Young Spikes Research Articles

Chromosomal mapping of a major genetic locus from Agropyron cristatum chromosome 6P that influences grain number and spikelet number in wheat.

A novel locus on Agropyron cristatum chromosome 6P that increases grain number and spikelet number was identified in wheat-A. cristatum derivatives and across 3 years. Agropyron cristatum (2n = 4x = 28, PPPP), which has the characteristics of high yield with multiple flowers and spikelets, is a promising gene donor for wheat high-yield improvement. Identifying the genetic loci and genes that regulate yield could elucidate the genetic variations in yield-related traits and provide novel gene sources and insights for high-yield wheat breeding. In this study, cytological analysis and molecular marker analysis revealed that del10a and del31a were wheat-A. cristatum chromosome 6P deletion lines. Notably, del10a carried a segment of the full 6PS and 6PL bin (1-13), while del31a carried a segment of the full 6PS and 6PL bin (1-8). The agronomic characterization and genetic population analysis confirmed that the 6PL bin (9-13) brought about an increase in grain number per spike (average increase of 10.43 grains) and spikelet number per spike (average increase of 3.67) over the three growing seasons. Furthermore, through resequencing, a multiple grain number locus was mapped to the physical interval of 593.03-713.89Mb on chromosome 6P of A. cristatum Z559. The RNA-seq analysis revealed the expression of 537 genes in the del10a young spike tissue, with the annotation indicating that 16 of these genes were associated with grain number and spikelet number. Finally, a total of ten A. cristatum-specific molecular markers were developed for this interval. In summary, this study presents novel genetic material that is useful for high-yield wheat breeding initiatives to meet the challenge of global food security through enhanced agricultural production.

Dissecting the molecular basis of spike traits by integrating gene regulatory networks and genetic variation in wheat

Spike architecture influences both grain weight and grain number per spike, which are the two major components of grain yield in bread wheat (Triticum aestivum L.). However, the complex wheat genome and the influence of various environmental factors pose challenges in mapping the causal genes that affect spike traits. Here, we systematically identified genes involved in spike trait formation by integrating information on genomic variation and gene regulatory networks controlling young spike development in wheat. We identified 170 loci that are responsible for variations in spike length, spikelet number per spike, and grain number per spike through genome-wide association study and meta-QTL analyses. We constructed gene regulatory networks for young inflorescences at the double ridge stage and the floret primordium stage, in which the spikelet meristem and the floret meristem are predominant, respectively, by integrating transcriptome, histone modification, chromatin accessibility, eQTL, and protein–protein interactome data. From these networks, we identified 169 hub genes located in 76 of the 170 QTL regions whose polymorphisms are significantly associated with variation in spike traits. The functions of TaZF-B1, VRT-B2, and TaSPL15-A/D in establishment of wheat spike architecture were verified. This study provides valuable molecular resources for understanding spike traits and demonstrates that combining genetic analysis and developmental regulatory networks is a robust approach for dissection of complex traits.

Systematic identification of wheat spike developmental regulators by integrated multi-omics, transcriptional network, GWAS, and genetic analyses

The spike architecture of wheat plays a crucial role in determining grain number, making it a key trait for optimization in wheat breeding programs. In this study, we used a multi-omic approach to analyze the transcriptome and epigenome profiles of the young spike at eight developmental stages, revealing coordinated changes in chromatin accessibility and H3K27me3 abundance during the flowering transition. We constructed a core transcriptional regulatory network (TRN) that drives wheat spike formation and experimentally validated a multi-layer regulatory module involving TaSPL15, TaAGLG1, and TaFUL2. By integrating the TRN with genome-wide association studies, we identified 227 transcription factors, including 42 with known functions and 185 with unknown functions. Further investigation of 61 novel transcription factors using multiple homozygous mutant lines revealed 36 transcription factors that regulate spike architecture or flowering time, such as TaMYC2-A1, TaMYB30-A1, and TaWRKY37-A1. Of particular interest, TaMYB30-A1, downstream of and repressed by WFZP, was found to regulate fertile spikelet number. Notably, the excellent haplotype of TaMYB30-A1, which contains a C allele at the WFZP binding site, was enriched during wheat breeding improvement in China, leading to improved agronomic traits. Finally, we constructed a free and open access Wheat Spike Multi-Omic Database (http://39.98.48.156:8800/#/). Our study identifies novel and high-confidence regulators and offers an effective strategy for dissecting the genetic basis of wheat spike development, with practical value for wheat breeding.

