Comprehensive comparative analysis of volatile compounds in citrus fruits of different species

- The volatiles of 108 citrus accessions were determined, including 22 wild or semi-wild germplasms.
- Citrus germplasms that accumulate specific volatile compounds were found.
- The clustering results of 34 distinctive volatiles via HCA agreed with classic citrus taxonomy.
- MVA pathway is enhanced in the peels of C. ichangensis 'Huaihua'.

The volatile profiles of fruit peels and juice sacs from 108 citrus accessions representing seven species were analyzed. Using GC-MS 162 and 107 compounds were determined in the peels and juice sacs, respectively. In the peels, monoterpene alcohols were accumulated in loose-skin mandarins; clementine tangerines and papedas were rich in sesquiterpene alcohols, sesquiterpenes, monoterpene alcohols and monoterpene aldehydes. β-pinene and sabinene were specifically accumulated in 4 of 5 lemon germplasms. Furthermore, concentrations of 34 distinctive compounds were selected to best represent the volatile profiles of seven species for HCA analysis, and the clustering results were in agreement with classic citrus taxonomy. Comparison of profiles from different growing seasons and production areas indicated that environmental factors play important roles in volatile metabolism. In addition, a few citrus germplasms that accumulated certain compounds were determined as promising breeding materials. Notably, volatile biosynthesis via MVA pathway in C. ichangensis 'Huaihua' was enhanced.