BMC Plant Biology

Improving photosynthesis is a promising approach to enhance sugar beet productivity. However, genetic variation in leaf photosynthesis and its relationship with disease resistance remain underexplored. We evaluated 98 sugar beet genotypes representing different breeding categories, including commercial F1 hybrids, seed-parent lines, and pollinator lines, in Hokkaido, northern Japan. Leaf gas exchange was measured during early growth under field conditions around the infection period of Cercospora leaf spot (CLS). To account for fluctuating irradiance during large-scale phenotyping, we applied a multilevel mixed-effects light-response model to estimate genotype-specific photosynthetic characteristics. Substantial genotypic variations in photosynthetic characteristics were detected. F1 hybrids exhibited higher photosynthetic capacity than breeding lines, whereas differences among breeding categories were unclear due to large within-category variation. Some breeding lines exhibited photosynthetic rates higher than those of hybrids, indicating exploitable genetic resources within the present genetic panel. We did not detect statistically significant trade-off between leaf photosynthesis and CLS resistance among 98 genotypes; in a subset of 19 genotypes analysed in detail, the relationship was even synergistic. Our results highlight the genetic diversity of leaf photosynthesis and its category-dependent structure, and suggest that selection for enhanced photosynthesis can proceed without substantial trade-off with CLS resistance. HighlightLeaf photosynthesis of 98 sugar beet genotypes showed significant genetic variation and dependence on breeding category. Active photosynthesis incurred minimal trade-off with Cercospora leaf spot resistance.

Grain mold severely constrains sorghum [Sorghum bicolor (L.) Moench] productivity and grain quality in subhumid environments. Photoperiod-sensitive flowering plays a key role in mold avoidance and yield stability along north-south rainfall gradients. In response to the high susceptibility of elite cultivars in subhumid zones of Senegal, we developed and characterized a recombinant inbred line (RIL) population derived from Nganda (grain mold-susceptible) and Grinkan (photoperiod-sensitive) varieties. The population was evaluated across three distinct agro-ecological zones over two years. Environmental indices derived from genotype-environmental interactions, together with defined growth windows, strongly influenced flag leaf appearance (FLA), a photoperiodic flowering trait. Plasticity parameters (intercept and slope) for environmental indices, FLA, grain mold severity, and yield enabled identification of loci contributing to flowering response, mold resistance, and yield stability. The maturity gene Ma1 and two QTLs for FLA, qFLA6.2 and qFLA6.3, were identified, stable across environments, and colocalized with grain mold and yield QTLs. The wild-type Ma1 allele from Grinkan delayed FLA and reduced grain mold damage but was not associated with increased yield. The Ma1 effect was confirmed using the developed breeder-friendly KASP marker, Sbv3.1_06_40312464K, in 174 F3 three-way cross families. Photoperiod-sensitive lines with intermediate-to-late FLA alleles showed strong negative associations with mold damage. Overall, the identified stable loci and candidate lines provide foundations for effective molecular breeding of climate-resilient varieties. PLAIN LANGUAGE SUMMARYGrain mold is a fungal disease that reduces sorghum grain yield and quality, particularly in subhumid climates. With the limited number of resistant elite varieties, photoperiod-sensitive flowering to day length variation can contribute to grain mold escape at the end of rainy seasons. We characterized 286 sorghum recombinant inbred lines across three contrasting environments over two years along rainfall gradients in Senegal. Using flag leaf appearance (FLA), which is a photoperiodic flowering trait, strong genotype-environment interactions for FLA and genotypic plasticity were revealed. We identified and validated the common genomic locus associated with FLA variation and its plasticity across environments, the canonical maturity gene Ma1, which was influenced by temperature variation across environments. The presence of Ma1 in the background of photoperiod-sensitive lines enhances grain mold avoidance and yield stability along rainfall gradients in Senegal. CORE IDEASO_LIWe investigated photoperiodic flowering plasticity in sorghum as a contributor to grain mold resistance and yield stability along rainfall gradients. C_LIO_LIThe Maturity locus Ma1 (qFLA6.1) is the major contributor of photoperiodic flowering and its plasticity across semi-arid and subhumid environments. C_LIO_LIHybrid genotypes carrying two stable loci qFLA6.1 and qFLA6.2 sustain high grain mold avoidance in diverse environments. C_LIO_LIPhotoperiod-sensitive lines with medium to late flowering times are effective in avoiding grain mold, while maintaining yield stability in subhumid regions. C_LI