Advantageous spike-to-stem competition for assimilates contributes to the reduction in grain number loss in wheat spikes under water deficit stress

This study was conducted to investigate the mechanisms of assimilate distribution and sugar metabolism in spike-stem that inhibit the formation of fertile florets and grains per spike in winter wheat under pre-reproductive drought stress. Two winter wheat cultivars, CH58 (relatively strongly drought tolerant) and LH6 (relatively weakly drought tolerant), were subjected to successive soil drought treatments from jointing to heading during the 2020–2022 growing seasons. The results showed that pre-reproductive drought stress intensified the degradation and abortion of wheat florets. Compared to CH58, the decrease in the number of fertile florets and grains per spike of LH6 under drought stress increased by an average of 5.3%−8.0% and 8.3%−9.0%, respectively. Drought significantly inhibited the distribution of 13C-photosynthates in wheat spikes (15.7%−24.7%) and stems (8.5%−11.7%) during the booting stage. The number of differentially expressed genes enriched in starch and sucrose metabolic pathways was much higher in the spike and stem of LH6 than in those of CH58. Drought significantly reduced sucrose and hexose in young spikes but increased hexose and fructan concentrations in stems. Compared to LH6, the higher invertase activity and accompanying high expression of sugar transporter protein (STP) in CH58 spikes under drought stress contributed to the utilization of sucrose in young spikes. Additionally, under severe drought, the higher fructan concentration and expression of sugar transport proteins (SWEET and SUT) in the stem of CH58 improved the ability of the stem to transport assimilates to young spikes and thus alleviated the loss of grain number per spike. Exogenous spermidine optimized hexose and sucrose allocation in young wheat spikes and stems after drought stress, thereby increasing the number of fertile florets under drought stress. Overall, the ability of the dominant spike to utilize sugar and the ability to compete for assimilates between the spike and stem contribute to the resistance to drought stress-induced grain reduction in the spike. Exogenous chemicals can regulate the number of fertile florets through this pathway, thereby promoting the formation of wheat grain number.

Generation of aroma in three-line hybrid rice through CRISPR/Cas9 editing of BETAINE ALDEHYDE DEHYDROGENASE2 (OsBADH2).

Aroma or fragrance in rice is a genetically controlled trait; Its high appreciation by consumers increases the rice market price. Previous studies have revealed that the rice aroma is controlled by a specific gene called BETAINE ALDEHYDE DEHYDROGENASE (OsBADH2), and mutation of this gene leads to the accumulation of an aromatic substance 2-acetyl-1-pyrroline (2-AP). The use of genetic engineering to produce aroma in commercial and cultivated hybrids is a contemporary need for molecular breeding. The current study reports the generation of aroma in the three-line hybrid restorer line Shu-Hui-313 (SH313). We created knock-out (KO) lines of OsBADH2 through the CRISPR/Cas9. The analysis of KO lines revealed a significantly increased content of 2AP in the grains compared with the control. However, other phenotypic traits (plant height, seed setting rate, and 1000-grain weight) were significantly decreased. These KO lines were crossed with a non-aromatic three-line hybrid rice male sterile line (Rong-7-A) to produce Rong-7-You-626 (R7Y626), R7Y627 and R7Y628. The measurement of 2-AP revealed significantly increased contents in these cross combinations. We compared the content of 2-AP in tissues at the booting stage. Data revealed that young spike stalk base contained the highest content of 2-AP and can be used for identification (by simple chewing) of aromatic lines under field conditions. In conclusion, our dataset offers a genetic source and illustrates the generation of aroma in non-aromatic hybrids, and outlines a straightforward identification under field conditions.

