Global crop productivity faces a significant threat from climate change-induced drought stress (DS), which is vital for sustainable agriculture and global food security. Uncovering DS adaptation and tolerance mechanisms in crops is necessary to alleviate climate challenges. Innovative plant breeding demands revolutionary approaches to develop stress-smart plants. Metabolomics, a promising field in plant breeding, offers a predictive tool to identify metabolic markers associated with plant performance under DS, enabling accelerated crop improvement. Central to DS adaptation is metabolomics-driven metabolic regulation, which is critical for maintaining cell osmotic potential in crops. Recent innovations allow rapid mapping of specific metabolites to their genetic pathways, providing a valuable resource for plant scientists. Metabolomics-driven molecular breeding, integrating techniques such as mQTL and mGWAS, enhances our ability to discover key genetic elements linked to stress-responsive metabolites. This integration offers a beneficial platform for plant scientists, yielding significant insights into the complex metabolic networks underlying DS tolerance. Therefore, this review discusses (1) insights into metabolic regulation for DS adaptation, (2) the multifaceted role of metabolites in DS tolerance and nutritional/yield trait improvement, (3) the potential of single-cell metabolomics and imaging, (4) metabolomics-driven molecular breeding, and (5) the application of metabolic and genetic engineering for DS-tolerant crops. We finally propose that the metabolomics-driven approach positions drought-smart crops as key contributors to future food production, supporting the vital goal of achieving “zero hunger”.
Sugarcane is recognized as the fifth largest crop globally, supplying 80% of sugar and 40% of bioenergy production. However, sugarcane genetic research has significantly lagged behind other crops due to its complex genetic background, high ploidy (8-13×), aneuploidy, limited flowering, and a long growth cycle (more than one year). Cross breeding began in 1887 following the discovery that sugarcane seeds could germinate. Both self- and cross-pollination and selection were conducted by sugarcane breeders, but new cultivars were often eliminated due to disease susceptibility. Within the Saccharum genus, different species possess variable numbers of chromosomes. Wild sugarcane species intercrossed with each other, leading to development of the ‘Nobilization’ breeding strategy, which significantly improved yield, sucrose, fiber content, and disease resistance, and accelerated genetic improvement of cultivars. In recent years, scientific achievements have also been made in sugarcane genome sequencing, molecular marker development, genetic linkage map construction, localization of quantitative trait locus (QTL), and trait-associated gene identification. This review focuses on the progress in sugarcane genetic research, analyzes the technical difficulties faced, presents opportunities and challenges, and provides guidance and references for future sugarcane genetics research and cultivar breeding. Finally, it offers directions for future on sugarcane genetics.
Foxtail millet (Setaria italica) is an important crop and an emerging model plant. Photoperiodic flowering is a key determinant of its production and geographic expansion. In this study, we found that SiPRR37 is responsible for the major quantitative trait locus (QTL) Heading date 2 (Hd2) identified in 680 foxtail millets using a genome-wide association study. Overexpression of SiPRR37 in foxtail millet significantly delayed the heading date under both natural long-day and short-day conditions. CRISPR/Cas9-induced Siprr37 mutants exhibited earlier flowering in long-day conditions but later flowering in short-day conditions. The critical day length (CDL) for the reversal of Siprr37’s function was around 14.3 h. Haplotype analysis revealed that accessions with the Tc1-Mariner transposon insertion in SiPRR37 (Hap 1) flowered significantly earlier at higher latitudes, and later at lower latitudes, indicating that natural variants of SiPRR37 exert dual functions in flowering regulation according to geographic latitude. The gradual, successive decrease in the frequency of Hap 2 from low to high latitudes, with the concurrent increase of Hap 1, demonstrates that these haplotypes have undergone artificial selection. Further FST analysis demonstrated that SiPRR37 has contributed to the ecological adaption of foxtail millet. Additionally, we reveal that OsPRR37 promotes flowering in rice, while GmPRR37 may only inhibit flowering in soybean. Further diurnal expression and transgenic analyses suggest that the dual function of SiPRR37 might depend on SiHd1. Our study uncovered the distinct functional reversal of SiPRR37 and functional diversification of PRR37 homologs in SD crops. These findings not only enrich knowledge about the regulation of photoperiodic flowering, but also contribute to genetic improvement of crops’ regional adaptability.
