Thaumatin-like proteins (TLPs) are involved in the plant defense response against pathogens, and most of them exhibit antifungal activity. However, the role of TLPs in pathogen-induced defense responses in spruce is not fully understood. In this study, four
TLP genes encoding thaumatin-like protein,
[...] Read more.
Thaumatin-like proteins (TLPs) are involved in the plant defense response against pathogens, and most of them exhibit antifungal activity. However, the role of TLPs in pathogen-induced defense responses in spruce is not fully understood. In this study, four
TLP genes encoding thaumatin-like protein, designated as
PlTLP1–4, were isolated and identified from
Picea likiangensis needles. Sequence analysis showed that
PlTLP1,
PlTLP3, and
PlTLP4 contained 16 conserved cysteine residues, while
PlTLP2 had only 10 conserved cysteine residues. qPCR analysis showed that
PlTLPs were expressed in all tissues tested,
PlTLP1,
PlTLP3, and
PlTLP4 had the highest expression levels in young fruits, while
PlTLP2 had the highest expression levels in roots. In addition, the expression levels of four
PlTLPs were significantly upregulated during infection by
Lophodermium piceae. Four recombinant
PlTLPs expressed in
Escherichia coli exhibited obvious β-1,3-glucanase activity. The antifungal activity assay showed that four recombinant
PlTLPs had significant inhibitory effects on the mycelial growth of
L. piceae,
Fusarium proliferatum,
Botrytis cinerea, and
Roussoella doimaesalongensis. Microscopic observation revealed that the recombinant
PlTLP1–4 induced the morphological changes of the mycelia of
L. piceae, and the recombinant
PlTLP2 and
PlTLP3 induced the morphological changes of the mycelia of
F. proliferatum and
R. doimaesalongensis, while all the recombinant
PlTLPs had no obvious negative effect on the morphology of
B. cinerea mycelium. These results suggest that
PlTLP genes may play an important role in the defense response of
P. likiangensis against
L. piceae invasion.
Full article