Citrus Research Institute, Southwest University, Chongqing, 400712, China; College of Plant Protection, Southwest University, Chongqing, 400715, China.
Citrus Research Institute, Southwest University, Chongqing, 400712, China.
Fungal Biol. 2020 Jun;124(6):562-570. doi: 10.1016/j.funbio.2020.02.008. Epub 2020 Feb 29.
To well cope with various external carbon sources, fungi have evolved an adaptive mechanism to overcome the adversity of carbon source deficiency. The sucrose non-fermenting (SNF1) protein kinase mainly mediates the utilization of non-fermentable carbon sources. In this study, we determined the function of Snf1, coding the α-subunit of SNF1 kinase, in the phytopathogenic fungus Alternaria alternata via analyzing the Snf1 deletion mutants (ΔAasnf1). Aasnf1 is required for growth, development of aerial mycelium, and conidiation. Results of pathogenicity test showed that ΔAasnf1 induced smaller lesions on detached citrus leaves. Moreover, in the carbon utilization assay, ΔAasnf1 showed growth inhibition on the minimal medium supplemented with polygalacturonic acid, sucrose or alcohol as the only carbon source. Compared to the wild type, ΔAasnf1 also exhibited stronger resistance to cell wall stressors of sodium dodecyl sulfate and congo red. In conclusion, Aasnf1 played important roles in the carbon utilization, vegetative growth, conidiation, cell wall functions and pathogenicity of A. alternata. This study is the first report on the functions of Aasnf1 and our results suggest that Snf1 is critical for the conidiogenesis and pathogenesis of the A. alternata tangerine pathotype.
为了很好地应对各种外源碳源，真菌已经进化出一种适应机制来克服碳源缺乏的逆境。蔗糖非发酵（SNF1）蛋白激酶主要介导不可发酵碳源的利用。在这项研究中，我们通过分析 SNF1 激酶的α亚基编码 Snf1 的缺失突变体（ΔAasnf1），确定了其在植物病原菌链格孢中的功能。Aasnf1 是生长、气生菌丝发育和分生孢子形成所必需的。致病性试验结果表明，ΔAasnf1 在柑橘离体叶片上诱导的病斑较小。此外，在碳源利用试验中，ΔAasnf1 在补充聚半乳糖醛酸、蔗糖或酒精作为唯一碳源的最小培养基上生长受到抑制。与野生型相比，ΔAasnf1 对十二烷基硫酸钠和刚果红等细胞壁应激物的抗性也更强。综上所述，Aasnf1 在 A. alternata 的碳利用、营养生长、分生孢子形成、细胞壁功能和致病性中发挥着重要作用。本研究首次报道了 Aasnf1 的功能，我们的结果表明 Snf1 对 A. alternata 宽皮柑橘致病菌的分生孢子形成和致病性至关重要。