Plant height and grain size are the most important factors determining rice yield. Here, in the rice mutant small plant and organ size1 (spos1) with reduced plant height and small grain, T-DNA insertion revealed that the mutant phenotype was caused by increased expression of of OsSAUR23 and OsRR9, which participate in auxin and cytokinin signal transduction, respectively. Knock out of OsSAUR23 increased rice grain size but did not change plant height. Double knock out of OsRR9 and its replicated gene OsRR10 also brought similar effects on rice as that of OsSAUR23 knock-out. Genetic analysis suggested that OsSAUR23 was a major recessive gene and OsRR9 was a minor dominant gene, which co-regulated the phenotype of spos1. Compared with wild type, auxin synthesis and signaling, cytokinin homeostasis and signaling, as well as GA, ABA and BR metabolism and signaling were regulated in seedlings of spos1. The increased concentrations of IAA and cytokinins in the mutant suggest hormonal co-regulation of rice organ size.
The leaf is a major organ for photosynthesis, and its shape plays an important role in plant development and yield determination in rice (Oryza sativa L.). In this study, an adaxial curled leaf mutant, termed curly leaf 1-1 (cul1-1), was obtained by chemical mutagenesis. The leaf rolling index of the cul1-1 mutant was higher than that of the wild-type, which was caused by the abnormal development of bulliform cells (BCs). We cloned the CUL1 gene by map-based cloning. A nonsense mutation was present in the cul1-1 mutant, converting a tryptophan codon into a stop codon. The CUL1 gene encodes a chromodomain, helicase/ATPase and DNA-binding domain containing protein. Genes related to leaf rolling and BC development, such as ADL1, REL1 and ROC5, were activated by the cul1-1 mutation. The trimethylation of lysine 27 in histone 3 (H3K27me3), but not H3K4me3, at the ADL1, REL1 and ROC5 loci, was reduced in the cul1-1 mutant. High-throughput mRNA sequencing indicated that the cul1-1 mutation caused genome-wide differential gene expression. The differentially expressed genes were classified into a few gene ontology terms and Kyoto encyclopedia of genes and genomes pathways. In the natural population, 22 missense genomic variations in the CUL1 locus were identified, which composed of 7 haplotypes. A haplotype network was also built with haplotype II as the ancestor. The findings revealed that CUL1 is essential for normal leaf development and regulates this process by inhibiting the expression of genes involved in leaf rolling and BC development.
The chalcone isomerase gene OsCHI, one of the key genes in the flavonoid biosynthesis pathway, plays an important role in rice (Oryza sativa) resistance to abiotic stresses. This study reveals how the chalcone isomerase gene family member OsCHI3 participates in rice responses to drought stress through the regulation of flavonoid biosynthesis. Overexpression of OsCHI3 increased the tolerance of rice to drought stress. In contrast, CRISPR/Cas9-mediated deletion of OsCHI3 reduced the drought tolerance of rice, an effect that is reversed by exogenous ABA treatment. Transcriptomic and physiological biochemical analyses indicated that flavonoids regulated by OsCHI3 not only scavenge reactive oxygen species (ROS) but also increase drought tolerance in rice by stimulating ABA biosynthesis through the regulation of OsNCED1 and OsABA8ox3 expression. These findings demonstrate that OsCHI3 increases drought stress tolerance in rice by activating the antioxidant defense system and the ABA metabolic pathway, providing new clues for drought-resistant rice breeding research.
The SnRK2 gene family plays important roles in ABA mediated abiotic stress responses. However, the roles and functional mechanism of the SnRK2 gene family in plant immunity are largely unknown. In this study, we report that OsSAPK10, a SnRK2 gene family protein in rice, positively regulates rice blast resistance. The ossapk10 mutation reduced rice blast resistance and overexpression of OsSAPK10 increased it. Furthermore, OsSAPK10 phosphorylates OsPAL1, a positive regulator of rice blast resistance, at Ser82 to stabilize it. Knocking out OsPAL1 also reduced rice blast resistance. Taken together, our findings revealed that OsSAPK10 positively regulates rice immunity via phosphorylating and stabilizing OsPAL1, providing new insight into the functional mechanism of the SnRK2 gene family in biotic stress responses.
Maize (Zea mays L.) is a globally significant crop essential for food, feed, and bioenergy production. The maize kernel, serving as a primary sink for starch, proteins, lipids, and essential micronutrients, is crucial for enhancing maize yield and quality. Previous studies have established the critical role of Polycomb Repressive Complex 2 (PRC2) in regulating kernel development. In this study, we applied a reverse genetics approach to investigate the role of ZmFIE1, the homolog of the PRC2 complex component Extra sex combs (Esc), in maize development. The functional loss of ZmFIE1 significantly reduces embryo size in the early stage but has a relatively small impact on mature kernels. Integrating transcriptional and metabolomic profiling suggests that ZmFIE1 is involved in regulating nutrient balance between the endosperm and embryo. In addition, we demonstrate that ZmFIE1 is maternally expressed, and that the maternal inheritance of the fie1 allele significantly affects the imprinting status of paternally imprinted genes. Overall, our results suggest that ZmFIE1 is a key gene involved in the modulation of embryo development via regulating genomic imprinting and nutrient balance between embryo and endosperm, which provides new insights into the regulation mechanism underlying kernel development.
