Trehalose (Tre) is a non-reducing disaccharide found in many species, including bacteria, fungi, invertebrates, yeast, and even plants, where it acts as an osmoprotectant, energy source, or protein/membrane protector. Despite relatively small amounts in plants, Tre concentrations increase following exposure to abiotic stressors. Trehalose-6-phosphate, a precursor of Tre, has regulatory functions in sugar metabolism, crop production, and stress tolerance. Among the various abiotic stresses, temperature extremes (heat or cold stress) are anticipated to impact crop production worldwide due to ongoing climate changes. Applying small amounts of Tre can mitigate negative physiological, metabolic, and molecular responses triggered by temperature stress. Trehalose also interacts with other sugars, osmoprotectants, amino acids, and phytohormones to regulate metabolic reprogramming that underpins temperature stress adaptation. Transformed plants expressing Tre-synthesis genes accumulate Tre and show improved stress tolerance. Genome-wide studies of Tre-encoding genes suggest roles in plant growth, development, and stress tolerance. This review discusses the functions of Tre in mitigating temperature stress—highlighting genetic engineering approaches to modify Tre metabolism, crosstalk, and interactions with other molecules—and in-silico approaches for identifying novel Tre-encoding genes in diverse plant species. We consider how this knowledge can be used to develop temperature-resilient crops essential for sustainable agriculture.

Precise timing of flowering in plants is critical for their growth and reproductive processes. One factor controlling flowering time is the cycle of light and darkness within a day, known as the photoperiod. Plants are classified into long-day, short-day, and day-neutral plants based on light requirements for floral initiation. Although the molecular mechanisms that govern this differentiation remain incompletely understood, studies have consistently shown that the circadian clock plays a central role in regulating photoperiod response across diverse plant species. However, there is a scarcity of reviews describing the regulatory network linking the circadian clock with photoperiodic flowering. This review summarizes that regulatory network, focusing on the distinct roles of clock genes in long-day and short-day plants. We also discuss the strategies of clock gene mutations contributing to geographic variation in long-day and short-day crops.

To fight against invasion by pathogens, plants have evolved an elaborate innate immune system, of which the nucleotide-binding domain leucine-rich repeat-containing receptor (NLR) acts as the sensor and immune executor. Potyviruses, comprising one of the largest genera of plant viruses, cause severe crop yield losses worldwide. Inherited crop resistance to potyviruses can be used in breeding and plant transgenesis to control disease development. This review summarizes achievements in mapping and cloning NLR genes conferring dominant resistance against potyvirus in the families Fabaceae, Solanaceae, Brassicaceae, and Cucurbitaceae. It compares mechanisms of potyviral protein recognition and downstream signaling employed by NLRs and discusses strategies for exploiting NLRs to better control diseases caused by potyviruses.

Cereal is an essential source of calories and protein for the global population. Accurately predicting cereal quality before harvest is highly desirable in order to optimise management for farmers, grading harvest and categorised storage for enterprises, future trading prices, and policy planning. The use of remote sensing data with extensive spatial coverage demonstrates some potential in predicting crop quality traits. Many studies have also proposed models and methods for predicting such traits based on multi-platform remote sensing data. In this paper, the key quality traits that are of interest to producers and consumers are introduced. The literature related to grain quality prediction was analyzed in detail, and a review was conducted on remote sensing platforms, commonly used methods, potential gaps, and future trends in crop quality prediction. This review recommends new research directions that go beyond the traditional methods and discusses grain quality retrieval and the associated challenges from the perspective of remote sensing data.

Plant height (PH) is associated with lodging resistance and planting density, which is regulated by a complicated gene network. In this study, we identified a spontaneous dwarfing mutation in maize, m30, with decreased internode number and length but increased internode diameter. A candidate gene, ZmCYP90D1, which encodes a member of the cytochrome P450 family, was isolated by map-based cloning. ZmCYP90D1 was constitutively expressed and showed highest expression in basal internodes, and its protein was targeted to the nucleus. A G-to-A substitution was identified to be the causal mutation, which resulted in a truncated protein in m30. Loss of function of ZmCYP90D1 changed expression of hormone-responsive genes, in particular brassinosteroid (BR)-responsive genes which is mainly involved in cell cycle regulation and cell wall extension and modification in plants. The concentration of typhasterol (TY), a downstream intermediate of ZmCYP90D1 in the BR pathway, was reduced. A haplotype conferring dwarfing without reducing yield was identified. ZmCYP90D1 was inferred to influence plant height and stalk diameter via hormone-mediated cell division and cell growth via the BR pathway.

