Genome-wide profiling of long noncoding RNAs involved in wheat spike development

Comparative transcriptomes reveal insights into different host responses associated with Fusarium head blight resistance in wheat

Fusarium head blight (FHB) has become a major challenge in global wheat production, causing severe yield losses and exacerbating food safety concerns. In recent years, FHB-related research has focused on understanding resistance mechanisms, identifying genetic markers, and breeding resistant varieties to mitigate the disease's impact on yield and quality. This study comparatively analyzed transcriptome data from six wheat materials with differing levels of resistance following infection by Fusarium graminearum (F. graminearum). The results displayed that a total of 26,767 protein-coding genes and 2,463 long non-coding RNAs (lncRNAs) showed differential expression levels between normal and FHB treatment in at least one material. Among them, 14,130 FHB-responsive protein-coding genes and 913 lncRNAs were identified as material-specific, with functions related to the unique disease resistance mechanisms of the respective materials. Some of these genes have previously been reported to participate in physiological processes related to wheat FHB resistance, including Pm3-like resistance proteins, lactoylglutathione lyase, serine/threonine protein phosphatases, NBS-LRR resistance proteins, glutathione S-transferase (GST), and RPM1 resistance proteins. Additionally, we integrated FHB-responsive genes and lncRNAs with previously reported FHB QTLs, and constructed an interaction regulatory network between pathogen and host through a co-expression network. Based on this network, we identified five genes (one gene encoding glutathione synthetase and four genes encoding glutathione transferase) in the glutathione metabolism pathway, which overlapped with Fhb2 QTLs regions and exhibited material-specific expression patterns. These results will provide new insights into further dissecting of the functional genes and lncRNAs involved in wheat FHB resistance.

Beyond the genome: unveiling tissue-specific non-coding RNAs in clove (Syzygium aromaticum L.)

Clove (Syzygium aromaticum), valued for its role in food preservation and medicine, has recently drawn research interest for its noncoding RNAs (ncRNAs). This study discovers 3274 long noncoding RNAs (lncRNAs) and 2404 circular RNAs (circRNAs) from publicly available RNAseq data. We identified the regulation of 834 genes through miRNA-lncRNA-mRNA network interactions. Additionally, 35 lncRNAs were predicted as precursors for 17 microRNAs (miRNAs), highlighting their role in post-transcriptional regulation. Tissue-specific analysis of circRNAs revealed their interaction with 1047 miRNAs and competing for binding sites on 2382 messenger RNAs (mRNAs). These results underscore their involvement in complex regulatory networks. To support further research and development, we developed SaroNcRDb (http://backlin.cabgrid.res.in/saroncrdb/), a web resource providing detailed insights into the types, chromosomal locations, tissue distributions, and interactions of identified ncRNAs. The findings pave the way for future studies to harness the regulatory roles of ncRNAs in improving Clove's agronomic traits and secondary metabolite production.

Identification and expression analysis of lncRNAs in rice roots (Oryza sativa L.) under elevated CO2 concentration and/or cadmium stress

The gradual rise of CO2 is one of the global climate changes, Cd stress is also a major abiotic stress factor that affects rice (Oryza sativa L.). The rice seedlings were treated under two CO2 concentrations and two CdCl2 concentrations for 7 days (treatments names: 400 ± 20 μmol mol-1 CO2 and 0 μmol L-1 CdCl2 concentrations, AC; 400 ± 20 μmol mol-1 CO2 and 150 μmol L-1 CdCl2 concentrations, Cd; 800 ± 20 μmol mol-1 CO2 and 0 μmol L-1 CdCl2 concentrations, EC; 800 ± 20 μmol mol-1 CO2 and 150 μmol L-1 CdCl2 concentrations, EC + Cd). The lncRNAs informations were analyzed and excavated using high-throughput sequencing, target genes annotation, and qRT-PCR analysis techniques so as to reveal the regulatory mechanism of lncRNAs in rice roots under high CO2 concentrations and/or Cd stress. The results show that: (1) 326 (AC vs Cd), 331 (AC vs EC), 343 (AC vs EC + Cd), 112 (Cd vs EC + Cd) DE-lncRNAs were identified. (2) MAPK signaling pathway-plant (relevant genes Os04g0534166, Os05g0399800 regulated by MSTRG.18576.11, MSTRG.20864.1) and diterpenoid biosynthesis (relevant genes Os12g0491800, Os02g0570400 regulated by MSTRG.8965.1, MSTRG.11509.1) were annotated in AC vs Cd; Under EC relative to AC, DE-lncRNAs were annotated significantly to the flavonoid biosynthesis (relevant genes Os10g0196100, Os10g0320100, Os11g0116300, Os03g0819600 regulated by MSTRG.4612.1, MSTRG.4668.1, MSTRG.6051.1, MSTRG.16669.1); Under composite treatments, relative to AC, DE-lncRNAs were mainly annotated in the plant hormone signal transduction pathway (relevant genes Os03g0180800, Os03g0180900, Os03g0181100 regulated by MSTRG.13776.1). Under combined treatment, elevated CO2 alleviates Cd stress damage by regulating phenylpropanoid biosynthesis through DE-lncRNAs (relevant genes Os09g0419200 regulated by MSTRG. 29,573.1).

