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Roses (Rosa rugosa) are a famous flower with high ornamental and economic value. But the petals of roses are usually pink and purple, which restricted its application in garden settings. Flavonols and anthocyanins are crucial secondary metabolites related to flower pigmentation in plants. While MYB transcription factors involved in the biosynthesis pathway of anthocyanins have been identified in roses, the functional characterization of the MYB transcription factor regulating flavonol synthesis in R. rugosa remains unexplored. In this study, we isolated and characterized the R2R3-MYB transcription factors RrMYB12 and RrMYB111 involved in regulation of the flavonol biosynthetic pathway from R. rugosa. The bioinformatics analysis indicated that both the RrMYB12 and RrMYB111 belong to the R2R3-MYB subgroup 7 family. qRT-PCR analysis showed that RrMYB12 and RrMYB111 were expressed at low levels in roots and flowers. And transactivation activity assay indicated that RrMYB12 and RrMYB111 were transcriptional activators. The overexpression of RrMYB12 and RrMYB111 in tobacco resulted in an elevation of flavonol levels and a reduction in anthocyanin levels in flowers due to the upregulation of structural genes involved in flavonol synthesis, while the biosynthesis genes for the anthocyanin pathway were significantly downregulated. The transient reporter assay demonstrated that RrMYB12 exhibited strong activation of the promoters of RrCHS and RrFLS in Nicotiana benthamiana leaves following transient transformation. Furthermore, it was observed that RrMYBs displayed binding specificity to the promoter region of CsFLS.The functional characterization of the flavonol synthesis regulatory factors RrMYB12 and RrMYB111 offers a deeper understanding of the regulatory mechanism governing flavonol biosynthesis in roses, while also presenting an effective tool for genetic manipulation aimed at creating new varieties. [ABSTRACT FROM AUTHOR]

Unlike that of other crops, the growth of tea plants can be promoted by aluminum, but its regulation mechanism remains unclear. Some endophytes can also promote growth of plant hosts. In this paper, tea roots treated with aluminum were used to study the growth-promoting traits and aluminum tolerance of endophytes. Meta-16S rDNA analysis revealed that Burkholderia was enriched in tea roots after aluminum treatment, and it was the dominant strain for hydroponic tea roots and field tea roots. Actinomycetes constituted the dominant strains in hydroponic tea seedlings treated with aluminum. Sixteen endophytic bacteria, including 12 strains of Firmicutes , 2 strains of Proteobacteria and 2 strains of Actinomycetes , were isolated and identified from hydroponic tea roots treated with different aluminum concentrations. Growth-promoting activity analysis showed that the isolated endophytic bacteria all had more than one plant growth-promoting trait. Among them, B4 (Bacillus nealsonii), B8 (Brevibacterium frigoritolerans) and A2 (Nocardia nova) bacteria each had three growth-promoting traits. Aluminum tolerance ability analysis indicated that endophyte A1 (Leifsonia shinshuensis) had the strongest aluminum tolerance ability, up to 200 mg l−1 aluminum. Plant–bacteria interactions showed that endophytes A1, A2 and B4 and their synthetic community all had a growth-promoting effect on the growth of wheat lateral roots. Moreover, endophytes A1 and B4 alleviated aluminum stress in wheat. Endophyte A1 also promoted the growth of tea cuttings, especially lateral roots, with/without aluminum. Taken together, aluminum enhanced the distribution of aluminum-tolerant and growth-promoting bacteria, thereby promoting the growth of tea roots. This study provides a new aspect for research on the mechanism by which aluminum promotes tea plant growth. [ABSTRACT FROM AUTHOR]

In acidic soil conditions, aluminium (Al) limits crop growth and yields but benefits the growth of tea plants. Flavonols are suggested to form complexes with Al, enhancing Al accumulation in tea plants. The role of flavonols in promoting lateral root formation under Al stress remains unclear. Here, we identified a 7-rhamnosylated type of flavonol glycosides (F2-type) crucial for this process in tea roots. Al treatment significantly stimulated lateral root initiation and bud germination in tea plants, enhancing flavonol glycoside accumulation, particularly the F2-type. Most genes in the flavonol biosynthetic pathway were upregulated post-Al treatment, including CsUGT89AC2/3 genes, which catalyze F2-type flavonol glycosides synthesis in vitro and in vivo. Overexpression of CsUGT89AC2/3 increased lateral root occurrence, flavonol glycoside accumulation and expression of biosynthetic pathway genes in tea roots. Kaempferol treatment activated flavonol pathway genes and stimulated lateral root growth. Al treatment, kaempferol treatment and CsUGT89AC3 overexpression accelerated auxin accumulation and expression of auxin-related genes. Therefore, Al stimulates flavonol biosynthetic pathway gene expression, regulates F2-type flavonol biosynthesis, and influences auxin homoeostasis, promoting lateral root formation in tea plants. These findings lay the foundation for further investigation into the mechanisms underlying the Al-mediated promotion of lateral root initiation in tea plants., (© 2025 John Wiley & Sons Ltd.)