Upland rice shows dryland adaptation in the form of a deeper and denser root system and greater drought resistance than its counterpart, irrigated rice. Our previous study revealed a difference in the frequency of the OsNCED2 gene between upland and irrigated populations. A nonsynonymous mutation (C to T, from irrigated to upland rice) may have led to functional variation fixed by artificial selection, but the exact biological function in dryland adaptation is unclear. In this study, transgenic and association analysis indicated that the domesticated fixed mutation caused functional variation in OsNCED2, increasing ABA levels, root development, and drought tolerance in upland rice under dryland conditions. OsNCED2-overexpressing rice showed increased reactive oxygen species-scavenging abilities and transcription levels of many genes functioning in stress response and development that may regulate root development and drought tolerance. OsNCED2^T-NILs showed a denser root system and drought resistance, promoting the yield of rice under dryland conditions. OsNCED2^T may confer dryland adaptation in upland rice and may find use in breeding dryland-adapted, water-saving rice.

A dynamic plant architecture is the basis of plant adaptation to changing environments. Although many genes regulating leaf rolling have been identified, genes directly associated with water homeostasis are largely unknown. Here, we isolated a rice mutant, dynamic leaf rolling 1 (dlr1), characterized by ‘leaf unfolding in the morning-leaf rolling at noon-leaf unfolding in the evening’ during a sunny day. Water content was decreased in rolled leaves and water sprayed on leaves caused reopening, indicating that in vivo water deficiency induced the leaf rolling. Map-based cloning and expression tests demonstrated that an A1400G single base mutation in Oryza sativa Polygalacturonase 1 (OsPG1)/PHOTO-SENSITIVE LEAF ROLLING 1 (PSL1) was responsible for the dynamic leaf rolling phenotype in the dlr1 mutant. OsPG1 encodes a polygalacturonase, one of the main enzymes that degrade demethylesterified homogalacturonans in plant cell walls. OsPG1 was constitutively expressed in various tissues and was enriched in stomata. Mutants of the OsPG1 gene exhibited defects in stomatal closure and decreased stomatal density, leading to reduced transpiration and excessive water loss under specific conditions, but had normal root development. Further analysis revealed that mutation of OsPG1 led to reduced pectinase activity in the leaves and increased demethylesterified homogalacturonans in guard cells. Our findings reveal a mechanism by which OsPG1 modulates water homeostasis to control dynamic leaf rolling, providing insights for plants to adapt to environmental variation.

The size and shape of rice grains influence their yield and commercial value. We investigated the role of OsDA1, a rice homolog of the Arabidopsis DA1 gene, in regulating grain size and shape. OsDA1 was highly expressed in young spikelets and glumes. Its overexpression led to enlarged seeds with increased width and decreased length/width ratio (LWR) and knocking out OsDA1 reduced grain width and increased grain length and LWR. A R310K point mutation in the DA1-like domain is a potential target for breeding for increased grain width and length. OsDA1 interacted with TCP gene-family proteins to regulate grain size and shape. Our findings deepen our understanding of the molecular mechanisms underlying grain size regulation and provide useful information for improving grain yield.

