Up to 20% of people worldwide develop gastrointestinal symptoms following a meal , leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specifc IgE antibodies in mice, which are limited to the intestine. Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell dependent mechanism induced increased visceral pain. This aberrant pain signaling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.(Nature )

• Tillering is an important parameter of plant architecture in cereal crops. In this study, we identified the PHYTOCHROME-INTERACTING FACTOR-LIKE (PIL) family transcription factors as new repressors of tillering in cereal crops. • Using biochemical and genetic approaches, we explore the roles of TaPIL1 in regulating wheat plant architecture. We found that the PIF-like protein TaPIL1 controls tiller number in wheat. • Overexpression of TaPIL1 reduces wheat tiller number; additionally, overexpression of TaPIL1-SRDX increases wheat tiller number. Furthermore, we show that TaPIL1 activates the transcriptional expression of TaTB1; moreover, TaPIL1 physically interacts with TaSPL3/17, which are activators of TaTB1 transcription. In rice, overexpression and loss-of-function mutations of OsPIL11 reduce or increase tiller number by regulating the expression of OsTB1. In Arabidopsis, we demonstrate that PIF4 interacts with SPL9 to inhibit shoot branching. • This study reveals that PIL family transcription factors directly interact with SPLs and play an important role in repressing tillering/branching in plants.(NEW PHYTOLOGIST)

Increasing evidence points to the tight relationship between alternative splicing (AS) and the salt stress response in plants. However, the mechanisms linking these two phenomena remain unclear. In this study, we have found that Salt-Responsive Alternatively Spliced gene 1 (SRAS1), encoding a RING-Type E3 ligase, generates two splicing variants: SRAS1.1 and SRAS1.2, which exhibit opposing responses to salt stress. The salt stress-responsive AS event resulted in greater accumulation of SRAS1.1 and a lower level of SRAS1.2. Comprehensive phenotype analysis showed that overexpression of SRAS1.1 made the plants more tolerant to salt stress, whereas overexpression of SRAS1.2 made them more sensitive. In addition, we successfully identified the COP9 signalosome 5A (CSN5A) as the target of SRAS1. CSN5A is an essential player in the regulation of plant development and stress. The full-length SRAS1.1 promoted degradation of CSN5A by the 26S proteasome. By contrast, SRAS1.2 protected CSN5A by competing with SRAS1.1 on the same binding site. Thus, the salt stress-triggered AS controls the ratio of SRAS1.1/SRAS1.2 and switches on and off the degradation of CSN5A to balance the plant development and salt tolerance. Together, these results provide insights that salt-responsive AS acts as post-transcriptional regulation in mediating the function of E3 ligase.(PLOS GENETICS)

Heat stress is a major limiting factor for global wheat production and causes dramatic yield loss worldwide. The TaMBF1c is up-regulated in response to heat stress in wheat. Understanding the molecular mechanisms associated with heat stress responses will pave the way to improve wheat thermotolerance in future.  Through CRISPR/Cas9-based gene editing, polysome profiling coupled with RNA-seq analysis, and protein–protein interaction, we proved that TaMBF1c conferred heat response via regulating specific gene translation in wheat.  Results showed that TaMBF1c is evolutionarily conserved in diploid, tetraploid and hexaploid wheat species, and its knock-down and knock-out lines show increased heat sensitivity. TaMBF1c is co-localized with stress granule complex and interacts with TaG3BP. TaMBF1c affects translation efficiency of a subset of heat responsive genes, which are significantly enriched in the ‘sequence-specific DNA binding’ term. Moreover, gene expression network analysis demonstrated that TaMBF1c is closely associated with the translation of heat shock proteins.  Our findings reveal a contribution of TaMBF1c regulating heat stress response via translation process, and provide new target for improving heat tolerance in wheat breeding programs.(NEW PHYTOLOGIST)

