Identification of secondary metabolites associated with protection against mango gall fly infestation and blossom malformation

The infestation of mango trees by orchard pests leads to a reduction in fruit yield. This study was focussed on two pests, i.e.mango gall fly (Procontarinia), and malformation caused by Fusarium [1]. Some mango cultivars are tolerant towards these organisms, while others are highly susceptible. This study elucidates the role of secondary metabolites contributing to tolerance. A few cultivars display the ability to inhibit the development of the insect within the leaves, resulting in the formation of pseudogalls, rather than true galls [2]. Metabolic profiles of mango cultivars of varying susceptibility to gall fly infestation and mango malformation were obtained by thermal desorption-gas chromatography-mass spectroscopy and by ultrahigh performance liquid chromatography- quadrupole time-of-flight-mass detection analysis. Chemometric models constructed from the chromatographic data revealed clear distinction between susceptibility and resistance as well as between true gall and pseudogall forming cultivars. The models developed allowed for the identification of biomarkers associated with susceptibility and pseudogall formation[3]. Three terpenes, α- and β-pinene as well as camphene, were identified as biomarkers for susceptibility to gall fly infestation. The presence of elevated levels of mangiferin, maclurin and maclurin O-galloyl-glucoside in the leaves were associated with a higher degree of tolerance to Fusarium infestation. Prediction models constructed from data obtained from the leaves of mango cultivars with varying susceptibilities were used to identify new cultivars that produce secondary metabolites that could play a role in protection against infestation. These models can serve as an important tool to screen susceptibility of new cultivars to these orchard pests.

Keywords: Mango malformation, Fusarium, mango gall fly, Procontarinia, chemometric models, biomarkers, prediction models.

References:

[1] Chakrabarti DK. Mango Malformation. Germany: Springer; 2011.

[2] Augustyn WA, du Plooy W, Botha BM, van Wilpe E. Infestation of Mangifera indica by the mango gall fly, Procontarinia matteiana, (Kieffer & Cecconi) (Diptera: Cecidomyiidae). Afr Entomol 2013; 21: 79 – 88

[3] Wishart DS. Metabolomics: applications to food science and nutrition research. Trends Food Sci Tech 2008; 19: 482 – 493