Additive roles of two TPS genes in trehalose synthesis, conidiation, multiple stress responses and host infection of a fungal insect pathogen.
Intracellular trehalose accumulation is relevant to fungal life and pathogenicity. Trehalose-6-phosphate synthase (TPS) is known to control the first step of trehalose synthesis, but functions of multiple TPS genes in some filamentous fungi are variable. Here, we examined the functions of two TPS genes (tpsA and tpsB) in Beauveria bassiana, a fungal insect pathogen widely applied in arthropod pest control. Intracellular TPS activity and trehalose content decreased by 71-75 and 72-80% in ΔtpsA, and 21-30 and 15-45% in ΔtpsB, respectively, and to undetectable levels in ΔtpsAΔtpsB, under normal and stressful conditions. The three mutants lost 33, 50, and 98% of conidiation capacity in standard cultures. Conidial quality indicated by viability, density, intracellular trehalose content, cell wall integrity, and hydrophobicity was more impaired in ΔtpsA than in ΔtpsB and mostly in ΔtpsAΔtpsB, which was also most sensitive to nutritional, chemical, and environmental stresses and least virulent to Galleria mellonella larvae. Almost all of phenotypic defects in ΔtpsAΔtpsB approached to the sums of those observed in ΔtpsA and ΔtpsB and were restored by targeted gene complementation. Altogether, TpsA and TpsB play complementary roles in sustaining trehalose synthesis, conidiation capacity, conidial quality, multiple stress tolerance, and virulence, highlighting a significance of both for the fungal adaptation to environment and host.
Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.|School of Biological Science and Biotechnology, University of Jinan, Jinan, Shandong, 250022, China.
Juan-Juan
JJ
Wang
Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
Qing
Q
Cai
Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.|School of bioengineering, Qilu University of Technology, Jinan, Shandong, 250353, China.
Lei
L
Qiu
Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
Sheng-Hua
SH
Ying
Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China. mgfeng@zju.edu.cn.
Ming-Guang
http://orcid.org/0000-0002-2657-0293
MG
Feng
D000818:Animals; D052982:Beauveria / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D007915:Lepidoptera / Q000382:microbiology*; D050296:Microbial Viability; D013172:Spores, Fungal / Q000254:growth & development*; D013312:Stress, Physiological; D016019:Survival Analysis; D014199:Trehalose / Q000096:biosynthesis*; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
D037521:Virulence Factors; D014199:Trehalose; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase
Asexual development; Entomopathogenic fungi; Gene expression and regulation; Pest control potential; Stress responses; Trehalose synthesis; Trehalose-6-phosphate synthase (TPS); Virulence