Pyrenophora teres f. teres (Ptt), the causal agent of net form net blotch disease in barley, is an economically important fungal pathogen worldwide. Understanding both host resistance mechanisms and pathogen virulence factors is essential for developing durable net form net blotch resistant barley cultivars. Quantitative trait loci (QTL) mapping was conducted using a cross between two Ptt isolates, one virulent on the barley cultivar Prior and the other being avirulent. A major QTL associated with virulence on Prior was detected on chromosome 5. A progeny isolate possessing this QTL, together with the two parental isolates, was subsequently used in the proteomic analyses. Label-free proteomics was used to quantify in planta the protein profile changes in Prior following inoculations with the virulent and avirulent parental Ptt isolates, and the virulent progeny isolate. Leaf samples were collected at two (D2) and five (D5) days post-inoculation, and proteomic analyses performed to identify proteins associated with host resistance and pathogen virulence. A dataset comprising 2,886 barley proteins and 51 Ptt proteins was analysed. Principal component analysis (PCA) of the barley Prior proteomes revealed distinct clustering based on resistance and susceptibility at D5, while D2 samples formed a separate cluster. The PCA of the Ptt proteomes identified separate clusters, one comprised of the D2 and D5 avirulent parental isolate and another cluster of the virulent isolates at D5 only. Gene ontology analysis of the Prior proteins that were significantly increased in the resistant compared to the susceptible groups revealed functional categories related to protein translation, biosynthesis and chloroplast activities. The proteins that were significantly increased in the susceptible compared to the resistant Prior group were associated with organic acid and carbohydrate metabolism. The proteomic profiles and bioinformatic analysis generated in our study provide novel insights into the molecular basis of resistance and virulence in the barley-P. teres pathosystem. Key messageThis study reveals the first in planta proteomic profiles of both barley and Pyrenophora teres f. teres, identifying unique virulence-associated proteins and host responses linked to resistance and susceptibility.

The chloroplast NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport (CET) around photosystem I (PSI) and contributes to photosynthetic regulation and photoprotection under various environmental stresses. Although NDH function has been extensively characterized under controlled conditions, NDH-deficient mutants often show only subtle phenotypes in such environments, leaving its physiological importance under naturally fluctuating field conditions poorly understood. Here, we evaluated growth, yield, and photosynthetic performance of NDH-deficient rice cultivated under field conditions. Mutant plants exhibited reduced biomass accumulation and grain yield compared with wild type. Detailed physiological analyses revealed that NDH deficiency markedly decreased PSI electron transport and CO2 assimilation, particularly under low temperature and sub-saturating irradiance. At moderate and high temperatures, reductions in carbon fixation were largely confined to low-light conditions, whereas at low temperatures, impairment extended across nearly the entire light response range. Under repetitive fluctuating light regimes, NDH-deficient plants showed progressive declines in photosynthesis accompanied by a selective decrease in PSI photochemical capacity without changes in PSII maximum efficiency, indicating PSI-specific photoinhibition. These findings demonstrate that NDH-dependent CET plays a crucial role in sustaining photosynthetic efficiency and crop productivity in dynamic field environments by stabilizing PSI redox balance and maintaining long-term carbon gain. Summary StatementNDH-dependent cyclic electron transport supports photosynthesis and yield in field-grown rice by maintaining PSI function under fluctuating light, low temperature, and sub-saturating irradiance.