Chromosomal DNA double-strand breaks (DSBs) are often generated in the genome of all living organisms. To combat DNA damage, organisms have evolved several DSB repair mechanisms, with nonhomologous end-joining (NHEJ) and homologous recombination (HR) being the two most prominent. Although two major pathways have been extensively studied in Arabidopsis, rice and other mammals, the exact functions and differences between the two DSB repair pathways in maize still remain less well understood. Here, we characterized mre11a and rad50, mutants of HR pathway patterns, which showed drastic degradation of the typically persistent embryo and endosperm during kernel development. Loss of MRE11 or RAD50 function led to chromosomal fragments and chromosomal bridges in anaphase. While we also reported that the NHEJ pathway patterns, KU70 and KU80 are associated with developmental growth and genome stability. ku70 and ku80 both displayed an obvious dwarf phenotype. Cytological analysis of the mutants revealed extensive chromosome fragmentation in metaphase and subsequent stages. Loss of KU70/80 function upregulated the expression of genes involved in cell cycle progression and nuclear division. These results provide insights into how NHEJ and HR are mechanistically executed during different plant developmental periods and highlight a competitive and complementary relationship between the NHEJ and HR pathways for DNA double-strand break repair in maize.
The development of maize (Zea mays) kernels is a complex physiological process regulated by numerous genes in a spatially and temporally coordinated manner. However, many regulatory genes involved in this process remain unidentified. In this study, we identified ZmZFP2, a gene encoding a C4HC3-type RING zinc finger protein, which regulates kernel size and weight. This discovery was based on suppression subtractive hybridization from maize endosperm in our previous research. We further investigated the role of ZmZFP2 in regulating kernel development. The zmzfp2-ems mutant exhibited significantly reduced kernel size and weight, accompanied by fewer endosperm cells and altered starch and protein accumulation. CRISPR/Cas9-mediated knockouts and overexpression lines confirmed that ZmZFP2 positively regulates kernel size and weight, with overexpression leading to increased kernel size and weight. Transcriptome analysis revealed that ZmZFP2 regulates genes involved in zeatin biosynthesis, starch metabolism, and protein processing, further supporting its role in kernel development. Additionally, ZmZFP2 was shown to interact with the transcription factor ZmEREB98, implicating it in the gene regulatory network during grain filling. Together, these findings demonstrate that ZmZFP2 is a key regulator of maize kernel size and weight, functioning through its E3 ubiquitin ligase activity and interactions with various metabolic pathways. This study provides novel insights into the genetic regulation of kernel development and presents potential strategies for improving maize yield and quality.
Recent studies have shown that mucilage secretion from aerial roots is an essential feature of modern maize inbred lines, with some retaining the nitrogen-fixing capabilities of ancient landraces. To explore the genetic basis of nitrogen fixation in mucilage and its evolution from teosinte (Zea mays ssp. mexicana) to modern maize, we developed a recombinant inbred line (RIL) population from teosinte and cultivated it under low-nitrogen conditions. Large-scale, multi-year, and multi-environment analyses of RIL-Teo, Doubled Haploid-A (DH-A), Doubled Haploid-B (DH-B), and association populations led to the identification of 15 quantitative trait loci (QTL), 68 quantitative trait nucleotides (QTN), and 59 candidate genes linked to mucilage secretion from aerial roots. Functional verification of the candidate gene ZmAco3, which is associated with mucilage secretion in aerial roots, demonstrated that deletion of this gene resulted in a reduction in mucilage secretion in aerial roots. In addition, most maize inbred lines exhibited stronger mucilage secretion from aerial roots under low-nitrogen conditions than under normal-nitrogen conditions. We categorized mucilage secretion into constitutive and low-nitrogen-inducible types. Through genotype-by-environment interaction studies, 8 QTL, 16 QTN, and 19 candidate genes were identified, revealing the genetic mechanisms underlying mucilage secretion under low-nitrogen conditions. These findings provide a comprehensive genetic analysis of the mucilage-secreting ability of maize aerial roots, contributing to our understanding of nitrogen fixation and offering potential avenues for enhancing nitrogen fixation in modern maize lines. This research advances knowledge of plant nutrient acquisition strategies and has implications for sustainable agricultural practices.
