A Microfluidic Assay for Identifying Differential Responses of Plant and Human Fungal Pathogens to Tobacco Phylloplanins

Phylloplanins are defensive glycoproteins secreted onto leaf surfaces by trichome-bearing plants such as tobacco (Nicotiana tabacum). They are of interest because of their antimicrobial properties, but like other natural product bioactives, the assessment and screening of phylloplanins biological activity is impeded by limited availabilities of active compounds. Here we report an inexpensive microfluidic approach that requires ≤ 20 microliters of tobacco phylloplanins to assess spore germination inhibition of plant and human fungal pathogens. Spores of Colletotrichum coccodes and Aspergillus fumigatus suspended in solutions containing tobacco phylloplanins did not germinate at 48 and 30 h post-treatment, respectively. Tobacco phylloplanins transiently inhibited spore germination of Fusarium sambucinum, but had no detectable activity against Alternaria solani or Verticillium albo-atrum at the concentrations tested, demonstrating differential sensitivity of fungi to tobacco phylloplanins. 4 August 2014. 14 August 2014.