Rational engineering of a synthetic insect-bacterial mutualism

Area of Science:

• Microbiology
• Evolutionary Biology
• Insect Science

Background:

• Insects frequently host mutualistic bacterial endosymbionts, crucial for their survival and reproduction.
• The natural origins and establishment of these insect-bacterial symbioses remain largely unexplored.
• Understanding symbiont acquisition is key to understanding insect evolution.

Purpose of the Study:

• To establish and manipulate a synthetic insect-bacterial symbiosis in a weevil host.
• To investigate the potential for environmental bacteria to initiate mutualistic associations.
• To engineer symbionts for enhanced host benefits and study symbiosis evolution.

Main Methods:

• Synthetic symbiosis establishment via egg injection of nascent symbionts into weevil hosts.
• Engineering of symbionts to overproduce specific aromatic amino acids (tyrosine and phenylalanine).
• Assessment of symbiont colonization, maternal transmission, and host benefits across generations.

Main Results:

• Successful colonization of weevil tissues, including bacteriomes, by the synthetic symbiont.
• Demonstrated maternal transmission of the symbiont over multiple generations.
• Engineered symbionts conferred benefits, including cuticle strengthening and accelerated larval development.

Conclusions:

• Mutualistic insect-bacterial symbioses can originate from the acquisition of environmental bacteria.
• The bacterial genus Sodalis is predisposed to form symbiotic associations due to its transmission capabilities.
• This synthetic system offers a platform for studying the evolution and molecular basis of insect-bacterial symbiosis.