The unprecedented wheat yield increases during the Green Revolution were achieved through the introduction of the Reduced height (Rht)-B1b and Rht-D1b semi-dwarfing alleles. These Rht-1 alleles encode growth-repressing DELLA genes containing a stop codon within their open reading frame that confers gibberellin (GA)-insensitive semi-dwarfism. In this study, we successfully took the hurdle of detecting wild-type RHT-1 proteins in different wheat organs and confirmed their degradation in response to GAs. We further demonstrated that Rht-B1b and Rht-D1b produce N-terminal truncated proteins through translational reinitiation. Expression of these N-terminal truncated proteins in transgenic lines and in Rht-D1c, an allele containing multiple Rht-D1b copies, demonstrated their ability to cause strong dwarfism, resulting from their insensitivity to GA-mediated degradation. N-terminal truncated proteins were detected in spikes and nodes, but not in the aleurone layers. Since Rht-B1b and Rht-D1b alleles cause dwarfism but have wild-type dormancy, this finding suggests that tissue-specific differences in translational reinitiation may explain why the Rht-1 alleles reduce plant height without affecting dormancy. Taken together, our findings not only reveal the molecular mechanism underlying the Green Revolution but also demonstrate that translational reinitiation in the main open reading frame occurs in plants.(Molecular Plant)

Structural variations (SVs), such as inversion and duplication, contribute to important agronomic traits in crops . Pan-genome studies revealed that SVs were a crucial and ubiquitous force driving genetic diversification. Although genome editing can effectively create SVs in plants and animals the potential of designed SVs in breeding has been overlooked. Here, we show that new genes and traits can be created in rice by designed large-scale genomic inversion or duplication using CRISPR/Cas9. A 911 kb inversion on chromosome 1 resulted in a designed promoter swap between CP12 and PPO1, and a 338 kb duplication between HPPD and Ubiquitin2 on chromosome 2 created a novel gene cassette at the joint, promoterUbiquitin2::HPPD. Since the original CP12 and Ubiquitin2 genes were highly expressed in leaves, the expression of PPO1 and HPPD in edited plants with homozygous SV alleles was increased by tens of folds and conferred sufficient herbicide resistance in field trials without adverse effects on other important agronomic traits. CRISPR/Cas-based genome editing for gene knock-ups has been generally considered very difficult without inserting donor DNA as regulatory elements. Our study challenges this notion by providing a donor-DNA-free strategy, thus greatly expanding the utility of CRISPR/Cas in plant and animal improvements.(Nature Plants)

The phytohormone auxin controls many processes in plants, at least in part through its regulation of cell expansion. The acid growth hypothesis has been proposed to explain auxin-stimulated cell expansion for five decades, but the mechanism that underlies auxin-induced cell-wall acidification is poorly characterized. Auxin induces the phosphorylation and activation of the plasma membrane H+ -ATPase that pumps protons into the apoplast, yet how auxin activates its phosphorylation remains unclear. Here we show that the transmembrane kinase (TMK) auxin-signalling proteins interact with plasma membrane H+-ATPases, inducing their phosphorylation, and thereby promoting cell-wall acidification and hypocotyl cell elongation in Arabidopsis. Auxin induced interactions between TMKs and H+ -ATPases in the plasma membrane within seconds, as well as TMK-dependent phosphorylation of the penultimate threonine residue on the H+-ATPases. Our genetic, biochemical and molecular evidence demonstrates that TMKs directly phosphorylate plasma membrane H+ -ATPase and are required for auxin-induced H+ -ATPase activation, apoplastic acidification and cell expansion. Thus, our findings reveal a crucial connection between auxin and plasma membrane H+ -ATPase activation in regulating apoplastic pH changes and cell expansion through TMK-based cell surface auxin signalling.(Nature)

Wheat stem (or black) rust, caused by Puccinia graminis f. sp. tritici (Pgt), has been historically among the most devastating global fungal diseases of wheat. The recent occurrence and spread of new virulent races such as Ug99 have prompted global efforts to identify and isolate more effective stem rust resistance (Sr) genes. Here, we report the map-based cloning of the Ug99- effective SrTm5 gene from diploid wheat Triticum monococcum accession PI 306540 that encodes a typical coiled-coil nucleotide-binding leucine-rich repeat protein. This gene, designated as Sr22b, is a new allele of Sr22 with a rare insertion of a large (13.8-kb) retrotransposon into its second intron. Biolistic transformation of an ~112-kb circular bacterial artificial chromosome plasmid carrying Sr22b into the susceptible wheat variety Fielder was sufficient to confer resistance to stem rust. In a survey of 168 wheat genotypes, Sr22b was present only in cultivated T. monococcum subsp. monococcum accessions but absent in all tested tetraploid and hexaploid wheat lines. We developed a diagnostic molecular marker for Sr22b and successfully introgressed a T. monococcum chromosome segment containing this gene into hexaploid wheat to accelerate its deployment and pyramiding with other Sr genes in wheat breeding programmes. Sr22b can be a valuable component of gene pyramids or transgenic cassettes combining different resistance genes to control this devastating disease.(Plant Biotechnology Journal)

