Madhuca longifolia (M. longifolia), a tropical tree valued for its medicinal, nutritional, and industrial applications, exhibits severe sensitivity to low-temperature stress in subtropical regions, particularly during seedling establishment. To address this challenge, this study systematically identified 109 NAC genes in M. longifolia and characterized their functional roles in cold adaptation via multi-omics analyses. All NAC proteins were hydrophilic. Key members (e.g., MlNAC026, MlNAC077, MlNAC076) were localized in the nucleus. Phylogenetic analysis grouped them with ANAC072 (RD26), a homolog involved in leaf senescence and ABA-regulated cold stress responses. The NAC family expanded primarily through segmental duplication. And low Ka/Ks ratios (<1) indicated purifying selection. Promoter analysis highlighted the prevalence of dehydration-responsive DRE and LTR cis-acting elements. Transcriptomic profiling under cold stress identified five continuous differentially expressed genes (MlNAC026, MlNAC040, MlNAC059, MlNAC077, and MlNAC078) linked to regulatory functions. Homology modeling predicted 3D structures of cold-responsive NAC proteins, and STRING network analysis indicated independent regulatory mechanisms due to the absence of prominent interaction nodes. These findings advance our understanding of NAC-mediated cold tolerance and offer genetic targets to enhance M. longifolia resilience in subtropical climates.

Snags are highly important for many wildlife species and ecological processes. In this study, we analyzed the relationship between snags and topographic factors in a secondary forest plot in South China. Data on 544 snags were collected and recorded from 236 subplots in a permanent plot (400 subplots). The frequency of Castanopsis carlesii and Schima superba was higher than that of other species. The snags derived mostly from saplings and small trees, and the presence of snags decreased as the DBH and height increased after 25 years of logging. The snags displayed an aggregated spatial pattern distribution, which was strongly correlated with elevation, slope steepness, and slope aspect (p < 0.05), as revealed by canonical correspondence analysis (CCA); however, the response of snags varied with topographic factors. Our results demonstrate that topography is an important factor that affects the snag spatial distribution in the subtropical secondary forest. These results will further improve our understanding of forest dynamics and provide guidance for forest management and biodiversity conservation.

The cellulose synthase gene superfamily encompasses two major groups, CesA and Csl, which are vital for synthesizing cellulose and hemicellulose in plant cell walls and fundamental to plant growth and developmental regulation. Madhuca pasquieri is a rare tree with high timber value. Currently, there is no relevant report on the identification and characterization of the CesA/Csl gene family in M. pasquieri. In this study, based on the high-quality genome of M. pasquieri, 47 members of the CesA/Csl superfamily were identified and classified into seven subfamilies, including CesA, CslA, CslB, CslC, CslD, CslE and CslG. Cis-acting elements were identified via analysis of the 2000 bp upstream sequences of MpCesA, suggesting extensive involvement in biotic and abiotic stress regulation. Based on the transcriptome data of five growth periods, the expression of the CesA/Csl family was analyzed. Combined with phylogenetic information, it is inferred that MpCesA4/7b/7a/8b may regulate the secondary wall, while MpCesA1/3b/6b may regulate the primary wall. Protein–protein interaction showed that MpCesA4/7b/8a were in the core site. Finally, we constructed the cellulose synthase complex (MpCesA4/7b/8b) model using AlphaFold3, which suggests that MpCesA4/7b/8b may form a complex on the plasma membrane to carry out cellulose synthesis. This study has a limitation in that the complex and its expression lack experimental validation, and only data analysis is provided as a reference, offering some directions for future research. In summary, the systematic characterization of the MpCesA/Csl gene family provides important insights into cell wall formation, genetic enhancement, and future biotechnological applications of this species.