Plasma membrane intrinsic proteins (PIPs) are conserved plant aquaporins that transport small molecules across the plasma membrane to trigger instant stress responses and maintain cellular homeostasis under biotic and abiotic stress. To elucidate their roles in plant immunity to pathogen attack, we characterized the expression patterns, subcellular localizations, and H₂O₂-transport ability of 11 OsPIPs in rice (Oryza sativa), and identified OsPIP2;6 as necessary for rice disease resistance. OsPIP2;6 resides on the plasma membrane and facilitates cytoplasmic import of the immune signaling molecule H₂O₂. Knockout of OsPIP2;6 increases rice susceptibility to Magnaporthe oryzae, indicating a positive function in plant immunity. OsPIP2;6 interacts with OsPIP2;2, which has been reported to increase rice resistance to pathogens via H₂O₂ transport. Our findings suggest that OsPIP2;6 cooperates with OsPIP2;2 as a defense signal transporter complex during plant-pathogen interaction.

Receptor-like cytoplasmic kinase OsBSK1-2 was reported to play an important role in regulation of response to rice blast, but the signaling pathway remained unknown. In this study, we identified OsMAPKKK18 and previously uncharacterized MAPKKKs OsMAPKKK16 and OsMAPKKK19 that interact with OsBSK1-2. Expression of all three MAPKKKs was induced by Magnaporthe oryzae infection, and all three induced cell death when transiently expressed in Nicotiana benthamiana leaves. Knockout of OsMAPKKK16 and OsMAPKKK18 compromised blast resistance and overexpression of OsMAPKKK19 increased blast resistance, indicating that all three MAPKKKs are involved in regulation of rice blast response. Furthermore, both OsMAPKKK16 and OsMAPKKK19 interacted with and phosphorylated OsMKK4 and OsMKK5, and chitin-induced MAPK activation was suppressed in osmapkkk16 and osbsk1-2 mutants. OsMAPKKK18 was earlier reported to interact with and phosphorylate OsMKK4 and affect chitin-induced MAPK activation, suggesting that OsBSK1-2 is involved in regulation of immunity through multiple MAPK signaling pathways. Unlike BSK1 in Arabidopsis, OsBSK1-2 was not involved in response to avirulent M. oryzae strains. Taken together, our results revealed important roles of OsMAPKKK16/18/19 and a OsBSK1-2-OsMAPKKK16/18/19-OsMKK4/5 module in regulating response to rice blast.

Elucidating the genetic basis of natural variation in grain size and weight among rice varieties can help breeders develop high-yielding varieties. We identified a novel gene, GW3a (Grain Weight 3a) (LOC_Os03g27350), that affects rice grain size and weight. gw3a mutants showed higher total starch content and dry matter accumulation than the wild type (WT), Nipponbare, suggesting that GW3a negatively regulates grain size and weight. Moreover, our study found that GW3a interacted with OsATG8 by cleaving it, suggesting that GW3a may be involved in the assembly of autophagosomes and starch degradation in plants. The haplotype analysis of GW3a showed functional differences between indica and japonica rice. Taken together, we conclude that GW3a is expressed in the autophagosome pathway regulating starch metabolism in rice, affecting yield-related traits, such as grain size, grain weight and thousand grain weight (TGW). Our findings also shed new light on autophagy-mediated yield trait regulation, proposing a possible strategy for the genetic improvement of high-yield germplasm in rice.

Poor seedling emergence is a challenge for direct seeding of rice under deep-sowing field conditions. Here we reveal that UDP-glucosyltransferase OsUGT75A promotes rice seedling emergence under deep-sowing conditions by increasing shoot length. Expression of OsUGT75A was higher in the middle regions of the shoot and in shoots under deep-sowing conditions. Levels of free abscisic acid (ABA) and jasmonates (JA) were higher in shoots of OsUGT75A mutants than in those of wild-type plants, and OsUGT75A mutants were more sensitive to ABA and JA treatments. Reduced shoot length was attributed to higher ABA INSENSITIVE 3 (OsABI3) expression and lower JASMONATE-ZIM domain protein (OsJAZ) expression in shoots. Shoot extension by OsUGT75A is achieved mainly by promotion of cell elongation. An elite haplotype of OsUGT75A associated with increased shoot length was identified among indica rice accessions. OsUGT75A acts to increase seedling emergence under deep-sowing conditions.