Rapeseed (Brassica napus L.) is a global oil crop. Salinity stress impedes the growth of rapeseed, especially during seed germination. The key genes mediating salinity stress response during seed germination in B. napus remain largely unknown. Here, we found that all six paralogs of C2H2 zinc finger transcription factor WIP DOMAIN PROTEIN 2 (BnaWIP2) showed increased expression during the initial 12 hours of germination, and expression was further enhanced by salinity stress. Under NaCl treatment, knocking out all six BnaWIP2 paralogs in B. napus led to significantly reduced germination, while overexpression of BnaC06.WIP2 promoted germination. Transcriptomic analysis revealed that BnaC06.WIP2 downregulated a series of genes related to abscisic acid (ABA) biosynthesis and signaling, among which BnaA05.NCED3, BnaC04.ABI5-2, BnaA03.EM6, and BnaA05.EM6 were directly repressed by BnaC06.WIP2. Further analysis showed that in germinating seeds, BnaC06.WIP2 was induced by ABA and in turn restrained ABA production, indicating that BnaC06.WIP2 forms a negative feedback loop with ABA to promote seed germination under salinity stress in B. napus. Collectively, these results enhance our understanding of the novel function of BnaWIP2 and provide valuable genetic resources for breeding salinity-tolerant rapeseed varieties.
Photoperiod and temperature are crucial factors that trigger flowering in Brassica juncea (B. juncea). However, the underlying regulatory mechanisms remain poorly understood. The MADS-box transcription factor AGL18 acts as a pivotal repressor of floral transition and functions redundantly with AGL15. In this study, we isolated BjuAGL18-1 from B. juncea and identified two unique transcripts, resulting in two distinct proteins: a full-length protein, BjuAGL18-1L, and a truncated protein, BjuAGL18-1S. Further investigation showed that the two isoforms had similar subcellular localizations but different expression patterns in various plant tissues. Notably, BjuAGL18-1L and BjuAGL18-1S were abundantly induced under short- and long-day photoperiods, respectively. BjuAGL18-1L overexpression in B. juncea and Arabidopsis thaliana (A. thaliana) led to late flowering, whereas BjuAGL18-1S overexpression resulted in early flowering. Yeast two-hybrid, bimolecular fluorescent complementation, and luciferase complementation assays showed that BjuAGL18-1L, but not BjuAGL18-1S (which lacked the EAR motif), interacted with the co-repressor BjuAFR2 and the histone deacetylase BjuHDA9 to form a multiprotein complex. Further analysis indicated that BjuAGL18-1L could also form a complex with BjuAGL15 and bind to the BjuFUL promoter, thus inhibiting its expression. However, BjuAGL18-1S interacted with BjuAGL18-1L to form heterodimers, which attenuated their activities, likely by disrupting their binding to target genes, resulting in accelerated flowering progression. These results suggest that BjuAGL18-1 is involved in photoperiod-induced flowering via different regulatory mechanisms in B. juncea.
The awn can contribute to photosynthesis and carbohydrates, enhancing grain yield in wheat. We mapped QAwn.sxau-5A, a major QTL for awn development in wheat (Triticum aestivum). This QTL was delimited to a 994-kb interval at the B1 locus on chromosome 5A, which included the candidate gene encoding a zinc finger protein (TraesCS5A01G542800) as an awn length inhibitor (ALI). The Ali-A1 allele for the awnless trait showed abundant sequence differences in the promoter regions compared to the ali-A1 allele for the long-awn trait. The results of the swap experiment on the promoters from the two ALI-A1 alleles showed that the two promoters caused a difference in the protein level, indicating the gene was regulated at the transcript level. However, the ali-A1 allele contained an SNP that caused a premature stop codon in its coding region, resulting in a truncated protein compared to the functional Ali-A1 protein. The Ali-A1 protein contained two ethylene-responsive element binding factor-associated amphiphilic repression (EAR) motifs, one at the N terminus (EAR-N) and the other at the C terminus (EAR-C), and they were involved in interactions with the wheat co-repressor protein TOPLESS (TPL1). The ali-A1 protein retained the EAR-N motif but lost the EAR-C motif, resulting in the attenuated ability to interact with TPL1. The tpl1 mutant produced a longer awn compared to the wild type. Ali-A1 repressed the transcription of two downstream genes, TaLRP-A1 and TaARF-B1, involved in endogenous auxin concentrations and auxin responses in wheat. We concluded that the awn length is regulated not only by the ALI-A1 gene at transcript levels but also by Ali-A1 and TPL1 at the protein level in wheat.
