Fig 1.
Symptoms of bacterial stem blight at 7 days after inoculation.
(A) Response of resistant plant. (B) Stem of resistant plant at inoculation site. (C) Leaf of resistant plant at site of infiltration. (D) Response of susceptible plant. (E) Stem of susceptible plant at inoculation site. (F) Leaf of susceptible plant at site of infiltration. Arrows indicate point of inoculation.
Table 1.
Counts of differentially expressed genes in cv. Maverick.
Fig 2.
Differentially expressed genes (DEGs) in alfalfa plants from cultivar Maverick in response to inoculation with P. syringae pv. syringae ALF3.
(A) Venn diagram depicting the unique and common up-regulated DEGs between susceptible and resistant plants at 72 hours after inoculation. (B) Functional profiling of the unique genes up-regulated genes in resistant plants (810 DEGs) using the Blast2Go tool. (C) Functional profiling of the unique genes up-regulated genes in susceptible plants (379 DEGs).
Fig 3.
Down-regulated differentially expressed genes (DEGs) in alfalfa plants from cultivar Maverick.
(A) Venn diagram depicting the unique and common down-regulated DEGs between susceptible and resistant plants at 72 hours after inoculation. (B) Functional profiling of the unique genes down-regulated in susceptible Maverick plants.
Table 2.
Counts of differentially expressed genes in cv. ZG9830.
Fig 4.
Differentially expressed genes (DEGs) in alfalfa plants from cultivar ZG9830 in response to inoculation with P. syringae pv. syringae ALF3.
(A) Venn diagram depicting a number of unique and common up-regulated DEGs between susceptible and resistant plants at 24 hours after inoculation. (B) Functional categorization of the unique genes up-regulated in resistant plants. (C) Functional categorization of the unique DEGs induced in susceptible plants at 24 hai.
Fig 5.
Down-regulated differentially expressed genes (DEGs) in alfalfa plants from cultivar ZG9830.
(A) Venn diagram depicting a number of unique and common down-regulated DEGs between susceptible and resistant plants 24 hours after inoculation. (B) Functional categorization of the unique genes down-regulated genes in susceptible plants.
Fig 6.
Comparison of differentially expressed genes (DEGs) in resistant plants from Maverick and ZG9830.
(A) Venn diagram depicting the number of common DEGs between resistant plants. (B) Functional categorization of biological processes associated with resistance responses to P. syringae in plants from cv. Maverick and cv. ZG9830.
Table 3.
Confirmation of the transcriptomic data by quantitative real-time PCR.
Table 4.
Candidate genes involved in the resistance response against PssALF3 in two alfalfa cultivars.
Fig 7.
Hypothetical mechanisms of resistance to PssALF3.
(A) Resistant plants of cv. Maverick. (B) Resistant plants of cv. ZG9830. PTI, pathogen-associated molecular patterns (PAMP)-triggered immunity. ETI, effector-triggered immunity [31].