Disentangling the role of the rhizobacterium Azospirillum brasilense on Zea spp. defenses to Spodoptera frugiperda (Lepidoptera: Noctuidae)

• Grant number: 24/13232-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2024
• End date: February 28, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: José Maurício Simões Bento
• Grantee: Isabella Rubio Cabral
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The selection of traits aimed at increasing growth rate and yield, driven by the domestication process, has incurred a high cost for plant defenses, rendering them more susceptibility to herbivore attack. While most research has traditionally focused on aboveground community interactions, it is increasingly clear that microbial plant symbionts can influence these interactions. Plant-growth promoting rhizobacteria (PGPR) can influence plant responses to herbivore attack, helping to compensate for weakened or lost defenses during artificial selection. However, there is a knowledge gap regarding the effects of Azospirillum brasilense inoculation on the performance of Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), one of the most relevant pests for maize cultivation. This study will explore the influence of the PRPG A. brasilense on the defense of maize (Zea mays. mays) and teosinte (Z. luxurians), its wild ancestor, against the fall armyworm, to evaluate: (i) the profile of constitutive and herbivore-induced plant volatiles; (ii) the behavior of the larval parasitoid Aleiodes ceres Shimbori (Hymenoptera: Braconidae); and (iii) the larval performance and oviposition preference of S. frugiperda. This study proposes to investigate the effect of A. brasilense inoculation on maize plant defenses and to characterize the resistance of Z. luxurians to S. frugiperda, contributing to understanding the effects of domestication on the functional response of beneficial microorganisms in plant protection against herbivores. The results of chemotactic responses of A. ceres to maize plant volatiles may provide insights for the development of biological control programs using semiochemicals for fall armyworm management.