Soybean (Glycine max) stands as a globally significant agricultural crop, and the comprehensive assembly of its genome is of paramount importance for unraveling its biological characteristics and evolutionary history. Nevertheless, previous soybean genome assemblies have harbored gaps and incompleteness, which have constrained in-depth investigations into soybean. Here, we present Telomere-to-Telomere (T2T) assembly of the Chinese soybean cultivar Zhonghuang 13 (ZH13) genome, termed ZH13-T2T, utilizing PacBio Hifi and ONT ultralong reads. We employed a multi-assembler approach, integrating Hifiasm, NextDenovo, and Canu, to minimize biases and enhance assembly accuracy. The assembly spans 1,015,024,879 bp, effectively resolving all 393 gaps that previously plagued the reference genome. Our annotation efforts identified 50,564 high-confidence protein-coding genes, 707 of which are novel. ZH13-T2T revealed longer chromosomes, 421 not-aligned regions (NARs), 112 structure variations (SVs), and a substantial expansion of repetitive element compared to earlier assemblies. Specifically, we identified 25.67 Mb of tandem repeats, an enrichment of 5S and 48S rDNAs, and characterized their genotypic diversity. In summary, we deliver the first complete Chinese soybean cultivar T2T genome. The comprehensive annotation, along with precise centromere and telomere characterization, as well as insights into structural variations, further enhance our understanding of soybean genetics and evolution.

Drought stress limits agricultural productivity worldwide. Identifying and characterizing genetic components of drought stress-tolerance networks may improve crop resistance to drought stress. We show that the regulatory module formed by miR166 and its target gene, ATHB14-LIKE, functions in the regulation of drought tolerance in soybean (Glycine max). Drought stress represses the accumulation of miR166, leading to upregulation of its target genes. Optimal knockdown of miR166 in the stable transgenic line GmSTTM166 conferred drought tolerance without affecting yield. Expression of ABA signaling pathway genes was regulated by the miR166-mediated regulatory pathway, and ATHB14-LIKE directly activates some of these genes. There is a feedback regulation between ATHB14-LIKE and MIR166 genes, and ATHB14-LIKE inhibits MIR166 expression. These findings reveal that drought-triggered regulation of the miR166-mediated regulatory pathway increases plants drought resistance, providing new insights into drought stress regulatory network in soybean.

WRKY transcription factors, transcriptional regulators unique to plants, play an important role in defense response to pathogen infection. However, the resistance mechanisms of WRKY genes in sugarcane remain unclear. In the present study, gene ontology (GO) enrichment analysis revealed that WRKY gene family in sugarcane was extensively involved in the response to biotic stress and in defense response. We identified gene ScWRKY4, a class IIc member of the WRKY gene family, in sugarcane cultivar ROC22. This gene was induced by salicylic acid (SA) and methyl jasmonate (MeJA) stress. Interestingly, expression of ScWRKY4 was down-regulated in smut-resistant sugarcane cultivars but up-regulated in smut-susceptible sugarcane cultivars infected with Sporisorium scitamineum. Moreover, stable overexpression of the ScWRKY4 gene in Nicotiana benthamiana enhanced susceptibility to Fusarium solani var. coeruleum and caused down-regulated expression of immune marker-related genes. Transcriptome analysis indicated suppressed expression of most JAZ genes in the signal transduction pathway. ScWRKY4 interacted with ScJAZ13 to repress its expression. We thus hypothesized that the ScWRKY4 gene was involved in the regulatory network of plant disease resistance, most likely through the JA signaling pathway. The present study depicting the molecular involvement of ScWRKY4 in sugarcane disease resistance lays a foundation for future investigation.

Drought stress impairs crop growth and development. BEL1-like family transcription factors may be involved in plant response to drought stress, but little is known of the molecular mechanism by which these proteins regulate plant response and defense to drought stress. Here we show that the BEL1-like transcription factor GhBLH5-A05 functions in cotton (Gossypium hirsutum) response and defense to drought stress. Expression of GhBLH5-A05 in cotton was induced by drought stress. Overexpression of GhBLH5-A05 in both Arabidopsis and cotton increased drought tolerance, whereas silencing GhBLH5-A05 in cotton resulted in elevated sensitivity to drought stress. GhBLH5-A05 binds to cis elements in the promoters of GhRD20-A09 and GhDREB2C-D05 to activate the expression of these genes. GhBLH5-A05 interacted with the KNOX transcription factor GhKNAT6-A03. Co-expression of GhBLH5-A05 and GhKNAT6-A03 increased the transcription of GhRD20-A09 and GhDREB2C-D05. We conclude that GhBLH5-A05 acts as a regulatory factor with GhKNAT6-A03 functioning in cotton response to drought stress by activating the expression of the drought-responsive genes GhRD20-A09 and GhDREB2C-D05.

