AUTHOR=Chen Jie , Han Shan , Li Shujiang , Wang Ming , Zhu Hanmingyue , Qiao Tianmin , Lin Tiantian , Zhu Tianhui 

TITLE=Comparative Transcriptomics and Gene Knockout Reveal Virulence Factors of Neofusicoccum parvum in Walnut

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.926620

DOI=10.3389/fmicb.2022.926620

ISSN=1664-302X

ABSTRACT=<p><italic>Neofusicoccum parvum</italic> can cause stem and branch blight of walnut (<italic>Juglans spp</italic>.), resulting in great economic losses and ecological damage. A total of two strains of <italic>N. parvum</italic> were subjected to RNA-sequencing after being fed on different substrates, sterile water (K1/K2), and walnut (T1/T2), and the function of <italic>ABC1</italic> was verified by gene knockout. There were 1,834, 338, and 878 differentially expressed genes (DEGs) between the K1 vs. K2, T1 vs. K1, and T2 vs. K2 comparison groups, respectively. The expression changes in thirty DEGs were verified by fluorescent quantitative PCR. These thirty DEGs showed the same expression patterns under both RNA-seq and PCR. In addition, <italic>ΔNpABC1</italic> showed weaker virulence due to gene knockout, and the complementary strain <italic>NpABC1c</italic> showed the same virulence as the wild-type strain. Compared to the wild-type and complemented strains, the relative growth of <italic>ΔNpABC1</italic> was significantly decreased when grown with H<sub>2</sub>O<sub>2</sub>, NaCl, Congo red, chloramphenicol, MnSO<sub>4</sub>, and CuSO<sub>4</sub>. The disease index of walnuts infected by the mutants was significantly lower than those infected by the wild-type and complementary strains. This result indicates that ABC1 gene is required for the stress response and virulence of <italic>N. parvum</italic> and may be involved in heavy metal resistance.</p>