Resistance identification and nitrogen management of wheat under late spring coldness

AbstractLate spring coldness has a profound impact on yield and quality of wheat (Triticum aestivum), the reasonable fertilization management significantly improved yield, quality, and cold resistance of plants. Here, 10 predominant wheat varieties cultivated in the Huang‐Huai‐Hai region were selected to investigate the detrimental influence mechanism of late spring coldness on wheat growth and screen three varieties with a strong resistance to coldness. Additionally, under late spring coldness, the three varieties were applied with varying ratios of base to topdressing nitrogen fertilizer to investigate the consequences on the establishment of population structure and subsequent formation of yield and quality. The results showed that late spring coldness exerted severely detrimental effect on wheat organs development, including the increased occurrence of dead tillers, elevated mortality of young spikes, and significant decrease kernels. However, compared to N1 treatment (a nitrogen fertilizer distribution of 100% base+0% jointing+0% booting), the N2 treatment (50% base+50% jointing+0% booting) exhibited favorable outcomes under late spring coldness, such as the decreased basic seedlings and tillers, increased flag leaf area, and leaf area index, contributing to the higher spike number, grain number, and 1000‐kernel weight. Ultimately, the grain yields of Jinan 17, Huaimai 28, and Yan'nong 5158 reached their maximum values, with a 23.5%, 10.6%, and 24.2% increase, respectively, and the membership function analysis confirmed the most favorable effect of N2 treatment. These findings underscore the appropriately increased ration of topdressing nitrogen fertilizer during late spring coldness as a prerequisite for achieving both high yield and good quality of wheat.

Gene Locus Mapping and Candidate Gene Screening for Branched Spike and Its Associated Traits of the Ynbs Mutant in Barley

The Ynbs (Yunnan branched-spike) mutant of naked barley with a branched spike displays some special traits, such as more degenerated multiple spikelets per spike and florets per multiple spikelets and a lower seed-setting rate. However, there is still a lack of understanding the loci of the trait. In the present study, the Ynbs mutant was crossed with Baodamai8 to breed F2 and F2:5 populations. The F2 and F2:5 populations were successively employed to map the loci for a branched spike, triplicate (or multiple) spikelet number per spike (T(M)SNS), degenerated triplicate (or multiple) spikelet number per spike (DT(M)SNS) and floret number per triplicate (or multiple) spikelet (FNT(M)S). The genetic interval mapped through the F2:5 population was flanked by markers HvSSR4 and HVSSR20, and, within that, mapped through the F2 population. The genetic distance of the branched-spike locus to HVSSR20 locus, T(M)SNS, FNT(M)S), and DT(M)SNS is 1.86 centiMorgan (cM), 0.27 cM, and 0.73 cM, respectively. The Morex genome sequence defined by markers HvSSR4 and HVSSR20 harbored 18 genes, among which HORVU.MOREX.r3.2HG0114260 belonged to the AP2/ERF domain transcription factor gene superfamily. In the Ynbs mutant, the C base at site 232 of the code domain sequence of the gene was substituted with T, leading to the substitution of arginine with cysteine at site 78 in the DNA-binding domain of the encoded protein. The gene harbors a new allele mutant in the Ynbs mutant and exhibits a pleiotropy in the development of a branched spike, spikelet, and floret. The results provide valuable information for elucidating the development mechanism of barley young spike.

TaSPL14-7A is a conserved regulator controlling plant architecture and yield traits in common wheat (Triticum aestivum L.).

Plant architecture is a crucial influencing factor of wheat yield and adaptation. In this study, we cloned and characterized TaSPL14, a homologous gene of the rice ideal plant architecture gene OsSPL14 in wheat. TaSPL14 homoeologs (TaSPL14-7A, TaSPL14-7B and TaSPL14-7D) exhibited similar expression patterns, and they were all preferentially expressed in stems at the elongation stage and in young spikes. Moreover, the expression level of TaSPL14-7A was higher than that of TaSPL14-7B and TaSPL14-7D. Overexpression of TaSPL14-7A in wheat resulted in significant changes in plant architecture and yield traits, including decreased tiller number and increased kernel size and weight. Three TaSPL14-7A haplotypes were identified in Chinese wheat core collection, and haplotype-based association analysis showed that TaSPL14-7A-Hap1/2 were significantly correlated with fewer tillers, larger kernels and higher kernel weights in modern cultivars. The haplotype effect resulted from a difference in TaSPL14-7A expression levels among genotypes, with TaSPL14-7A-Hap1/2 leading to higher expression levels than TaSPL14-7A-Hap3. As favorable haplotypes, TaSPL14-7A-Hap1/2 underwent positive selection during global wheat breeding over the last century. Together, the findings of our study provide insight into the function and genetic effects of TaSPL14 and provide a useful molecular marker for wheat breeding.

