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A meta-analysis of multiple published simulations of crop yields predicts aggregate production losses for wheat, rice ( I Oryza sativa i ), and maize in both temperate and tropical regions by 2 °C warming with even greater crop losses in the second half of the 21st century (Challinor et al., 2014). Global emissions of CO SB 2 sb and other greenhouse gases have increased steadily since the pre-industrial era (Pedersen et al., 2021) leading to global temperature increases of >1 °C with most of this increase occurring within the last 50 years (IPCC, 2021). Also focusing on drought and the different molecular mechanisms involved in drought tolerance and drought recovery, Tang and Bassham (2022) address the important process of autophagy and its role in inducing drought tolerance. In their review article, Berrío et al. (2022) discuss several strategies to enhance drought resilience in crops focusing on "growth-centered" and "drought resilience without growth penalty" strategies. [Extracted from the article]

Katherine Denby is taking over as the new Editor in Chief of The Plant Journal (TPJ), following the work of Lee Sweetlove. Denby aims to continue the journal's reputation as a platform for excellent plant science and provide a high-quality publishing experience. TPJ is part-owned by the Society of Experimental Biology (SEB) and supports scientific meetings and early career researchers. The journal publishes original research articles, commissioned reviews, perspectives, technical advances, and resource articles. Denby expresses gratitude to Sweetlove for his leadership and hopes to continue building TPJ's reputation in the changing publishing landscape. [Extracted from the article]

We report the characterization of anArabidopsis thalianamutant,ups1, isolated on the basis of reduced expression of phosphoribosylanthranilate transferase, a tryptophan biosynthetic enzyme.ups1also exhibits defects in a wide range of defence responses. After infection withPseudomonas syringaeorBotrytis cinerea, the expression of genes regulated by both the salicylic acid and jasmonic acid/ethylene pathways is reduced inups1compared with wild type. Camalexin accumulation inups1is greatly reduced after infection with these two pathogens, as well as after amino acid starvation or oxidative stress. Reactive oxygen species (ROS)-mediated gene expression is also compromised inups1indicating that this mutant is defective in signalling pathways activated in response to both biotic and abiotic stress. The fact that all three major defence signalling pathways are disrupted inups1, together with the oxidative stress phenotype, leads us to suggest that UPS1 is involved in ROS signal transduction. [ABSTRACT FROM AUTHOR]

Botrytis cinerea is a major pathogen of fruit and vegetable crops causing both pre- and post-harvest grey mould. We have analysed 16 Arabidopsis thaliana ecotypes for natural variation in B. cinerea susceptibility. Susceptibility was associated with lower camalexin accumulation, and three ecotypes (Cape Verdi Islands (Cvi-0), Slavice (Sav-0) and Kindalville (Kin-0)) showed differential susceptibility to the two B. cinerea isolates used. Subsequently, to better understand the genetic control of grey mould disease, we assayed the Arabidopsis Landsberg erecta (L er) × Columbia (Col-0) recombinant inbred population with the two isolates, and identified multiple small-to-medium-effect quantitative trait loci (QTL) governing susceptibility. Interestingly, the QTL for each isolate are distinct, suggesting that different mechanisms govern defence against these two isolates. Two QTL for each isolate exhibited epistatic interactions with specific allele combinations generating heightened B. cinerea susceptibility. [ABSTRACT FROM AUTHOR]

