stable transformation, but many virus-silencing vectors, especially in grasses, induce only transient silencing phenotypes. A major reason for transient phenotypes is the instability of the foreign gene fragment (insert) in the vector during VIGS.

Maize Elongin C interacts with the viral genome-linked protein, VPg, of Sugarcane mosaic virus and facilitates virus infection.

The viral genome-linked protein, VPg, of potyviruses is involved in viral genome replication and translation. To determine host proteins that interact with Sugarcane mosaic virus (SCMV) VPg, a yeast two-hybrid screen was used and a maize (Zea mays) Elongin C (ZmElc) protein was identified. ZmELC transcript was observed in all maize organs, but most highly in leaves and pistil extracts, and ZmElc was present in the cytoplasm and nucleus of maize cells in the presence or absence of SCMV.

Differential requirements for Tombusvirus coat protein and P19 in plants following leaf versus root inoculation.

Traditional virus inoculation of plants involves mechanical rubbing of leaves, whereas in nature viruses like Tomato bushy stunt virus (TBSV) are often infected via the roots. A method was adapted to compare leaf versus root inoculation of Nicotiana benthamiana and tomato with transcripts of wild-type TBSV (wtTBSV), a capsid (Tcp) replacement construct expressing GFP (T-GFP), or mutants not expressing the silencing suppressor P19 (TBSVΔp19). In leaves, T-GFP remained restricted to the cells immediately adjacent to the site of inoculation, unless Tcp was expressed in trans from a Potato virus X vector; while T-GFP inoculation of roots gave green fluorescence in upper tissues in the absence of Tcp.

Rationale for developing new virus vectors to analyze gene function in grasses through virus-induced gene silencing.

The exploding availability of genome and EST-based sequences from grasses requires a technology that allows rapid functional analysis of the multitude of genes that these resources provide. There are several techniques available to determine a gene's function. For gene knockdown studies, silencing through RNAi is a powerful tool.

Functions of rice NAC transcriptional factors, ONAC122 and ONAC131, in defense responses against Magnaporthe grisea.

NAC (NAM/ATAF/CUC) transcription factors have important functions in regulating plant growth, development, and abiotic and biotic stress responses. Here, we characterized two rice pathogen-responsive NAC transcription factors, ONAC122 and ONAC131. We determined that these proteins localized to the nucleus when expressed ectopically and had transcriptional activation activities.

Analysis of gene function in rice through virus-induced gene silencing.

Virus-induced gene silencing (VIGS) is a powerful RNA-silencing based technology adapted for the study of host-gene function. VIGS functions through the expression of a host gene from a virus vector. Both the virus-encoded host sequence and the homologous host target messenger RNA are destroyed or made inactive through a host surveillance system.

Characterization of a Brome mosaic virus strain and its use as a vector for gene silencing in monocotyledonous hosts.

Virus-induced gene silencing (VIGS) is used to analyze gene function in dicotyledonous plants but less so in monocotyledonous plants (particularly rice and corn), partially due to the limited number of virus expression vectors available. Here, we report the cloning and modification for VIGS of a virus from Festuca arundinacea Schreb. (tall fescue) that caused systemic mosaic symptoms on barley, rice, and a specific cultivar of maize (Va35) under greenhouse conditions.

The Tobacco mosaic virus 126-kDa protein associated with virus replication and movement suppresses RNA silencing.

Systemic symptoms induced on Nicotiana tabacum cv. Xanthi by Tobacco mosaic virus (TMV) are modulated by one or both amino-coterminal viral 126- and 183-kDa proteins: proteins involved in virus replication and cell-to-cell movement. Here we compare the systemic accumulation and gene silencing characteristics of TMV strains and mutants that express altered 126- and 183-kDa proteins and induce varying intensities of systemic symptoms on N.