Biocontrol of antifungal volatiles produced by Ceriporia lacerate HG2011 against citrus fruit rot incited by Penicillium spp.

Developing effective bio-control agents can safely and effectively reduce the high rate of citrus fruit decay caused by Penicillium spp. in post-harvest storage. Thus, present experiments were conducted to investigate the biocontrol efficiency of volatiles produced by Ceriporia lacerate HG2011 against Penicillium spp., P. italicum infection of wounds artificially created on citrus fruit, and fruit rot in storage. This fungus greatly suppressed the growth and sporulation of P. italicum and P. digitatum in pure culture. Among the 35 volatiles produced by C. lacerate HG2011, 12 were known as antimicrobial substances without toxicity to humans and 6 showed direct inhibitory effects on P. italicum (3 were known as antifungal substances, whilst linoleyl acetate, n-pentadecanol, and 2-nonadecanone have not been reported with antifungal potential in literature). The volatiles induced differential expression of numerous genes in P. italicum, including those responsible for the GO terms involved in the response to toxic substances and pathways SNARE interaction in vesicular transport and synthesis and degradation of ketone bodies. These results implied that the volatiles were toxic to P. italicum and interfered with energy supply, acid-base balance, protein processing, biological macromolecule breakdown, material transport, etc. in pathogen cells. As a result, the control efficiency of the volatiles reached 72 % against P. italicum infection of wounds on citrus fruit and 60 % against fruit rot in storage. Taken together, C. lacerate HG2011 produced multiple antifungal volatiles and interfered with pathogen metabolisms in many ways, showing a promising use in citrus fruit storage.