3. Results
3.1. The relative expression of RBSDV genes in rice, wheat, maize, and SBPH
To analyze the relative abundance of each gene in the RBSDV genome
in different hosts, the expression levels of the thirteen RBSDV
genes were examined in SBPH, and plant hosts including rice, maize,
and wheat that had shown typical symptoms of RBSDV infection. The
relative expression levels of viral genes in individual host are presented
in Fig. 1 and Supplementary Table 3. P10 and P7-1 were expressed at
relatively high levels whereas P8 and P7-2 were expressed at low levels
in the three distinct plants. Specifically, P7-1 was the most abundant
gene in rice; inmaize and wheat, the expression of P10 was the highest
and P7-1was the second highest. In SBPH, P7-1was themost abundantly
expressed gene and P8 was the lowest. Different fromthe expression
in plant hosts, P10 was expressed significantly lower than P7-1, and P5-1
ranked as the second abundant gene in SBPH. The genes encoded by S5,
S7, and S9 were expressed in different patterns in distinct hosts. P7-1
was expressed higher than P7-2 in both plant and insect hosts. P5-1
was expressed lower than P5-2 in maize and wheat while its expression
was higher than P5-2 in SBPH. The expression of P9-1 was higher than
P9-2 in wheat and SBPH whereas there were no significant differences
in rice and maize.
To compare the abundance of each viral gene in different hosts, the
expression level of each gene is calculated relative to the sum of the
whole viral genome in individual host and the results are shown in
Fig. 2 and Supplementary Table 4. The abundance of P10 in wheat was
the highest among the plant hosts. However, P10 was expressed at a
relatively low level in SBPH. Besides, the abundance of P6 in SBPH was
significantly lower than in plant hosts whereas the abundance of P7-2
in SBPH was higher than in plant hosts.