Grapevine cluster architecture is a key selection target in breeding programs because it influences disease susceptibility, yield stability and juice quality. High-throughput phenotyping offers a rapid and non-destructive approach to capture biochemical and structural variation in these traits, yet the influence of plant organ reflectance and data partitioning strategies on trait prediction remains poorly understood. In this study, we evaluated how hyperspectral reflectance from different grapevine organs contributes to the prediction of cluster architecture and juice quality traits in two clonal populations of Riesling and Pinot. Using partial least squares regression (PLSR), we assessed the prediction accuracy of eight cluster architecture and six juice quality traits under two data partitioning strategies. Models based on cluster reflectance outperformed those using dry leaf reflectance for most traits, except for pH. Partitioning the dataset by cluster type increased trait variance and improved predictions for number of berries (R{superscript 2} = 0.53), berry diameter (R{superscript 2} = 0.79), and total acidity (R{superscript 2} = 0.48). Visible, red-edge and NIR spectra were most informative regions to predict the traits studied. Together, our results highlight the importance of organ-specific data and appropriate calibration strategies to improve phenomic models for the development of scalable proxies for grapevine improvement. HighlightSpectral phenomics reveals that prediction accuracy in grapevine depends on organ spectral signatures and traits, with cluster reflectance outperforming leaves, informing new phenotyping strategies for breeding improvement.

Fruit softening is primarily determined by modifications in the cell wall architecture, which are mediated by the coordinated activity of cell wall-degrading enzymes. In strawberry (Fragaria x ananassa Duch.), transgenic suppression of the genes encoding the pectinases polygalacturonase (PG), {beta}-galactosidase ({beta}Gal), and rhamnogalacturonan lyase (RGLyase), reduced fruit softening. In this study, we evaluated the fruit firmness phenotype of selected transgenic lines across several harvest years, from 3 to 9 years depending on the line, and analyzed the cell wall composition of ripe fruits using a carbohydrate microarray. Multiple linear regression analysis revealed that fruit firmness was significantly affected by both genotype and harvest year, while fruit size and soluble solids content showed no significant contribution. All pectinase-silenced lines exhibited increased firmness relative to the wild type, with those lines with PG down-regulated showing the most significant effects, followed by B-Gal and RGLyase fruits. The firmer phenotype was maintained stably in all the transgenic lines during the different years analyzed. Carbohydrate microarray analyses of sequentially extracted cell wall fractions demonstrated that transgenic ripe fruits retained higher levels of low methyl-esterified homogalacturonan (HG) and rhamnogalacturonan I (RG-I) epitopes compared to wild-type ripe fruits, resembling the composition of white-stage control fruits. Principal component analysis of microarray data revealed a clear separation between wild-type ripe fruits and transgenic lines, with the latter clustering near the earlier developmental stages of wild-type fruits. Correlation analysis further revealed positive associations between increased firmness and the abundance of high-methylated HG pectic epitopes in the water fraction, recognized with JIM7, and low-methylated HG abundance in the rest of the fractions (JIM5, LM18, and LM19). Overall, these results suggest that suppressing pectinase genes alters pectin remodeling during ripening, resulting in the retention of structurally intact pectin domains and increased fruit firmness. These genes are therefore excellent candidates for the improvement of this key quality trait in strawberry.

The Dense and erect particle 1 (HvDEP1) gene, located on chromosome 5H in barley (Hordeum vulgare L.), encodes a heterotrimeric G-protein {gamma}-subunit that regulates grain size and stem elongation. Multiple alleles of HvDEP1 have been identified, including the widely utilized semi-dwarf allele HvDEP1.GP, caused by an insertion mutation, and a recently discovered variant, HvDEP1.V, characterized by two deletions in the putative cis-regulatory region. In this study, we evaluated the phenotypic effects of HvDEP1.V relative to HvDEP1.GP and the wild-type allele (HvDEP1.WT) using two BC{square}F{square} populations across multi-environment field trials spanning two locations and three years. HvDEP1.V was associated with plants that were 5-14.6 cm taller, had 3-6.7 higher lodging score, and increased head loss compared to HvDEP1.GP. HvDEP1.V showed comparable agronomic attributes to HvDEP1.WT. Substituting HvDEP1.V for HvDEP1.GP significantly increased all physical grain attributes, including grain width (1.44-4.24% in three out of five environments), grain length (4.88-8.69 %), grain area (6.45-11.06%) and thousand-grain weight (6.75-13.8%). Out of five environments, compared to HvDEP1.WT, HvDEP1.V was associated with wider grain in three environments, shorter grain in four environments, and increased grain roundness in four environments. These findings link allelic variation of the HvDEP1 gene to key agronomic and physical grain traits and demonstrate the functional consequences of HvDEP1.V in diverse genetic backgrounds and field conditions, providing valuable insights for barley improvement. Key messageBy evaluating agronomic performance and physical grain traits in two genetically distinct barley populations across multiple environments, we reveal strong environment- and background-dependent effects of HvDEP1 alleles.