Rht-B1b and Rht-D1b, the ‘Green Revolution’ (GR) genes, greatly improved yield potential of wheat under nitrogen fertilizer application, but reduced coleoptile length, seedling vigor and grain weight. Thus, mining alternative reduced plant height genes without adverse effects is urgently needed. We isolated the causal gene of Rht24 through map-based cloning and characterized its function using transgenic, physiobiochemical and transcriptome assays. We confirmed genetic effects of the dwarfing allele Rht24b with an association analysis and also traced its origin and distribution. Rht24 encodes a gibberellin (GA) 2-oxidase, TaGA2ox-A9. Rht24b conferred higher expression of TaGA2ox-A9 in stems, leading to a reduction of bioactive GA in stems but an elevation in leaves at the jointing stage. Strikingly, Rht24b reduced plant height, but had no yield penalty; it significantly increased nitrogen use efficiency, photosynthetic rate and the expression of related genes. Evolutionary analysis demonstrated that Rht24b first appeared in wild emmer and was detected in more than half of wild emmer and wheat accessions, suggesting that it underwent both natural and artificial selection. These findings uncover an important genetic resource for wheat breeding and also provide clues for dissecting the regulatory mechanisms underlying GA-mediated morphogenesis and yield formation. (New Phytologist)

Hybridization plays a decisive role in the evolution and diversification of angiosperms. However, the mechanisms of wide hybridization remain open because pre- and post-fertilization barriers limit the production and development of inter-subfamily/intergeneric zygotes, respectively. We examined hybridization between wheat and rice using an in vitro fertilization (IVF) system to bypass these barriers. Several gamete combinations of allopolyploid wheat–rice hybrid zygotes were successfully produced, and the developmental profiles of hybrid zygotes were analyzed. Hybrid zygotes derived from one rice egg cell and one wheat sperm cell ceased at the multicellular embryo-like structure stage. This developmental barrier was overcome by adding one wheat egg cell to the wheat–rice hybrid zygote. In the reciprocal combination, one wheat egg and one rice sperm cell, the resulting hybrid zygotes failed to divide. However, doubling the dosage of rice sperm cell allowed the hybrid zygotes to develop into plantlets. Rice chromosomes appeared to be progressively eliminated during the early developmental stage of these hybrid embryos, and c. 20% of regenerated plants showed abnormal morphology. These results suggest that hybrid breakdown can be overcome through optimization of gamete combinations, and the present hybrid will provide a new horizon for utilization of inter-subfamily genetic resources.(New Phytol )

In a sign of the United Kingdom’s intentions to move away from European Union (EU) restrictions following Brexit, its Department for Environment, Food & Rural Affairs (DEFRA) has given scientists at Harpenden-based Rothamsted Research the go-ahead for the first field trials of gene-edited wheat made using CRISPR technology anywhere in the UK. The wheat has reduced amounts of the naturally occurring amino acid asparagine, which converts to the potentially carcinogenic chemical acrylamide when bread is baked or toasted. By knocking out the asparagine synthetase gene TaASN2, researchers have demonstrated more than a 90% reduction of asparagine concentrations in the grain of one line of edited wheat. The trials are expected to run for five years, measuring the amount of asparagine in the same wheat grain when grown in the field, as well as assessing other aspects such as yield and protein content. The aim is to produce ultra-low-asparagine, non-gene-modified wheat, according project leader Nigel Halford. Current EU regulations treat gene editing of crops the same as genetic modification, though in April the European Commission launched a review of its rules on genetically modified organisms, paving the way to a possible loosening of restrictions for plants resulting from gene-editing technology. DEFRA secretary George Eustice said at a farming conference last January that the UK, outside of the EU, was now free to make its own decisions based on the science, calling the current EU approach—enshrined in a 2018 European Court of Justice ruling— “flawed and stifling to scientific progress.(Nature Biotechnology)