Productive tiller number (PTN) is a pivotal trait that significantly influences wheat grain yield. To date, there have been limited reports on the cloning of genes that regulate PTN in wheat. The quantitative trait locus (QTL) QPtn.sau-4B, associated with PTN, was previously mapped between the markers KASP-1 and KASP-3 on the chromosome 4B. Here, utilizing 12 newly developed markers and phenotypic data of PTN from recombinants identified within this interval, QPtn.sau-4B was further fine-mapped to a 2.58 Mb interval on wheat chromosome arm 4BS. Within this interval, we identified 14 genes with high-confidence and 32 genes with low-confidence. A 0.17 Mb deletion fragment contained TraesCS4B03G0092600 and TraesCS4B03G0093100, which were assigned as candidate genes for QPtn.sau-4B. Additionally, QPtn.sau-4B had potential to enhance both PTN and grain yield in wheat. Cloning this locus would support the development of wheat cultivars with increased grain yield.
A later heading date generally leads to higher grain yield in favorable ecological regions; however, grain yield reaches a limit as the heading date exceeds a certain threshold. Ghd7 is the first cloned major gene that regulates heading date, plant height and grain number. Here, we investigated the relationship between Ghd7 and florigen genes Hd3a and RFT1, to determine their roles in regulating heading date and grain number under different photoperiods. Our results revealed that under long-day (LD) conditions, Hd3a acts prior to RFT1 to promote heading while negatively regulating plant height and grain number. In contrast, Ghd7 positively regulates heading date, plant height, and grain number by inhibiting both Hd3a and RFT1. Under short-day (SD) conditions, the functions of Hd3a and RFT1 remain consistent with those under LD conditions, but Ghd7 does not inhibit their expression, resulting in a weaker phenotypic effect compared to Hd3a. Additionally, under both LD and SD conditions, increased Ghd7 expression enhances its inhibitory effect on Hd3a and RFT1, leading to later heading and increased grain number; however, once the heading date exceeds 94 d, grain number no longer increases. Moreover, the gn1a allele increased grain number by 16.5% to 42.5%, while combinations of the elite alleles from Ghd7, Hd3a, RFT1, and Gn1a significantly increased grain number by up to 240.9%. Therefore, we propose a new breeding strategy to optimize the heading date and grain number using the Ghd7Hd3aRFT1gn1a combination of Ghd7, Hd3a, RFT1, and Gn1a under LD conditions, and the Ghd7hd3aRFT1gn1a combination under SD conditions. This strategy improved the yield of the high-quality Northeast variety Kongyu 131 (KY131) by 69.1% in Beijing and 93.7% in Hainan. This strategy will greatly improve the efficiency of north-to-south adaptation in rice, providing theoretical guidance for expanding the geographical adaptability of rice varieties.
Computer simulation permits answering theoretical and applied questions in animal and plant breeding. Blib is a novel multi-module simulation platform, which is able to handle more complicated genetic effects and models than most existing tools. In this study, we describe one major and unified application module of Blib, i.e., ISB (abbreviated from in silico breeding), for simulating the three categories of breeding programs for developing clonal, pure-line and hybrid cultivars in plants. Genetic models on environments and breeding-targeted traits, one or several parental populations, and a number of breeding methods are key elements to run simulation experiments in ISB, which are arranged in three external input files by given formats. Applications of ISB are illustrated by three case studies, representing the three categories of plant breeding programs. Under the condition that 5000 F1 progenies were generated and tested from 50 heterozygous parents, Case study I showed that 50 crosses, each of 100 progenies, made the best balance between genetic achievement and field cost. In Case study II, one optimum breeding method was identified by which the pure lines with high yield and medium maturity could be developed. Case study III investigated the genetic consequence in hybrid breeding from five testers. One tester was identified for the simultaneous improvement in F1 hybrids and inbred lines. In summary, ISB identified a balanced crossing scheme, an optimum pure-line selection method, and an optimized tester in three case studies which are relevant to plant breeding. We believe the prediction by simulation would be highly required in front of the next generation of breeding to be driven by informatics and intelligence.