Background and AimsL-DOPA is an important pharmaceutical that accumulates to high levels in the legume faba bean (Vicia faba). L-DOPA is likely derived from L-tyrosine but the responsible enzyme (L-tyrosine oxidase) remains unknown. Availability of L-tyrosine may be a key factor controlling L-DOPA accumulation. In legumes, L-tyrosine is supplied via either a plastidial TyrA enzyme (ADH) or a deregulated cytosolic homolog (PDH). This study aimed at identifying L-tyrosine oxidase and TyrA genes from faba bean. MethodsWe used gene-to-metabolite correlations and homology-based searches to select fifteen L-tyrosine oxidase candidates, which were tested in yeast and in the model plant Nicotiana benthamiana. We also used isotopically labeled L-tyrosine to measure biosynthetic activity in different faba bean tissues and to test an alternative biosynthetic hypothesis. Three faba bean TyrA genes were inferred by homology and assayed in N. benthamiana by co-expression with a known L-tyrosine oxidase, CYP76AD6. Key ResultsNone of the L-tyrosine oxidase candidates produced L-DOPA upon heterologous expression. Feeding experiments showed a lack of correlation between L-DOPA accumulation and biosynthetic capacity. Feeding studies also disproved an alternative route to L-DOPA by oxidation of 4-hydroxyphenylpyruvate. Of the TyrA genes, two were able to increase L-tyrosine levels in N. benthamiana 2-3-fold (VfADH and VfPDH), and one of them was able to boost the levels of L-DOPA derivatives up to 6-fold (VfADH). ConclusionsThe faba bean L-tyrosine oxidase remains unidentified, with a possible transport of L-DOPA across tissues likely having confounded our correlation-based selection strategies. In N. benthamiana, both VfADH and VfPDH can increase the levels of L-tyrosine, while VfADH can further boost the levels of L-DOPA derivatives. Our work delivers a strategy to boost the provision of L-tyrosine in N. benthamiana and provides valuable insights in the search for the elusive L-tyrosine oxidase from faba bean.

CONTEXTRapeseed is a globally significant oil crop, exhibiting highly plastic responses among seed yield components (seed number and weight). However, there remains a notable gap in knowing the distribution of quality traits among seed size categories and understanding how seed size and source-sink (S-S) ratio influence comprehensive seed quality traits. OBJECTIVEThis study investigated the effects of seed size and S-S ratio reduction on the quality traits of winter and spring rapeseed genotypes. METHODSThe experiments were carried out at field conditions in Valdivia, Chile, where seed yield, yield components, oil, protein, and element concentrations (P, K, S, Ca, Mg, B, Cu, Fe, Mn, Zn, and Na) were evaluated across five seed size categories; very small (< 1.4 mm), small (1.4-1.7 mm), medium (1.7-2.0 mm), large (2.0-2.36 mm), and very large (> 2.36 mm). Treatments included a control and a reduced S-S ratio (75% shading), which significantly increased seed weight (P < 0.05). RESULTSBoth genotype and seed size affected (P< 0.050) the quality traits. Larger seeds exhibited higher Mg and B concentrations, as well as lower K, Ca, Fe and Na. Shading affected seed size distribution, favouring a higher proportion of large seeds. Under the shading treatment, the small seed category reached 5% lower oil concentration, while protein seed concentration increases 6% in both genotypes. Principal component analysis highlighted the complex interaction between yield, yield components, and quality traits, since there was no clear separation between different seed size categories and S-S ratio treatments. CONCLUSIONThese results provide insights into the plasticity of rapeseed quality traits, highlighting their collective impact on nutrient profiles. SIGNIFICANCEThis information is helpful for optimising cultivation practices and informing breeding programmes aimed at improving seed quality, particularly in high-yielding environments susceptible to environmental stresses. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=90 SRC="FIGDIR/small/707178v1_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@19d16eforg.highwire.dtl.DTLVardef@4cc16forg.highwire.dtl.DTLVardef@12f741borg.highwire.dtl.DTLVardef@6fa37a_HPS_FORMAT_FIGEXP M_FIG C_FIG