Subgroup 4 (Sg4) members of the R2R3-MYB are generally known as negative regulators of the phenylpropanoid pathway in plants. Our previous research showed that a R2R3-MYB Sg4 member from Camellia sinensis (CsMYB4a) inhibits expression of some genes in the phenylpropanoid pathway, but its physiological function in the tea plant remained unknown. Here, CsMYB4a was found to be highly expressed in anther and filaments, and participated in regulating filament growth. Transcriptome analysis and exogenous auxin treatment showed that the target of CsMYB4a might be the auxin signal pathway. Auxin/indole-3-acetic acid 4 (AUX/IAA4), a repressor in auxin signal transduction, was detected from a yeast two-hybrid screen using CsMYB4a as bait. Gene silencing assays showed that both CsIAA4 and CsMYB4a regulate filament growth. Tobacco plants overexpressing CsIAA4 were insensitive to exogenous α-NAA, consistent with overexpression of CsMYB4a. Protein-protein interaction experiments revealed that CsMYB4a interacts with N-terminal of CsIAA4 to prevent CsIAA4 degradation. Knock out of the endogenous NtIAA4 gene, a CsIAA4 homolog, in tobacco alleviated filament growth inhibition and α-NAA insensitivity in plants overexpressing CsMYB4a. All results strongly suggest that CsMYB4a works synergistically with CsIAA4 and participates in regulation of the auxin pathway in stamen.

Increasing effective panicle number per plant (EPN) is one approach to increase yield potential in rice. However, molecular mechanisms underlying EPN remain unclear. In this study, we integrated map-based cloning and genome-wide association analysis to identify the EPN4 gene, which is allelic to NARROW LEAF1 (NAL1). Overexpression lines containing the Teqing allele (TQ) of EPN4 had significantly increased EPN. NIL-EPN4^TQ in japonica (geng) cultivar Lemont (LT) exhibited significantly improved EPN but decreased grain number and flag leaf size relative to LT. Haplotype analysis indicated that accessions with EPN4-1 had medium EPN, medium grain number, and medium grain weight, but had the highest grain yield among seven haplotypes, indicating that EPN4-1 is an elite haplotype of EPN4 for positive coordination of the three components of grain yield. Furthermore, accessions carrying the combination of EPN4-1 and haplotype GNP1-6 of GNP1 for grain number per panicle showed higher grain yield than those with other allele combinations. Therefore, pyramiding of EPN4-1 and GNP1-6 could be a preferred approach to obtain high yield potential in breeding.

Doubled haploid (DH) technology is an important tool in crop breeding because it can significantly accelerate the breeding process. ZmPLA1/MATL/NLD and ZmDMP are two key genes controlling haploid induction (HI) in maize, exhibiting a synergistic effect. However, it is unknown whether knock out of ZmDMP orthologs can stimulate HI in rice. In this study, a ZmPLA1 ortholog (OsPLA1) and two ZmDMP orthologs (OsDMP3 and OsDMP6) were identified in rice. All three genes encode plasma membrane-localized proteins and were highly expressed in mature anthers. Knockout of OsPLA1 in both Minghui 63 and Nipponbare resulted in reduced seed setting rate (SSR) and caused HI. The osdmp3, osdmp6 and the double mutant failed to trigger HI independently, nor increased the haploid induction rate (HIR) when combined with ospla1. Repeated pollinations operations of QX654A with the ospla1 mutant significantly improve SSR, while reducing HIR. RNA-seq profiling of mature ospla1 mutant anthers indicated that a large number of differentially expressed genes (DEGs) were enriched in redox homeostasis and lipid metabolic GO terms, plant hormone signal transduction, and MAPK signaling pathways. These findings provide important insights towards construction of an efficient DH breeding technology and study of the molecular mechanism of HI in rice.