Overexpression of Wheat TaELF3-1BL Delays Flowering in Arabidopsis

EARLY FLOWERING 3 (ELF3), a light zeitnehmer (time-taker) gene, regulates circadian rhythm and photoperiodic flowering in Arabidopsis, rice, and barley. The three orthologs of ELF3 (TaELF3-1AL, TaELF3-1BL, and TaELF3-1DL) have been identified in wheat too, and one gene, TaELF3-1DL, has been associated with heading date. However, the basic characteristics of these three genes and the roles of the other two genes, TaELF3-1BL and, TaELF3-1AL, remain unknown. Therefore, the present study obtained the coding sequences of the three orthologs (TaELF3-1AL, TaELF3-1BL, and TaELF3-1DL) of ELF3 from bread wheat and characterized them and investigated the role of TaELF3-1BL in Arabidopsis. Protein sequence comparison revealed similarities among the three TaELF3 genes of wheat; however, they were different from the Arabidopsis ELF3. Real-time quantitative PCR revealed TaELF3 expression in all wheat tissues tested, with the highest expression in young spikes; the three genes showed rhythmic expression patterns also. Furthermore, the overexpression of the TaELF3-1BL gene in Arabidopsis delayed flowering, indicating their importance in flowering. Subsequent overexpression of TaELF3-1BL in the Arabidopsis ELF3 nonfunctional mutant (elf3 mutant) eliminated its early flowering phenotype, and slightly delayed flowering. The wild-type Arabidopsis overexpressing TaELF3-1BL demonstrated reduced expression levels of flowering-related genes, such as CONSTANS (AtCO), FLOWERING LOCUS T (AtFT), and GIGANTEA (AtGI). Thus, the study characterized the three TaELF3 genes and associated TaELF3-1BL with flowering in Arabidopsis, suggesting a role in regulating flowering in wheat too. These findings provide a basis for further research on TaELF3 functions in wheat.

Mapping open chromatin by ATAC-seq in bread wheat.

Gene transcription is largely regulated by cis-regulatory elements. Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) is an emerging technology that can accurately map cis-regulatory elements in animals and plants. However, the presence of cell walls and chloroplasts in plants hinders the extraction of high-quality nuclei, thereby affects the quality of ATAC-seq data. Meanwhile, it is tricky to perform ATAC-seq with different tissue types, especially for those with limited size and amount. Moreover, with rapid growth of ATAC-seq datasets from plants, powerful and easy-to-use data analysis pipelines for ATAC-seq, especially for wheat is lacking. Here, we provided an all-in-one solution for mapping open chromatin in wheat including both experimental and data analysis procedure. We efficiently obtained nuclei with less cell debris from various wheat tissues. High-quality ATAC-seq data from young spike and ovary, which are hard to harvest were generated. We determined that the saturation sequencing depth of wheat ATAC-seq is about 16 Gb. Particularly, we developed a powerful and easy-to-use online pipeline to analyze the wheat ATAC-seq data and this pipeline can be easily extended to other plant species. The method developed here will facilitate plant regulatory genome study not only for wheat but also for other plant species.

TaABI19 positively regulates grain development in wheat

Starch is the most important component in the endosperm, and its synthesis is regulated by multiple transcription factors (TFs) in cereals. However, whether the functions of these TFs are conserved among cereals remains unclear. In this study, we cloned a B3 family TF in wheat, named TaABI19, based on its orthologous sequence in maize (Zea mays L.). Alignment of the DNA and protein sequences showed that ABI19 is conserved in maize and wheat (Triticum aestivum L.). We found that TaABI19 is highly expressed in young spikes and developing grains, and encodes a nucleus-localized transcriptional activator in wheat. The taabi19-b1 null mutants obtained by EMS exhibited a down-regulation of starch synthesis, shorter grain length and lower thousand-grain weight (TGW). Furthermore, we proved that TaABI19 could bind to the promoters of TaPBF homologous genes and enhance their expression. Haplotype association showed that TaABI19-B1 is significantly associated with TGW. We found that Hap2 and Hap3 were favored and had undergone positive selection in China’s wheat breeding programs. Less than 50% of the modern cultivars convey the favored haplotypes, indicating that TaABI19 still can be considered as a target locus for marker-assisted selection breeding to increase TGW in China.

