AUTHOR=Roylawar Praveen , Khandagale Kiran , Nanda Satyabrata , Soumia Parakkattu Sulochanan , Jadhav Sangita , Mahajan Vijay , Gawande Suresh 

TITLE=Colonization of Serendipita indica promotes resistance against Spodoptera exigua in onion (Allium cepa L.)

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1190942

DOI=10.3389/fmicb.2023.1190942

ISSN=1664-302X

ABSTRACT=<p>Plant-endophyte symbiosis influences plant defense and growth. <italic>Serendipita indica</italic> is a root endophyte that promotes growth and induces tolerance against biotic and abiotic stress in plants. In this study, we examined the effect of <italic>S. indica</italic> colonization on herbivore (<italic>Spodoptera exigua</italic>) resistance of onion (<italic>Allium cepa</italic> L.). We found that colonization of <italic>S. indica</italic> in the roots of onion significantly reduced the feeding damage of leaves by <italic>S. exigua</italic> larvae, and also resulted in a reduction in weight gain of the larvae when fed on <italic>S. indica</italic> plants. This enhanced resistance is a result of modulation of antioxidant and defense enzymes/genes in the host by <italic>S. indica</italic> mutualism. Specifically, the activities of enzymes such as Superoxide dismutase, peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, and H<sub>2</sub>O<sub>2</sub> content were significantly higher in the early stages of <italic>S. exigua</italic> feeding in the <italic>S. indica</italic> colonized plants compared to the non-colonized counterparts. Similarly, defense genes also showed modulation in response to this tripartite interaction of onion -<italic>S. indica</italic> mutualism and <italic>S. exigua</italic> herbivory. The hierarchical cluster analysis and principal component analysis indicated a clear difference in the onion biochemical responses, which is due to the <italic>S. indica</italic> symbiosis. Our investigation demonstrates that onion-<italic>S. indica</italic> symbiosis significantly decreases chewing injury by efficiently modulating antioxidant and defense enzyme activities and gene expression in response to <italic>S. exigua</italic> herbivory. Therefore, <italic>S. indica</italic> can be used as a potential biocontrol agent for sustainable management of this important pest of Alliums.</p>