Rice production in the Anhui province is threatened by fungal diseases. We obtained twenty-five fungal isolates from rice and wild rice leaves showing leaf spot disease collected along the Yangtze River. A phylogenetic analysis based on internal transcribed spacer (ITS), translation elongation factor 1 alpha (TEF1-α), and beta tubulin (TUB2) sequences revealed one isolate (SS-2-JB-1B) grouped with Nigrospora sphaerica, one (QY) with Nigrospora chinensis, twenty-two with Nigrospora oryzae, and one isolate (QY-2) grouped in its own clade, which are related to but clearly different from N. oryzae. Nineteen tested isolates, including sixteen strains from the N. oryzae clade and the three isolates of the other three clades, caused disease on detached rice leaves. The three isolates that did not belong to N. oryzae were also able to cause disease in rice seedlings, suggesting that they were rice pathogens. Isolate QY-2 differed from the other isolates in terms of colony morphology, cell size, and susceptibility to fungicides, indicating that this isolate represents a new species that we named Nigrospora anhuiensis. Our analysis showed that N. sphaerica, N. chinensis, and the new species, N. anhuiensis, can cause rice leaf spot disease in the field. This research provides new knowledge for understanding rice leaf spot disease.

Effects of the arbuscular mycorrhizal fungus (AMF), Glomus mosseae, on growth, antioxidant, osmoregulation, and nutrition were investigated in “Britewell” (Vaccinium ashei) and “Misty” (Vaccinium corymbosum) plants exposed to low temperature (10°C). At low temperature, the two cultivars showed similar decreases in leaf concentrations of soluble sugars, phosphorus (P), and potassium (K). However, similar increases were observed in levels of leaf antioxidants, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), superoxide anion radical ( ), and proline. AM inoculation increased leaf activities of superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, ascorbate, and glutathione, but decreased leaf concentrations of , MDA, and H₂O₂ in the two cultivars. AMF caused greater changes in leaf composition in “Britewell.” AM-inoculated “Britewell” and “Misty” plants had higher concentrations of soluble sugar, proline, P, and K than non-AM-inoculated plants, especially in the former cultivar. These results indicate that G. mosseae has the potential to enhance resistance of “Britewell” blueberry plants against low-temperature stress.

Vaccinium bracteatum Thunb., an important native Chinese wild blueberry species, is widely used as a rootstock and in blueberry cultivar breeding, as well as in traditional medicine and local food. We report here the genome sequence of V. bracteatum using a combination of Oxford Nanopore Technologies long-read and Illumina HiSeq short-read sequencing technologies to obtain 65.30 Gb of clean data, achieving 114.60-fold genome coverage. The assembled genome has a total sequence length of 569.81 Mb and consists of 36,756 predicted genes. Repetitive DNA sequences represent 57.78% of the genome sequence. Comparative genomic analysis revealed that a total of 336 gene families had expanded and that 298 candidate genes had undergone positive selection during evolution in V. bracteatum. The divergence of V. bracteatum from the related Rhododendron williamsianum and Rhododendron delavayi occurred ~13−85 million years ago. The genome sequence of V. bracteatum allowed us to identify some important genes associated with traits involved in fruit development, such as flavonoid biosynthesis, sugar and acid metabolism, MYB transcription factor gene expression, and hormone regulation. The differential expression patterns of genes encoding flavonoid biosynthesis enzymes and MYB transcription factors might explain the high flavonoid content of V. bracteatum. This chromosome-level genome assembly provides reference sequences for the identification and characterization of genes important in the improvement of blueberry and related research.

Flowering and fruit set are important traits affecting fruit quality and yield in rabbiteye blueberry (Vaccinium ashei). Intense efforts have been made to elucidate the influence of vernalization and phytohormones on flowering, but the molecular mechanisms of flowering and fruit set remain unclear. To unravel these mechanisms, we performed transcriptome analysis to explore blueberry transcripts from flowering to early fruit stage. We divided flowering and fruit set into flower bud (S2), initial flower (S3), bloom flower (S4), pad fruit (S5), and cup fruit (S6) based on phenotype and identified 1,344, 69, 658, and 189 unique differentially expressed genes (DEGs) in comparisons of S3/S2, S4/S3, S5/S4, and S6/S5, respectively. There were obviously more DEGs in S3/S2 and S5/S4 than in S4/S3, and S6/S5, suggesting that S3/S2 and S5/S4 represent major transitions from buds to fruit in blueberry. GO and KEGG enrichment analysis indicated these DEGs were mostly enriched in phytohormone biosynthesis and signaling, transporter proteins, photosynthesis, anthocyanins biosynthesis, disease resistance protein and transcription factor categories, in addition, transcript levels of phytohormones and transporters changed greatly throughout the flowering and fruit set process. Gibberellic acid and jasmonic acid mainly acted on the early stage of flowering development like expression of the florigen gene FT, while the expression of auxin response factor genes increased almost throughout the process from bud to fruit development. Transporter proteins were mainly associated with minerals during the early flowering development stage and sugars during the early fruit stage. At the early fruit stage, anthocyanins started to accumulate, and the fruit was susceptible to diseases such as fungal infection. Expression of the transcription factor MYB86 was up-regulated during initial fruit development, which may promote anthocyanin accumulation. These results will aid future studies exploring the molecular mechanism underlying flowering and fruit set of rabbiteye blueberry.