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As the most abundant form of methylation modification in messenger RNA (mRNA), the distribution of N6‐methyladenosine (m6A) has been preliminarily revealed in herbaceous plants under salt stress, but its function and mechanism in woody plants were still unknown. Here, we showed that global m6A levels increased during poplar response to salt stress. Methylated RNA immunoprecipitation sequencing (MeRIP‐seq) revealed that m6A significantly enriched in the coding sequence region and 3′‐untranslated regions in poplar, by recognising the conserved motifs, AGACU, GGACA and UGUAG. A large number of differential m6A transcripts have been identified, and some have been proved involving in salt response and plant growth and development. Further combined analysis of MeRIP‐seq and RNA‐seq revealed that the m6A hypermethylated and enrich in the CDS region preferred to positively regulate expression abundance. Writer inhibitor, 3‐deazaneplanocin A treatment increased the sensitivity of poplar to salt stress by reducing mRNA stability to regulate the expression of salt‐responsive transcripts PagMYB48, PagGT2, PagNAC2, PagGPX8 and PagARF2. Furthermore, we verified that the methyltransferase PagFIP37 plays a positively role in the response of poplar to salt stress, overexpressed lines have stronger salt tolerance, while RNAi lines were more sensitive to salt, which relied on regulating mRNA stability in an m6A manner of salt‐responsive transcripts PagMYB48, PagGT2, PagNAC2, PagGPX8 and PagARF2. Collectively, these results revealed the regulatory role of m6A methylation in poplar response to salt stress, and revealed the importance and mechanism of m6A methylation in the response of woody plants to salt stress for the first time. Summary statement: We revealed the regulatory role of m6A methylation in poplar response to salt stress, and revealed the importance and mechanism of m6A methylation in the response of woody plants to salt stress for the first time. [ABSTRACT FROM AUTHOR]

Summary: Wood formation, intricately linked to the carbohydrate metabolism pathway, underpins the capacity of trees to produce renewable resources and offer vital ecosystem services. Despite their importance, the genetic regulatory mechanisms governing wood fibre properties in woody plants remain enigmatic. In this study, we identified a pivotal module comprising 158 high‐priority core genes implicated in wood formation, drawing upon tissue‐specific gene expression profiles from 22 Populus samples. Initially, we conducted a module‐based association study in a natural population of 435 Populus tomentosa, pinpointing PtoDPb1 as the key gene contributing to wood formation through the carbohydrate metabolic pathway. Overexpressing PtoDPb1 led to a 52.91% surge in cellulose content, a reduction of 14.34% in fibre length, and an increment of 38.21% in fibre width in transgenic poplar. Moreover, by integrating co‐expression patterns, RNA‐sequencing analysis, and expression quantitative trait nucleotide (eQTN) mapping, we identified a PtoDPb1‐mediated genetic module of PtoWAK106‐PtoDPb1‐PtoE2Fa‐PtoUGT74E2 responsible for fibre properties in Populus. Additionally, we discovered the two PtoDPb1 haplotypes that influenced protein interaction efficiency between PtoE2Fa‐PtoDPb1 and PtoDPb1‐PtoWAK106, respectively. The transcriptional activation activity of the PtoE2Fa‐PtoDPb1 haplotype‐1 complex on the promoter of PtoUGT74E2 surpassed that of the PtoE2Fa‐PtoDPb1 haplotype‐2 complex. Taken together, our findings provide novel insights into the regulatory mechanisms of fibre properties in Populus, orchestrated by PtoDPb1, and offer a practical module for expediting genetic breeding in woody plants via molecular design. [ABSTRACT FROM AUTHOR]

Salt stress is a universal abiotic stress that severely affects plant growth and development. Understanding the mechanisms of Maclura tricuspidate's adaptation to salt stress is crucial for developing salt-tolerant plant varieties. This article discusses the integration of physiology, transcriptome, and metabolome to investigate the mechanism of salt adaptation in M. tricuspidata under salt stress conditions. Overall, the antioxidant enzyme system (SOD and POD) of M. tricuspidata exhibited higher activities compared with the control, while the content of soluble sugar and concentrations of chlorophyll a and b were maintained during salt stress. KEGG analysis revealed that deferentially expressed genes were primarily involved in plant hormone signal transduction, phenylpropanoid and flavonoid biosynthesis, alkaloids, and MAPK signaling pathways. Differential metabolites were enriched in amino acid metabolism, the biosynthesis of plant hormones, butanoate, and 2-oxocarboxylic acid metabolism. Interestingly, glycine, serine, and threonine metabolism were found to be important both in the metabolome and transcriptome–metabolome correlation analyses, suggesting their essential role in enhancing the salt tolerance of M. tricuspidata. Collectively, our study not only revealed the molecular mechanism of salt tolerance in M. tricuspidata, but also provided a new perspective for future salt-tolerant breeding and improvement in salt land for this species. [ABSTRACT FROM AUTHOR]

