Seed dormancy 4 like1 of Arabidopsis is a key regulator of phase transition from embryo to vegetative development.

Seed dormancy is an adaptive trait that enables plants to survive adverse conditions and restart growth in a season and location suitable for vegetative and reproductive growth. Control of seed dormancy is also important for crop production and food quality because it can help induce uniform germination and prevent preharvest sprouting. Rice preharvest sprouting quantitative trait locus analysis has identified Seed dormancy 4 (Sdr4) as a positive regulator of dormancy development. Here, we analyzed the loss-of-function mutant of the Arabidopsis ortholog, Sdr4 Like1 (SFL1), and found that the sfl1-1 seeds showed precocious germination at the mid- to late-maturation stage similar to rice sdr4 mutant, but converted to become more dormant than the wild type during maturation drying. Coordinated with the dormancy levels, expression levels of the seed maturation and dormancy master regulator genes, ABI3, FUS3, and DOG1 in sfl1-1 seeds were lower than in wild type at early- and mid-maturation stages, but higher at the late-maturation stage. In addition to the seed dormancy phenotype, sfl1-1 seedlings showed a growth arrest phenotype and heterochronic expression of LAFL (LEC1, ABI3, FUS3, LEC2) and DOG1 in the seedlings. These data suggest that SFL1 is a positive regulator of initiation and termination of the seed dormancy program. We also found genetic interaction between SFL1 and the SFL2, SFL3, and SFL4 paralogs of SFL1, which impacts on the timing of the phase transition from embryo maturation to seedling growth.

ABA biosynthesis gene OsNCED3 contributes to preharvest sprouting resistance and grain development in rice.

Preharvest sprouting (PHS) is an unfavorable trait in cereal crops and causes serious yield loss. However, the molecular mechanism underlying PHS remains largely elusive. Here, we identified a member of 9-cis-epoxycarotenoid dioxygenase family, OsNCED3, which regulates PHS and grain development in rice (Oryza sativa L.). OsNCED3 encodes a chloroplast-localized abscisic acid (ABA) biosynthetic enzyme highly expressed in the embryo of developing seeds. Disruption of OsNCED3 by CRISPR/Cas9-mediated mutagenesis led to a lower ABA and higher gibberellic acid (GA) levels (thus a skewed ABA/GA ratio) in the embryo, promoting embryos growth and breaking seed dormancy before seed maturity and harvest, thus decreased seed dormancy and enhanced PHS in rice. However, the overexpression of OsNCED3 enhanced PHS resistance by regulating proper ABA/GA ratio in the embryo. Intriguingly, the overexpression of OsNCED3 resulted in increased grain size and weight, whereas the disruption of OsNCED3 function decreased grain size and weight. Nucleotide diversity analyses suggested that OsNCED3 may be selected during japonica populations adaptation of seed dormancy and germination. Taken together, we have identified a new OsNCED regulator involved rice PHS and grain development, and provide a potential target gene for improving PHS resistance and grain development in rice.

Catalase associated with antagonistic changes of abscisic acid and gibberellin response, biosynthesis and catabolism is involved in eugenol-inhibited seed germination in rice.

KEY MESSAGE: The inhibitory effect of eugenol on rice germination is mediated by a two-step modulatory process: Eugenol first regulates the antagonism of GA and ABA, followed by activation of catalase activity. The natural monoterpene eugenol has been reported to inhibit preharvest sprouting in rice. However, the inhibitory mechanism remains obscure. In this study, simultaneous monitoring of GA and ABA responses by the in vivo GA and ABA-responsive dual-luciferase reporter system showed that eugenol strongly inhibited the GA response after 6 h of imbibition, whereas eugenol significantly enhanced the ABA response after 12 h of imbibition. Gene expression analysis revealed that eugenol significantly induced the ABA biosynthetic genes OsNCED2, OsNCED3, and OsNCED5, but notably suppressed the ABA catabolic genes OsABA8ox1 and OsABA8ox2. Conversely, eugenol inhibited the GA biosynthetic genes OsGA3ox2 and OsGA20ox4 but significantly induced the GA catabolic genes OsGA2ox1 and OsGA2ox3 during imbibition. OsABI4, the key signaling regulator of ABA and GA antagonism, was notably induced before 12 h and suppressed after 24 h by eugenol. Moreover, eugenol markedly reduced the accumulation of H2O2 in seeds after 36 h of imbibition. Further analysis showed that eugenol strongly induced catalase activity, protein accumulation, and the expression of three catalase genes. Most importantly, mitigation of eugenol-inhibited seed germination was found in the catc mutant. These findings indicate that catalase associated with antagonistic changes of ABA and GA is involved in the sequential regulation of eugenol-inhibited seed germination in rice.