The Emerging Role of Non-Coding RNAs (ncRNAs) in Plant Growth, Development, and Stress Response Signaling

Plant species utilize a variety of regulatory mechanisms to ensure sustainable productivity. Within this intricate framework, numerous non-coding RNAs (ncRNAs) play a crucial regulatory role in plant biology, surpassing the essential functions of RNA molecules as messengers, ribosomal, and transfer RNAs. ncRNAs represent an emerging class of regulators, operating directly in the form of small interfering RNAs (siRNAs), microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). These ncRNAs exert control at various levels, including transcription, post-transcription, translation, and epigenetic. Furthermore, they interact with each other, contributing to a variety of biological processes and mechanisms associated with stress resilience. This review primarily concentrates on the recent advancements in plant ncRNAs, delineating their functions in growth and development across various organs such as root, leaf, seed/endosperm, and seed nutrient development. Additionally, this review broadens its scope by examining the role of ncRNAs in response to environmental stresses such as drought, salt, flood, heat, and cold in plants. This compilation offers updated information and insights to guide the characterization of the potential functions of ncRNAs in plant growth, development, and stress resilience in future research.

Deciphering spike architecture formation towards yield improvement in wheat

Wheat is the most widely grown crop globally, providing 20% of the daily consumed calories and protein content around the world. With the growing global population and frequent occurrence of extreme weather caused by climate change, ensuring adequate wheat production is essential for food security. The architecture of the inflorescence plays a crucial role in determining the grain number and size, which is a key trait for improving yield. Recent advances in wheat genomics and gene cloning techniques have improved our understanding of wheat spike development and its applications in breeding practices. Here, we summarize the genetic regulation network governing wheat spike formation, the strategies used for identifying and studying the key factors affecting spike architecture, and the progress made in breeding applications. Additionally, we highlight future directions that will aid in the regulatory mechanistic study of wheat spike determination and targeted breeding for grain yield improvement.

A high-resolution genotype-phenotype map identifies the TaSPL17 controlling grain number and size in wheat

BACKGROUND

Large-scale genotype-phenotype association studies of crop germplasm are important for identifying alleles associated with favorable traits. The limited number of single-nucleotide polymorphisms (SNPs) in most wheat genome-wide association studies (GWASs) restricts their power to detect marker-trait associations. Additionally, only a few genes regulating grain number per spikelet have been reported due to sensitivity of this trait to variable environments.

RESULTS

We perform a large-scale GWAS using approximately 40 million filtered SNPs for 27 spike morphology traits. We detect 132,086 significant marker-trait associations and the associated SNP markers are located within 590 associated peaks. We detect additional and stronger peaks by dividing spike morphology into sub-traits relative to GWAS results of spike morphology traits. We propose that the genetic dissection of spike morphology is a powerful strategy to detect signals for grain yield traits in wheat. The GWAS results reveal that TaSPL17 positively controls grain size and number by regulating spikelet and floret meristem development, which in turn leads to enhanced grain yield per plant. The haplotypes at TaSPL17 indicate geographical differentiation, domestication effects, and breeding selection.

CONCLUSION

Our study provides valuable resources for genetic improvement of spike morphology and a fast-forward genetic solution for candidate gene detection and cloning in wheat.

A framework for improving wheat spike development and yield based on the master regulatory TOR and SnRK gene systems

The low rates of yield gain in wheat breeding programs create an ominous situation for the world. Amongst the reasons for this low rate are issues manifested in spike development that result in too few spikelets, fertile florets, and therefore grains being produced. Phases in spike development are particularly sensitive to stresses of various kinds and origins, and these are partly responsible for the deficiencies in grain production and slow rates of gain in yield. The diversity of developmental processes, stresses, and the large numbers of genes involved make it particularly difficult to prioritize approaches in breeding programs without an overarching, mechanistic framework. Such a framework, introduced here, is provided around the master regulator target of rapamycin and sucrose non-fermenting-1 (SNF1)-related protein kinase complexes and their control by trehalose-6-phosphate and other molecules. Being master regulators of the balance between growth and growth inhibition under stress, these provide genetic targets for creating breakthroughs in yield enhancement. Examples of potential targets and experimental approaches are described.