Numerous studies have suggested that plant/pathogen interactions are partially mediated via plant secondary metabolite production and corresponding pathogen tolerance. However, there are inconsistent reports on the ability of particular compounds to provide resistance to a pathogen. Most of these studies have focused on individual isolates of a given pathogen, suggesting that pathogens vary in their sensitivity to plant-produced toxins. We tested variability in virulence among pathogen isolates, and the impact on this by plant production of, and pathogen tolerance to, secondary metabolites. Botrytis cinerea isolates showed differing sensitivity to purified camalexin, and camalexin-sensitive isolates produced larger lesions on camalexin-deficient Arabidopsis genotypes than on the wild type. In contrast, the camalexin-insensitive isolate produced lesions of similar size on wild-type and camalexin-deficient Arabidopsis. Additional analysis with Arabidopsis secondary metabolite biosynthetic mutants suggests that Botrytis also has variable sensitivity to phenylpropanoids and glucosinolates. Furthermore, Botrytis infection generates a gradient of secondary metabolite responses emanating from the developing lesion, with the Botrytis isolate used determining the accumulation pattern. Collectively, our results indicate that Arabidopsis/ Botrytis interactions are influenced at the metabolic level by variations in toxin production in the host and sensitivity in the pathogen. [ABSTRACT FROM AUTHOR]

SUMMARY: The photosynthetic capacity of mature leaves increases after several days' exposure to constant or intermittent episodes of high light (HL) and is manifested primarily as changes in chloroplast physiology. How this chloroplast‐level acclimation to HL is initiated and controlled is unknown. From expanded Arabidopsis leaves, we determined HL‐dependent changes in transcript abundance of 3844 genes in a 0–6 h time‐series transcriptomics experiment. It was hypothesized that among such genes were those that contribute to the initiation of HL acclimation. By focusing on differentially expressed transcription (co‐)factor genes and applying dynamic statistical modelling to the temporal transcriptomics data, a regulatory network of 47 predominantly photoreceptor‐regulated transcription (co‐)factor genes was inferred. The most connected gene in this network was B‐BOX DOMAIN CONTAINING PROTEIN32 (BBX32). Plants overexpressing BBX32 were strongly impaired in acclimation to HL and displayed perturbed expression of photosynthesis‐associated genes under LL and after exposure to HL. These observations led to demonstrating that as well as regulation of chloroplast‐level acclimation by BBX32, CRYPTOCHROME1, LONG HYPOCOTYL5, CONSTITUTIVELY PHOTOMORPHOGENIC1 and SUPPRESSOR OF PHYA‐105 are important. In addition, the BBX32‐centric gene regulatory network provides a view of the transcriptional control of acclimation in mature leaves distinct from other photoreceptor‐regulated processes, such as seedling photomorphogenesis. Significance Statement: Identifying genes that control plants' intrinsic photosynthetic capacity would provide opportunities for increasing crop productivity. Photosynthetic capacity in mature leaves increases after several days' exposure to episodes of high‐light intensity (HL), which is defined as HL acclimation. Using temporal transcriptomics data and dynamic modelling, we inferred a BBX32‐centric 47‐member Gene Regulatory Network, members of which control, in the first hours of HL exposure, cellular processes that result in enhanced photosynthetic capacity 5 days later. [ABSTRACT FROM AUTHOR]

Summary: Traditional crops have historically provided accessible and affordable nutrition to millions of rural dwellers but have been neglected, with most modern agricultural systems over‐reliant on a small number of internationally traded crops. Traditional crops are typically well‐adapted to local agro‐ecological conditions and many are nutrient‐dense. They can play a vital role in local food systems through enhanced nutrition (particularly where diets are dominated by starch crops), food security and livelihoods for smallholder farmers, and a climate‐resilient and biodiverse agriculture. Using short‐read, long‐read and phased sequencing technologies, we generated a high‐quality chromosome‐level genome assembly for Amaranthuscruentus, an under‐researched crop with micronutrient‐ and protein‐rich leaves and gluten‐free seed, but lacking improved varieties, with respect to productivity and quality traits. The 370.9 Mb genome demonstrates a shared whole genome duplication with a related species, Amaranthushypochondriacus. Comparative genome analysis indicates chromosomal loss and fusion events following genome duplication that are common to both species, as well as fission of chromosome 2 in A. cruentus alone, giving rise to a haploid chromosome number of 17 (versus 16 in A. hypochondriacus). Genomic features potentially underlying the nutritional value of this crop include two A. cruentus‐specific genes with a likely role in phytic acid synthesis (an anti‐nutrient), expansion of ion transporter gene families, and identification of biosynthetic gene clusters conserved within the amaranth lineage. The A. cruentus genome assembly will underpin much‐needed research and global breeding efforts to develop improved varieties for economically viable cultivation and realization of the benefits to global nutrition security and agrobiodiversity. [ABSTRACT FROM AUTHOR]

