Functional diversification gave rise to allelic specialization in a rice NLR immune receptor pair

Cooperation between receptors from the nucleotide-binding, leucine-rich repeats (NLR) superfamily is important for intracellular activation of immune responses. NLRs can function in pairs that, upon pathogen recognition, trigger hypersensitive cell death and stop pathogen invasion. Natural selection drives specialization of host immune receptors towards an optimal response, whilst keeping a tight regulation of immunity in the absence of pathogens. However, the molecular basis of co-adaptation and specialization between paired NLRs remains largely unknown. Here, we describe functional specialization in alleles of the rice NLR pair Pik that confers resistance to strains of the blast fungus Magnaporthe oryzae harbouring AVR-Pik effectors. We revealed that matching pairs of allelic Pik NLRs mount effective immune responses, whereas mismatched pairs lead to autoimmune phenotypes, a hallmark of hybrid necrosis in both natural and domesticated plant populations. We further showed that allelic specialization is largely underpinned by a single amino acid polymorphism that determines preferential association between matching pairs of Pik NLRs. These results provide a framework for how functionally linked immune receptors undergo co-adaptation to provide an effective and regulated immune response against pathogens. Understanding the molecular constraints that shape paired NLR evolution has implications beyond plant immunity given that hybrid necrosis can drive reproductive isolation

Nine things to know about elicitins

Elicitins are structurally conserved extracellular proteins in Phytophthora and Pythium oomycete pathogen species. They were first described in the late 1980s as abundant proteins in Phytophthora culture filtrates that have the capacity to elicit hypersensitive (HR) cell death and disease resistance in tobacco. Later, they became well-established as having features of microbe-associated molecular patterns (MAMPs) and to elicit defences in a variety of plant species. Research on elicitins culminated in the recent cloning of the elicitin response (ELR) cell surface receptor-like protein, from the wild potato Solanum microdontum, which mediates response to a broad range of elicitins. In this review, we provide an overview on elicitins and the plant responses they elicit. We summarize the state of the art by describing what we consider to be the nine most important features of elicitin biology

Adaptive evolution of rice immune receptors

Plants have evolved intracellular immune receptors, known as nucleotide-binding domain leucine-rich repeat-containing (NLR) proteins, that trigger effective immune responses upon perception of pathogen-derived effectors. Although typical NLRs share a conserved multidomain architecture, some of them carry unconventional so-called integrated domains that appear to have evolved from host targets of pathogen effectors. One example of such NLR is Pik-1—a rice immune receptor that confers disease resistance to the blast fungus Magnaporthe oryzae. Pik-1 carries a heavy metal–associated (HMA) domain that directly binds the AVR-Pik effector from M. oryzae by mimicking the host targets of this effector. In this thesis, I aimed to understand the evolutionary history of the Pik-1 receptor and its partner, Pik-2, and test hypotheses about adaptive evolution of the Pik-1–integrated HMA domain. Phylogenetic analyses of Pik orthologues revealed that the HMA domain integrated into Pik-1 before Oryzinae speciation and has been subject to the strong diversifying selection. Ancestral HMA sequence reconstruction coupled with functional studies showed that different allelic variants of Pik-1, Pikp-1 and Pikm-1, convergently evolved to recognise AVR-PikD. Using biochemical and biophysical approaches, I functionally characterised two regions in the Pik-1 HMA that independently evolved towards high-affinity AVR-PikD binding from the weaker ancestral state. In both cases the HMA domain only recently acquired the capacity to bind the AVR-PikD effector with high affinity, indicating that for most of its evolutionary history the HMA had not been subject to selection pressure imposed by this blast effector. In addition, although Pikp-1 and Pikm-1 receptors evolved to produce similar phenotypic outcomes, they underwent different evolutionary trajectories to do so. These findings paint a complex picture of the mechanisms and evolutionary dynamics of NLR adaptation and provide a robust evolutionary framework that can contribute a more comprehensive understanding of plant–microbe systems

Is the transfer process regarding property purchases legally safe in Sweden? : A study with focus on power of attorney and title deed

