Dual role of endophytic entomopathogenic fungi: induce plant growth and control tomato leafminer Phthorimaea absoluta

Abstract

BACKGROUNDEntomopathogenic fungi (EPF) are multifunctional microorganisms acting not only as biopesticides against insect pests but also as endophytes which regulate plant growth. The tomato leafminer, Phthorimaea absoluta (Tuta absoluta) is a devastating invasive pest of tomatoes worldwide. However, effective alternatives are needed for a sustainable management of this invasive pest. In this study, the functional effects of five EPF isolates Metarhizium flavoviride, M. anisopliae, M. rileyi, Cordyceps fumosorosea and Beauveria bassiana were evaluated on tomato growth promotion and pest protection against P. absoluta.RESULTSWhen directly sprayed with conidia, P. absoluta larvae showed high cumulative mortality of 100% to M. anisopliae under 1 × 108 conidia/mL, whereas M. flavoviride, B. bassiana, C. fumosorosea and M. rileyi caused cumulative mortality of 92.65%, 92.62%, 92.16% and 68.95%, respectively. Moreover, all five EPF isolates can successfully colonize tomato plants, whilst the colonization rate for each EPF depends on the inoculation method used. The most efficient inoculation method for M. flavoviride and M. rileyi was root dipping, for M. anisopliae and C. fumosorosea it was coating seed, and for B. bassiana it was foliage spraying. The highest plant colonization was obtained by M. flavoviride. Meanwhile, all these isolates promoted tomato plant growth upon inoculation. Furthermore, endophytic colonization of plants by the five EPF negatively affected the performance of P. absoluta, among them M. anisopliae and C. fumosorosea showed strong negative effects on the performance of P. absoluta.CONCLUSIONOur results highlight the potential of incorporating entomopathogenic fungi as endophytes in integrated pest management practices to protect tomatoes against P. absoluta. © 2023 Society of Chemical Industry.

Endophytic Beauveria bassiana promotes plant biomass growth and suppresses pathogen damage by directional recruitment

“…Our study highlights that plants can regulate EPF distribution in plant tissues and their own defense responses under abiotic stress. However, the inhibitory effects of beneficial microbes against phytopathogens largely depend on their competition for nutrients and niches with the host plant, which could result in insufficient resources for phytopathogens for growth maintenance, in The investigated EPF exhibited multifaceted functions (Vega et al, 2009;Zheng et al, 2023). The present reveals how B. bassiana varies under B. cinerea infection and identifies the potential mechanisms via which the observed shifts in microbiome could have helped plants cope with pathogen pressure.…”

“…The investigated EPF exhibited multifaceted functions ( Vega et al, 2009 ; Zheng et al, 2023 ). The present study reveals how B. bassiana varies under B. cinerea infection and identifies the potential mechanisms via which the observed shifts in microbiome could have helped plants cope with pathogen pressure.…”

Impact of Three Entomopathogenic Fungal Isolates on the Growth of Tomato Plants—Ectoapplication to Explore Their Effect on Tetranychus urticae

“…Before inoculation, the viability of each entomopathogenic isolate was determined through germination tests as in the previous section. Three different methods were used for each isolate for their endophytic establishment in tomato plants as follows [72]: (1) Seed inoculation method: The sterilized seeds were immersed in a suspension of 1 × 10 8 conidia/mL in a 100 mL glass bottle with the respective fungus for 16-24 h [59,73]. Seeds that were treated with 0.01% Triton X-100 acted as controls.…”

“…The plants were uprooted gently to avoid any breakage of roots and other tissues. Per plant, five pieces of randomly selected leaves of 10 mm 2 each, stems of 10 mm, and roots were cut with a sterilized blade [72]. They were sterilized with 1% NaClO for 300 s, then washed thrice with distilled H 2 O, and dried on sterile tissue paper [78].…”

“…No contamination was observed in any of these dishes after sterilization of leaves, stems, and roots. After the sterilization process, with the help of a scalpel, the edges of the samples were trimmed and cut into pieces of 5 mm 2 for leaves, 5 mm for stems, and 5 mm for roots [72]. These inoculated plant samples were placed in dishes containing the respective Beauveria or Metarhizium selective media as described by Rivas-Franco et al [80].…”