Sapindus mukorossi is an important woody oil plant and clean energy tree species in China. This study employed the Biomod2 ensemble model to simulate the potentially suitable distribution areas of S. mukorossi across different periods and to analyze the dominant environmental factors limiting its distribution. The aim was to provide a theoretical basis for the cultivation zoning of S. mukorossi.

Geographical distribution data of S. mukorossi for the current period were obtained through database queries, literature retrieval, and field surveys. R language and ArcGIS software were used to screen the geographical distribution points. Variance inflation factor (VIF) and Pearson correlation coefficient tests were applied to screen climate, soil, and topographic factors. Model accuracy was evaluated using the true skill statistic (TSS), Kappa coefficient, and the area under the receiver operating characteristic curve (AUC). The dominant environmental factors constraining the geographical distribution of S. mukorossi were identified using the jackknife test combined with environmental factor contribution rates. Species distribution models within the Biomod2 package were integrated using a weighted mean approach to build an ensemble model. This model was used to simulate the potential distribution areas of S. mukorossi during the last glacial maximum (LGM), mid-holocene, current period (1970-2000s), and Future period (2041-2060s). The natural breaks method was used to classify the suitability levels of the distribution areas.

The ensemble model demonstrated higher accuracy and better performance than all individual models. The dominant environmental factors constraining the geographical distribution of S. mukorossi were: mean precipitation of the warmest quarter (350-1 650 mm), isothermality (5%-53%), maximum temperature of the warmest month (18-37 ℃), and Mean Temperature of Wettest Quarter (15-32 ℃). From the LGM to the Mid-Holocene, S. mukorossi was mainly distributed on the Tibetan Plateau. Since the Mid-Holocene, the area of its potentially suitable distribution has continuously expanded. Under future climate scenarios, the potentially suitable distribution area for S. mukorossi is projected to continue expanding.

The Tibetan Plateau may have served as a glacial refuge for S. mukorossi. The dominant environmental factors influencing its geographical distribution are temperature, precipitation, and isothermality during its growth and development period. The species is most suitable for distribution in subtropical monsoon humid climate zones. Under different future climate scenarios, the potentially suitable distribution area of S. mukorossi shows a trend of fragmented expansion. The findings of this study provide guidance for promoting the cultivation of S. mukorossi plantation resources and the development of its related industries.

This study was conducted to identify and bioinformatically analysis of proanthocyanidin (PA, condensed tannin) synthesis genes of Quercus glauca, which could lay a molecular foundation for development and utilization of Q. glauca fruit resources and variety improvement.

Based on published whole genome sequencing data of Q. glauca, the PA synthesis genes were identified, and the protein sequence, chromosome location, interspecific collinearity, gene structure and phylogenetic relationship were analyzed using bioinformatic methods.

The 11 PA synthesis genes of Q. glauca contain 42 family members, which are distributed on 11 chromosomes; The physical and chemical characters of protein are different among QgPAL, QgC4H, Qg4CL and QgF3′H gene family members with multiple copies; Qg4CL8, Qg4CL14, Qg4CL17, QgF3’H2 and QgC4H4 proteins had 2-3 transmembrane regions, suggesting that these proteins might play an important role in intracellular and extracellular signal transduction; The members of the gene family were relatively conservative in evolution in genus Quercus, through the ancient whole genome duplication, tandem duplication and fragment duplication expansion of genus Quercus; QgPAL2-6 and Qg4CL15 genes clustered in the same branch as AtPAL1-2 and At4CL3 involved in PA biosynthesis in Arabidopsis thaliana, respectively, which might play an important role in PA biosynthesis; The Qg4CL gene family had evolved into new branches in the phylogenetic tree, in which family members exhibit diversity of gene structure, and mutation of amino acid sites occurs in the highly conservative motif of 4CL gene. It was speculated that these genes may be preserved due to the evolution of new functions.

The PA synthesis genes of Q. glauca expand through various replication methods. The replication genes are relatively conservative in the Quercus, and show a diversity of physicochemical properties, protein structures and evolutionary patterns in Q. glauca. The characteristics and evolutionary patterns of proanthocyanidin synthesis genes are analyzed by bioinformatics methods, which lay the molecular foundation for an in-depth analysis of the mechanism of tannin synthesis in genus Quercus.