BackgroundMelastomes are well known for their striking diversity in stamen morphologies mostly adapted to buzz pollination by bees. The variously modified connective appendages and heteranthery in the family have fascinated botanists for more than two centuries and a variety of functions associated with pollination have been discovered for these staminal traits over the years. The repeated evolutionary shifts in these traits have been linked to pollinator shifts, likely contributing to diversification in the family. The evolutionary lability of staminal traits, especially the connective morphology, led us to hypothesize that these traits might be controlled by relatively simple genetic mechanisms and we here take the first steps to test this hypothesis by using a comparative transcriptomics approach with Arthrostemma ciliatum as our model. We also tested the functional significance of heteranthery and whether the classical division of labour hypothesis holds true for this species by comparing the number, size and viability of pollen in the two stamen types. ResultsStaminal development of this species was studied and suitable stages for transcriptome comparisons were identified. Differential expression analyses between the morphologically distinct stamen whorls at four developmental stages showed the differential expression of several transcripts involved in stamen development/elongation. Pollen comparisons between the two whorls showed that the antepetalous/inner whorl stamens have a significantly higher number of pollen and higher germination rates while the antesepalous/outer whorl stamens have significantly larger pollen. ConclusionsWe identified Jasmonate and Gibberellin signalling pathway genes (JAZ, GID1, DELLA and ARF homologs), EPF/EPFL family genes, autophagy related genes (VPE homologs) and S Locus ELF homologs as putative candidates involved in causing staminal dimorphism in A. ciliatum. Our results indicate that, for the heterantherous morph of this species, the shorter stamens (antepetalous/inner whorl) have both pollinating and feeding functions contradicting the division of labour theory. We also report the possible existence of heterostyly in A. ciliatum as an outbreeding mechanism.

Subgenome dominance is a phenomenon observed in many allopolyploids where one parental genome exhibits stronger influence over phenotype than the other parental genomes. This may present as preferential retention of one subgenome through fractionation, replacement via homoeologous exchange, or as subgenome expression bias, where one subgenome is expressed at a higher abundance compared to other subgenomes. Sour cherry (Prunus cerasus) is an allotetraploid fruit tree species resulting from an interspecific cross between extant relatives of ground cherry (P. fruticosa) and sweet cherry (P. avium). Prior comparative genomic analyses suggest that the sour cherry cultivar Montmorency contains three subgenomes. Subgenomes A and A, each present in one copy, are derived from a P. fruticosa-like ancestor, and B, present in two copies, is derived from a P. avium-like ancestor. In this study we investigated the subgenome dynamics of the three subgenomes of sour cherry in four diverse landraces and two cultivars, including Montmorency. We found evidence of 26 homoeologous exchange events and five whole-homoeolog replacements relative to Montmorency in three of the six accessions. We also detected subgenome expression bias favoring the A and A subgenomes over the B subgenome, the magnitude of which differs between accessions and changes over the course of fruit development. Lastly, we show differences in dosage variation and expression bias of four previously-described genes in Montmorency associated with fruit softening, a key trait in this crop. These findings on subgenome dominance offer valuable insights into how this phenomenon may influence traits important for sour cherry breeding.

Published studies have reported species-variance between profiles of Calvin-Benson cycle (CBC) intermediates, not only between C4 species and C3 species, but also within C3 species (Arrivault et al., 2019, Borghi et al. 2019). It was proposed that this variance reflects lineage-dependent changes in the balance between different reactions, or poising, of the CBC. These earlier studies investigated phylogenetically-unrelated C3 species. In the current study, CBC intermediates were profiled in five closely-related species from Solanum sect. lycopersicon subsect. Lycopersicum. The levels of individual CBC intermediates showed many significant differences. In a principal component analysis, whilst three species (Solanum lycopersicum, Solanum cheesmaniae, Solanum neorickii) overlapped, Solanum pimpinellifolium and especially Solanum pennellii grouped separately, and were at opposing ends of the distribution. When combined with published data, whilst the separation between Solanum species was retained, they formed a group that was separated from five other C3 species, as well as two C4 species. It is discussed that the observed variation in CBC metabolites profiles within Solanum, together with their separation from other C3 species, supports the idea that CBC evolution is shaped both by phylogenetic relatedness and lineage-specific adaptation. HighlightVariance of intermediate levels points to poising of the Calvin-Benson cycle varying between closely-related species in the tomato clade Solanum sect. lycopersicon subsect. Lycopersicum

