Trehalose increases tomato drought tolerance, induces defenses, and increases resistance to bacterial wilt disease

Abstract

Ralstonia solanacearum causes plant bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in host produced trehalose. Water stressed plants accumulate the disaccharide trehalose, which increases drought tolerance via abscisic acid (ABA) signaling networks. Because infected plants have reduced water flow, we hypothesized that bacterial wilt physiologically mimics drought stress, which trehalose could mitigate. Transcriptomic responses of susceptible vs. resistant tomato plants to R. solanacearum infection revealed differential expression of drought-associated genes, including those involved in ABA and trehalose metabolism. ABA was enriched in xylem sap from R. solanacearum-infected plants. Treating roots with ABA lowered stomatal conductance and reduced R. solanacearum stem colonization. Treating roots with trehalose increased ABA in xylem sap and reduced plant water use by reducing stomatal conductance and temporarily improving water use efficiency. Further, trehalose-treated plants were more resistant to bacterial wilt disease. Trehalose treatment also upregulated expression of salicylic acid (SA)-dependent defense genes, increased xylem sap levels of SA and other antimicrobial compounds, and increased wilt resistance of SA-insensitive NahG tomato plants. Additionally, trehalose treatment increased xylem concentrations of jasmonic acid and related oxylipins. Together, these data show that exogenous trehalose reduced both water stress and bacterial wilt disease and triggered systemic resistance. This suite of responses revealed unexpected linkages between plant responses to biotic and abiotic stress and suggests that that R. solanacearum-infected tomato plants produce more trehalose to improve water use efficiency and increase wilt disease resistance. In turn, R. solanacearum degrades trehalose as a counter-defense.

Alterations in Primary Carbon Metabolism in Cucumber Infected with Pseudomonas syringae pv lachrymans: Local and Systemic Responses

“…Trehalose is also involved in plant–pathogen interactions, but the exact mechanism remains unclear. It is required for the infectivity of pathogens [ 64 ], and at the same time, exogenous trehalose elicits plant defense responses and endogenous trehalose signals microbial pathogen attack [ 65 , 66 ]. In our study, Psl induced trehalose accumulation, which was virtually absent from control leaves at 0 and 2 day.…”

Plant pathogenicRalstoniaphylotypes evolved divergent respiratory strategies and behaviors to thrive in xylem

“…Several aromatics have been detected and quantified in tomato xylem sap during infection with phyl. I strain GMI1000: salicylic acid (∼20-200 nM), benzoic acid (∼10 nM), and coumaric acid (∼100 nM) (34). Our analyses found that phyl.…”

Recent Advances in the Bacterial Phytohormone Modulation of Plant Growth

“…The co-application of MT and SA markedly improved plant functions such as the photosynthetic pigments content, photochemical reactions of photosynthesis, net photosynthetic rate, transpiration rate, stomatal conductance, as well as the osmoprotectants accumulation [ 62 ]. In the case of trehalose, it is well known that this disaccharide, which is produced by various species of PGPB, plays important roles in plant and microbial resistance to heat, drought, salt, cold stress, or even resistance to biotic factors, such as bacterial pathogens [ 63 , 64 , 65 ]. In this case, the application of trehalose and SA decreased the negative effects of drought stress on sweet basil plants.…”