Molecular characterization of GAS1 gene from entomopathogenic fungi and their virulence against Fall Armyworm Spodoptera Frugiperda Smith.

Abstract

Globally, there is a fierce fight to ensure food security for the soaring population in the stare of global warming that has caused a paradigm shift in the agricultural industry. The weather patterns have not only become unpredictable but also unfathomable. Notably, other regions of the world have slowed down in population growth, however, the Food and Agriculture Organization estimates that the population of Africa still grows at about 3%. Prominently, maize has been a major crop in many countries and contributing immensely to food that is consumed either by humans or animals. However, in the year 2016, maize in Africa received a new invasive pest from the Americas known as Fall Armyworm (Spodoptera frugiperda Smith). Soon after, the pest had reached Asia and the devastation of maize plantations has been immense. Fall armyworm is an insect pest of more than 100 plant species with a preference for graminaceious species mainly causing damage to economically important cultivated cereals such as maize, rice, sorghum, Bermuda grass, crabgrass, and also to vegetable crops and cotton. Notably, controlling fall armyworm has mainly depended on synthetic chemicals even though, biological control has been used time and again. Since its discovery in Africa and Asia, research has been going on with the aim of finding a biological control in addition to the chemicals that are already in place and continue to be sought. Therefore, this research aimed at using Beauveria bassiana to control fall armyworm in maize. Six isolates of Beauveria bassiana (BCMU1, BCMU2, BCMU3, BCMU4, BCMU5, and BCMU6) were tested against the second instar larvae of fall armyworm in the laboratory by dipping them in two different concentrations and observations done daily to record mortality with three replications. Additionally, the glycosyl transferase-like protein 1 (GAS1) gene was analyzed. All the isolates caused mortality to fall armyworm with BCMU6 causing the highest mortality of 91.67%. Consequently, all the isolates of Beauveria bassiana contained the GAS1 gene which codes for cuticle penetration and aides in the infection process. This result shows the potentiality of controlling fall armyworm using Beauveria bassiana which is a biological intervention that is ecofriendly. In addition, the presence of glycosyl transferase-like protein 1 (GAS1) gene in Beauveria bassiana further corroborates their infection potential to fall armyworm.