Plant respiratory burst oxidase homolog (rboh) genes appear to play crucial roles in plant development, defense reactions and hormone signaling. In this study, a total of seven rboh genes from grape were identified and characterized. Genomic structure and predicted protein sequence analysis indicated that the sequences of plant rboh genes are highly conserved. Synteny analysis demonstrated that several Vvrboh genes were found in corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of the respective lineages. The expression pattern of Vvrboh genes in different tissues was assessed by qRT-PCR and two were constitutively expressed in all tissues tested. The expression profiles were similarly analyzed following exposure to various stresses and hormone treatments. It was shown that the expression levels of VvrbohA, VvrbohB and VvrbohC1 were significantly increased by salt and drought treatments. VvrbohB, VvrbohC2, and VvrbohD exhibited a dramatic up-regulation after powdery mildew (Uncinula necator (Schw.) Burr.) inoculation, while VvrbohH was down-regulated. Finally, salicylic acid treatment strongly stimulated the expression of VvrbohD and VvrbohH, while abscisic acid treatment induced the expression of VvrbohB and VvrbohH. These results demonstrate that the expression patterns of grape rboh genes exhibit diverse and complex stress-response expression signatures.

Grapes are globally recognized as economically significant fruit trees. Among grape varieties, Thompson Seedless holds paramount influence for fresh consumption and for extensive applications in winemaking, drying, and juicing. This variety is one of the most efficient genotypes for grape genetic modification. However, the lack of a high-quality genome has impeded effective breeding efforts. Here, we present the high-quality reference genome of Thompson Seedless with all 19 chromosomes represented as 19 contiguous sequences (N50 = 27.1 Mb) with zero gaps and prediction of all telomeres and centromeres. Compared with the previous assembly (TSv1 version), the new assembly incorporates an additional 31.5 Mb of high-quality sequenced data with annotation of a total of 30 397 protein-coding genes. We also performed a meticulous analysis to identify nucleotide-binding leucine-rich repeat genes (NLRs) in Thompson Seedless and two wild grape varieties renowned for their disease resistance. Our analysis revealed a significant reduction in the number of two types of NLRs, TIR-NB-LRR (TNL) and CC-NB-LRR (CNL), in Thompson Seedless, which may have led to its sensitivity to many fungal diseases, such as powdery mildew, and an increase in the number of a third type, RPW8 (resistance to powdery mildew 8)-NB-LRR (RNL). Subsequently, transcriptome analysis showed significant enrichment of NLRs during powdery mildew infection, emphasizing the pivotal role of these elements in grapevine’s defense against powdery mildew. The successful assembly of a high-quality Thompson Seedless reference genome significantly contributes to grape genomics research, providing insight into the importance of seedlessness, disease resistance, and color traits, and these data can be used to facilitate grape molecular breeding efforts.

Rhizosphere microbial communities have abundant species and a large number, and affect the physiology and growth of plants. When studying rhizosphere microbes, the rhizosphere ecosystem function and protection of wild orchids will be facilitated. By using high-throughput sequencing technology, the rhizosphere and non-rhizosphere bacteria and fungi of wild Cymbidium goeringii and Cymbidium faberi in the Qinling Mountains were analyzed at phylum, class, order, family, and genus levels to explore the rhizosphere bacterial and fungal community structure and diversity of orchid plants (C. goeringii and C. faberi) under natural conditions. The results showed that at the phylum level Proteobacteria was dominant in rhizosphere and non-rhizosphere soil of C. goeringii and C. faberi, but the proportion was different. The abundance of Proteobacteria in rhizosphere soil of C. faberi was the highest (35.5%), which was about 1.3 times of that in non-rhizosphere soil. Bacteroidetes accounted for 17.2% in rhizosphere soil of C. goeringii, much higher than that of non-rhizosphere soil (7.92%). The dominant groups of fungi in rhizosphere soil of C. goeringii and C. faberi were both Ascomycota. At the genus level, PCoA analysis showed that the community structure of bacteria and fungi in different samples was not only common but also specific, which was manifested in the similar dominant species but different subdominant species. This difference is reflected in the composition and relative abundance of microbial communities between different samples, and will gradually become obvious with the refinement of genera.

Paperbark maple (Acer griseum), an endemic and endangered wild plant in China, has red-colored autumn leaves of high ornamental and garden application value. Leaf color change serves as a crucial indicator for evaluating garden tree aesthetics; however, research on A. griseum's leaf color change remains limited. This study aims to elucidate the physiological and molecular mechanisms underlying leaf color change in maple leaves through physiological, transcriptional, and metabolic assays. Data analysis encompasses gene expression levels and metabolite changes in three distinct states of maple leaves: green, half-red, and red. The progessive decrease of chlorophyll and carotenoids and the continuous accumulation of anthocyanidins caused a sharp change in leaf coloration, which was most drastic in the green to half-red period. Subsequently, targeted metabolomics analysis was performed, and a total of 71 anthocyanidins were detected, and the content of eight types of anthocyanidins increased significantly in the half-red and red periods, compared with that in the green period; of which the multiplicative difference was the largest for cyanidin-3,5-O diglucoside, delivering the largest multiplicative difference. Thus, it was plausible that cyanidin-3,5-O-diglucoside-dominated compoundswere likely to be the main metabolites associated with leaf reddening. Correlation analysis revealed that 12 key transcription factors (TFs) were significantly correlated with the anthocyanin-related metabolites and structural genes, which play important regulatory roles during the biosynthesis of anthocyanosides in A. griseum. These findings offered useful insights into the molecular basis of leaf color variation in A. griseum; providing valuable information to guide targeted genetic breeding and varietal improvement strategies.

Resveratrol is an important secondary metabolite not only owing to its function as a phytoalexin, but also its potential benefits to human health. In this study, the content of trans-resveratrol was documented in seven accessions of grapevine, in the seed, pulp and skin of berries, and at three developmental stages. The highest amount (2.99 µg g⁻¹ FW) was found in the skin of berries at the ripe stage from V. amurensis 'Tonghua-3'. Resveratrol was not detected in several samples, including skin of berries at the green hard or véraison stage from V. davidii 'Tangwei'. We carried out transcriptional profiling of developing 'Tonghua-3' and 'Tangwei' berries to identify gene expression patterns that may be linked with the difference in resveratrol content between these accessions. The expression levels of several differentially expressed genes (DEGs) with presumed function in resveratrol biosynthesis, including STILBENE SYNTHASEs (STSs), CINNAMATE 4-HYDROXYLASEs (C4Hs) and 4-COUMARATE-COA LIGASEs (4CLs), were significantly higher in 'Tonghua-3', than in 'Tangwei' during the véraison and ripe stages. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses suggested that these DEGs were enriched for multiple biological processes at the three stages of fruit development. Additionally, we identified a total of 36 transcription factors, including MYBs, WRKYs, ERFs, bHLHs and bZIPs, that were co-expressed with 17 STSs via a weighted gene co-expression network analysis, suggesting roles as regulators of resveratrol biosynthesis. Overall, these findings provide insight into genotypic differences in resveratrol biosynthesis in grapevine, as well as the molecular genetics of its regulation.