TY - JOUR
T1 - Culture degeneration in conidia of Beauveria bassiana and virulence determinants by proteomics
AU - Jirakkakul, Jiraporn
AU - Roytrakul, Sittiruk
AU - Srisuksam, Chettida
AU - Swangmaneecharern, Pratchya
AU - Kittisenachai, Suthathip
AU - Jaresitthikunchai, Janthima
AU - Punya, Juntira
AU - Prommeenate, Peerada
AU - Senachak, Jittisak
AU - So, Laihong
AU - Tachaleat, Anuwat
AU - Tanticharoen, Morakot
AU - Cheevadhanarak, Supapon
AU - Wattanachaisaereekul, Songsak
AU - Amnuaykanjanasin, Alongkorn
PY - 2018/2
Y1 - 2018/2
N2 - The quality of Beauveria bassiana conidia directly affects the virulence against insects. In this study, continuous subculturing of B. bassiana on both rice grains and potato dextrose agar (PDA) resulted in 55 and 49 % conidial yield reduction after 12 passages and 68 and 60 % virulence reduction after 20 and 12 passages at four d post-inoculation, respectively. The passage through Tenebrio molitor and Spodoptera exigua restored the virulence of rice and PDA subcultures, respectively. To explore the molecular mechanisms underlying the conidial quality and the decline of virulence after multiple subculturing, we investigated the conidial proteomic changes. Successive subculturing markedly increased the protein levels in oxidative stress response, autophagy, amino acid homeostasis, and apoptosis, but decreased the protein levels in DNA repair, ribosome biogenesis, energy metabolism, and virulence. The nitro blue tetrazolium assay verified that the late subculture's colony and conidia had a higher oxidative stress level than the early subculture. A 2A-type protein phosphatase and a Pleckstrin homology domain protein Slm1, effector proteins of the target of rapamycin (TOR) complex 1 and 2, respectively, were dramatically increased in the late subculture. These results suggest that TOR signalling might be associated with ageing in B. bassiana late subculture, in turn affecting its physiological characteristics and virulence.
AB - The quality of Beauveria bassiana conidia directly affects the virulence against insects. In this study, continuous subculturing of B. bassiana on both rice grains and potato dextrose agar (PDA) resulted in 55 and 49 % conidial yield reduction after 12 passages and 68 and 60 % virulence reduction after 20 and 12 passages at four d post-inoculation, respectively. The passage through Tenebrio molitor and Spodoptera exigua restored the virulence of rice and PDA subcultures, respectively. To explore the molecular mechanisms underlying the conidial quality and the decline of virulence after multiple subculturing, we investigated the conidial proteomic changes. Successive subculturing markedly increased the protein levels in oxidative stress response, autophagy, amino acid homeostasis, and apoptosis, but decreased the protein levels in DNA repair, ribosome biogenesis, energy metabolism, and virulence. The nitro blue tetrazolium assay verified that the late subculture's colony and conidia had a higher oxidative stress level than the early subculture. A 2A-type protein phosphatase and a Pleckstrin homology domain protein Slm1, effector proteins of the target of rapamycin (TOR) complex 1 and 2, respectively, were dramatically increased in the late subculture. These results suggest that TOR signalling might be associated with ageing in B. bassiana late subculture, in turn affecting its physiological characteristics and virulence.
KW - Ageing
KW - Entomopathogenic fungi
KW - Proteomic analysis
KW - Subculture
KW - Target of rapamycin
KW - Virulence against insects
UR - http://www.scopus.com/inward/record.url?scp=85044457675&partnerID=8YFLogxK
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-85044457675&origin=recordpage
U2 - 10.1016/j.funbio.2017.12.010
DO - 10.1016/j.funbio.2017.12.010
M3 - RGC 21 - Publication in refereed journal
SN - 1878-6146
VL - 122
SP - 156
EP - 171
JO - Fungal Biology
JF - Fungal Biology
IS - 2-3
ER -