Nitrogen (N) fertilizer application is essential for crop-plant growth and development. Identifying genetic loci associated with N-use efficiency (NUE) could increase wheat yields and reduce environmental pollution caused by overfertilization. We subjected a panel of 389 wheat accessions to N and chlorate (a nitrate analog) treatments to identify quantitative trait loci (QTL) controlling NUE-associated traits at the wheat seedling stage. Genotyping the panel with a 660K single-nucleotide polymorphism (SNP) array, we identified 397 SNPs associated with N-sensitivity index and chlorate inhibition rate. These SNPs were merged into 49 QTL, of which eight were multi-environment stable QTL and 27 were located near previously reported QTL. A set of 135 candidate genes near the 49 QTL included TaBOX (F-box family protein) and TaERF (ethylene-responsive transcription factor). A Tabox mutant was more sensitive to low-N stress than the wild-type plant. We developed two functional markers for Hap 1, the favorable allele of TaBOX.

Shade tolerance is essential for soybeans in inter/relay cropping systems. A genome-wide association study (GWAS) integrated with transcriptome sequencing was performed to identify genes and construct a genetic network governing the trait in a set of recombinant inbred lines derived from two soybean parents with contrasting shade tolerance. An improved GWAS procedure, restricted two-stage multi-locus genome-wide association study based on gene/allele sequence markers (GASM-RTM-GWAS), identified 140 genes and their alleles associated with shade-tolerance index (STI), 146 with relative pith cell length (RCL), and nine with both. Annotation of these genes by biological categories allowed the construction of a protein-protein interaction network by 187 genes, of which half were differentially expressed under shading and non-shading conditions as well as at different growth stages. From the identified genes, three ones jointly identified for both traits by both GWAS and transcriptome and two genes with maximum links were chosen as beginners for entrance into the network. Altogether, both STI and RCL gene systems worked for shade-tolerance with genes interacted each other, this confirmed that shade-tolerance is regulated by more than single group of interacted genes, involving multiple biological functions as a gene network.

Drought is one of the abiotic stresses limiting the production of soybean (Glycine max). Elucidation of the genetic and molecular basis of the slow-wilting (SW) trait of this crop offers the prospect of its genetic improvement. A panel of 188 accessions and a set of recombinant inbred lines produced from a cross between cultivars Liaodou 14 and Liaodou 21 were used to identify quantitative-trait loci (QTL) associated with SW. Plants were genotyped by Specific-locus amplified fragment sequencing and seedling leaf wilting was assessed under three water-stress treatments. A genome-wide association study identified 26 SW-associated single-nucleotide polymorphisms (SNPs), including three located in a 248-kb linkage-disequilibrium (LD) block on chromosome 2. Linkage mapping revealed a major-effect QTL, qSW2, associated with all three treatments and adjacent to the LD block. Fine mapping in a BC₂F₃ population derived from a backcross between Liaodou 21 and R26 confined qSW2 to a 60-kb interval. Gene expression and sequence variation analysis identified the gene Glyma.02 g218100, encoding an auxin transcription factor, as a candidate gene for qSW2. Our results will contribute significantly to improving drought-resistant soybean cultivars by providing genetic information and resources.

Sesame Fusarium wilt (SFW), caused by Fusarium oxysporum f. sp. sesami (Fos), is one of the most devastating diseases affecting sesame cultivation. Deciphering the genetic control of SFW resistance is pivotal for effective disease management in sesame. An inheritance study on a cross between the highly resistant variety Yuzhi 11 and the highly susceptible accession Sp1 using a Fos pathogenicity group 1 isolate indicated that resistance was conferred by a single dominant allele. The target locus was located in a 1.24 Mb interval on chromosome 3 using a combination of cross-population association mapping and bulked segregant analysis. Fine genetic mapping further narrowed the interval between 21,350 and 21,401 kb. The locus Sindi_0812400 was identified as the SFW resistance gene and officially designated SiRLK1. This gene encodes a specific malectin/receptor-like protein kinase with three putative tandem kinase domains and is considered a kinase fusion protein. Sequence analysis revealed that a high proportion (49.44%) of variants within the locus was located within the kinase domain III, and several of which were evidently associated with the diversity in SFW response, indicating the critical role of kinase domain III in expression of disease resistance. These findings provide valuable information for further functional analysis of SFW resistance genes and marker-assisted resistance breeding in sesame.

