Transcriptomic insights into the resistance mechanism of Penaeus vannamei against highly lethal Vibrio parahaemolyticus

Abstract

Highly lethal Vibrio disease (HLVD) caused by a virulent strain of Vibrio parahaemolyticus (Vp_HLVD), which poses a significant threat to Penaeus vannamei post-larvae, leads to substantial mortality and economic losses. To address this challenge, researchers have recently isolated a highly disease-resistant strain of P. vannamei shrimp. However, the underlying mechanisms that could improve disease resistance require further investigation. Our study found that disease-resistant shrimp exhibited a remarkable ability to prevent Vp_HLVD invasion effectively. To unravel the genetic basis of this resistance, we conducted a transcriptomic analysis with susceptible and disease-resistant shrimp at various time points (0, 6, and 12 h) post-infection with Vp_HLVD. Differential gene expression (DEGs) analysis of uninfected shrimp revealed that disease-resistant individuals displayed higher expression of immune-related genes and pathways compared to their susceptible counterparts. Simultaneously, they exhibited lower expression of Vibrio toxin-binding genes and Vibrio colonization gene, indicating enhanced defense mechanisms in the resistant shrimp. Upon Vp_HLVD infection, DEGs analysis also showed that susceptible shrimp attempt to mount a similar immune response as the disease-resistant shrimp during the early stages of infection. However, as the infection progresses, the defense strategies diverge between the two groups, with the peak of gene response occurring later in the disease-resistant shrimp. Our findings indicated that disease-resistant shrimp did not experience significant stress during the early stages of infection and are capable of effectively enhancing their immune response in the middle and late stages of the infection. In summary, our study enhanced the understanding of the mechanisms employed by disease-resistant shrimp to combat Vibrio, and would help to develop effective strategies for disease prevention and control, ultimately reducing the impact of HLVD on shrimp aquaculture.

Keywords: Penaeus vannamei; Vibrio parahaemolyticus; Highly lethal Vibrio disease; Transcriptomic analysis.

Fig. 1

Survival rate statistics of disease-resistant and susceptible shrimp post-larvae. One hundred post-larvae from each group (C3, S, B13, B20) were immersed in seawater containing 2.5 × 10⁵ CFU/mL Vp_HLVD, and their survival rates were determined at various time points. The data were analyzed statistically using a paired Student’s t-test, with a significant result (p < 0.0001).

Fig. 2

Fecal adhesion in susceptible shrimp. The red arrow indicates the adhesion of fecal matter to the shrimp’s body, a phenomenon specifically observed in susceptible shrimp.

Fig. 3

Detection of transcript levels of Vp_HLVD Tc toxins in shrimp post-larvae. (A) Transcript levels of susceptible group C3 TcA subunits. (B) Transcript levels of susceptible group C3 TcB subunits. (C) Transcript levels of susceptible group S TcA subunits. (D) Transcript levels of susceptible group S TcB subunits, with 16S rRNA serving as an internal control. Statistical analysis was performed using a paired Student’s t-test, and asterisks indicate significant differences (*p < 0.05, ***p < 0. 001).

Fig. 4

Gene ontology (GO) enrichment analysis.

Fig. 5

KEGG enrichment analysis.

Fig. 6

Volcano plots illustrating DEGs in shrimp. (A) DEGs in disease-resistant and susceptible shrimp uninfected with Vp_HLVD. (B) DEGs in susceptible shrimp at 6 h post-infection compared to 0 h. (C) DEGs in disease-resistant shrimp at 6 h post-infection compared to 0 h. (D) DEGs in susceptible shrimp at 12 h post-infection compared to 0 h. (E) DEGs in disease-resistant shrimp at 12 h post-infection compared to 0 h.

Fig. 7

Sankey diagrams illustrating KEGG pathway enrichment for DEGs in shrimp^–. (A) Upregulated DEGs in uninfected Vp_HLVD-resistant shrimp. (B) Downregulated DEGs in uninfected Vp_HLVD-resistant shrimp, using uninfected susceptible shrimp as a control. (C) Upregulated DEGs in susceptible shrimp at 6 h post-infection with Vp_HLVD. (D) Upregulated DEGs in disease-resistant shrimp at 6 h post-infection. (E) Downregulated DEGs in susceptible shrimp at 6 h post-infection. (F) Downregulated DEGs in disease-resistant shrimp at 6 h post-infection. (G) Upregulated DEGs in susceptible shrimp at 12 h post-infection. (H) Upregulated DEGs in disease-resistant shrimp at 12 h post-infection. (I) Downregulated DEGs in susceptible shrimp at 12 h post-infection. (J) Downregulated DEGs in disease-resistant shrimp at 12 h post-infection.

Fig. 8

Line graphs illustrating GO annotations for DEGs in shrimp. (A) GO annotations for DEGs in disease-resistant and susceptible shrimp uninfected with Vp_HLVD. (B) GO annotations for DEGs in susceptible shrimp at 6 h post-infection with Vp_HLVD. (C) GO annotations for DEGs in disease-resistant shrimp at 6 h post-infection. (D) GO annotations for DEGs in susceptible shrimp at 12 h post-infection. (E) GO annotations for DEGs in disease-resistant shrimp at 12 h post-infection.