Transcriptional regulation mechanism of wheat varieties with different nitrogen use efficiencies in response to nitrogen deficiency stress

Background

As one of the microelements, nitrogen play essential roles in cereal production. Although the use of chemical fertilizers has significantly improved the yield of wheat, it has also caused increasingly adverse environmental pollution. Revealing the molecular mechanism manipulating wheat nitrogen use efficiency (NUE), and cultivating wheat germplasms with high nitrogen use efficiency has become important goals for wheat researchers. In this study, we investigated the physiological and transcriptional differences of three wheat cultivars with different NUE under low nitrogen stress.

Results

The results showed that, under low nitrogen conditions, the activities of nitrogen metabolism-related enzymes (GS, NR, GDH), antioxidant enzymes (SOD, POD, CAT) and soluble protein contents of ZM366 (high NUE cultivar) were higher than those of JD8 (low NUE cultivar). The hybrid cultivar of ZM366 and JD8 showed mid-parent or over-parent heterosis. Transcriptome analysis revealed that ‘alanine, aspartate and glutamate metabolism’, ‘terpenoid backbone biosynthesis’ and ‘vitamin B6 metabolism’ pathways play key roles in nitrogen use efficiency in wheat. The significant enhancement of the ‘Calvin cycle’ and ‘photorespiration’ in ZM366 contributed to its higher level of carbon metabolism under low nitrogen stress, which is an important attribute differs from the other two varieties. In addition, the activation of ABA signal transduction and biosynthesis pathways also helps to maintain NUE under low- nitrogen conditions. Moreover, bHLH transcription factors were also found to play a positive role in wheat NUE.

Conclusions

In conclusion, these results enriched our knowledge of the mechanism of wheat NUE, and provided a theoretical basis for improving wheat NUE and breeding new cultivars.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08948-0.

Identification of Long Non-Coding RNAs and Their Target Genes from Mycelium and Primordium in Model Mushroom Schizophyllum commune

Schizophyllum commune has emerged as the most promising model mushroom to study developmental stages (mycelium, primordium), which are two primary processes of fruit body development. Long non-coding RNA (lncRNA) has been proved to participate in fruit development and sex differentiation in fungi. However, potential lncRNAs have not been identified in S. commune from mycelium to primordium developmental stages. In this study, lncRNA-seq was performed in S. commune and 61.56 Gb clean data were generated from mycelium and primordium developmental stages. Furthermore, 191 lncRNAs had been obtained and a total of 49 lncRNAs were classified as differently expressed lncRNAs. Additionally, 26 up-regulated differently expressed lncRNAs and 23 down-regulated between mycelium and primordia libraries were detected. Further, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that differentially expressed lncRNAs target genes from the MAPK pathway, phosphatidylinositol signal, ubiquitin-mediated proteolysis, autophagy, and cell cycle. This study provides a new resource for further research on the relationship between lncRNA and two developmental stages (mycelium, primordium) in S. commune.

Genome-wide identification and characterization of lncRNAs in sunflower endosperm

BACKGROUND

Long non-coding RNAs (lncRNAs), as important regulators, play important roles in plant growth and development. The expression and epigenetic regulation of lncRNAs remain uncharacterized generally in plant seeds, especially in the transient endosperm of the dicotyledons.

RESULTS

In this study, we identified 11,840 candidate lncRNAs in 12 day-after-pollination sunflower endosperm by analyzing RNA-seq data. These lncRNAs were evenly distributed in all chromosomes and had specific features that were distinct from mRNAs including tissue-specificity expression, shorter and fewer exons. By GO analysis of protein coding genes showing strong correlation with the lncRNAs, we revealed that these lncRNAs potential function in many biological processes of seed development. Additionally, genome-wide DNA methylation analyses revealed that the level of DNA methylation at the transcription start sites was negatively correlated with gene expression levels in lncRNAs. Finally, 36 imprinted lncRNAs were identified including 32 maternally expressed lncRNAs and four paternally expressed lncRNAs. In CG and CHG context, DNA methylation levels of imprinted lncRNAs in the upstream and gene body regions were slightly lower in the endosperm than that in embryo tissues, which indicated that the maternal demethylation potentially induce the paternally bias expression of imprinted lncRNAs in sunflower endosperm.

CONCLUSION

Our findings not only identified and characterized lncRNAs on a genome-wide scale in the development of sunflower endosperm, but also provide novel insights into the parental effects and epigenetic regulation of lncRNAs in dicotyledonous seeds.

Identification of long non-coding RNA-microRNA-mRNA regulatory modules and their potential roles in drought stress response in wheat (Triticum aestivum L.)