Comparative genomic and transcriptomic analyses uncover the molecular basis of high nitrogen-use efficiency in the wheat cultivar Kenong 9204

Studying the regulatory mechanisms that drive nitrogen-use efficiency (NUE) in crops is important for sustainable agriculture and environmental protection. In this study, we generated a high-quality genome assembly for the high-NUE wheat cultivar Kenong 9204 and systematically analyzed genes related to nitrogen uptake and metabolism. By comparative analyses, we found that the high-affinity nitrate transporter gene family had expanded in Triticeae. Further studies showed that subsequent functional differentiation endowed the expanded family members with saline inducibility, providing a genetic basis for improving the adaptability of wheat to nitrogen deficiency in various habitats. To explore the genetic and molecular mechanisms of high NUE, we compared genomic and transcriptomic data from the high-NUE cultivar Kenong 9204 (KN9204) and the low-NUE cultivar Jing 411 and quantified their nitrogen accumulation under high- and low-nitrogen conditions. Compared with Jing 411, KN9204 absorbed significantly more nitrogen at the reproductive stage after shooting and accumulated it in the shoots and seeds. Transcriptome data analysis revealed that nitrogen deficiency clearly suppressed the expression of genes related to cell division in the young spike of Jing 411, whereas this suppression of gene expression was much lower in KN9204. In addition, KN9204 maintained relatively high expression of NPF genes for a longer time than Jing 411 during seed maturity. Physiological and transcriptome data revealed that KN9204 was more tolerant of nitrogen deficiency than Jing 411, especially at the reproductive stage. The high NUE of KN9204 is an integrated effect controlled at different levels. Taken together, our data provide new insights into the molecular mechanisms of NUE and important gene resources for improving wheat cultivars with a higher NUE trait.

Developmental stages of young spikes in six-rowed qingke (Hordeum vulgare L.)

Developmental stages of young spikes in six-rowed qingke (Hordeum vulgare L.)

Genome-wide identification and expression analysis of CPP-like gene family in Triticum aestivum L. under different hormone and stress conditions.

The CPP-like plant‐specific transcription factor has a prominent role in plant development and growth through cell division and differential activities. However, little information is available about the CPP gene family in Triticum aestivum L. Herein, we identified 37 and 11 CPP genes in the wheat and rice genome databases, respectively. The phylogeny of the CPP protein-like family members was further divided into five subfamilies based on structural similarities and phenotypic functional diversities. The in silico expression analysis showed that CPP genes are highly expressed in some tissues, such as shoot apex, shoot, leaf, leaf sheath, and microspore. Furthermore, the qRT-PCR found higher expression for TaCPP gene family members in leaf, leaf blade, young spike, mature spike, and differential expression patterns under abiotic stresses, including heat, drought, salt, and hormonal treatment, such as indole acetic acid and 1-aminocyclopropane-1 carboxylic acid. We found that CPP gene family members are mostly located in the nucleus after infiltrating the CPP5-1B-GFP and TaCPP11-3B-GFP into tobacco leaves. The overexpression of the TaCPP5-1D gene revealed that the CPP gene positively regulates the germanium, shoot, and root activities in Arabidopsis. The TaCPP5-1D-overexpressed plants showed less anti-oxidative sensitivity under drought stress conditions. These results demonstrated that TaCPP5-1D protein has a crucial contribution by interacting with TaCPP11-3B protein in maintaining stress homeostasis under the natural and unfavorable environmental conditions for growth, development, and stress resistance activities. Therefore, this study could be used as pioneer knowledge to further investigate the function of CPP genes in plant growth and development.

A Multi-Omics Approach for Rapid Identification of Large Genomic Lesions at the Wheat Dense Spike (wds) Locus.

Optimal spike architecture provides a favorable structure for grain development and yield improvement. However, the number of genes cloned to underlie wheat spike architecture is extremely limited. Here, we obtained a wheat dense spike mutant (wds) induced by 60Co treatment of a common wheat landrace Huangfangzhu that exhibited significantly reduced spike and grain lengths. The shortened spike length was caused by longitudinal reduction in number and length of rachis cells. We adopted a multi-omics approach to identify the genomic locus underlying the wds mutant. We performed Exome Capture Sequencing (ECS) and identified two large deletion segments, named 6BL.1 at 334.8∼424.3 Mb and 6BL.2, 579.4∼717.8 Mb in the wds mutant. RNA-seq analysis confirmed that genes located in these regions lost their RNA expression. We then found that the 6BL.2 locus was overlapping with a known spike length QTL, qSL6B.2. Totally, 499 genes were located within the deleted region and two of them were found to be positively correlated with long spike accessions but not the ones with short spike. One of them, TraesCS6B01G334600, a well-matched homolog of the rice OsBUL1 gene that works in the Brassinosteroids (BR) pathway, was identified to be involved in cell size and number regulation. Further transcriptome analysis of young spikes showed that hormone-related genes were enriched among differentially expressed genes, supporting TraesCS6B01G334600 as a candidate gene. Our work provides a strategy to rapid locate genetic loci with large genomic lesions in wheat and useful resources for future wheat study.

