Role of citrus volatiles in host recognition, germination and growth of Penicillium digitatum and Penicillium italicum.

01/2008; DOI: 10.1016/j.postharvbio.2008.01.016
Source: OAI

ABSTRACT Volatiles emitted from wounded peel tissue of various citrus cultivars had a pronounced stimulatory effect on germination and germ tube elongation of both Penicillium digitatum and P. italicum; however, P. digitatum appeared to be more sensitive to the stimulatory action of citrus peel volatiles. When exposed to volatiles from grapefruit peel discs, the percentage of germinated spores of P. digitatum and P. italicum was 75.1% and 37.5%, respectively, whereas germination of controls was 6.8% and 14.7%, respectively. In contrast, Botrytis cinerea and P. expansum were either not affected or inhibited by the peel volatiles. GS-MS analysis of volatiles present in the peel of various citrus fruit cultivars revealed that limonene is the major fruit peel volatile. Its percentage ranged from 89% to 95% at the early stages of fruit development throughout the harvest season. Myrcene and α-pinene made up the second and third greatest amounts among the volatiles found in these oils, ranging from 2.12% to 2.33% and from 0.71% to 1.25%, respectively. All four monoterpenes, limonene, α-pinene, β-pinene and myrcene were stimulatory to P. digitatum and P. italicum but inhibitory to or had no effect on P. expansum and B. cinerea. Germ tube elongation in P. digitatum responded most strongly to limonene and less strongly to α-pinene and β-pinene while myrcene had little effect. In contrast in P. italicum, myrcene stimulated germ tube elongation the most followed by limonene, with α-pinene, and β-pinene being about equal. Germination of P. italicum conidia was highest in response to myrecene with the effect of the other compounds being about equal at concentrations of 5μL or more per plate.

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    Postharvest Biology and Technology 11/2014; · 2.45 Impact Factor
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    ABSTRACT: The apple (Malus × domestica Borkh.) cultivar (cv) ‘Golden Delicious’ is one of the most important apple varieties worldwide, and is widely cultivated for export of fruit to Europe and other countries. However, if damaged, the fruit becomes susceptible to opportunistic infection by postharvest phytopathogens such as Botrytis cinerea (gray mould) and Penicillium expansum (blue mould), which annually lead to large economic losses. Therefore, the study of fruit responses to wounding at the proteome level can contribute to a better understanding of the physiological mechanisms underlying fruit stress responses. In this study we report the first systematic description of the changes in protein abundance following wounding of ‘Golden Delicious’ apples, using 2D-PAGE and MS. At the proteome level, the dominant biological process in wounding response was ‘response to stress’, whereas proteins without abundance changes were found to be mainly involved in ‘metabolism’, ‘response to stress’, and ‘oxidation-reduction processes’. We speculate that fruit respond to wound stress by modulating the abundance of appropriate proteins and to react to mechanical damage by synthesizing a broad range of PR proteins. Therefore, increasing the information on apple fruit proteins after wounding will be a useful resource in developing strategies to minimize postharvest losses.
    Postharvest Biology and Technology 01/2014; 87:51–60. · 2.45 Impact Factor

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