Drought is one of the most severe abiotic stresses that influence wheat production across the globe. Understanding the molecular regulatory network of wheat in response to drought is of great importance in molecular breeding. Noncoding RNAs influence plant development and resistance to abiotic stresses by regulating gene expression. In this study, whole-transcriptome sequencing was performed on the seedlings of two wheat varieties with contrasting levels of drought tolerance under drought and control conditions to identify long noncoding RNAs (lncRNAs), micro RNAs (miRNAs), and mRNAs related to drought stress and explore the potential lncRNA-miRNA-mRNA regulatory modules in controlling wheat drought stress response. A total of 1515 differentially expressed lncRNAs (DELs), 209 differentially expressed miRNAs (DEMs), and 20462 differentially expressed genes (DEGs) were identified. Of the 20462 DEGs, 1025 were identified as potential wheat drought resistance-related DEGs. Based on the regulatory relationship and expression patterns of DELs, DEMs, and DEGs, 10 DEL-DEM-DEG regulatory modules related to wheat drought stress response were screened, and preliminary expression verification of two important candidate modules was performed. Our results revealed the possible roles of lncRNA-miRNA-mRNA modules in regulatory networks related to drought tolerance and provided useful information as valuable genomic resources in molecular breeding of wheat.

Population transcriptomic analysis identifies the comprehensive lncRNAs landscape of spike in wheat (Triticum aestivum L.)

BACKGROUND

Long noncoding RNAs (lncRNAs) are emerging as the important regulators involving in growth and development as well as stress response in plants. However, current lncRNA studies were mainly performed at the individual level and the significance of it is not well understood in wheat.

RESULTS

In this study, the lncRNA landscape of wheat spike was characterized through analysing a total of 186 spike RNA-seq datasets from 93 wheat genotypes. A total of 35,913 lncRNAs as well as 1,619 lncRNA-mRNA pairs comprised of 443 lncRNAs and 464 mRNAs were obtained. Compared to coding genes, these lncRNAs displayed rather low conservation among wheat and other gramineous species. Based on re-sequencing data, the genetic variations of these lncRNA were investigated and obvious genetic bottleneck were found on them during wheat domestication process. Furthermore, 122 lncRNAs were found to act as ceRNA to regulate endogenous competition. Finally, association and co-localization analysis of the candidate lncRNA-mRNA pairs identified 170 lncRNAs and 167 target mRNAs significantly associated with spike-related traits, including lncRNA.127690.1/TraesCS2A02G518500.1 (PMEI) and lncRNA.104854.1/TraesCS6A02G050300.1 (ATG5) associated with heading date and spike length, respectively.

CONCLUSIONS

This study reported the lncRNA landscape of wheat spike through the population transcriptome analysis, which not only contribute to better understand the wheat evolution from the perspective of lncRNA, but also lay the foundation for revealing roles of lncRNA playing in spike development.

Cryo-Treatment Enhances the Embryogenicity of Mature Somatic Embryos via the lncRNA-miRNA-mRNA Network in White Spruce

In conifers, somatic embryogenesis is uniquely initiated from immature embryos in a narrow time window, which is considerably hindered by the difficulty to induce embryogenic tissue (ET) from other tissues, including mature somatic embryos. In this study, the embryogenic ability of newly induced ET and DNA methylation levels was detected, and whole-transcriptome sequencing analyses were carried out. The results showed that ultra-low temperature treatment significantly enhanced ET induction from mature somatic embryos, with the induction rate from 0.4% to 15.5%, but the underlying mechanisms remain unclear. The newly induced ET showed higher capability in generating mature embryos than the original ET. DNA methylation levels fluctuated during the ET induction process. Here, WGCNA analysis revealed that OPT4, TIP1-1, Chi I, GASA5, GST, LAX3, WRKY7, MYBS3, LRR-RLK, PBL7, and WIN1 genes are involved in stress response and auxin signal transduction. Through co-expression analysis, lncRNAs MSTRG.505746.1, MSTRG.1070680.1, and MSTRG.33602.1 might bind to pre-novel_miR_339 to promote the expression of WRKY7 genes for stress response; LAX3 could be protected by lncRNAs MSTRG.1070680.1 and MSTRG.33602.1 via serving as sponges for novel_miR_495 to initiate auxin signal transduction; lncRNAs MSTRG.505746.1, MSTRG.1070680.1, and MSTRG.33602.1 might serve as sponges for novel_miR_527 to enhance the expression of Chi I for early somatic embryo development. This study provides new insight into the area of stress-enhanced early somatic embryogenesis in conifers, which is also attributable to practical applications.