Pyrenophora teres f. teres (Ptt), the causal agent of net-form net blotch in barley, was studied using a bi-parental mapping population (Pop1) of 305 isolates derived from a cross between two isolates with contrasting virulence on barley cultivars Skiff and Prior. QTL analysis identified virulence loci on chromosomes (Chr) 3 and 10 for Skiff, and on Chr 1, 4, and 5 for Prior. Major QTL on Chr 3 and 5 explained 24% and 40% of phenotypic variation, respectively. A second population (Pop2) was developed by crossing two Pop1 isolates, one carrying major QTL on Chr 3 and 5 and one avirulent. Isolates from Pop2 with single QTL were phenotyped across a Prior/Skiff recombinant inbred line population to identify corresponding host susceptibility/resistance loci. Skiff virulence QTL on Chr 3 corresponded to barley Chr 3H and 6H, while Prior virulence QTL on Chr 5 mapped to Chr 6H. RNA expression analysis of virulent and avirulent Pop2 isolates identified five candidate genes linked to the Chr 5 QTL, including two predicted effectors. These findings suggest both gene-for-gene and inverse gene-for-gene interactions in the Ptt-barley pathosystem and advance the understanding of molecular mechanisms underlying host-pathogen specificity.

Host resistance is a critical component of oat crown rust disease management. Pc94 is a qualitative resistance locus derived from diploid Avena strigosa with several independent introgressions into A. sativa that have been used in cultivar deployment. Quantitative trait locus (QTL) analysis combining previously published data for a historic A. strigosa population segregating for Pc94 revealed a large effect QTL on the distal end of A. strigosa chromosome 7A. Genome assembly of the parents identified a cluster of five nucleotide binding site leucine-rich repeat receptor (NLR) candidate genes within the QTL region. A single candidate NLR with an integrated zinc finger BED domain, AstNLR94, was determined as necessary for Pc94 resistance based on map-based cloning and forward mutagenesis. A presence/absence allele specific PCR marker was designed in AstNLR94 and verified for accuracy and specificity in a diverse panel of A. strigosa and A. sativa. Pc94 introgressions in A. sativa ranged in size from 1.7-71 Mbp and two different introgression locations appear to have occurred. In A. sativa Leggett, a 6.3 Mbp Pc94 introgression is located at the end of chromosome 2A, and the same sized introgression was discovered in the OT3098 v2 genome. Finally, a QTL analysis identified an additional minor resistance locus on A. strigosa chromosome 4A, which has complicated previous efforts to characterize the Pc94 locus. This is the first report of an NLR gene underlying disease resistance in Avena spp. and delivers a Pc94 marker for marker assisted selection to produce disease resistant cultivars. Key messageWe mapped a zfBED-NLR encoding gene necessary for Pc94 resistance, developed a diagnostic marker, and revealed diverse introgression sizes, clarifying Pc94s history and utility for durable oat crown rust resistance.

Carmenere is a widely cultivated and internationally recognized grapevine cultivar in Chile, yet genetic variation among its clones remains poorly characterized. Early studies based on SSR and AFLP markers detected limited polymorphism, but these approaches interrogate only a small fraction of the genome, leaving the extent of clonal diversity unresolved. Here, we generated an improved chromosome-scale diploid genome assembly of Carmenere FPS clone 02 and characterized clonal genomic diversity by sequencing 36 biological replicates representing 12 clones maintained in Chile, including heritage selections rescued from old producer vineyards by Vina Santa Carolina as part of its Bloque Herencia conservation program, and commercial nursery-derived clones. Focusing on low-frequency variants and using replicate-aware consensus calling, we identified more than 9,000 private single nucleotide variants (SNVs) and small indels per clone, providing high-resolution markers for clonal identification. Although most variants were located in repetitive or intergenic regions, a subset affected coding sequences, with genes involved in plant-pathogen interactions, transport, and secondary metabolism most frequently impacted. While variant-affected genes associated with wine anthocyanin content, TA, pH, and alcohol percentage were identified, broader phenotypic characterization will be required to assess their biological significance. Overall, this study provides a genome-wide characterization of extant clonal diversity in Carmenere, with implications for clonal selection and genetic resource conservation.

