Fungal Pathogens of Maize Gaining Free Passage Along the Silk Road

Abstract

Silks are the long threads at the tips of maize ears onto which pollen land and sperm nuclei travel long distances to fertilize egg cells, giving rise to embryos and seeds; however fungal pathogens also use this route to invade developing grain, causing damaging ear rots with dangerous mycotoxins. This review highlights the importance of silks as the direct highways by which globally important fungal pathogens enter maize kernels. First, the most important silk-entering fungal pathogens in maize are reviewed, including Fusarium graminearum, Fusarium verticillioides, and Aspergillus flavus, and their mycotoxins. Next, we compare the different modes used by each fungal pathogen to invade the silks, including susceptible time intervals and the effects of pollination. Innate silk defences and current strategies to protect silks from ear rot pathogens are reviewed, and future protective strategies and silk-based research are proposed. There is a particular gap in knowledge of how to improve silk health and defences around the time of pollination, and a need for protective silk sprays or other technologies. It is hoped that this review will stimulate innovations in breeding, inputs, and techniques to help growers protect silks, which are expected to become more vulnerable to pathogens due to climate change.

Evaluation of the Phenol Production Potential in Maize (Zea mays L.) in Response to Infection Caused by Fusariun verticillioides (Niren.)

“…Virulence of F. verticillioides that ranged from 25.21% in ART-98-SW6 to 19.01% in ART-98-SW1 demonstrated small but significant variation in the severity of systemic infection on the host. While environmental factors also play a major in the activities of this cosmopolitan pathogen [18,19] variation recorded here in the growth rate and resistance of maize varieties to F. verticillioides infections is consistent with earlier findings in which host resistance was reported as a major determinant of variation in the activities of the pathogen [20,21].…”

Impact of push–pull cropping system on pest management and occurrence of ear rots and mycotoxin contamination of maize in western Kenya

“…Insects feeding on maize ears either act as vectors of ear rot fungi or open the ear to fungal inocula dispersed by raindrops and wind (Mays, 2015). Maize ear rot fungi also cause infection by entering through the silk as the kernels develop (Thompson et al ., 2018). F .…”

Occurrence, Pathogenicity, and Mycotoxin Production of Fusarium temperatum in Relation to Other Fusarium Species on Maize in Germany

“…Several Fusarium species infecting maize are known to produce toxic secondary metabolites, called mycotoxins, which impair grain quality and threaten the safety of animal feed and food products [ 2 , 3 ]. Among the most important Fusarium species inciting pre- and post-harvest ear rot of maize are F. graminearum and F. verticillioides [ 4 , 5 , 6 ], but also other species such as Fusarium poae [ 7 , 8 ], Fusarium proliferatum [ 1 ], F. subglutinans [ 9 ], and F. temperatum [ 10 ] are frequently reported. Ear infection is typically characterized by the growth of white or reddish mycelium with rot induced on the cob and on stored grains.…”