The GATA transcription factor TaGATA1 recruits demethylase TaELF6-A1 and enhances seed dormancy in wheat by directly regulating TaABI5.

Seed dormancy is an important agronomic trait in crops, and plants with low dormancy are prone to preharvest sprouting (PHS) under high-temperature and humid conditions. In this study, we report that the GATA transcription factor TaGATA1 is a positive regulator of seed dormancy by regulating TaABI5 expression in wheat. Our results demonstrate that TaGATA1 overexpression significantly enhances seed dormancy and increases resistance to PHS in wheat. Gene expression patterns, abscisic acid (ABA) response assay, and transcriptome analysis all indicate that TaGATA1 functions through the ABA signaling pathway. The transcript abundance of TaABI5, an essential regulator in the ABA signaling pathway, is significantly elevated in plants overexpressing TaGATA1. Chromatin immunoprecipitation assay (ChIP) and transient expression analysis showed that TaGATA1 binds to the GATA motifs at the promoter of TaABI5 and induces its expression. We also demonstrate that TaGATA1 physically interacts with the putative demethylase TaELF6-A1, the wheat orthologue of Arabidopsis ELF6. ChIP-qPCR analysis showed that H3K27me3 levels significantly decline at the TaABI5 promoter in the TaGATA1-overexpression wheat line and that transient expression of TaELF6-A1 reduces methylation levels at the TaABI5 promoter, increasing TaABI5 expression. These findings reveal a new transcription module, including TaGATA1-TaELF6-A1-TaABI5, which contributes to seed dormancy through the ABA signaling pathway and epigenetic reprogramming at the target site. TaGATA1 could be a candidate gene for improving PHS resistance.

Improvement of preharvest sprouting resistance with MOTHER OF FT AND TFL 1 + mutated ABA 8'-hydroxylase in white-seeded durum wheat.

Improvement of preharvest sprouting (PHS) resistance is an important objective in the breeding of durum wheat (Triticum turgidum ssp. durum (Desf.) Husn.) in Japan, where the harvest timing overlaps with the rainy season. In a previous study, we showed that an R-gene associated with red seed color was the most effective at promoting PHS resistance in durum wheat. However, red-seeded durum wheat is not popular because it discolors pasta. Here, to improve PHS resistance without the R-gene, we introduced a PHS resistance allele of MOTHER OF FT AND TFL 1 (MFT) and a mutated ABA 8'-hydroxylase (ABA8'OH1-A), which is involved in abscisic acid (ABA) catabolism, singly or together into white-seeded durum wheat. The introduction of both genes reliably and stably improved PHS resistance under all tested conditions. Modification of ABA catabolism might be an effective way to improve PHS resistance in durum wheat. Our findings will contribute to improved PHS resistance in breeding for white-seeded durum wheat.

Genetic variation and genetic control of intraspikelet differences in grain weight and seed dormancy in wild and domesticated emmer wheats.

Seed dormancy, a vital strategy for wild plant species to adapt to an unpredictable environment in their natural habitats, was eliminated from cereals during the domestication process. Intraspikelet differences in grain size and seed dormancy have been observed in wild emmer wheat. To elucidate the genetic variation of these intraspikelet differences and to determine their genetic control, grain weight ratio (first florets/second florets) (GWR), germination rate, and germination index (GI) were analyzed in 67 wild and 82 domesticated emmer wheat accessions, as well as F1 hybrids, F2 populations, and F3-F6 populations derived from reciprocal crosses between wild and domesticated lines. Only the grains on the first florets of two-grained spikelets in wild accessions had varying degrees of dormancy with GI ranging from 0 to 1, which positively correlated with their GWR. This implies that wild emmer populations comprised genotypes with varying degrees of dormancy, including nondormant genotypes. According to segregations observed in F2 populations, the intraspikelet grain weight difference was controlled by two independently inherited loci. Furthermore, low-GWR populations with low or high GI values could be selected in F5 and F6 generations, implying that the major loci associated with dormancy might be independent of intraspikelet grain weight difference.

As the number falls, alternatives to the Hagberg-Perten falling number method: A review.

