Zhao Pei-Bao, Ren Ai-Zhi, Li Duo-Chuan
Department of Plant Protection, Liaocheng University, Liaocheng, China.
J Mol Microbiol Biotechnol. 2011;21(3-4):110-9. doi: 10.1159/000330630. Epub 2012 Jan 31.
Fusarium proliferatum is an important pathogen of maize that is responsible for ear rots, stalk rots and seeding blight worldwide. During the past decade, F. proliferatum has caused several severe epidemics of maize seedling blight in many areas of China, which led to significant losses in maize. To understand the molecular mechanisms in the fungal developmental regulation and pathogenicity, we isolated and characterized the FPK1 gene (GenBank accession No. HQ844224) encoding a MAP kinase homolog of FUS3/KSS1 in yeast. The gene includes a 1,242-bp DNA sequence from ATG to TAA, with a coding region of 1,068 bp, 3 introns (58 bp, 56 bp and 60 bp) and a predicted protein of 355 aa.The mutant ΔFPK1, which has a disruption of the FPK1 gene, showed reduced vegetative growth, fewer and shorter aerial mycelia, strongly impaired conidiation and spore germination, as well as deviant germ tube outgrowth. When the strain was inoculated in susceptible maize varieties, the infection of the mutant ΔFPK1 was delayed, and the infection efficiency was reduced compared to the wild-type strain. Complementation of the disruptions within the FPK1 open reading frame restored wild-type levels of conidiation, growth rate and virulence to maize seedlings. Our results indicated that the FPK1 gene functioned in hyphal growth, conidiation, spore germination and virulence in F. proliferatum.
层出镰刀菌是玉米的一种重要病原菌，在全球范围内引发穗腐病、茎腐病和幼苗枯萎病。在过去十年中，层出镰刀菌在中国许多地区引发了几次严重的玉米幼苗枯萎病流行，给玉米造成了重大损失。为了解该真菌发育调控和致病性的分子机制，我们分离并鉴定了编码酵母中FUS3/KSS1 MAP激酶同源物的FPK1基因（GenBank登录号：HQ844224）。该基因包含一个从ATG到TAA的1242 bp DNA序列，编码区为1068 bp，有3个内含子（58 bp、56 bp和60 bp），预测蛋白质为355个氨基酸。FPK1基因被破坏的突变体ΔFPK1表现出营养生长减少、气生菌丝更少且更短、分生孢子形成和孢子萌发严重受损，以及芽管生长异常。当该菌株接种到易感玉米品种中时，与野生型菌株相比，突变体ΔFPK1的感染延迟，感染效率降低。在FPK1开放阅读框内对破坏进行互补恢复了分生孢子形成、生长速率和对玉米幼苗毒力的野生型水平。我们的结果表明，FPK1基因在层出镰刀菌的菌丝生长、分生孢子形成、孢子萌发和毒力中发挥作用。