The circadian clock, an internal time-keeping mechanism, allows plants to anticipate regular changes in the environment, such as light and dark, and biotic challenges such as pathogens and herbivores. Here, we demonstrate that the plant circadian clock influences susceptibility to the necrotrophic fungal pathogen, Botrytis cinerea. Arabidopsis plants show differential susceptibility to B. cinerea depending on the time of day of inoculation. Decreased susceptibility after inoculation at dawn compared with night persists under constant light conditions and is disrupted in dysfunctional clock mutants, demonstrating the role of the plant clock in driving time-of-day susceptibility to B. cinerea. The decreased susceptibility to B. cinerea following inoculation at subjective dawn was associated with faster transcriptional reprogramming of the defence response with gating of infection-responsive genes apparent. Direct target genes of core clock regulators were enriched among the transcription factors that responded more rapidly to infection at subjective dawn than subjective night, suggesting an influence of the clock on the defence-signalling network. In addition, jasmonate signalling plays a crucial role in the rhythmic susceptibility of Arabidopsis to B. cinerea with the enhanced susceptibility to this pathogen at subjective night lost in a jaz6 mutant. [ABSTRACT FROM AUTHOR]

A model is presented describing the gene regulatory network surrounding three similar NAC transcription factors that have roles in Arabidopsis leaf senescence and stress responses. ANAC019, ANAC055 and ANAC072 belong to the same clade of NAC domain genes and have overlapping expression patterns. A combination of promoter DNA/protein interactions identified using yeast 1-hybrid analysis and modelling using gene expression time course data has been applied to predict the regulatory network upstream of these genes. Similarities and divergence in regulation during a variety of stress responses are predicted by different combinations of upstream transcription factors binding and also by the modelling. Mutant analysis with potential upstream genes was used to test and confirm some of the predicted interactions. Gene expression analysis in mutants of ANAC019 and ANAC055 at different times during leaf senescence has revealed a distinctly different role for each of these genes. Yeast 1-hybrid analysis is shown to be a valuable tool that can distinguish clades of binding proteins and be used to test and quantify protein binding to predicted promoter motifs. [ABSTRACT FROM AUTHOR]

Summary In Arabidopsis, resistance to the necrotrophic fungus Botrytis cinerea is conferred by ethylene via poorly understood mechanisms. Metabolomic approaches compared the responses of the wild-type, the ethylene-insensitive mutant etr1-1, which showed increased susceptibility, and the constitutively active ethylene mutants ctr1-1 and eto2 both exhibited decreased susceptibility to B. cinerea. Fourier transform-infrared (FT-IR) spectroscopy demonstrated reproducible biochemical differences between treatments and genotypes. To identify discriminatory mass-to-charge ratios ( m/ z) associated with resistance, discriminant function analysis was employed on spectra derived from direct injection electrospray ionisation-mass spectrometry on the derived principal components of these data. Ethylene-modulated m/z were mapped onto Arabidopsis biochemical pathways and many were associated with hydroxycinnamate and monolignol biosynthesis, both linked to cell wall modification. A high-resolution linear triple quadrupole-Orbitrap hybrid system confirmed the identity of key metabolites in these pathways. The contribution of these pathways to defence against B. cinerea was validated through the use of multiple Arabidopsis mutants. The FT-IR microspectroscopy indicated that spatial accumulation of hydroxycinnamates and monolignols at the cell wall to confine disease was linked ot ethylene. These data demonstrate the power of metabolomic approaches in elucidating novel biological phenomena, especially when coupled to validation steps exploiting relevant mutant genotypes. [ABSTRACT FROM AUTHOR]