Metabolic profiling reveals local and systemic responses of kiwifruit to Pseudomonas syringae pv. actinidiae

Abstract

Pseudomonas syringae pv. actinidiae (Psa), a bacterial pathogen, causes bacterial canker disease in kiwifruit. To elucidate the local and systemic influences of Psa infection on kiwifruit, comprehensive analyses were conducted by combining metabolomic and physiological approach under Psa‐infected treatment and mock‐inoculated control in leaves, stems, and bleeding saps. Our results show that Psa infection stimulated kiwifruit metabolic reprogramming. Levels of many sugars, fumarate, and malic acid were decreased in Psa‐infected leaves and stems, accompanied by the increased level of amino acids (AAs), which implies the anaplerotic reaction to replenish the TCA cycle generating energy and intermediates for defense‐related metabolic pathways, such as phenylpropanoid metabolism. The inconsistent results were observed in bleeding saps, which may be attributed to the induced phloem transport of carbon (C) out of leaves and such a transport benefits bacterium movement. Arg, Gln, and pyroglutamic acid systematically were accumulated in long‐distance leaves, which probably confers to systemic acquired resistance (SAR) and Psa inoculation accelerated the nitrogen (N) cycling in kiwifruit. Moreover, Psa infection specifically affected the content of phenolic compounds and lignin. Phenolic compounds were negatively and lignin was positively related to kiwifruit Psa resistance, respectively. Our results first reveal that Psa enhances infection by manipulating C/N metabolism and sweet immunity, and that host lignin synthesis is a major physical barrier for restricting bacterial infection. This study provides an insight into the complex remodeling of plant metabolic response to Psa stress.

Chemical Composition, Production of Secondary Metabolites and Antioxidant Activity in Coffee Cultivars Susceptible and Partially Resistant to Bacterial Halo Blight

“…garcae. The decrease in sugars was observed by Li et al [15] in kiwi leaves infected with Pseudomonas syringae pv. actinidae (Psa).…”

“…Then, our results suggested that P. syringae pv. garcae may induce reduction in the compounds (sugars, phenolic compounds and flavonoids) in coffee seedlings during the infection process as observed in other pathosystems [ 15 , 34 ]. Higher concentrations of gallic, caffeic, and chlorogenic acids and the presence of vanillin were detected in the Iapar-59 cultivar inoculated with P. syringae pv.…”

“…Plants have many bioactive compounds with high antioxidant activity, which indicates a plant’s ability to scavenge free radicals [ 9 , 10 ], and this activity is related to the severity of diseases [ 11 ]. The antioxidant activity, flavonoids, phenolic compounds and sugars in plants can vary according to species, cultivar, resistance level to diseases, and are also dependent on the plant pathogen/pest interaction as Oidium xanthami in Xanthium strumarium [ 11 ], Leucoptera coffeella and Hemileia vastatrix in coffee [ 12 , 13 ], and Pseudomonas syringae in Arabidopsis thaliana , kiwi, and tomato [ 5 , 14 , 15 , 16 ].…”

Transcriptomic and Proteomic Profiling Reveal the Key Role of AcMYB16 in the Response of Pseudomonas syringae pv. actinidiae in Kiwifruit

“…These data showed that suppression of cell wall synthesis is crucial for Psa infection. However, our previous study showed that most of the phenolic compounds were reduced in ‘Jinkui’ but increased in ‘Hongyang’ after Psa inoculation, while lignin changed in the opposite direction ( Li et al, 2020 ), indicating that phenolic compounds were negatively related to kiwifruit Psa resistance, and lignin was positively related to kiwifruit Psa resistance. It has been reported that various MYB transcription factor genes, including a large class of plant transcription factors, directly or indirectly regulate the expression of lignin biosynthesis genes in many plant species ( Kim et al, 2020 ).…”

“…chinensis, including 'Hongyang, ' 'Hort16A, ' and 'Jintao' , are considered more susceptible to biovar 3 than A. chinensis var. deliciosa, including 'Jinkui' and 'Xuxiang' (Li et al, 2020;Wang et al, 2020).…”