College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Agricultural College, Yangzhou University, Yangzhou 225009, China.
Int J Mol Sci. 2021 Nov 12;22(22):12258. doi: 10.3390/ijms222212258.
The smut fungus infects and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by and and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from , which may conduct fungus growth and infection at the initial stage of stem-gall formation.
污损菌侵染并诱导茎部扩张，形成一种名为茭白的独特蔬菜。虽然先前的研究表明激素控制对于触发茎部肿胀至关重要，但 和 合成的激素的作用以及潜在的分子机制尚不清楚。为了研究触发肿胀茎形成的机制，我们在最初触发茭白瘤形成时分析了两种相互作用的生物体的基因表达模式，此时感染性菌丝也广泛繁殖并穿透宿主茎细胞。转录分析表明，大量涉及真菌致病性和植物抗性的基因被重新编程，以维持寄生虫和宿主之间的微妙平衡。此外，在茎部肿胀过程中， 的生长素生物合成相关基因表达明显下降，而大量与宿主植物激素的合成、代谢和信号转导相关的基因被刺激并表现出特定的表达模式，特别是黄素单加氧酶（关键酶在吲哚-3-乙酸（IAA）生物合成途径中）的表达显著增加。同时，IAA 的含量显著增加，而细胞分裂素和赤霉素的含量则呈现相反的趋势。我们推测，是宿主植物而不是真菌产生的生长素触发了茎部肿胀。此外，从差异表达的基因中，我们从 中鉴定出两个候选 Cys2-His2（C2H2）锌指蛋白 GME3058_g 和 GME5963_g，它们可能在茎瘤形成的初始阶段进行真菌生长和感染。
