Trehalose and some members of the trehalose 6-phosphate synthase (TPS) gene family play important roles in response to abiotic stress in plants. However, no studies investigating the TPS gene in rose have been reported. In this study, the trehalose content in the stems and roots of Rosa chinensis was significantly increased under heat stress, and nine TPS family members were identified from the genome of R. chinensis. The R. chinensis TPS (RcTPS) family members could be divided into two subfamilies based on the structure and phylogenetic analysis. In this study, we found that segmental duplications contributed to the expansion of the RcTPS gene family, and the type II subfamily gene pairs RcTPS9–RcTPS10 and RcTPS7a–RcTPS7b were created by segmental duplication events. The type I subfamily RcTPS members contained 17 exons in the protein-coding region, whereas type II subfamily members only had 3 or 4 exons. Most cis-acting elements in the promoters of RcTPS members were related to plant hormones, especially ABA hormones. A phylogenetic tree of 78 TPS homologous amino acids from R. chinensis and another 7 species was constructed, which could be divided into 5 clades, and purity selection was observed to be the dominant evolutionary selection pressure. Under heat stress, except for RcTPS1b, the other eight RcTPS members were upregulated in the roots, stems, orleaves. The type II subfamily members RcTPS7a and RcTPS7b showed significantly high expression patterns in response to heat stress in all three tissues. Our findings indicate that RcTPS7a and RcTPS7b may play important roles in the heat tolerance of R. chinensis and are helpful for future functional studies of the two RcTPS members during heat stress.

The mechanism through which Hydrangea macrophylla are able to change color has been the focus of investigation for many studies. However, the molecular mechanism involved in the complexation of aluminum ions and anthocyanins to regulate the color change remains unclear. Here, the color-changing mechanism was investigated in Hydrangea macrophylla plants under aluminum stress using proteome and transcriptome sequencing methods. Catalase, peroxidase, superoxide dismutase, 3-O-delphinidin and Al³⁺ contents in sepal were significantly upregulated upon Al³⁺ treatment. Moreover, 1628 differentially expressed genes and 448 differentially expressed proteins were identified between the treated and untreated conditions. GO and KEGG enrichment analyses revealed that the differentially expressed genes and differentially expressed proteins were enriched in categories related to the cell wall, peroxidase activity, and peroxisome pathways. Importantly, eight genes involved in anthocyanin biosynthesis were significantly downregulated at the transcript and protein levels under aluminum stress. These results suggest that aluminum ions induce expression changes of related key genes, which regulate the hydrangea’s flower color. Overall, this study provides a valuable reference for the molecular mechanism relating to the color change and adaptation of Hydrangea macrophylla in response to aluminum stress.

Global warming-induced heat stress increasingly threatens the ornamental quality and productivity of roses. Previous studies have indicated that trehalose and the trehalose-6-phosphate synthase (TPS) gene family regulate plants' stress resistance, yet their roles in thermotolerance in rose remain uncharacterized. We previously identified RcTPS7b as a putative heat-responsive gene in Rosa chinensis 'Slater's Crimson China'. This study aimed to investigate whether exogenous trehalose enhances heat tolerance in rose, and elucidate the functional role of RcTPS7b in heat stress regulation. The results showed that exogenous application of 5 mmol/L trehalose significantly enhanced rose's heat tolerance by reducing the heat damage index, elevating superoxide dismutase (SOD) activity, and preserving the efficiency of Photosystem II (PSII). Overexpression of RcTPS7b in Arabidopsis thaliana enhanced the heat tolerance and antioxidant enzyme activities in transgenic plants, concomitant with upregulated expression of heat-resistant genes such as HEAT SHOCK FACTOR/PROTEIN (AtHSF/P). Furthermore, tobacco rattle virus-induced silencing of RcTPS7b in R. chinensis compromised thermotolerance and induced severe oxidative damage. Transient overexpression of RcTPS7b in rose petals reduced heat damage and maintained petal integrity through redox homeostasis under high temperature treatment. Collectively, this study demonstrates that exogenous trehalose potentiates RcTPS7b expression to enhance thermotolerance, revealing the trehalose metabolism pathway's pivotal role in heat stress regulation in R. chinensis, and will be helpful for the molecular breeding of heat tolerance in R. chinensis.

The main goal set by researchers in this article was to gather knowledge on the structure of the basic biometric features of tree-rings of two species of poplars, belonging to different sections of Aegeiros – Populus xcanadensis and Tacamahaca – Populus maximowiczii, and to define and understand the correlation between weather and annual increment. A supplementary objective of the article was to determine pointer years of species found in individual populations. Our research used the standard methodology applied in dendroclimatology. In the analysis of correlation of the tree species studied, stronger statistically significant relationships were obtained in terms of precipitation-increment compared to temperature-increment. The annual increment in the Canadian poplar was enhanced by wet autumns and winters, especially by the rainfall in Oct and Dec in the previous year, as well as in Apr of this year. The tested Maximovich's poplars tested preferred rainfall during spring going into summer, especially in June of this year. Seven specific pointer years were determined for the Canadian poplar, comprising 4 positive (1987, 2008, 2010, 2012) and 3 negative years (2000, 2011, 2014). For P. maximowiczii, 11 pointer years were determined, i.e. 5 positive years (1987, 1991, 1999, 2009, 2012) and 6 negative (1984, 2000, 2002, 2010, 2013, 2015). In the pointer years, monthly sums of atmospheric precipitation and the average monthly air temperatures differed from the multi-year period. In the process of forming the secondary growth of the wood of the studied poplar species, the predominant role was played by atmospheric precipitation.