This review examines the application, limitations, and potential alternatives to the Hagberg-Perten falling number (FN) method used in the global wheat industry for detecting the risk of poor end-product quality mainly due to starch degradation by the enzyme α-amylase. By viscometry, the FN test indirectly detects the presence of α-amylase, the primary enzyme that digests starch. Elevated α-amylase results in low FN and damages wheat product quality resulting in cakes that fall, and sticky bread and noodles. Low FN can occur from preharvest sprouting (PHS) and late maturity α-amylase (LMA). Moist or rainy conditions before harvest cause PHS on the mother plant. Continuously cool or fluctuating temperatures during the grain filling stage cause LMA. Due to the expression of additional hydrolytic enzymes, PHS has a stronger negative impact than LMA. Wheat grain with low FN/high α-amylase results in serious losses for farmers, traders, millers, and bakers worldwide. Although blending of low FN grain with sound wheat may be used as a means of moving affected grain through the marketplace, care must be taken to avoid grain lots from falling below contract-specified FN. A large amount of sound wheat can be ruined if mixed with a small amount of sprouted wheat. The FN method is widely employed to detect α-amylase after harvest. However, it has several limitations, including sampling variability, high cost, labor intensiveness, the destructive nature of the test, and an inability to differentiate between LMA and PHS. Faster, cheaper, and more accurate alternatives could improve breeding for resistance to PHS and LMA and could preserve the value of wheat grain by avoiding inadvertent mixing of high- and low-FN grain by enabling testing at more stages of the value stream including at harvest, delivery, transport, storage, and milling. Alternatives to the FN method explored here include the Rapid Visco Analyzer, enzyme assays, immunoassays, near-infrared spectroscopy, and hyperspectral imaging.

Genome-Wide Identification and Expression Analysis of OsbZIP09 Target Genes in Rice Reveal Its Mechanism of Controlling Seed Germination.

Seed dormancy and germination are key events in plant development and are critical for crop production, and defects in seed germination or the inappropriate release of seed dormancy cause substantial losses in crop yields. Rice is the staple food for more than half of the world's population, and preharvest sprouting (PHS) is one of the most severe problems in rice production, due to a low level of seed dormancy, especially under warm and damp conditions. Therefore, PHS leads to yield loss and a decrease in rice quality and vitality. We reveal that mutation of OsbZIP09 inhibited rice PHS. Analysis of the expression of OsbZIP09 and its encoded protein sequence and structure indicated that OsbZIP09 is a typical bZIP transcription factor that contains conserved bZIP domains, and its expression is induced by ABA. Moreover, RNA sequencing (RNA-seq) and DNA affinity purification sequencing (DAP-seq) analyses were performed and 52 key direct targets of OsbZIP09 were identified, including OsLOX2 and Late Embryogenesis Abundant (LEA) family genes, which are involved in controlling seed germination. Most of these key targets showed consistent changes in expression in response to abscisic acid (ABA) treatment and OsbZIP09 mutation. The data characterize a number of key target genes that are directly regulated by OsbZIP09 and contribute to revealing the molecular mechanism that underlies how OsbZIP09 controls rice seed germination.

Important agronomic characteristics of yielding ability in common buckwheat; ecotype and ecological differentiation, preharvest sprouting resistance, shattering resistance, and lodging resistance.

Common buckwheat is recognized as a healthy food because its seed contains large amounts of protein, minerals, and rutin. However, the yielding ability of common buckwheat is lower than that of other major crops. The short growing period, moisture injury, occurrence of sterile seeds due to lack of flower-visiting insects, and yield loss due to lodging and shattering cause low and unstable grain yield. Therefore, many common buckwheat breeders have tried to increase yielding ability by improving various characteristics. Recently, new breeding objectives for improving yielding ability by increasing preharvest sprouting resistance; reducing shattering loss; introducing self-compatibility; the ecotype, and semidwarf have been reported. In this review, we introduce the research on the important agronomic characteristics, preharvest sprouting resistance, ecotype and ecological differentiation, shattering resistance, and lodging resistance in common buckwheat.

Plant hormone profiling in developing seeds of common wheat (Triticum aestivum L.).

