In rubber tree, bark is one of important agricultural and biological organs. However, the molecular mechanism involved in the bark formation and development in rubber tree remains largely unknown, which is at least partially due to lack of bark transcriptomic and genomic information. Therefore, it is necessary to carried out high-throughput transcriptome sequencing of rubber tree bark to generate enormous transcript sequences for the functional characterization and molecular marker development.

Powdery mildew, caused by Blumeria graminearum f.sp. tritici (Bgt), is one of the most severe fungal diseases of wheat. The exploration and utilization of new gene resources is the most effective approach for the powdery mildew control. We report the cloning and functional analysis of two wheat LRR-RLKs from T. aestivum c.v. Prins- T. timopheevii introgression line IGV1-465, named TaRLK1 and TaRLK2, which play positive roles in regulating powdery mildew resistance in wheat. The two LRR-RLKs contain an ORF of 3,045 nucleotides, encoding a peptide of 1014 amino acids, with seven amino acids difference. Their predicted proteins possess a signal peptide, several LRRs, a trans-membrane domain, and a Ser/Thr protein kinase domain. In response to Bgt infection, the TaRLK1/2 expression is up-regulated in a developmental-stage-dependent manner. Single-cell transient over-expression and gene-silencing assays indicate that both genes positively regulate the resistance to mixed Bgt inoculums. Transgenic lines over-expressing TaRLK1 or TaRLK2 in a moderate powdery mildew susceptible wheat variety Yangmai 158 led to significantly enhanced powdery mildew resistance. Exogenous applied salicylic acid (SA) or hydrogen peroxide (H2O2) induced the expression of both genes, and H2O2 had a higher accumulation at the Bgt penetration sites in RLK over-expression transgenic plants, suggesting a possible involvement of SA and altered ROS homeostasis in the defense response to Bgt infection. The two LRR-RLKs are located in the long arm of wheat chromosome 2B, in which the powdery mildew resistance gene Pm6 is located, but in different regions. Two members of TaRLK family were cloned from IGV1-465. TaRLK1 and TaRLK2 contribute to powdery mildew resistance of wheat, providing new resistance gene resources for wheat breeding.

Plant PP2C genes are crucial for various biological processes. To elucidate the potential functions of these genes in rubber tree (Hevea brasiliensis), we conducted a comprehensive analysis of these genes using bioinformatics methods. The 60 members of the PP2C family in rubber tree were identified and categorized into 13 subfamilies. The PP2C proteins were conserved across different plant species. The results revealed that the HbPP2C genes contained multiple elements responsive to phytohormones and stresses in their promoters, suggesting their involvement in these pathways. Expression analysis indicated that 40 HbPP2C genes exhibited the highest expression levels in branches and the lowest expression in latex. Additionally, the expression of A subfamily members significantly increased in response to abscisic acid, drought, and glyphosate treatments, whereas the expression of A, B, D, and F1 subfamily members notably increased under temperature stress conditions. Furthermore, the expression of A and F1 subfamily members was significantly upregulated upon powdery mildew infection, with the expression of the HbPP2C6 gene displaying a remarkable 33-fold increase. These findings suggest that different HbPP2C subgroups may have distinct roles in the regulation of phytohormones and the response to abiotic and biotic stresses in rubber tree. This study provides a valuable reference for further investigations into the functions of the HbPP2C gene family in rubber tree.

Taraxacum kok‐saghyz (TKS) synthesises natural rubber (NR) and inulin using sucrose as a carbon source. However, molecular mechanisms regulating inulin and NR accumulation remain largely unclear. Here, we report the generation of double‐gene homozygous mutants, 1‐sst1‐fft , by simultaneously knocking out two key genes responsible for inulin biosynthesis ( Tk1‐SST and Tk1‐FFT ) using CRISPR/Cas9 technology. The 1‐sst1‐fft mutants exhibited significant increases in rosette leaf number, flower number, leaf area, whole‐plant biomass and seed set. Moreover, inulin biosynthesis was abolished in 1‐sst1‐fft , leading to significant changes in sugar composition, particularly a marked increase in sucrose levels. Notably, NR accumulation more than doubled, with no significant change in molecular weight and most terpenoid accumulation also increased in 1‐sst1‐fft , both being positively correlated with sucrose levels. For the first time, this study reports the generation of an inulin synthesis‐deficient mutant in plants, emphasising the essential roles of 1‐SST and 1‐FFT in regulating carbon partitioning and, consequently, modulating important traits and metabolite accumulation. Transcriptomic analysis revealed fundamental genes involved in sucrose metabolism, sugar signalling and transport and NR elongation were significantly upregulated in 1‐sst1‐fft ; accompanied by enhanced enzymatic activities of sucrose–phosphate synthase and invertase. These findings demonstrate that blocking inulin biosynthesis in 1‐sst1‐fft redirects sucrose towards NR biosynthesis, highlighting the dual role of sucrose as both a carbon source and signalling molecule in modulating plant growth and development and metabolite synthesis. Our study provides a successful approach to enhancing NR accumulation by modifying carbon allocation in TKS, offering novel insights into high‐yield breeding strategies.