Excessive accumulation of cadmium (Cd) impairs crop growth by inducing oxidative damage through the generation of reactive oxygen species (ROS). In this study, a biocompatible ferruginated carbon quantum dots (Fe-CQDs) nanozyme is developed to target ROS, thereby reducing oxidative damage and improving the absorption and transfer of Cd ions in wheat. Notably, Fe-CQDs exhibit multi-enzyme activities mimicking peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD), enabling effective neutralization of active species such as hydroxyl radicals (•OH), hydrogen peroxide (H2O2), and superoxide anions (O2•−). Importantly, root application of 10 mg L−1 Fe-CQDs alleviates Cd stress and promotes wheat growth in both hydroponic and soil cultures. Specifically, the levels of O2•−, H2O2, and malondialdehyde (MDA) in leaf tissues decrease, whereas the non-enzyme antioxidant, reduced glutathione (GSH), increases. Cell wall thickness in the Fe-CQDs-treated group is reduced by 42.4% compared with the Cd group. Moreover, Fe-CQDs enhance the expression of genes related to antioxidants, stress resistance, Cd detoxification, and nutrient transport. Transcriptomic and metabolomic analyses show that Fe-CQDs stimulate the production of flavonoids and regulate the activity of metal transporter genes (YSL, ABC, ZIP) to maintain ROS homeostasis. These findings highlight the potential of Fe-CQDs nanozyme platforms in mitigating oxidative damage and enhancing crop growth, offering new insights into the application of nanobiotechnology in agriculture.
With the objective of investigating the basis of phosphorus (P) utilization efficiency (PUE), physiological and morphological traits, two P-efficient and two P-inefficient rapeseed (Brassica napus L.) cultivars were compared at the seedling stage. P-efficient cultivars showed root morphological adaptation, high P uptake activity, and greater phospholipid degradation under low P stress. Improving root morphological adaptation and reducing lipid-P allocation could allow increasing PUE in rapeseed seedlings.
High-density planting increases maize yield but also canopy crowding and stalk lodging. Aiming this contradiction, a wavy canopy was created using interlaced chemical application (IC) of a plant growth retardant at the V14 stage with three densities (60,000, 75,000, and 90,000 plants ha−1, indicated by D1, D2, and D3, respectively) for two seasons. The results showed that the IC-treated wavy canopy featuring both natural height (IC-H) and dwarfed (IC-L) plants, improved light transmission by 8.54%, 8.49%, and 16.49% on average than the corresponding controls (CK) at D1, D2, and D3, respectively. The alleviation of canopy crowding stimulated leaf photosynthesis, sugar availability, basal-internode strength, and decreased plant lodging ratios in both IC-H and IC-L, particularly under higher densities. Meanwhile, the IC populations produced significantly higher yield than CK, with an average increase of 3.38%, 16.70%, and 15.28% at D1, D2, and D3, respectively. Collectively, this study proposed a new wavy canopy strategy using plant growth retardant to simultaneously increase yield performance and lodging resistance, thus offering a sustainable solution for further development of high-density maize production.
Heat stress, a major challenge in modern agriculture due to global warming, significantly reduces crop productivity. To mitigate its adverse effects on maize yield, it is crucial to understand the mechanisms by which heat stress impacts reproductive development. This study investigated the impact of heat stress during the 12th leaf (V12) stage, where silk development begins on grain yield formation, using heat-sensitive and heat-tolerant cultivars. Compared to pollen, silks were found to be more vulnerable to heat stress. Heat stress disrupted hormone balance and inhibited hormone signaling transduction pathways in silks, delaying silk emergence from bracts and reducing fertilization and grain yield. The heat-tolerant cultivar maintained silk growth by activating more response pathways, displaying faster hormone responses, and up-regulating hormones. Taken together, we propose that hormones play an essential role in silk development and later fertilization process.