This study examined contents of nine plant hormones in developing seeds of field-grown wheat varieties (Triticum aestivum L.) with different seed dormancy using liquid chromatography-mass spectrometry. The varieties showed marked diversity in germination indices at 15°C and 20°C. Contents of the respective hormones in seeds showed a characteristic pattern during seed maturation from 30-day post anthesis to 60-day post anthesis. Principal component analysis and hierarchical clustering analysis revealed that plant hormone profiles were not correlated with dormancy levels, indicating that hormone contents were not associated with preharvest sprouting (PHS) susceptibility. Indole acetic acid (IAA) contents of mature seeds showed positive correlation with the germination index, but no other hormone. Response of embryo-half seeds to exogenous abscisic acid (ABA) indicates that ABA sensitivity is correlated with whole-seed germinability, which can be explained in part by genotypes of MOTHER OF FT AND TFL (MFT) allele modulating ABA signaling of wheat seeds. These results demonstrate that variation in wheat seed dormancy is attributable to ABA sensitivity of mature seeds, but not to ABA contents in developing seeds.

Mechanisms of Maturation and Germination in Crop Seeds Exposed to Environmental Stresses with a Focus on Nutrients, Water Status, and Reactive Oxygen Species.

Environmental stresses can reduce crop yield and quality considerably. Plants protect cell metabolism in response to abiotic stresses at all stages of their life cycle, including seed production. As the production of vigorous seeds is important to both yield and crop growth, we analyzed causes of yield loss and reduced grain quality in staple crops exposed to environmental stresses such as drought and temperature extremes, with a focus on the remobilization of nutrients and water status during seed filling. Because water is one of the factors that limit seed development, seeds must have mechanisms that allow them to withstand water loss during seed maturation. In addition, analysis of the effects of reactive oxygen species (ROS) on transcription regulation and signaling should help to elucidate the regulation of seed dormancy and germination. In this review, we focus on nutrient remobilization, water mobility, plant hormones (gibberellins, abscisic acid, and ethylene), and ROS in sink and source organs and describe how rice, wheat, barley, soybean, and cowpea plants control seed maturation and germination under environmental stresses.

Improving preharvest sprouting resistance in durum wheat with bread wheat genes.

Preharvest sprouting (PHS) of durum wheat (Triticum turgidum ssp. durum (Desf.) Husn.) is an important problem in Japan, where the rainy season overlaps with the harvest season. Since there are few PHS-resistant genetic resources in durum wheat, we introduced an R-gene for red seeds, the MFT gene, and the QPhs-5AL QTL, all of which are associated with PHS resistance, into durum wheat from a PHS-resistant bread wheat (T. aestivum L.) cultivar, 'Zenkoujikomugi' (Zen), by backcross breeding. Developed near isogenic lines (NILs) with red seeds had a lower percentage germination (PG) and germination index (GI) than the recurrent parent, and seed color had the greatest effect. A NIL combining all three sequences had the lowest GI and PG, with a similar GI to that of 'Shiroganekomugi' bread wheat. Among NILs with white seeds, a NIL combining MFT and QPhs-5AL had the lowest GI and PG. As the combination of all three sequences from Zen conferred PHS resistance on durum wheat, PHS-resistant genetic resources in bread wheat can be used in breeding durum wheat.

Abscisic acid metabolic genes of wheat (Triticum aestivum L.): identification and insights into their functionality in seed dormancy and dehydration tolerance.

MAIN CONCLUSION: The three homeologues of wheat NCED2 were identified; the wheat NCED2A and CYP707A1B affect seed ABA level and dormancy but not leaf ABA level and transpirational water loss in Arabidopsis. Biosynthesis and catabolism of abscisic acid (ABA) in plants are primarily regulated by 9-cis-epoxycarotenoid dioxygenases (NCEDs) and ABA 8'-hydroxylase (ABA8'OH), respectively. The present study identified the complete coding sequences of a second NCED gene, designated as TaNCED2, and its homeologues (TaNCED2A, TaNCED2B and TaNCED2D) in hexaploid wheat, and characterized its functionality in seed dormancy and leaf dehydration tolerance using the TaNCED2A homeologue. The study also investigated the role of the B genome copy of the cytochrome P450 monooxygenase 707A1 (CYP707A1) gene of hexaploid wheat (TaCYP707A1B), which encodes ABA8'OH, in regulating the two traits as this has not been studied before. Ectopic expression of TaNCED2A and TaCYP707A1B in Arabidopsis resulted in altered seed ABA level and dormancy with no effect on leaf ABA content and transpirational water loss. To gain insights into the physiological roles of TaNCED2 and TaCYP707A1 in wheat, the study examined their spatiotemporal expression patterns and determined the genomic contributions of transcripts to their total expression.

