Biology subjects

Goh, F.-J.

Publications and source records attributed to Goh, F.-J..

4 recordsLinked to original sources

bioRxiv2025

A hydrophobic core in the coiled-coil domain essential for NRC resistosome function

The nucleotide-binding leucine-rich repeat protein (NLR) required for cell death (NRC) family represents a group of helper NLRs that are required by sensor NLRs to execute hypersensitive cell death during pathogen infection. NRCs contain an N-terminal coiled-coil (CC) domain essential for their function, yet our knowledge of how this domain contributes to NRC function remains limited. Here, we identified a novel hydrophobic feature within the CC domain that contributes to NRC-mediated immunity. We screened for conserved hydrophobic residues among NRCs and identified seven required for NRC4-mediated cell death. Structural analysis revealed that four of these residues form a hydrophobic core in the CC domain. This hydrophobic core is important for NRC4 subcellular localization, oligomerization, and phospholipid association, but not for NRC4 focal accumulation at the extrahaustorial membrane during Phytophthora infestans infection. Sequence analysis and functional assays revealed this core is highly conserved in NRCs and some singleton NLRs but has degenerated in NRC-dependent sensor NLRs. Our study identifies a novel hydrophobic feature in the CC domain of NRCs and reveals its contribution to NLR-mediated immunity.

plant biology↗

bioRxiv2024

Rhizobium rhizogenes A4-derived strains mediate hyper-efficient transient gene expression in Nicotiana benthamiana and other solanaceous plants

Agroinfiltration, a method utilizing agrobacteria to transfer DNA into plant cells, is widely used for transient gene expression in plants. Besides the commonly used Agrobacterium strains, Rhizobium rhizogenes can also introduce foreign DNA into host plants for gene expression. While many R. rhizogenes strains have been known for inducing hairy root symptoms, their use for transient expression has not been fully explored. Here, we showed that R. rhizogenes A4 outperformed all other tested agrobacterial strains in agroinfiltration experiments on leaves of Nicotiana benthamiana and other solanaceous plants. By conducting an agroinfiltration screening in N. benthamiana leaves using various agrobacterial strains carrying the RUBY reporter gene cassette, we discovered that A4 mediates the strongest and fastest transient expression. Utilizing the genomic information, we developed a collection of disarmed and modified strains derived from A4. By performing vacuum infiltration assays, we demonstrated that these A4-derived strains efficiently transiently transform 6-week-old N. benthamiana leaves, showing less sensitivity to the age of plants compared to the laboratory strain GV3101. Furthermore, we performed agroinfiltration using AS109, an A4-derived disarmed strain, on the leaves of tomato, pepper, and eggplant. Remarkably, AS109 mediated transient gene expression on tested solanaceous plants more effectively than all the tested commonly used agrobacterial strains. This discovery paves the way for establishing R. rhizogenes A4-derived strains as a new option for enhancing transient expression in N. benthamiana and facilitating the functional study of plant genes in other solanaceous species.

plant biology↗

bioRxiv2024

Development of a tightly regulated copper-inducible transient gene expression system in Nicotiana benthamiana incorporating suicide exon and Cre recombinase

Chemical-inducible gene expression systems have been frequently used to regulate gene expression for functional genomics in various plant species. However, a convenient chemical-inducible system that can tightly regulate transgene expression in Nicotiana benthamiana is still missing. In this study, we developed a tightly regulated copper-inducible system that can be used to regulate transgene expression and perform cell death assays in N. benthamiana. We tested several chemical-inducible systems using Agrobacterium-mediated transient expression and found that the copper-inducible system showed the least concerns of leakiness issues. Using the MoClo-based synthetic biology approach, we optimized the design of the copper-inducible system and incorporated the use of the suicide exon HyP5SM/OsL5 and Cre/LoxP as additional regulatory elements to enhance the tightness of the regulation. This new design allowed us to tightly control the hypersensitive cell death induced by several tested NLRs and their matching AVRs, and it can also be easily applied to regulate the expression of other transgenes in transient expression assays. Our findings provide new approaches for both fundamental and translational studies in plant functional genomics.

plant biology↗

bioRxiv2023

NRC immune receptor networks show diversified hierarchical genetic architecture across plant lineages

Plants developed sophisticated immune systems with nucleotide-binding domain and leucine-rich repeat-containing (NLR) proteins to repel invading pathogens. The NRC (NLR required for cell death) family includes helper NLRs that form a complex genetic network with multiple sensor NLRs to provide resistance against pathogens of solanaceous plants. However, the evolution and function of NRC networks outside solanaceous plants is currently unknown. We conducted phylogenomic and macroevolutionary analyses comparing NLRs identified from different asterids lineages and found that NRC networks expanded significantly in most lamiids but not in Ericales and campanulids. Using transient expression assays in Nicotiana benthamiana, we show that NRC networks are simple in Ericales and campanulids, but are with high complexity in lamiids. Phylogenetic analyses grouped the NRC helper NLRs into three NRC0 subclades that are conserved, and several family-specific NRC subclades of lamiids that show signatures of diversifying selection. Functional analyses revealed that members of the NRC0 subclades are partially interchangeable, whereas family-specific NRC members in lamiids lack interchangeability. Our findings highlight the distinctive evolutionary patterns of the NRC networks in asterids and provide potential insights into transferring disease resistance across plant lineages.

plant biology↗