A Bacterial Endophyte <i>Bacillus amyloliquefaciens</i> W10 Enhances the Tomato Resistance Against <i>Tuta absoluta</i>

The tomato leafminer, <i>Tuta absoluta</i>, is a destructive invasive tomato pest worldwide. <i>Bacillus amyloliquefaciens</i> W10, a bacterium isolated from the rhizosphere of tomatoes, is classified as a plant growth-promoting rhizobacterium. However, whether <i>B. amyloliquefaciens</i> W10 can improve the resistance of tomato against <i>T. absoluta</i> remains unclear. In this study, we found that <i>B. amyloliquefaciens</i> W10 promoted the tomato growth and significantly reduced the fecundity of <i>T. absoluta</i>. To further evaluate the effects of <i>B. amyloliquefaciens</i> W10 on the tomato’s resistance to <i>T. absoluta</i>, the age-stage, two-sex life table, and oviposition preference test were carried out to investigate the individual fitness, population parameters, and preference behavior of <i>T. absoluta</i>. Compared to the control, the intrinsic rate of increase (<i>r_m</i>), net reproductive rate (<i>R</i>₀), and finite rate of increase (<i>λ</i>) of <i>T. absoluta</i> in the treatment group were significantly reduced, while the population doubling time (<i>DT</i>) was significantly increased. Meanwhile, the oviposition preferences of <i>T. absoluta</i> for the treated tomato plants were reduced. After <i>T</i>. <i>absoluta</i> infestation, electrical conductivity and hydrogen peroxide (H₂O₂) content in tomato leaves after <i>B. amyloliquefaciens</i> W10 treatment were significantly lower than those in the control, while peroxidase (POD), polyphenol oxidase (PPO), jasmonic acid (JA), and salicylic acid (SA) levels were significantly higher. In addition, the O₂⁻, superoxide dismutase (SOD), and catalase (CAT) levels were also affected. qRT-RCR analyses revealed that <i>B. amyloliquefaciens</i> W10 colonization induced the expressions of JA- and SA-related genes, including <i>AOS1</i>, <i>AOC</i>, <i>PAL1,</i> and <i>SAMT,</i> in tomato plants after <i>T</i>. <i>absoluta</i> infestation. These findings provide valuable insights and theoretical support for the application of beneficial endophytes to induce the resistance in tomatoes against <i>T. absoluta</i>.