Pinus massoniana Lamb. is an important, common afforestation and timber tree species in China. Species of Pestalotiopsis are well-known pathogens of needle blight. In this study, the five representative strains were isolated from needle blight from needles of Pi. massoniana in Nanjing, Jiangsu, China. Based on multi-locus phylogenetic analyses of the three genomic loci (ITS, TEF1, and TUB2), in conjunction with morphological characteristics, a new species, namely Pestalotiopsis jiangsuensis sp. nov., was described and reported. Pathogenicity tests revealed that the five representative strains of the species described above were pathogenic to Pi. massoniana. The study revealed the diversity of pathogenic species of needle blight on Pi. massoniana. This is the first report of needle blight caused by P. jiangsuensis on Pi. massoniana in China and worldwide. This provides useful information for future research on management strategies of this disease.

Cunninghamia lanceolata (Lamb.) Hook. is an important conifer species widely planted in southern China. A top blight, with an incidence of 20% (40/200 seedlings), occurred on 1-year-old seedlings o...

Traditional control methods have drawbacks in controlling Verticillium wilt diseases caused by Verticillium dahliae Kleb.; therefore, an efficient and environmentally friendly strategy for disease control must be identified and the mechanisms determined. In this study, a soil-isolated strain SBB was identified as Bacillus velezensis based on 16S rRNA, gyrA, and gyrB gene sequences. In vitro, strain SBB had excellent inhibitory effects on V. dahliae, with the highest inhibition rate of 70.94%. Moreover, strain SBB inhibited production of the conidia of V. dahliae and suppressed the production of microsclerotia and melanin. Through gas chromatograph–mass spectrometer analysis, nine compounds were detected from the volatile organic compounds produced by SBB, among which 2-nonanol, 2-heptanone, 6-methyl-2-heptanone, and 2-nonanone could completely inhibit V. dahliae growth. Strain SBB produced cellulase, amylase, protease, and siderophore. During inhibitory action on V. dahliae, strain SBB showed upregulated expression of genes encoding non-volatile inhibitory metabolites, including difficidin, bacilysin, and bacillaene, at 1.923-, 1.848-, and 1.448-fold higher, respectively. Thus, our study proved that strain SBB had an efficient antagonistic effect on V. dahliae, suggesting strain SBB can be used as a potential biological control agent against Verticillium wilt.

Chinese fir (Cunninghamia lanceolata) is a special fast-growing commercial tree species in China with high economic value. In recent years, leaf blight disease on C. lanceolata has been observed frequently. The diversity of Fusarium species associated with leaf blight on C. lanceolata in China (Fujian, Guangxi, Guizhou, and Hunan provinces) was evaluated using morphological study and molecular multi-locus analyses based on RNA polymerase second largest subunit (RPB2), translation elongation factor 1-alpha (TEF-1α), and RNA polymerase largest subunit (RPB1) genes/region as well as the pairwise homoplasy index tests. A total of five Fusarium species belonging to four Fusarium species complexes were recognized in this study. Two known species including Fusarium concentricum and F. fujikuroi belonged to the F. fujikuroi species complex, and three new Fusarium species were described, i.e., F. fujianense belonged to the F. lateritium species complex, F. guizhouense belonged to the F. sambucinum species complex, and F. hunanense belonged to the F. solani species complex. To prove Koch’s postulates, pathogenicity tests on C. lanceolata revealed a wide variation in pathogenicity and aggressiveness among the species, of which F. hunanense HN33-8-2 caused the most severe symptoms and F. fujianense LC14 led to the least severe symptoms. To our knowledge, this study also represented the first report of F. concentricum, F. fujianense, F. fujikuroi, F. guizhouense, and F. hunanense causing leaf blight on C. lanceolata in China.

Cryptomeria japonica D. Don is a coniferous tree species widely grown in southern China for its high ornamental value. Recently, during disease surveys in China, a symptom of dieback occurred on C. japonica in Nanjing, Jiangsu Province, China. A total of 130 trees were surveyed and more than 90% showed the same symptom. The crowns of affected trees were brown when viewing from a distance, and the bark showed no difference from the healthy ones. In this study, 157 isolates were isolated from the 3 affected plants of C. japonica, and based on the living culture on PDA, the fungal isolates were preliminarily divided into 6 groups. Thirteen representative isolates were selected for the pathogenicity test, and seven of them showed obvious pathogenicity on C. japonica, causing stem basal canker. These isolates were identified based on comparisons of the DNA sequences of the internal transcribed spacer regions (ITS), partial translation elongation factor 1-alpha (tef1), β-tubulin (tub2), and DNA-directed RNA polymerase II subunit (rpb2) and combined with their morphological characteristics. Results showed that these seven isolates belong to two taxa in Neofusicoccum, including a species new to science. The new species, Neofusicoccum cryptomeriae, was hereby described and illustrated. The other species was N. parvum. Both species were pathogens of stem basal canker of Cryptomeria japonica.