Department of Plant Pathology, Shandong Provincial Key Laboratory for Biology of Vegetable Diseases and Insect Pests, Shandong Agricultural University, 61, Daizong Street, Tai'an, Shandong, 271018, China.
Department of Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
Sci Rep. 2017 Aug 11;7(1):7932. doi: 10.1038/s41598-017-08471-3.
Ulocladium was thought to be a strictly asexual genus of filamentous fungi. However, Ulocladium strains were shown to possess both MAT1-1-1 and MAT1-2-1 genes as observed in homothallic filamentous Ascomycetes. Here, we demonstrate that the U. botrytis MAT genes play essential roles for controlling asexual traits (conidial size and number). Using reciprocal genetic transformation, we demonstrate that MAT genes from the related heterothallic species Cochliobolus heterostrophus can also influence U. botrytis colony growth, conidial number and size, and have a strong effect on the range of the number of septa/conidium. Moreover, U. botrytis MAT genes can also affect similar aspects of asexual reproduction when expressed in C. heterostrophus. Heterologous complementation using C. heterostrophus MAT genes shows that they have lost the ability to regulate sexual reproduction in U. botrytis, under the conditions we employed, while the reciprocal heterologous complementation demonstrates that U. botrytis MAT genes have the ability to partially induce sexual reproduction in C. heterostrophus. Thus, the genetic backgrounds of C. heterostrophus and U. botrytis play significant roles in determining the function of MAT genes on sexual reproduction in these two fungi species. These data further support the role of MAT genes in controlling asexual growth in filamentous Ascomycetes but also confirm that heterothallic and homothallic Dothideomycete fungi can be interconverted by the exchange of MAT genes.
层出孔菌曾被认为是严格的丝状真菌无性种属。然而，正如在同宗配合的丝状子囊菌中观察到的那样，层出孔菌菌株被证明同时拥有 MAT1-1-1 和 MAT1-2-1 基因。在这里，我们证明 U. botrytis 的 MAT 基因在控制无性特征（分生孢子大小和数量）方面起着重要作用。通过相互遗传转化，我们证明来自相关异宗配合种 Cochliobolus heterostrophus 的 MAT 基因也可以影响 U. botrytis 菌落生长、分生孢子数量和大小，并对隔数/分生孢子的数量范围有很强的影响。此外，当在 Cochliobolus heterostrophus 中表达时，U. botrytis MAT 基因也可以影响无性繁殖的相似方面。使用 Cochliobolus heterostrophus MAT 基因进行异源互补显示，它们在我们所采用的条件下失去了在 U. botrytis 中调节有性繁殖的能力，而反向异源互补则表明 U. botrytis MAT 基因具有在 Cochliobolus heterostrophus 中部分诱导有性繁殖的能力。因此， Cochliobolus heterostrophus 和 U. botrytis 的遗传背景在决定 MAT 基因在这两种真菌物种的有性繁殖中的功能方面起着重要作用。这些数据进一步支持 MAT 基因在控制丝状子囊菌无性生长中的作用，但也证实了异宗配合和同宗配合的长喙壳菌真菌可以通过 MAT 基因的交换进行相互转换。
