TY - JOUR
T1 - The global regulator LaeA controls biosynthesis of host-specific toxins, pathogenicity and development of Alternaria alternata pathotypes
AU - Takao, Kazumi
AU - Akagi, Yasunori
AU - Tsuge, Takashi
AU - Harimoto, Yoshiaki
AU - Yamamoto, Mikihiro
AU - Kodama, Motoichiro
N1 - Funding Information:
We thank R. P. Oliver for providing pAN7-1 and J. Hille, B. F. Brandwagt, D. G. Gilchrist, K. Akimitsu and T. L. Peever for providing Alternaria strains. This work was supported by a Grant-in-Aid for JSPS Fellows (Grant 24·8246), and Grant-in-Aid for Scientific Research (S) (19108001), (A) (23248007), (B) (23380025) and (B) (26304025) from the Japanese Society for Promotion of Sciences, and Global COE Program “Advanced Utilization of Fungus/Mushroom Resources for Sustainable Society in Harmony with Nature” by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.
Publisher Copyright:
© 2016, The Phytopathological Society of Japan and Springer Japan.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - The global regulator LaeA is required for the expression of biosynthetic genes for secondary metabolites in filamentous fungi such as Aspergillus nidulans. To learn more about the regulation of these genes in Alternaria alternata, which has at least seven pathogenic variants (pathotypes) that produce host-specific toxins (HSTs) and cause severe diseases in their host plants, we identified LaeA homologs encoding methyltransferase in tomato, strawberry and apple pathotypes of A. alternata, designating them AtLAE1, AsLAE1 and AaLAE1, respectively. In the AtLAE1-deleted mutant of the tomato pathotype (∆AtLAE1), expression of the AAL-toxin biosynthetic gene ALT1 was lower than that in the wild type. Correspondingly, AAL-toxin production and virulence of the mutant were significantly lower as were spore production and hyphal growth. Similarly, the AsLAE1-deleted mutant of the strawberry pathotype (∆AsLAE1) and the AaLAE1-deleted mutant of the apple pathotype (∆AaLAE1) produced less of their host-specific toxin (AF- and AM-toxin, respectively), had reduced virulence on the host plant, and hyphal growth and sporulation were defective. Thus, the global regulator gene LaeA positively regulates HST biosynthesis, pathogenicity, growth and differentiation in A. alternata pathotypes.
AB - The global regulator LaeA is required for the expression of biosynthetic genes for secondary metabolites in filamentous fungi such as Aspergillus nidulans. To learn more about the regulation of these genes in Alternaria alternata, which has at least seven pathogenic variants (pathotypes) that produce host-specific toxins (HSTs) and cause severe diseases in their host plants, we identified LaeA homologs encoding methyltransferase in tomato, strawberry and apple pathotypes of A. alternata, designating them AtLAE1, AsLAE1 and AaLAE1, respectively. In the AtLAE1-deleted mutant of the tomato pathotype (∆AtLAE1), expression of the AAL-toxin biosynthetic gene ALT1 was lower than that in the wild type. Correspondingly, AAL-toxin production and virulence of the mutant were significantly lower as were spore production and hyphal growth. Similarly, the AsLAE1-deleted mutant of the strawberry pathotype (∆AsLAE1) and the AaLAE1-deleted mutant of the apple pathotype (∆AaLAE1) produced less of their host-specific toxin (AF- and AM-toxin, respectively), had reduced virulence on the host plant, and hyphal growth and sporulation were defective. Thus, the global regulator gene LaeA positively regulates HST biosynthesis, pathogenicity, growth and differentiation in A. alternata pathotypes.
KW - Alternaria alternata pathotypes
KW - Global regulator
KW - Host-specific toxin
KW - LaeA
KW - Secondary metabolite
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U2 - 10.1007/s10327-016-0656-9
DO - 10.1007/s10327-016-0656-9
M3 - Article
AN - SCOPUS:84961204446
VL - 82
SP - 121
EP - 131
JO - Journal of General Plant Pathology
JF - Journal of General Plant Pathology
SN - 1345-2630
IS - 3
ER -