Engineering high α-amylase levels in wheat grain lowers Falling Number but improves baking properties.

Late maturity α-amylase (LMA) and preharvest sprouting (PHS) are genetic defects in wheat. They are both characterized by the expression of specific isoforms of α-amylase in particular genotypes in the grain prior to harvest. The enhanced expression of α-amylase in both LMA and PHS results in a reduction in Falling Number (FN), a test of gel viscosity, and subsequent downgrading of the grain, along with a reduced price for growers. The FN test is unable to distinguish between LMA and PHS; thus, both defects are treated similarly when grain is traded. However, in PHS-affected grains, proteases and other degradative process are activated, and this has been shown to have a negative impact on end product quality. No studies have been conducted to determine whether LMA is detrimental to end product quality. This work demonstrated that wheat in which an isoform α-amylase (TaAmy3) was overexpressed in the endosperm of developing grain to levels of up to 100-fold higher than the wild-type resulted in low FN similar to those seen in LMA- or PHS-affected grains. This increase had no detrimental effect on starch structure, flour composition and enhanced baking quality, in small-scale 10-g baking tests. In these small-scale tests, overexpression of TaAmy3 led to increased loaf volume and Maillard-related browning to levels higher than those in control flours when baking improver was added. These findings raise questions as to the validity of the assumption that (i) LMA is detrimental to end product quality and (ii) a low FN is always indicative of a reduction in quality. This work suggests the need for a better understanding of the impact of elevated expression of specific α-amylase on end product quality.

Auxin controls seed dormancy through stimulation of abscisic acid signaling by inducing ARF-mediated ABI3 activation in Arabidopsis.

The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy; it acts through a gene expression network involving the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3). However, whether other phytohormone pathways function in the maintenance of seed dormancy in response to environmental and internal signals remains an important question. Here, we show that the plant growth hormone auxin, which acts as a versatile trigger in many developmental processes, also plays a critical role in seed dormancy in Arabidopsis. We show that disruptions in auxin signaling in MIR160-overexpressing plants, auxin receptor mutants, or auxin biosynthesis mutants dramatically release seed dormancy, whereas increases in auxin signaling or biosynthesis greatly enhance seed dormancy. Auxin action in seed dormancy requires the ABA signaling pathway (and vice versa), indicating that the roles of auxin and ABA in seed dormancy are interdependent. Furthermore, we show that auxin acts upstream of the major regulator of seed dormancy, ABI3, by recruiting the auxin response factors AUXIN RESPONSE FACTOR 10 and AUXIN RESPONSE FACTOR 16 to control the expression of ABI3 during seed germination. Our study, thus, uncovers a previously unrecognized regulatory factor of seed dormancy and a coordinating network of auxin and ABA signaling in this important process.

Novel assay procedures for the measurement of α-amylase in weather-damaged wheat.

BACKGROUND: The measurement of α-amylase (EC 3.2.1.1) in sprout-damaged grains is a crucial analysis yet a problematic one owing to the typically low α-amylase levels in ground wheat samples. A number of standardised methods such as the Falling Number method and the Ceralpha method exist which are routinely used for the assay of α-amylase. These methods, however, are either highly substrate-dependent or lack the required sensitivity to assess sprout damage. RESULTS: Novel colorimetric and fluorometric reagents have been prepared (Amylase HR, Amylase SD, BzCNPG7 reagent and BzMUG7 reagent) for the direct and specific assay of α-amylase activity in sprout-damaged wheat. Assays employing these reagents have been developed and optimised to include a decolourisation step using activated charcoal. When used in a convenient assay format, Amylase SD--containing EtNPG7 (II) as the colorimetric substrate and α-glucosidase as the ancillary enzyme--was found to be an excellent reagent for the assessment of sprout damage in wheat with incubation times as short as 5 min. CONCLUSION: The assay using Amylase SD is completely specific for α-amylase. The use of the Amylase SD assay represents a sensitive and valid alternative to the traditionally used Falling Number values for the assessment of sprout damage in wheat samples.

Independent mis-splicing mutations in TaPHS1 causing loss of preharvest sprouting (PHS) resistance during wheat domestication.

