by Ujwal Chaudhary, Bin Xia, Stefano Silvoni, Leonardo G. Cohen, Niels Birbaumer

by Elizabeth K. Brauer, George V. Popescu, Dharmendra K. Singh, Mauricio Calviño, Kamala Gupta, Bhaskar Gupta, Suma Chakravarthy, Sorina C. Popescu

Plant protein kinases form redundant signaling pathways to perceive microbial pathogens and activate immunity. Bacterial pathogens repress cellular immune responses by secreting effectors, some of which bind and inhibit multiple host kinases. To understand how broadly bacterial effectors may bind protein kinases and the function of these kinase interactors, we first tested kinase–effector (K-E) interactions using the Pseudomonas syringae pv. tomato–tomato pathosystem. We tested interactions between five individual effectors (HopAI1, AvrPto, HopA1, HopM1, and HopAF1) and 279 tomato kinases in tomato cells. Over half of the tested kinases interacted with at least one effector, and 48% of these kinases interacted with more than three effectors, suggesting a role in the defense. Next, we characterized the role of select multi-effector–interacting kinases and revealed their roles in basal resistance, effector-triggered immunity (ETI), or programmed cell death (PCD). The immune function of several of these kinases was only detectable in the presence of effectors, suggesting that these kinases are critical when particular cell functions are perturbed or that their role is typically masked. To visualize the kinase networks underlying the cellular responses, we derived signal-specific networks. A comparison of the networks revealed a limited overlap between ETI and basal immunity networks. In addition, the basal immune network complexity increased when exposed to some of the effectors. The networks were used to successfully predict the role of a new set of kinases in basal immunity. Our work indicates the complexity of the larger kinase-based defense network and demonstrates how virulence- and avirulence-associated bacterial effectors alter sectors of the defense network.

by Tadeusz Wróblewski, Laurentiu Spiridon, Eliza Cristina Martin, Andrei-Jose Petrescu, Keri Cavanaugh, Maria Jose-Truco, Huaqin Xu, Dariusz Gozdowski, Krzysztof Pawłowski, Richard W. Michelmore, Frank L.W. Takken

The ability to induce a defense response after pathogen attack is a critical feature of the immune system of any organism. Nucleotide-binding leucine-rich repeat receptors (NLRs) are key players in this process and perceive the occurrence of nonself-activities or foreign molecules. In plants, coevolution with a variety of pests and pathogens has resulted in repertoires of several hundred diverse NLRs in single individuals and many more in populations as a whole. However, the mechanism by which defense signaling is triggered by these NLRs in plants is poorly understood. Here, we show that upon pathogen perception, NLRs use their N-terminal domains to transactivate other receptors. Their N-terminal domains homo- and heterodimerize, suggesting that plant NLRs oligomerize upon activation, similar to the vertebrate NLRs; however, consistent with their large number in plants, the complexes are highly heterometric. Also, in contrast to metazoan NLRs, the N-terminus, rather than their centrally located nucleotide-binding (NB) domain, can mediate initial partner selection. The highly redundant network of NLR interactions in plants is proposed to provide resilience to perturbation by pathogens.

by Eirini M. Kallimasioti-Pazi, Keerthi Thelakkad Chathoth, Gillian C. Taylor, Alison Meynert, Tracy Ballinger, Martijn J. E. Kelder, Sébastien Lalevée, Ildem Sanli, Robert Feil, Andrew J. Wood

Genome editing occurs in the context of chromatin, which is heterogeneous in structure and function across the genome. Chromatin heterogeneity is thought to affect genome editing efficiency, but this has been challenging to quantify due to the presence of confounding variables. Here, we develop a method that exploits the allele-specific chromatin status of imprinted genes in order to address this problem in cycling mouse embryonic stem cells (mESCs). Because maternal and paternal alleles of imprinted genes have identical DNA sequence and are situated in the same nucleus, allele-specific differences in the frequency and spectrum of mutations induced by CRISPR-Cas9 can be unequivocally attributed to epigenetic mechanisms. We found that heterochromatin can impede mutagenesis, but to a degree that depends on other key experimental parameters. Mutagenesis was impeded by up to 7-fold when Cas9 exposure was brief and when intracellular Cas9 expression was low. In contrast, the outcome of mutagenic DNA repair was unaffected by chromatin state, with similar efficiencies of homology-directed repair (HDR) and deletion spectra on maternal and paternal chromosomes. Combined, our data show that heterochromatin imposes a permeable barrier that influences the kinetics, but not the endpoint, of CRISPR-Cas9 genome editing and suggest that therapeutic applications involving low-level Cas9 exposure will be particularly affected by chromatin status.

Since Seattle high schools decided to start an hour later, students have been getting more sleep – and school attendance and grades have improved

First full reconstruction of Thylacoleo carnifex shows it tore apart its prey like a Tasmanian devil, had the bite strength of a lion, and climbed like a koala

White holes are black ones in reverse, spewing out matter– and they could give us our first glimpse of the quantum source of space-time, says physicist Carlo Rovelli

Bitcoin investors have had a rough ride this year as the price of the cryptocurrency has tumbled, making it less economical to produce the coins

A multi-user quantum network shows that secure quantum links between several people at once could be possible using standard telecommunications equipment

The genes involved in producing hair follicles are partly to blame for acne, according to an analysis of the DNA of over 5000 people with severe acne

The genes involved in producing hair follicles are partly to blame for acne, according to an analysis of the DNA of over 5000 people with severe acne

White holes are black ones in reverse, spewing out matter– and they could give us our first glimpse of the quantum source of space-time, says physicist Carlo Rovelli

The Hainan gymnure is a stinky but spine-free relative of the hedgehog that we thought was rare – a new discovery in northern Vietnam suggests we were wrong

The Hainan gymnure is a stinky but spine-free relative of the hedgehog that we thought was rare – a new discovery in northern Vietnam suggests we were wrong

A lab-on-a-chip that fits inside a smartphone is set to change our relationship with food and the chemicals we use to make it

A lab-on-a-chip that fits inside a smartphone is set to change our relationship with food and the chemicals we use to make it

When humans have vanished from Earth, one of the most enduring marks of our impact will be the sudden appearance of copious chicken bones in the fossil record

As larvae, corals drift around the ocean searching for somewhere to live – and they seem to appreciate a spot in an area full of loud fish

Barbary macaques became more relaxed and friendlier after seeing another macaque being groomed – a finding that may help explain ‘head orgasm’ videos

When humans have vanished from Earth, one of the most enduring marks of our impact will be the sudden appearance of copious chicken bones in the fossil record