Cuticular wax of mandarin fruit promotes conidial germination and germ tube elongation, and impairs colony expansion of the green mold pathogen, Penicillium digitatum
Mo Zhu, Jie Ji, Menglei Wang, Miao Zhao, Ying Yin, Jiali Kong, Man Liu and Yong-Fang Li
Postharvest Biology and Technology, Volume 169, November 2020, 111296
2020
บทคัดย่อ
The cuticle of citrus is known to modulate fruit postharvest quality and is hypothesized to be involved in resistance against the fungal pathogen, Penicillium digitatum. However, only scarce information is available on the effect of cuticular wax on the conidial germination, germ tube elongation, and colony development of P. digitatum. Utilizing a versatile Formvar®-based in vitro system, we were able to assess the development of P. digitatum in the absence of secondary effects of its host. In vivo and in vitro, we found that the cuticular wax of mandarin (Citrus reticulata) fruit impaired P. digitatum colony expansion. Compared with the colony size of P. digitatum on intact fruit, the area of colonies on fruit supplemented with mandarin cuticular wax decreased significantly by 1.7 times, whereas it increased 1.6 times on dewaxed fruit 72 h post inoculation. Similar results were observed at 96 h post inoculation. Thus, the cuticular wax of mandarin fruit, acting as a physical barrier, impairs the colony expansion of P. digitatum, making it a viable alternative for citrus fruit coating that effectively controls green mold colony formation during postharvest storage. Interestingly, in vitro cuticular wax of mandarin fruit dramatically stimulated conidial germination and germ tube elongation of this pathogen. These results suggest that the cuticular wax might be the chemical cue for P. digitatum during host-recognition processes. Overall, our results suggest that the cuticular wax of mandarin fruit plays meaningful roles in the interaction between the citrus fruit and P. digitatum, and hence, can be considered for postharvest disease management.