Abstract: In order to better understand the functional mechanisms of the secretome of Rhodosporidium paludigenum in its interactions with Botrytis cinerea and tomatoes, Q Exactive UHMR hybrid quadrupole-orbitrap mass spectrometry combined with bioinformatics was employed to identify the unique peptide sequences of the proteins. The results showed that 1 632 unique peptide sequences from Rhodotorula sourced proteins were found in the fermentation supernatant of R. paludigenum, and 58 classical secretory proteins and 433 non-classical secretory proteins were identified using the software SignalP, WoLF PSORT, TargetP, TMHMM, big-PI Predictor and Secretome P. The secretory proteins of R. paludigenum effectively inhibited the spore germination of B. cinerea by 31.4%, and enhanced resistance of tomato fruits to B. cinerea infection around the wound with an inhibition rate of 50.1%. Moreover, based on the UniParc data, 18 (31.0%) carbohydrate-active enzymes such as alginate lyase and β-glucosidase were found in the secretome of R. paludigenum, which may play a vital role in the interaction between R. paludigenum and Botrytis cinerea and in inducing systematic resistance of tomato fruits to gray mold.

Key words: biological control; secretome; microbial interaction; induced resistance