Comparative Physiology and Transcriptome Analysis of Young Spikes in Response to Late Spring Coldness in Wheat (Triticum aestivum L.).

Late spring coldness (LSC) is critical for wheat growth and development in the Huang-Huai valleys of China. However, little is known about the molecular mechanisms for young spikes responding to low temperature (LT) stress during anther connective tissue formation phase (ACFP). To elucidate the molecular mechanisms associated with low temperature, we performed a comparative transcriptome analysis of wheat cultivars Xinmai26 (XM26: cold-sensitive) and Yannong19 (YN19: cold-tolerant) using RNA-seq data. Over 4000 differently expressed genes (DEGs) were identified under low temperature conditions (T1: 4°C) and freezing conditions (T2: −4°C) compared with control (CK: 16°C). The number of DEGs associated with two cultivars at two low temperature treatments (T1: 4°C and T2: −4°C) were 834, 1,353, 231, and 1,882 in four comparison groups (Xinmai26-CK vs. Xinmai26-T1, Xinmai26-CK vs. Xinmai26-T2, Yannong19-CK vs. Yannong19-T1, and Yannong19-CK vs. Yannong19-T2), respectively. Furthermore, to validate the accuracy of RNA-seq, 16 DEGs were analyzed using quantitative real-time RT-PCR. Several transcriptome changes were observed through Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway functional enrichment analysis in plant hormone signal transduction, circadian rhythm-plant, and starch and sucrose metabolism under low temperature. In addition, 126 transcription factors (TFs), including AP2-ERF, bHLH, WRKY, MYB, HSF, and members of the bZIP family, were considered as cold-responsive. It is the first study to investigate DEGs associated with low temperature stress at the transcriptome level in two wheat cultivars with different cold resistance capacities. Most likely, the variations in transcription factors (TFs) regulation, and starch and sucrose metabolism contribute to different cold resistance capacities in the two cultivars. Further, physiological activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) enzymes, malondialdehyde (MDA), soluble sugar (SS), and sucrose contents were evaluated to investigate the negative impacts of low temperature in both cultivars. These findings provide new insight into the molecular mechanisms of plant responses to low temperature and potential candidate genes that required for improving wheat’s capacity to withstand low temperature stress.

Effects of Low-Temperature Stress during the Anther Differentiation Period on Winter Wheat Photosynthetic Performance and Spike-Setting Characteristics.

Climate change has caused frequent extreme low-temperature events to threaten global food security. Spring low-temperature stress is one of the major limiting factors for high and stable yields of wheat. We used two wheat varieties differing in spring cold-sensitivity (cold-tolerant variety Yannong 19 and cold-sensitive variety Xinmai 26) to examine the effects of low-temperature stress during the anther differentiation period on wheat photosynthetic performance and spike-setting characteristics. Low-temperature stress was simulated in a climate box at −2 °C, 0 °C or 2 °C (night) and 15 °C (day) for 24 h, 48 h or 72 h. With the extension of the treatment time and the decrease of temperature, the photosynthetic rate, stomatal conductance and transpiration rate of wheat leaves gradually decreased. All treatments except −2 °C for 72 h recovered slowly within 7–15 days after treatment. Low-temperature stress greatly reduced grains per spikelet, 1000-grain weight and yield per plant. By analyzing the spikelets in different stalk locations (upper, middle and lower), we found that the number of upper spikelets was significantly less than lower and middle spikelets after low-temperature stress. The sterile grain of upper spikelets (Xinmai 26, for example) can reach 100% at −2 °C for 48 h and 72 h, and the yield loss rate was 90.52% at 2 °C for 24 h, which was much higher than for the lower spikelets (60.73%) and middle spikelets (50.94%). Overall, these findings suggest that low-temperature stress during the anther differentiation period alters the photosynthetic activity involved in the accumulation of dry matter in wheat, which leads to delaying young spike growth, especially for upper spikelets, and ultimately in a decrease in yield.

