Auxin, abscisic acid and jasmonate are the central players in rice sheath rot caused by Sarocladium oryzae and Pseudomonas fuscovaginae
Sheath rot is an emerging rice disease that causes severe yield losses worldwide. The main causal agents are the toxin producers Sarocladium oryzae and Pseudomonas fuscovaginae. The fungus S. oryzae produces helvolic acid and cerulenin and the bacterium P. fuscovaginae produces cyclic lipopeptides. Helvolic acid and the lipopeptide, fuscopeptin, inhibit membrane-bound H+-ATPase pumps in the rice plant. To manage rice sheath rot, a better understanding of the host response and virulence strategies of the pathogens is required. This study investigated the interaction of the sheath rot pathogens with their host and the role of their toxins herein. Japonica rice was inoculated with high- and low-helvolic acid-producing S. oryzae isolates or with P. fuscovaginae wild type and fuscopeptin mutant strains. During infection, cerulenin, helvolic acid and the phytohormones abscisic acid, jasmonate, auxin and salicylic acid were quantified in the sheath. In addition, disease severity and grain yield parameters were assessed. Rice plants responded to high-toxin-producing S. oryzae and P. fuscovaginae strains with an increase in abscisic acid, jasmonate and auxin levels. We conclude that, for both pathogens, toxins play a core role during sheath rot infection. S. oryzae and P. fuscovaginae interact with their host in a similar way. This may explain why both sheath rot pathogens cause very similar symptoms despite their different nature.
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Posted 23 Sep, 2020
On 26 Nov, 2020
Received 03 Nov, 2020
On 03 Nov, 2020
Received 30 Oct, 2020
On 24 Oct, 2020
Invitations sent on 23 Oct, 2020
On 23 Oct, 2020
On 21 Sep, 2020
On 20 Sep, 2020
On 20 Sep, 2020
Received 27 Aug, 2020
On 27 Aug, 2020
On 13 Aug, 2020
Received 12 Aug, 2020
Invitations sent on 28 Jul, 2020
On 28 Jul, 2020
On 20 Jul, 2020
On 19 Jul, 2020
On 19 Jul, 2020
On 17 Jul, 2020
Auxin, abscisic acid and jasmonate are the central players in rice sheath rot caused by Sarocladium oryzae and Pseudomonas fuscovaginae
Posted 23 Sep, 2020
On 26 Nov, 2020
Received 03 Nov, 2020
On 03 Nov, 2020
Received 30 Oct, 2020
On 24 Oct, 2020
Invitations sent on 23 Oct, 2020
On 23 Oct, 2020
On 21 Sep, 2020
On 20 Sep, 2020
On 20 Sep, 2020
Received 27 Aug, 2020
On 27 Aug, 2020
On 13 Aug, 2020
Received 12 Aug, 2020
Invitations sent on 28 Jul, 2020
On 28 Jul, 2020
On 20 Jul, 2020
On 19 Jul, 2020
On 19 Jul, 2020
On 17 Jul, 2020
Sheath rot is an emerging rice disease that causes severe yield losses worldwide. The main causal agents are the toxin producers Sarocladium oryzae and Pseudomonas fuscovaginae. The fungus S. oryzae produces helvolic acid and cerulenin and the bacterium P. fuscovaginae produces cyclic lipopeptides. Helvolic acid and the lipopeptide, fuscopeptin, inhibit membrane-bound H+-ATPase pumps in the rice plant. To manage rice sheath rot, a better understanding of the host response and virulence strategies of the pathogens is required. This study investigated the interaction of the sheath rot pathogens with their host and the role of their toxins herein. Japonica rice was inoculated with high- and low-helvolic acid-producing S. oryzae isolates or with P. fuscovaginae wild type and fuscopeptin mutant strains. During infection, cerulenin, helvolic acid and the phytohormones abscisic acid, jasmonate, auxin and salicylic acid were quantified in the sheath. In addition, disease severity and grain yield parameters were assessed. Rice plants responded to high-toxin-producing S. oryzae and P. fuscovaginae strains with an increase in abscisic acid, jasmonate and auxin levels. We conclude that, for both pathogens, toxins play a core role during sheath rot infection. S. oryzae and P. fuscovaginae interact with their host in a similar way. This may explain why both sheath rot pathogens cause very similar symptoms despite their different nature.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7