Maize pollen alters the reaction of cowpea to pathogens

Abstract

Maize pollen stimulated conidial germination of Colletotrichum lindemuthianum (Sacc. and Magn.) Bri. and Cav., a fungal pathogen which causes anthracnose in cowpea ( Vigna unguiculata (L.) Walp.). Instead of forming appressoria, which are necessary for penetration of plant tissues, most of the germinating spores developed long undifferentiated germ tubes. However, the addition of maize pollen to conidial inoculum of C. lindemuthianum increased the severity of anthracnose in cowpea seedlings, possibly through an effect of pollen on host resistance mechanisms. Maize pollen inhibited the development of necrotic local lesions in cowpea cv. ‘Early Red’ which possesses hypersensitive resistance to cowpea (yellow) mosaic virus (CYMV). Since we obtained no evidence that systematic infection with CMYV increased in pollen-treated seedlings, it is probable that pollen had an inhibitory effect on virus infection.