Fullmakten är en rättshandling där en person, även kallad fullmaktsgivare, ger en annan person, fullmäktige, rätten att företräda, ingå avtal, utföra betalningar eller ingå i andra rättshandlingar åt fullmaktsgivaren mot tredje man. Fullmäktige kan bland annat få i uppdrag att utföra bankärenden samt fastighetsförsäljning eller köp. Det finns olika typer av fullmakt som utgör vilken typ av behörighet eller befogenhet den fullmäktige har gentemot fullmaktsgivaren. Fullmakt regleras i Avtalslagen. Det finns ett formkrav för fullmakt vid försäljning av fast egendom, vilket är att fullmakten ska vara skriftlig för att den ska vara giltig. Utöver det finns det inga ytterligare formkrav för hur en fullmakt ska vara utformad.  Lagfart är en inskrivning av fastighetsförvärv som ansöks hos inskrivningsmyndigheten. Lagfarten är en slags bekräftelse på att den personen som har beviljats lagfart är den nya ägaren till fastigheten. När en lagfartsansökan har beviljats kan man bland annat söka inteckning i fastigheten. Lagfart regleras i Jordabalken, där framkommer vilka krav som finns gällande lagfarten. Lagfartskapning kan ske när någon med hjälp av en förfalskad fångeshandling beviljas lagfart på en fastighet som egentligen tillhör någon annan, vilket kan leda till skador för den rätta ägaren. Syftet med arbetet är att undersöka hur kontrollen kring lagfart kan motverka förekomsten av lagfartskapning samt undersöka fullmaktens reglering och rättssäkerhet. I slutsatsen framkommer det att det finns ett större behov av att stärka regleringen för fullmakt när det kommer till fastighetsköp samt ta till ytterligare åtgärder för att säkerställa att lagfart som ansöks görs med äkta fångeshandlingar. Genom ytterligare reglering och åtgärder kan man öka skyddet för de parter som är involverade i överlåtelseprocessen. The power of attorney is a legal act where a person, also known as the principal, gives another person, council, the right to represent, enter into agreements, make payments or engage in other legal acts on behalf of the principal with third parties. The council can among other things be tasked with performing bank transactions and real estate sales or purchases. There are different types of powers of attorney that determine the type of authority or authorization that the council has towards the principal. Power of attorney is regulated in the Swedish law called Avtalslagen. There is a form requirement for power of attorney when it comes to selling real estate, which is that the power of attorney must be in writing form to be valid. Apart from that, there are no further form requirements for how a power of attorney should be formulated.  Title deed is a registration of real estate acquisitions that is applied for at the registration authority. Title deed is a kind of confirmation that the person who has been granted the title deed is the new owner of the property. When a deed application has been granted, one can among other things, apply for a mortgage on the property. Title deeds are regulated in the Swedish law called Jordabalken, where requirements for the title deed are specified among other things. Title deed frauds can occur when someone is granted title deed for a property with falsified documents that actually belongs to someone else, which can lead to damages for the rightful owner. The purpose of this work is to examine how the control of title deeds can counteract the occurrence of title deed frauds, as well as to examine the regulation and legal security of the power of attorney.  In conclusion, it appears that there is a greater need to strengthen the regulation of power of attorney when it comes to real estate purchases and to take additional measures to ensure that title deeds that are being applied for are done with authentic documents. Through further regulation and measures, an increased protection for the parties involved in the transfer process can be made

Is the transfer process regarding property purchases legally safe in Sweden? : A study with focus on power of attorney and title deed

Fullmakten är en rättshandling där en person, även kallad fullmaktsgivare, ger en annan person, fullmäktige, rätten att företräda, ingå avtal, utföra betalningar eller ingå i andra rättshandlingar åt fullmaktsgivaren mot tredje man. Fullmäktige kan bland annat få i uppdrag att utföra bankärenden samt fastighetsförsäljning eller köp. Det finns olika typer av fullmakt som utgör vilken typ av behörighet eller befogenhet den fullmäktige har gentemot fullmaktsgivaren. Fullmakt regleras i Avtalslagen. Det finns ett formkrav för fullmakt vid försäljning av fast egendom, vilket är att fullmakten ska vara skriftlig för att den ska vara giltig. Utöver det finns det inga ytterligare formkrav för hur en fullmakt ska vara utformad.  Lagfart är en inskrivning av fastighetsförvärv som ansöks hos inskrivningsmyndigheten. Lagfarten är en slags bekräftelse på att den personen som har beviljats lagfart är den nya ägaren till fastigheten. När en lagfartsansökan har beviljats kan man bland annat söka inteckning i fastigheten. Lagfart regleras i Jordabalken, där framkommer vilka krav som finns gällande lagfarten. Lagfartskapning kan ske när någon med hjälp av en förfalskad fångeshandling beviljas lagfart på en fastighet som egentligen tillhör någon annan, vilket kan leda till skador för den rätta ägaren. Syftet med arbetet är att undersöka hur kontrollen kring lagfart kan motverka förekomsten av lagfartskapning samt undersöka fullmaktens reglering och rättssäkerhet. I slutsatsen framkommer det att det finns ett större behov av att stärka regleringen för fullmakt när det kommer till fastighetsköp samt ta till ytterligare åtgärder för att säkerställa att lagfart som ansöks görs med äkta fångeshandlingar. Genom ytterligare reglering och åtgärder kan man öka skyddet för de parter som är involverade i överlåtelseprocessen. The power of attorney is a legal act where a person, also known as the principal, gives another person, council, the right to represent, enter into agreements, make payments or engage in other legal acts on behalf of the principal with third parties. The council can among other things be tasked with performing bank transactions and real estate sales or purchases. There are different types of powers of attorney that determine the type of authority or authorization that the council has towards the principal. Power of attorney is regulated in the Swedish law called Avtalslagen. There is a form requirement for power of attorney when it comes to selling real estate, which is that the power of attorney must be in writing form to be valid. Apart from that, there are no further form requirements for how a power of attorney should be formulated.  Title deed is a registration of real estate acquisitions that is applied for at the registration authority. Title deed is a kind of confirmation that the person who has been granted the title deed is the new owner of the property. When a deed application has been granted, one can among other things, apply for a mortgage on the property. Title deeds are regulated in the Swedish law called Jordabalken, where requirements for the title deed are specified among other things. Title deed frauds can occur when someone is granted title deed for a property with falsified documents that actually belongs to someone else, which can lead to damages for the rightful owner. The purpose of this work is to examine how the control of title deeds can counteract the occurrence of title deed frauds, as well as to examine the regulation and legal security of the power of attorney.  In conclusion, it appears that there is a greater need to strengthen the regulation of power of attorney when it comes to real estate purchases and to take additional measures to ensure that title deeds that are being applied for are done with authentic documents. Through further regulation and measures, an increased protection for the parties involved in the transfer process can be made

Plant immunity switched from bacteria to virus

A plant immune receptor is engineered to recognize viruses rather than bacteria