As a medicinal tree species, ginkgo (Ginkgo biloba L.) and terpene trilactones (TTLs) extracted from its leaves are the main pharmacologic activity constituents and important economic indicators of its value. The accumulation of TTLs is known to be affected by environmental stress, while the regulatory mechanism of environmental response mediated by microRNAs (miRNAs) at the post-transcriptional levels remains unclear. Here, we focused on grafted ginkgo grown in northwestern, southwestern, and eastern-central China and integrally analyzed RNA-seq and small RNA-seq high-throughput sequencing data as well as metabolomics data from leaf samples of ginkgo clones grown in natural environments. The content of bilobalide was highest among detected TTLs, and there was more than a twofold variation in the accumulation of bilobalide between growth conditions. Meanwhile, transcriptome analysis found significant differences in the expression of 19 TTL-related genes among ginkgo leaves from different environments. Small RNA sequencing and analysis showed that 62 of the 521 miRNAs identified were differentially expressed among different samples, especially the expression of miRN50, miR169h/i, and miR169e was susceptible to environmental changes. Further, we found that transcription factors (ERF, MYB, C3H, HD-ZIP, HSF, and NAC) and miRNAs (miR319e/f, miRN2, miRN54, miR157, miR185, and miRN188) could activate or inhibit the expression of TTL-related genes to participate in the regulation of terpene trilactones biosynthesis in ginkgo leaves by weighted gene co-regulatory network analysis. Our findings provide new insights into the understanding of the regulatory mechanism of TTL biosynthesis but also lay the foundation for ginkgo leaves' medicinal value improvement under global change. [ABSTRACT FROM AUTHOR]

Pollination dynamics was studied in a first-generation Platycladus orientalis (L.) Franco seed orchard with pedigree reconstruction using eight nuclear and four chloroplast SSRs. The pedigree reconstruction assigned 371 of 448 studied seeds to one of the orchard's 192 candidate male parents and showed a high level of outcrossing and pollen contamination in the orchard's seed crop. While the orchard's seed population showed greater allelic richness compared with the parental population, a few alleles present in the parental population were missing in the seed crop. Additionally, we detected no significant correlation between male reproductive energy (pollen yield) and male reproductive success; however, uneven parental contribution was also observed. Pollen management practices were recommended to ensure the maintenance of genetic diversity in the seed crops and increase in genetic gain. Key words: seed orchard, pedigree reconstruction, gametic contribution, pollen contamination, selfing rate, genetic diversity. La dynamique de la pollinisation a ete etudiee dans un verger a graines de premiere generation de Platycladus orientalis (L.) Franco a l'aide de la reconstruction de pedigree se basant sur huit marqueurs SSRs de type nucleaire et quatre de type chloroplastique. La reconstruction de pedigree a permis d'assigner 371 des 448 graines etudiees a l'un des 192 parents males candidats du verger, tout en indiquant un niveau eleve d'exogamie et de contamination pollinique parmi la recolte de graines du verger. Alors que la population de graines du verger avait une richesse allelique plus elevee comparativement a la population parentale, certains des alleles presents dans la population parentale etaient absents des graines recoltees. De plus, une correlation significative a ete detectee entre l'energie des males consacree a la reproduction (production de pollen) et leur succes reproducteur; toutefois, des contributions parentales inegales ont aussi ete observees. Des pratiques de gestion du pollen sont recommandees afin d'assurer le maintien de la diversite genetique des recoltes de graines et d'augmenter le gain genetique. [Traduit par la Redaction] Mots-cles: verger a graines, reconstruction de pedigree, contribution gametique, contamination pollinique, taux d'autofecondation, diversite genetique., Introduction Platycladus orientalis (L.) Franco, the only member of the family Cupressaceae, is native to northwestern China, Korea, and the Russian far east (Cheng and Fu 1978). As a pioneer [...]