Lysine content is a criterion of the nutritional quality of rice. Understanding the process of lysine biosynthesis in early-flowering superior grain (SG) and late-flowering inferior grain (IG) of rice would advance breeding and cultivation to improve nutritional quality. However, little information is available on differences in lysine anabolism between SG and IG and the underlying mechanism, and whether and how irrigation regimes affect lysine anabolism in these grains. A japonica rice cultivar was grown in the field and two irrigation regimes, continuous flooding (CF) and wetting alternating with partial drying (WAPD), were imposed from heading to the mature stage. Lysine content and activities of key enzymes of lysine biosynthesis, and levels of brassinosteroids (BRs) were lower in the IG than in the SG at the early grain-filling stage but higher at middle and late grain-filling stages. WAPD increased activities of these key enzymes, BR levels, and contents of lysine and total amino acids in IG, but not SG relative to CF. Application of 2,4-epibrassinolide to rice panicles in CF during early grain filling reproduced the effects of WAPD, but neither treatment altered the activities of enzymes responsible for lysine catabolism in either SG or IG. WAPD and elevated BR levels during grain filling increased lysine biosynthesis in IG. Improvement in lysine biosynthesis in rice should focus on IG.

Nitrogen (N) fertilization is critical for spike and floret development, which affects the number of fertile florets per spike (NFFs). However, the physiological regulation of the floret development process by N fertilization is largely unknown. A high temporal-resolution investigation of floret primordia number and morphology, dry matter, and N availability was conducted under three N fertilization levels: 0 (N0), 120 (N1) and 240 (N2) kg ha⁻¹. Interestingly, fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage: meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets. Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability, the NFFs increased gradually as N application increased, but the increase range decreased under N2. There were no differences in spike N concentration among treatments, but leaf N concentration was increased in the N1 and N2 treatments. Correspondingly, dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0. Clearly, optimal N fertilization increased leaf N availability and transport of assimilates to spikes, and allowed more floret primordia to acquire meiotic ability and become fertile florets, finally increasing NFFs. There was no difference in leaf N concentration between N1 and N2 treatment, whereas soil N concentration at 0-60 cm soil layers was higher in N2 than in N1 treatment, implying that there was still some N fertilization that remained unused. Therefore, improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.

Accurate cropland information is critical for agricultural planning and production, especially in food-stressed countries like China. Although widely used medium-to-high-resolution satellite-based cropland maps have been developed from various remotely sensed data sources over the past few decades, considerable discrepancies exist among these products both in total area and in spatial distribution of croplands, impeding further applications of these datasets. The factors influencing their inconsistency are also unknown. In this study, we evaluated the consistency and accuracy of six cropland maps widely used in China in circa 2020, including three state-of-the-art 10-m products (i.e., Google Dynamic World, ESRI Land Cover, and ESA WorldCover) and three 30-m ones (i.e., GLC_FCS30, GlobeLand 30, and CLCD). We also investigated the effects of landscape fragmentation, climate, and agricultural management. Validation using a ground-truth sample revealed that the 10-m-resolution WorldCover provided the highest accuracy (92.3%). These maps collectively overestimated Chinese cropland area by up to 56%. Up to 37% of the land showed spatial inconsistency among the maps, concentrated mainly in mountainous regions and attributed to the varying accuracy of cropland maps, cropland fragmentation and management practices such as irrigation. Our work shed light on the promotion of future cropland mapping efforts, especially in highly inconsistent regions.