BackgroundEnsete ventricosum, also known as the "tree against hunger" plays a key role in Ethiopian food security and farming systems, feeding more than 20 million people. Since domestication via clonal selection in the south-west Ethiopian highlands, todays diverse enset landraces contribute multiple benefits including food, fibre by-product, animal bedding and cattle fodder to farmers and local communities. Improved genomic resources for this highly drought-tolerant plant are essential to supplement the conventional clonal selection-based breeding programme and pave the way towards targeted breeding. ResultsWe sequenced the genome of enset landrace Mazia, which is partially resistant/tolerant to Xanthomonas wilt and predicted 38,940 protein-coding genes. The Mazia assembly (540.14 Mb) is more complete than the previously published genome assembly of landrace Bedadeti (451.28 Mb) and displayed 1.41% heterozygosity and 64.64% repetitive DNA content. Comparative analyses with the Bedadeti assembly and chromosome-level genome sequences of the two main banana progenitors (Musa acuminata, AA genome; Musa balbisiana, BB genome) unexpectedly revealed [~]25% of the Mazia genome is unique to enset. Gene Ontology (GO) and sequence similarity search analysis of enset-specific protein-coding genes identified distinct functional signatures that underpin the lifestyle, adaptation, and corm productive quality of enset, including functions related to DNA integration, carbohydrate metabolism, disease resistance and transcriptional regulation. In contrast, Musa-specific genes showed enrichment for defence response, protein phosphorylation and fruit development pathways. Focusing on the classical nucleotide binding site leucine rich repeat (NLR) disease resistance genes, we identified and characterised NLRs in enset and Musa species genomes, revealing a considerable expansion in the Musa acuminata genome. We also identified unique genes in enset and banana genomes whose functional and evolutionary roles are yet to be determined. ConclusionsHere, we report a de novo genome assembly for the enset (Ensete ventricosum) landrace Mazia and provide a high-quality annotation of both Mazia and the previously published assembly of the landrace Bedadeti. Collectively, these genomic resources provide a valuable foundation for comparative genomics within the Musaceae family and open new opportunities for the development of marker-assisted breeding strategies to accelerate the improvement of agronomically important traits in enset.

Chickpea is predominantly grown under rainfed conditions in regions where terminal drought limits yield, yet little is known about how this stress influences both vegetative allocation and reproductive dynamics leading to altered grain composition. We imposed a controlled terminal drought, with a rewatered treatment group, on three Desi cultivars (ICC4958, ICC1882 and CBA Captain) reported to have contrasting drought tolerance, quantifying vegetative biomass, reproductive node productivity across developmental regions and grain macronutrient composition. Under drought, vegetative responses reflected genotype-specific resource partitioning strategies particularly evident in severe root degradation and increase stem dry matter content that was only partially alleviated in rewatered plants. Reproductive outcomes were strongly influenced by developmental stage at the time of stress, with increased pod abortion observed particularly at nodes initiating seed development under drought treatment. Grain composition of seeds filled under drought was significantly altered by stress, with increased protein concentration and decreased starch content under both Drought and Recovery treatments independent of cultivar, likely due to water limitation at crucial filling stages. These findings demonstrate that the developmental timing of terminal drought interacts with cultivar growth strategy to influence pod production and grain nutritional quality in chickpea. HighlightThe developmental timing of terminal drought interacts with cultivar-dependent growth strategies to influence pod productivity and grain nutritional quality in chickpea.

