Malania oleifera Chun et S.K. Lee is a woody oil tree species and is rich in nervonic acid, which is associated with brain development. The variation in fatty acid composition and its response to environmental factors in natural populations has not been well studied. A total of 97 mature fruiting individuals were sampled from seven natural populations in Guangxi and Yunnan provinces, China. The fatty acid content (FAC) was 53.85%. Thirteen fatty acid components were identified. Nervonic acid (NVA), octadecenoic acid (OEA) and docosenoic acid (DSA) were the top three, averaging 45.68%, 30.21% and 14.03% of the FAC, respectively; the saturated fatty acid and unsaturated fatty acid contents were 4.82% and 95.18%, respectively. Coefficients of variation were low to moderate (7.64-18.42%) and Shannon-Wiener indices were moderate to high (1.80–2.04) for FAC, NVA, OEA and DSA. Significant variation between populations was observed for all traits, explaining 62.83%, 40.54%, 21.98% and 32.85% of the variance for FAC, NVA, OEA and DSA, respectively. The strong collinearity among traits summarized them into three principal components. FAC was positively correlated with NVA and NVA was negatively correlated with OEA and DSA at both the population and phenotypic levels. This pattern was significantly divergent from those documented in tree species with low NVA yields. The production of FAC and NVA is facilitated by elevated temperatures and reduced relative humidity. These findings provide a foundation for genetic improvement, industrial exploitation, resource management, and sustainable development of this species.

Prunus mume Siebold & Zucc (mei) is a horticulturally important fruit tree that undergoes anthesis in winter. Therefore, its flowering process is challenged by low-temperatures conditions. The transcription factor (TF) MYB21 is pivotal in regulating the flowering process, and particularly functions in petal expansion and filament elongation. However, the regulatory mechanism of PmMYB21 in mei remains unknown. To breed early-flowering cultivars, a deeper understanding of PmMYB21-regulated genes is essential. We employed DNA affinity purification sequencing (Dap-seq) to identify downstream genes bound by PmMYB21. The results revealed the promoter region is the primary binding region of PmMYB21, and the AGTTAGGTARR motif (motif1) is the predominant binding sequence type. Our analysis identified 8533 genes that are potentially bound by PmMYB21 with the motif1 sequence type, within the promoter region. These genes are involved in biological processes critical to flowering. Further refinement of candidate genes was achieved through Weighted Gene Co-expression Network Analysis (WGCNA), which identified the co-expressed genes of PmMYB21 during flowering activity. Integrating Dap-seq and WGCNA data, we narrowed down the candidate gene list to 54, with a focus on 4 MADS-box genes and 2 hormone signaling genes that are crucial to the flowering process under low-temperature conditions. This study offers valuable insights into the molecular underpinnings of PmMYB21’s role in the low-temperature flowering regulation of mei, paving the way for the development of new cultivars adapted to early blooming.

Mercury, a global pollutant with both persistence and high toxicity, has remained a focal point in environmental science research over the past half-century. As a key pathway in the terrestrial mercury cycle, plants actively assimilate gaseous elemental mercury (Hg⁰) through leaf stomata, constituting a critical pathway for terrestrial mercury cycling. The litterfall mercury concentration serves as a biological indicator to quantify vegetation’s mercury interception capacity, providing essential data for global mercury cycle modelling. To investigate this, 15 sampling sites throughout the country were selected, and litterfall was collected monthly for 12 consecutive months to determine the litterfall amount, composition, and leaf mercury dynamics. The results revealed that annual litterfall production ranged from 1.10–8.56 t·hm⁻², with leaf components dominating (45.58%–89.11%). Furthermore, three seasonal litterfall patterns emerged: unimodal, bimodal, and irregular. Regarding mercury, the mercury concentration in leaf litter exhibited a certain seasonal variation trend, with the mercury content in leaves in most areas being higher in autumn and winter. Specifically, the mercury concentration in litterfall showed a significant negative correlation with latitude and a significant positive correlation with air temperature, precipitation, and litterfall amount (p < 0.05). Additionally, the concentration of Hg in dying leaves exhibited some geographical variations.

Malus niedzwetzkyana (MN) is the mother of Rosybloom hybrids, ornamental crabapples with red and purple flowers. We present a high-quality chromosome-scale genome for MN with a size of 672.64 Mb, anchored to 17 chromosomes and with a high BUSCO completeness score of 98.6%, reaching the ‘gold standard’ level. Moreover, our assembly has captured 28 telomeres. A total of 43,813 protein-coding genes was annotated in the MN genome. The assembled high quality provides a valuable opportunity to enhance our understanding of the genetic basis of flower colour and other ornamental traits in crabapples, thereby advancing the field of genetics and breeding.

DNA methylation is important for many developmental processes. Its role in plant’s adaptation to light conditions, however, remains unclear. In this study, we examined the DNA methylomes of Norway spruce ( Picea abies (L.) Karst.) under different light conditions, a combination of both light intensities (10, and 80 µmolm ⁻² s ^− 1 ) and light qualities (with or without far-red light). The result showed that both light intensity and quality affected seedling growth, with the former playing a major role. Both light intensity and quality drove genome-wide methylation changes, which varied among cytosine contexts (CG/CHG vs. CHH). The changes in light quality and intensity yielded a similar number of differentially methylated regions (DMRs), but light intensity was a major contributor in gene expression changes. At the genome-wide level, DNA methylation changes showed no consistent correlation with gene expression alterations. However, a subset of genes—particularly those involved in photosynthesis and circadian rhythms—exhibited coordinated methylation and expression changes, suggesting context-specific regulatory links. The findings indicate that DNA methylation may directly modulate photosynthesis and photoperiod genes and trigger an epigenetic memory, which in turn affects growth of Norway spruce seedlings in response to light conditions. In sum, our study provides a global picture of DNA methylation and gene expression under different light conditions in conifers and thus paves a way for future studies of light-directed gene regulation in plants.