Some haplotypes of the sucrose synthase gene TaSus1 are associated with thousand-grain weight (TGW) in wheat (Triticum aestivum L.). However, no mutations have been identified within the gene to test this association. The effects of TaSus1 on grain number per spike (GNS) also are largely unknown. Our previous genome-wide association study identified TaSus-A1 as a candidate gene controlling fertile spikelet number per spike (FSN). In the present study, we generated two independent mutants for the three TaSus1 homoeologs by CRISPR/Cas9-mediated genome editing. The triple mutants displayed lower FSN, GNS, grain number per spikelet (GNST), and TGW than wild-type plants. In 306 hexaploid wheat accessions, two single-nucleotide polymorphisms in TaSus-A1 contributed differently to GNS. Introgression of the two alleles into a wheat genetic background confirmed their effects. The alleles differed in geographical distribution among the accessions.

Transcription factors (TFs) play essential roles in transcriptional reprogramming during activation of plant immune responses to pathogens. OsSPL10 (SQUAMOSA promoter binding protein-like10) is an important TF regulating trichome development and salt tolerance in rice. Here we report that knockout of OsSPL10 reduces whereas its overexpression enhances rice resistance to blast disease. OsSPL10 positively regulates chitin-induced immune responses including reactive oxygen species (ROS) burst and callose deposition. We show that OsSPL10 physically associates with OsJAmyb, an important TF involved in jasmonic acid (JA) signaling, and positively regulates its protein stability. We then prove that OsJAmyb positively regulates resistance to blast. Our results reveal a molecular module consisting of OsSPL10 and OsJAmyb that positively regulates blast resistance.

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a devastating disease that seriously threatens wheat yield and quality. To control this disease, host resistance is the most effective measure. Compared with the resistance genes from common wheat, alien resistance genes can better withstand infection of this highly variable pathogen. Development of elite alien germplasm resources with powdery mildew resistance and other key breeding traits is an attractive strategy in wheat breeding. In this study, three wheat-rye germplasm lines YT4-1, YT4-2, and YT4-3 were developed through hybridization between octoploid triticale and common wheat, out of which the lines YT4-1 and YT4-2 conferred adult-plant resistance (APR) to powdery mildew while the line YT4-3 was susceptible to powdery mildew during all of its growth stages. Using genomic in situ hybridization, multi-color fluorescence in situ hybridization, multi-color GISH, and molecular marker analysis, YT4-1, YT4-2, and YT4-3 were shown to be cytogenetically stable wheat-rye 6R addition and T1RS·1BL translocation line, 6RL ditelosomic addition and T1RS·1BL translocation line, and T1RS·1BL translocation line, respectively. Compared with previously reported wheat-rye derivative lines carrying chromosome 6R, YT4-1 and YT4-2 showed stable APR without undesirable pleiotropic effects on agronomic traits. Therefore, these novel wheat-rye 6R derivative lines are expected to be promising bridge resources in wheat disease breeding.

The introduction of alleles into commercial crop breeding pipelines is both time consuming and costly. Two technologies that are disrupting traditional breeding processes are doubled haploid (DH) breeding and genome editing (GE). Recently, these techniques were combined into a GE trait delivery system called HI-Edit (Haploid Inducer-Edit) [1]. In HI-Edit, the pollen of a haploid inducer line is reprogrammed to deliver GE traits to any variety, obviating recurrent selection. For HI-Edit to operate at scale, an efficient transformable HI line is needed, but most maize varieties are recalcitrant to transformation, and haploid inducers are especially difficult to transform given their aberrant reproductive behaviors. Leveraging marker assisted selection and a three-tiered testing scheme, we report the development of new Iodent and Stiff Stalk maize germplasm that are transformable, have high haploid induction rates, and exhibit a robust, genetically-dominant anthocyanin native trait that may be used for rapid haploid identification. We show that transformation of these elite “HI-Edit” lines is enhanced using the BABYBOOM and WUSCHEL morphogenetic factors. Finally, we evaluate the HI-Edit performance of one of the lines against both Stiff Stalk and non-Stiff Stalk testers. The strategy and results of this study should facilitate the development of commercially scalable HI-Edit systems in diverse crops.