Preharvest sprouting (PHS) is one of the major constraints of wheat production in areas where prolonged rainfall occurs during harvest. TaPHS1 is a gene that regulates PHS resistance on chromosome 3A of wheat, and two causal mutations in the positions +646 and +666 of the TaPHS1 coding region result in wheat PHS susceptibility. Three competitive allele-specific PCR (KASP) markers were developed based on the two mutations in the coding region and one in the promoter region and validated in 82 wheat cultivars with known genotypes. These markers can be used to transfer TaPHS1 in breeding through marker-assisted selection. Screening of 327 accessions of wheat A genome progenitors using the three KASP markers identified different haplotypes in both diploid and tetraploid wheats. Only one Triticum monococcum accession, however, carries both causal mutations in the TaPHS1 coding region and shows PHS susceptibility. Five of 249 common wheat landraces collected from the Fertile Crescent and surrounding areas carried the mutation (C) in the promoter (-222), and one landrace carries both the causal mutations in the TaPHS1 coding region, indicating that the mis-splicing (+646) mutation occurred during common wheat domestication. PHS assay of wheat progenitor accessions demonstrated that the wild-types were highly PHS-resistant, whereas the domesticated type showed increased PHS susceptibility. The mis-splicing TaPHS1 mutation for PHS susceptibility was involved in wheat domestication and might arise independently between T. monococcum and Triticum aestivum.

Barley Ant17, encoding flavanone 3-hydroxylase (F3H), is a promising target locus for attaining anthocyanin/proanthocyanidin-free plants without pleiotropic reduction of grain dormancy.

Preharvest sprouting is a serious problem in grain crop production because it causes quality deterioration and economic losses. It is well known that grain colour is closely associated with grain dormancy in wheat; white-grained lines without accumulating proanthocyanidins in testa tend to be more susceptible to preharvest sprouting than red ones. All available white-grained wheat lines are restricted to triple recessive mutations at the R loci (R-A1, R-B1, and R-D1), but barley is known to have 11 independent loci conferring the proanthocyanidin-free grain phenotype. In this study, we evaluated the dormancy levels of anthocyanin/proanthocyanidin-free ant17 mutants. Three ant17 mutants showed the same levels of dormancy as their respective wild types. Sequencing of three independent ant17 alleles detected a point mutation within the coding regions of flavanone-3-hydroxylase (F3H), which are predicted to cause a premature stop codon at different sites. The F3H locus completely cosegregated with the Ant17 position on the chromosome arm 2HL. Expression of the barley F3H gene was observed in pigmented tissues, but not in nonpigmented roots and stems. This result indicates that wheat F3H may be a promising new target locus for breeding white-grained lines with a practical level of preharvest sprouting resistance.

OsABA3 is Crucial for Plant Survival and Resistance to Multiple Stresses in Rice.

Preharvest sprouting (PHS) is a serious problem in rice production as it leads to reductions in grain yield and quality. However, the underlying mechanism of PHS in rice remains unclear. In this study, we identified and characterized a preharvest sprouting and seedling lethal (phssl) mutant. The heterozygous phssl/+ mutant exhibited normal plant development, but severe PHS in paddy fields. However, the homozygous phssl mutant was seedling lethal. Gene cloning and genetic analysis revealed that a point mutation in OsABA3 was responsible for the mutant phenotypes. OsABA3 encodes a molybdenum cofactor (Moco) sulfurase. The activities of the sulfureted Moco-dependent enzymes such as aldehyde oxidase (AO) and xanthine dehydrogenase (XDH) were barely detectable in the phssl mutant. As the final step of abscisic acid (ABA) de novo biosynthesis is catalyzed by AO, it indicated that ABA biosynthesis was interrupted in the phssl mutant. Exogenous application of ABA almost recovered seed dormancy of the phssl mutant. The knock-out (ko) mutants of OsABA3 generated by CRISPR-Cas9 assay, were also seedling lethal, and the heterozygous mutants were similar to the phssl/+ mutant showing reduced seed dormancy and severe PHS in paddy fields. In contrast, the OsABA3 overexpressing (OE) plants displayed a significant increase in seed dormancy and enhanced plant resistance to PHS. The AO and XDH activities were abolished in the ko mutants, whereas they were increased in the OE plants. Notably, the Moco-dependent enzymes including nitrate reductase (NR) and sulfite oxidase (SO) showed reduced activities in the OE plants. Moreover, the OE plants exhibited enhanced resistances to osmotic stress and bacterial blight, and flowered earlier without any reduction in grain yield. Taken together, this study uncovered the crucial functions of OsABA3 in Moco sulfuration, plant development, and stress resistance, and suggested that OsABA3 is a promising target gene for rice breeding.