An inducible potato (E,E)‐farnesol synthase confers tolerance against bacterial pathogens in potato and tobacco

Abstract

SUMMARY Terpene synthases (TPSs) have diverse biological functions in plants. Though the roles of TPSs in herbivore defense are well established in many plant species, their role in bacterial defense has been scarce and is emerging. Through functional genomics, here we report the in planta role of potato (Solanum tuberosum) terpene synthase (StTPS18) in bacterial defense. Expression of StTPS18 was highest in leaves and was induced in response to Pseudomonas syringae and methyl jasmonate treatments. The recombinant StTPS18 exhibited bona fide (E,E)‐farnesol synthase activity forming a sesquiterpenoid, (E,E)‐farnesol as the sole product, utilising (E,E)‐farnesyl diphosphate (FPP). Subcellular localization of GFP fusion protein revealed that StTPS18 is localized to the cytosol. Silencing and overexpression of StTPS18 in potato resulted in reduced and enhanced tolerance, respectively, to bacterial pathogens P. syringae and Ralstonia solanacearum. Bacterial growth assay using medium containing (E,E)‐farnesol significantly inhibited P. syringae growth. Moreover, StTPS18 overexpressing transgenic potato and Nicotiana tabacum leaves, and (E,E)‐farnesol and P. syringae infiltrated potato leaves exhibited elevated expression of sterol pathway and members of pathogenesis‐related genes with enhanced phytosterol accumulation. Interestingly, enhanced phytosterols in 13C3‐(E,E)‐farnesol infiltrated potato leaves were devoid of any noticeable 13C labeling, indicating no direct utilization of (E,E)‐farnesol in phytosterols formation. Furthermore, leaves of StTPS18 overexpressing transgenic lines had no detectable (E,E)‐farnesol similar to the control plant, and emitted lower levels of sesquiterpenes than the control. These findings point towards an indirect involvement of StTPS18 and its product (E,E)‐farnesol in bacterial defense through upregulation of phytosterol biosynthesis and defense genes.

Characterization of Volatile Organic Compounds in Five Celery (Apium graveolens L.) Cultivars with Different Petiole Colors by HS-SPME-GC-MS

“…In combination with the celery genome data, 15 key genes for terpene synthesis were screened: DXS, DXR, and HMGR genes regulate and control DXP, MEP, and MVA synthesis; IDI genes catalyze the isomerization reaction of IPP and DMAPP; and IDI genes regulate the terpene raw materials GPP, GGPP, and FPP synthesis of GPPS, GGPPS, and FPPS genes [43]. Genes such as HMGR, DXS, IDI, and TPS play a crucial role in terpene production in plants, yeast, and bacteria [44,45]. Most of the celery cultivars exhibited higher relative expressions in leaves than in petioles, with green celery expressing most of the genes at higher levels, and the top three celery varieties with high gene expressions were 'Hanyu Nencuixiqin', 'Jinpin Saixue', and 'Siji Lvxiangqin' varieties exhibited high expression levels.…”

Identification and functional analysis of ZmDLS associated with the response to biotic stress in maize

“…Overexpression of StTPS18 in potatoes made the plant more susceptible to the bacterial pathogen P. syringae . The tolerance to the Ralstonia solanacearum was enhanced ( Dwivedi et al., 2022 ). Similarly, overexpression of OsTPS19 in rice plants increased resistance to M. oryzae , whereas those with OsTPS19 RNAi had increased susceptibility to this disease ( Chen et al., 2018 ).…”

Phosphorylation of Metabolites Involved in Salvage Pathways for Isoprenoid Biosynthesis in Plants

“…For example, farnesol functions as an insect attractor [37], has fungistatic effects on Monilinia laxa, a fungal nectarine pathogen [38], and insecticidal effects have been demonstrated against green peach aphids [39]. In plants, farnesol was described as a co-product of terpene synthases [40], but specific farnesol synthases were also characterized in both animals [41] and plants [42][43][44]. However, the metabolite is not just toxic for pathogens, it is also toxic for plant cells.…”