Glutathione peroxidases (GPXs) are widely recognized as key antioxidants that mitigate oxidative stress by detoxifying reactive oxygen species (ROS). However, GPXs are largely uncharacterized in citrus. Here, we demonstrated that Citrus sinensis contains four GPX proteins (CsGPX1-4). Unexpectedly, overexpression of CsGPX4, a homolog of AtGPX8 in Arabidopsis, in citrus resulted in typical oxidative stress phenotypes including severe growth inhibition, chlorosis, and elevated intracellular ROS accumulation. Transmission electron microscopy (TEM) analysis further revealed stress responses at cellular level. Whole genome shot gun sequencing analysis showed that T-DNA insertion occurs in the UTR of SWEET2 gene, which is unlikely to be responsible for the oxidative stress phenotypes. Immunoblotting revealed that CsGPX4 accumulates as a truncated protein in citrus, in contrast to the full-length version expressed in Nicotiana benthamiana. MALDI-TOF assays further confirmed the truncation of CsGPX4 in the transgenic line with the predicted cleavage site between L115-K117. This truncation was associated with altered subcellular localization, shifting from cytoplasmic and nuclear distribution in N. benthamiana to membrane association in citrus. Proteomic profiling further indicated extensive reprogramming of pathways involved in detoxification, cytoskeletal stability, hormone signaling, and cell wall modification. Our data suggests that de facto overexpression of truncated CsGPX4 may have dominant-negative effects on proteins interacting with CsGPX4, thus interfering with their normal functions. In conclusion, our study demonstrates CsGPX4 as a critical regulator of redox homeostasis and ROS homeostasis in citrus and reveals selective truncation of CsGPX4 as a unique proteolytic or regulatory strategies in such processes.

Climate change and increasing global demand for animal products are intensifying the need to accelerate genetic improvement of forage crops. Speed breeding (SB) has emerged as a powerful tool to shorten generation cycles; however, its application in perennial and autotetraploid forage legumes remains limited, particularly regarding reproductive performance and physiological constraints. Here, we optimized photoperiod, light intensity, and light quality to accelerate the life cycle of Medicago sativa (alfalfa) and its diploid relative Medicago truncatula under controlled conditions. We evaluated flowering, fruiting, seed harvest time, seed set, and germination across independent and combined SB treatments, and assessed photosynthetic performance to identify potential physiological trade-offs. Blue- red light supplementation, moderate-to-high irradiance (450 {micro}mol m-2 s-1), and extended photoperiods significantly accelerated reproductive development in both species, although optimal combinations differed between the diploid and autotetraploid backgrounds. A combined SB regime (20/4 h photoperiod at 450 {micro}mol m-2 s-1) reduced time to harvest by 17% in M. sativa and 28% in M. truncatula, while maintaining viable seed production. Chlorophyll fluorescence analysis revealed a higher photosynthetic plasticity in alfalfa compared with M. truncatula, indicating species-specific physiological limits to SB intensification. Our results establish practical SB conditions for alfalfa and an agronomically relevant M. truncatula genotype, providing an enabling platform to accelerate breeding cycles and trait evaluation in forage legumes.

Developing grapevine cultivars with genetic resistance to pathogens is a key strategy to reduce fungicide use and enhance sustainability. The French INRAE-ResDur program aims to pyramid several resistance loci against Plasmopara viticola (Rpv), the causal agent of downy mildew, while integrating factors against Erysiphe necator (Ren/Run) which causes powdery mildew. We evaluated in field the performance of grapevine genotypes carrying single or pyramided Rpv loci during the exceptionally severe downy mildew epidemic of 2024. Disease severity was quantified as the proportion of leaf foliage exhibiting symptoms. Susceptible controls averaged 66.6 % symptomatic leaves, Rpv1/3.1 combination remained below 16.1 %. whereas the Rpv1/Rpv3.1/Rpv10 pyramid showed only 4.9 % symptomatic leaves. The single loci provided partial protection, but the effect varied with genetic background. Pyramiding improved resistance effectiveness and stability, indicating synergistic interactions among loci. These findings demonstrate that pyramiding Rpv loci is an effective strategy for durable downy mildew resistance and should be the preferred strategy in grapevine breeding programs and genetic resistance deployment strategies.