Impact of Spodoptera litura Attack on Chlorophyll and Biomass Content of Vigna mungo Colonized with Arbuscular Mycorrhizal Fungi and Rhizobium

Abstract

The first and foremost response of plants to any external stimuli, includingherbivorous insect attack is the generation of reactive oxygen species, whichmajorly occurs in the chloroplast followed by mitochondria, peroxisomes, cellmembrane, and cell wall. Under these circumstances, the photosyntheticefficiency of the plant system dramatically influences the plant biomass andyield. Although arbuscular mycorrhizal fungi (AMF), Glomus intraradices andRhizobium improve plant growth through nutritional modes, their impact onprotecting chloroplast from herbivore-induced damage is not yet explored.In this regard, experiments were carried out to examine the changes inchlorophyll composition (Chl a & b), and biomass production of Rhizobiumbrand AMF inoculated plants infested with Spodoptera litura. Among varioustreatments, AMF and Rhizobium inoculated plants showed higher chlorophylla and b than un-inoculated control. Upon the herbivore attack, there wasa drastic reduction in the chlorophyll content (a & b) in all the treatments.However, the reduction in chlorophyll content upon S. litura attack waslesser in plants inoculated either with AMF or in the combination of AMFand Rhizobium. Similarly, these microbial inoculants protected the plantsfrom S. litura damage by sustaining the biomass productivity. These resultshighlight the synergistic effects of AMF and Rhizobium in protecting the blackgram plants from herbivore-induced damage.