Reduction of pyrrolizidine alkaloids by cooking pre-treatment for the petioles and the young spikes of <i>Petasites japonicus</i>

This study aimed to find an effective protocol as a cooking pre-treatment for the petioles and young spikes of Petasites japonicus to reduce their contents of pyrrolizidine alkaloids (PAs), a type of natural toxin in plants such as the Asteraceae and Boraginaceae families. After determining the most common cooking pre-treatment methods for petioles and young spikes of Petasites japonicus from a survey of recipes, various treatments were examined for their effectiveness at reducing PAs. It was concluded that both boiling and soaking processes were important for the reduction of PAs in pre-treatment of cooking the petioles and the young spikes of Petasites japonicus, and that a longer soaking time had a greater effect in reducing PAs. PAs in the petioles and young spikes decreased to less than 50% of the original amount in 1 h and 6 h, respectively during soaking after boiling (and peeling).

Comparative Metabolomic Analysis of Multi-Ovary Wheat under Heterogeneous Cytoplasm Suppression

The multi-ovary trait of wheat inbred line DUOII is controlled by a dominant gene whose expression can be suppressed by the heterogeneous cytoplasm of TeZhiI (TZI), another inbred line with the nucleus of common wheat and the cytoplasm of Aegilops. DUOII (♀) × TZI (♂) shows multi-ovary trait, while TZI (♀) × DUOII (♂) shows mono-ovary. To elucidate the molecular mechanism regulating heterogeneous cytoplasmic suppression of the multi-ovary gene, we performed an untargeted metabolomic analysis of 2–6 mm young spikes of reciprocal crosses between DUOII and TZI at the critical stage of additional pistil primordium development. We identified 198 annotated differentially expressed metabolites and analyzed them according to their biological functions. The results showed that these metabolites had obvious functional pathways mainly implicated in amino acid, carbohydrate, nicotinate and nicotinamide, and purine metabolism and isoquinoline alkaloid biosynthesis. We also found that shikimate, phosphoglycolic acid, nicotinamide, guanine, and xanthine might play essential roles in cytoplasmic suppression of multi-ovary trait. Chloroplast metabolism was also implicated in the nuclear-cytoplasmic effect of the multi-ovary gene. The findings provide solid theoretical and empirical foundations for future studies elucidating the mechanisms controlling heterogeneous cytoplasmic suppression of the nuclear multi-ovary gene in wheat.

Pleiotropic function of the SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE gene TaSPL14 in wheat plant architecture

Main conclusionThe function of SQUAMOSA PROMOTER-BINDING PROTEIN-BOX gene TaSPL14 in wheat is similar to that of OsSPL14 in rice in regulating plant height, panicle length, spikelet number, and thousand-grain weight of wheat, but differs during tiller development. TaSPL14 may regulate spike development via ethylene-response gene EIN3-LIKE 1 (TaEIL1), ETHYLENE-RESPONSIVE TRANSCRIPTION FACTOR 2.11 (TaRAP2.11), and ETHYLENE-RESPONSIVE TRANSCRIPTION FACTOR 1 (TaERF1), but not DENSE AND ERECT PANICLE 1 (TaDEP1) in wheat.The SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE gene OsSPL14 from rice is considered to be a major determinant of ideal plant architecture consisting of few unproductive tillers, more grains per spike, and high resistance of stems to lodging. However, the function of its orthologous gene, TaSPL14, in wheat is unknown. Here, we reported the functional similarities and differences between TaSPL14 and OsSPL14. Similar to OsSPL14 knock-outs in rice, wheat TaSPL14 knock-out plants exhibited decreased plant height, panicle length, spikelet number, and thousand-grain weight. In contrast to OsSPL14, however, TaSPL14 did not affect tiller number. Transcriptome analysis revealed that the expression of genes related to ethylene response was significantly decreased in young spikes of TaSPL14 knock-out lines as compared with wild type. TaSPL14 directly binds to the promoters of the ethylene-response genes TaEIL1, TaRAP2.11, and TaERF1, and promotes their expression, suggesting that TaSPL14 might regulate wheat spike development via the ethylene-response pathway. The elucidation of TaSPL14 will contribute to understanding of the molecular mechanisms that underlie wheat plant architecture.