The unreasonable application of nitrogen fertilizer poses a threat to agricultural productivity and the environment protection in Northeast China. Therefore, accurately assessing crop nitrogen requirements and optimizing fertilization are crucial for sustainable agricultural production. A three-year field experiment was conducted to evaluate the effects of planting density on the critical nitrogen concentration dilution curve (CNDC) for spring maize under drip irrigation and fertilization integration, incorporating two planting densities: D1 (60,000 plants ha−1) and D2 (90,000 plants ha−1) and six nitrogen levels: no nitrogen (N0), 90 (N90), 180 (N180), 270 (N270), 360 (N360), and 450 (N450) kg ha−1. A Bayesian hierarchical model was used to develop CNDC models based on dry matter (DM) and leaf area index (LAI). The results revealed that the critical nitrogen concentration exhibited a power function relationship with both DM and LAI, while planting density had no significant impact on the CNDC parameters. Based on these findings, we propose unified CNDC equations for maize under drip irrigation and fertilization integration: Nc = 4.505DM−0.384 (based on DM) and Nc = 3.793LAI−0.327 (based on LAI). Additionally, the nitrogen nutrition index (NNI), derived from the CNDC, increased with higher nitrogen application rates. The nitrogen nutrition index (NNI) approached 1 with a nitrogen application rate of 180 kg ha−1 under the D1 planting density, while it reached 1 at 270 kg ha−1 under the D2 planting density. The relationship between NNI and relative yield (RY) followed a “linear + plateau” model, with maximum RY observed when the NNI approached 1. Thus, under the condition of drip irrigation and fertilization integration in Northeast China’s spring maize production, the optimal nitrogen application rates for achieving the highest yields were 180 kg ha−1 at a planting density of 60,000 plants ha−1, and 270 kg ha−1 at a density of 90,000 plants ha−1. The CNDC and NNI models developed in this study are valuable tools for diagnosing nitrogen nutrition and guiding precise fertilization practices in maize production under integrated drip irrigation and fertilization systems in Northeast China.
The increase in soil temperature associated with climate change has introduced considerable challenges to crop production. Split nitrogen application (SN) represents a potential strategy for improving crop nitrogen use efficiency and enhancing crop stress resistance. Nevertheless, the precise interaction between soil warming (SW) and SN remains unclear. In order to ascertain the impact of SW on maize growth and whether SN can improve the tolerance of maize to SW, a two-year field experiment was conducted (2022-2023). The aim was to examine the influence of two SW ranges (MT, warming 1.40 °C; HT, warming 2.75 °C) and two nitrogen application methods (N1, one-time basal application of nitrogen fertilizer; N2, one third of base nitrogen fertilizer + two thirds of jointing stage supplemental nitrogen fertilizer) on maize root growth, photosynthetic characteristics, nitrogen use efficiency, and yield. The results demonstrated that SW impeded root growth and precipitated the premature aging of maize leaves following anthesis, particularly in the HT, which led to a notable reduction in maize yield. In comparison to N1, SN has been shown to increase root length density by 8.54%, root bleeding rate by 8.57%, and enhance root distribution ratio in the middle soil layers (20-60 cm). The interaction between SW and SN had a notable impact on maize growth and yield. The SN improved the absorption and utilization efficiency of nitrogen by promoting root development and downward canopy growth, thus improving the tolerance of maize to SW at the later stage of growth. In particular, the N2HT resulted in a 14.51% increase in the photosynthetic rate, a 18.58% increase in nitrogen absorption efficiency, and a 18.32% increase in maize yield compared with N1HT. It can be posited that the SN represents a viable nitrogen management measure with the potential to enhance maize tolerance to soil high-temperature stress.
Long-term straw return with appropriate nitrogen (N) fertilization increases seedcotton yield and fiber quality, and the root system plays an important role in cotton production. However, under straw return and N fertilization, the relationship between the cotton boll-loading capacity of the root system and seedcotton yield remains unclear. In this study, a ten years of long-term field experiment was conducted in a wheat-cotton rotation system. The effects of straw treatments (straw return and straw removal) and N rates (N0, N75, N150 and N300 representing 0, 75, 150 and 300 kg N ha−1, respectively) on cotton root activity, boll-loading capacity of the root system and their relationship to seedcotton yield from 2019 to 2022 were quantified. The results showed that straw return with an appropriate N fertilization of N150 increased root biomass, the rate and components of root-bleeding sap, as well as boll-loading capacity of the root system and seedcotton yield, but decreased the ratio of root to shoot biomass. Furthermore, the root-bleeding sap rate reached the maximum at 30 d post anthesis (DPA) during the peak boll setting stage. However, the contents of nitrate-N, free amino acids and soluble sugar in root-bleeding sap decreased from 10 DPA. Notably, in 2021 and at 30 DPA, the highest contents of nitrate-N (4.8 μg mL−1) and free amino acids (8.3 μg mL−1), as well as soluble sugar (3.4 μg mL−1) were observed at N150 under straw return. The increase in seedcotton yield is positively correlated to the soluble sugar content. Straw return significantly increased the boll-loading capacity of the root system, which first increased but then decreased with the increase in N fertilization. Under straw return with N150, the maximum seecotton yield (3455-4544 kg ha−1) was recorded, and the largest boll loading (49-54 boll 100 g−1) and boll capacity (242-292 g 100 g−1) of root system at the boll opening stage were observed. Therefore, straw return with appropriate N fertilization improved root activity and the boll-loading capacity of the root system, thereby increasing seedcotton yield. This study provides new insights into improving seedcotton yield from the perspective of coordinating cotton growth.
