Fungal endophytes of betel leaves: the need to study mycotoxin-producing endophytes in leafy vegetables

Ethiraj Thirumalai, Ambayeram Venkatachalam & Trichur Subramanian Suryanarayanan

Sydowia 73: 83-88

Published online on December 4th, 2020

There are very few studies on endophyte communities of freshly consumed leaves. This is vital as some endophytes which continue to survive in detached leaves belong to mycotoxin producing genera. We studied the endophyte community of betel leaf, which is eaten fresh by a huge population, especially in Asia. Young and mature leaves of betel vine were screened for their endophyte assemblage. In addition, mature leaves collected during dry and wet seasons and those stored in the market were studied for endophyte presence. The entire leaf was infected with endophytes. Though endophyte colonization frequency (CF %) increased with leaf age, their species composition did not vary. The CF % of most of the endophytes was low (0.7 %–8.7 %) while that of Colletotrichum sp. 1 was high irrespective of leaf age or season (46 %–78.67 %). The CF % of Fusarium pallidoroseum increased with leaf age and storage period; the presence of F. mangiferae increased with storage time. The two Fusarium endophytes isolated from betel leaf produce an array of mycotoxins including beauvericin, enniatin, nivalenol, fusarenon X, equisetin, HT2 toxin, diacetoxyscirpenol and neosolaniol. This study underscores the importance of investigating the endophyte communities of leafy vegetables, especially those having relatively longer shelf life.

Keywords: Fusarium mangiferae, Fusarium pallidoroseum.

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