The effects of micro-ridge-furrow planting (MR) on yield and the efficiency of light, water, and thermal resource use in rapeseed were tested in a three-year field experiment comparing MR to conventional flat planting. MR enhanced canopy heterogeneity by altering the leaf angle between plants on ridges and furrows. The heterogeneous canopy environment increased intercepted photosynthetic active radiation, alleviated canopy temperature stress, and optimized canopy humidity, leading to improvements in light-nitrogen matching and net photosynthetic rate. Consequently, dry matter and yield increased by 13.0% and 11.0%, respectively, while radiation, thermal, and precipitation utilization efficiency increased by 12.3%-16.2%. The corresponding improvements in yield and resource use efficiency were attributed to a heterogeneous canopy environment that improved microclimatic conditions.
Herbicide safeners alleviate herbicide toxicity while preserving weed-control efficacy in common buckwheat. A three-year field experiment was performed to measure the effects of quizalofop-P-ethyl (QPE) alone or in combination with gibberellin or brassinolide on soil enzyme activity and yield components in common buckwheat. The herbicide-brassinolide application yielded the greatest increases in soil enzyme activity and yield components without sacrificing weed control efficacy. It is recommended for use in common buckwheat cultivation in the Loess Plateau.
Observing plants across time and diverse scenes is critical in uncovering plant growth patterns. Classic methods often struggle to observe or measure plants against complex backgrounds and at different growth stages. This highlights the need for a universal approach capable of providing realistic plant visualizations across time and scene. Here, we introduce PlantGaussian, an approach for generating realistic three-dimensional (3D) visualization for plants across time and scenes. It marks one of the first applications of 3D Gaussian splatting techniques in plant science, achieving high-quality visualization across species and growth stages. By integrating the Segment Anything Model (SAM) and tracking algorithms, PlantGaussian overcomes the limitations of classic Gaussian reconstruction techniques in complex planting environments. A new mesh partitioning technique is employed to convert Gaussian rendering results into measurable plant meshes, offering a methodology for accurate 3D plant morphology phenotyping. To support this approach, PlantGaussian dataset is developed, which includes images of four crop species captured under multiple conditions and growth stages. Using only plant image sequences as input, it computes high-fidelity plant visualization models and 3D meshes for 3D plant morphological phenotyping. Visualization results indicate that most plant models achieve a Peak Signal-to-Noise Ratio (PSNR) exceeding 25, outperforming all models including the original 3D Gaussian Splatting and enhanced NeRF. The mesh results indicate an average relative error of 4% between the calculated values and the true measurements. As a generic 3D digital plant model, PlantGaussian will support expansion of plant phenotype databases, ecological research, and remote expert consultations.
Rapid, accurate seed classification of soybean varieties is needed for product quality control. We describe a hyperspectral image-based deep-learning model called Dual Attention Feature Fusion Networks (DAFFnet), which sequentially applies 3D Convolutional Neural Network (CNN) and 2D CNN. A fusion attention mechanism module in 2D CNN permits the model to capture local and global feature information by combining with Convolution Block Attention Module (CBAM) and Mobile Vision Transformer (MViT), outperforming conventional hyperspectral image classification models in seed classification.
Nicotiana tabacum (2n = 4x = 48), an economically important non-food crop and a model plant for genetic studies, faces challenges in efficient genotyping of novel germplasm. To address this, we developed the Ta-LD-SC, a 20K SNP Affymetrix Axiom array, based on resequencing data from 150 tobacco accessions. A total of 20,213 unique SNPs were carefully selected, achieving coverage of over 90% of the tobacco genome (Ni
Grain yield variation has been associated to variation in grain number per unit area (GN). It has been shown in the last about 40 years that GN is linearly associated to the spike dry weight (SDW) at anthesis in wheat, fact that has been useful to understand mechanistically potential grain yield. Fruiting efficiency (FE, grains per gram of spike dry weight), the slope between GN and SDW relationship, has been proposed as a possible trait to improve wheat yield potential. The linear relationship between GN and SDW implies a constant increase in GN per unit increase in spike growth and, then a constant FE. However, there are empirical and theoretical elements suggesting that this relationship would not be linear. In this study, we hypothesised and showed that the linearity of the relationship between GN and SDW would be non-linear for extreme values of SDW, implying that the FE would be noticeably reduced at these extreme cases of dry matter allocation to the juvenile spikes. These results have implications for both, genetic and management improvements in grain yield.
